Causes and treatment of cracks in tunnel lining

Tunnel cracks are one of the common diseases of tunnel linings. Cracking of linings is manifested in both the primary lining and the secondary lining, of which the secondary lining is the most serious.

The distribution of lining cracks is the most on the left side of the lower line, followed by the left side of the upward line, and the right side of the downward line. The distribution of lining cracks is concentrated in sections. The lower left is mainly concentrated in the sections K10 + 300 to K10 + 585 and K21 + 765 to K21 + 885. The location of the cracks corresponds between the up and down lines, and between the left and right sides of the down line, reflecting the uniformity of the crack generation mechanism.

Most of the tunnel cracks appeared in the early stages of tunnel construction, and some even had a large number of cracks during the tunnel construction process, and they were less likely to appear 5 years after construction.

The formation and development of tunnel cracks is a time process. Tunnel cracks are usually small and scattered at first, and gradually deteriorate over time. This shows that the formation and development of tunnel cracks are related to the deformation, relaxation, and spalling of surrounding rock. The formation and development of cracks and their closure are constantly changing over time. Concrete cracks can be divided into oblique cracks, longitudinal cracks and transverse cracks according to the occurrence. The oblique cracks are bounded by the maximum buried depth of the tunnel (approximately at K10 + 750). The cracks in sections K21 + 620 to 750 tend to import, and the cracks in sections K23 + 750 to 855 tend to export. According to the survey results, oblique cracks accounted for 16%, longitudinal cracks accounted for 59%, and transverse cracks accounted for 25%. The cracks generally open from the inside of the lining and gradually decrease along the thickness of the lining, and generally do not penetrate the entire lining thickness.

The tunnel concrete maintenance formwork

Most of the cracks are located in places such as cave entrances where the rock layer is thin, the rock mass is loose, and the cracks are developed. The distribution of cracks is 49% of the partition wall, 33% of the arch top, and 18% of the side wall. The openings accounted for 40% and the cave body accounted for 60%.

Cracks can be divided into unidirectional misalignment, bidirectional misalignment and tridirectional misalignment according to the misalignment mode.

The number of unidirectionally displaced cracks is the largest, showing as opening. Two-way staggered cracks are followed by open and shear staggers. Three-way staggered cracks. The amount of crack displacement varies from 0.1mm to 1mm, followed by 1mm to 2mm, and the maximum displacement is 6mm to 8mm. Most cracks are wide and narrow down until they are sharp.

Analysis of crack causes

The types of these cracks are roughly divided into dry shrinkage cracks, temperature cracks, load deformation cracks and construction joints. In this paper, the tunnel lining is used as the force entity, focusing on the horizontal stress (mainly due to temperature shrinkage due to dry shrinkage and thermal expansion and contraction), uneven settlement of the lining, and uneven arch force (saddle-shaped stress Force) and other three aspects for analysis.

The dry shrinkage cracks are mostly surface, the texture is small, and the direction is irregular. The occurrence of cracks has a great relationship with the construction process, including the choice of the driving method, the concrete vibration, the determination of the water-cement ratio, the removal of the mold, the arch backfilling, and maintenance. The demoulding is too early, and the concrete begins to be stressed before it reaches the design strength, which causes cracks in the concrete, especially the backfill of the vault is not dense. The top pressure is dispersed on the sides of the arch waist, and the “saddle” load appears on the arch The form of ground pressure distribution is very different from the original design of the lining. When the arch waist is opened, the shrinkage and cold shrinkage of the concrete itself are also important reasons for cracks.

Tunnel waterproof board laying formwork

A large amount of heat is generated during the hydration of the cement, and a temperature gradient is formed between the interior and the surface of the concrete to generate stress. When the temperature stress exceeds the binding force inside and outside the concrete, temperature cracks will occur. The tunnel lining concrete has dry shrinkage, thermal expansion and cold shrinkage. Since the surrounding rock of the lining hinders the free expansion and contraction of the lining, temperature stress is generated inside the lining concrete. The magnitude of this temperature stress is related to the dielectric properties (elastic modulus) , Linear expansion coefficient), rising and falling temperature (temperature difference), the resistance of rock and soil media to the tunnel wall and the length of the tunnel. Concrete is a material with low tensile strength, so it can often resist the compressive stress generated during heating, but it is difficult to resist the tensile stress generated during cooling.

When the tensile stress inside the lining exceeds the tensile strength of the tunnel lining concrete, cracking occurs in the tunnel lining, and this cracking starts from the middle of the tunnel. The maximum horizontal stress of the tunnel is in the middle of the tunnel. If the tensile strength of the tunnel lining concrete is exceeded, the lining cracks. The maximum horizontal stress still occurs in the middle of each section after cracking. When it exceeds the tensile strength R of the concrete, a second crack will occur. This continues until the intermediate maximum tensile stress is less than the tensile strength of the concrete. The cracks are stable and no longer increase.

Rectification of concrete cracks

According to the crack conditions of the secondary lining, repairing the stable cracks can be divided into 3 cases:

1. If the crack width is less than 0.3mm, the surface is mainly closed and observed. The characteristics of cracks, surrounding rocks, etc., are covered with carbon fiber when necessary.
For fine cracks smaller than 0.3mm, first use a wire brush to roughen the concrete surface to remove surface attachments; then fill the concrete surface with epoxy resin slurry, use the capillary action of the crack to absorb the repair glue, and close the crack; then use the repair material to coat Cover the surface until it is flat with the original structure surface, and finally treat the concrete surface with scraper and coloring material to make it the same color as the surrounding lining concrete.

2. For cracks with crack widths ranging from 0.3m to 0.5m, perform low pressure injection repair. The epoxy resin slurry is used for the injection to repair the cracks in the lining. The following steps should be followed:

Single-track railway lining trolley

(1) Clean the crack surface and use dry, oil-free compressed air to remove dust and scum inside the crack.

(2) Use sealing glue to adhere and fix the base of an injection cylinder on the concrete surface on both sides of the crack at a certain distance, while sealing along the entire length of the crack.

(3) After the sealant is cured, it can be injected.

(4) Use a special syringe to inject the low-viscosity crack repair glue into the crack cavity and maintain the pressure.

(5) After the glue injected into the crack is solidified, remove the injection cylinder and remove its base, if necessary, level the concrete surface with a grinding wheel.

(6) The surface should be cured, preferably covered with a plastic film.

3. For cracks with a width greater than 0.5mm, first perform low pressure injection to repair the cracks. In addition, for severe cracks such as wide cracks, wide openings, dense distribution, unfavorable combination, or staggered longitudinal rings or linings, certain serious diseases (such as It is located in the section of reinforced concrete second lining area that is not in the surrounding rock. Carbon fiber reinforcement should be pasted on the surface.

All cracks with a width of ≥ 0.5mm are first repaired by injection, and a low-viscosity, high-strength repair glue is injected into the crack cavity with a certain pressure. After the low-pressure injection is completed, the carbon fiber is stuck after the repair glue reaches the strength.

The causes of tunnel cracks are complex and changeable, which mainly include geology, design, construction and other aspects. The engineering geological survey must be strengthened. In addition to the topography, climate, stratum, age, lithology, and hydrology of the tunnel site, efforts must be made to identify structures, bad geological bodies, and hazards to the project. , Mismeasured. Improving engineering design capabilities, eliminating hasty practices, and careful design and construction are essential ways to prevent disease.

Analysis of key points of tunnel lining construction in tunnel engineering

Tunnel lining construction is a key construction content of tunnel engineering, which is related to construction quality and construction safety. So what are the common causes of common problems in tunnel lining construction? What control measures can ensure the quality of tunnel lining construction? The following is an analysis of the main points of tunnel lining construction in tunnel engineering, so that you can easily avoid common problems in tunnel lining construction.

Quality issues and phenomena

1.There are holes behind the lining;

2.The lining is obviously wrong, the slurry is leaking, the quicksand is serious, and the appearance quality is poor;

3.The thickness of the lining does not meet the design requirements;

4. Leakage of lining;

5.Cracking of lining concrete;

6.The appearance quality of the cable trench is poor;

7. Drainage ditch is not smooth.

Cause analysis of cavities behind the lining

1.The construction of backfilling was not carried out according to the specifications;

2. When the lining is filled with concrete, the arch is not full, and the vibration is not enough;

3. Pumping concrete is hollow at the far end of the conveying pipe due to pressure loss, slope and other reasons;

4. The looseness control of the waterproof board is not in place.

The prevention of cavities behind the lining

1. The excavation surface of the tunnel is inevitably uneven. For pits caused by over-excavation in a small area, the backfill of lining concrete is generally used during construction. Pay attention to the fact that the waterproof board should be closely attached to the rock surface, and the tightness is suitable; Deep subsidence pits should be backfilled smoothly before the second lining construction;

2. General lining formwork trolleys have one reserved pumping hole before and after the top of the arch. If the formwork trolley is longer, additional reserved holes can be added in the middle to prevent the pouring concrete from being in place when the longitudinal slope of the tunnel is large. Backfill grouting after construction;

3. The new lining formwork trolley is equipped with an attached vibrator on the side wall and arch waist. At the same time, two plug-in vibrators are provided on each side of the trolley during concrete pouring. Layer vibration, these can effectively solve the vibration problem.

Pipeline municipal lining trolley

Analysis of the cause of poor apparent lining quality

1. The rigidity of the lining trolley is insufficient, and the formwork is not properly repaired;

2. The lining concrete is not easy to work with, and the bleeding is serious;

3.No symmetrical pouring on both sides;

4. The pouring speed is too fast, the trolley floats up;

5. The template is too oiled, and fish scale clouds are formed after the mold is removed;

6. The partial template is not cleaned up, and the phenomenon of “skinning” and falling off is formed after the mold is removed.

Preventive measures for poor lining apparent quality

1. The lining trolleys are processed by regular manufacturers, and they have been checked for strength and stiffness before processing. Check the check data when purchasing;

2. If the lining formwork trolley overlaps less than 0.5m during lining construction, generally no misplacement will occur. Therefore, it is necessary to plan the mileage of the trolley in place before lining construction to avoid long overlaps. At the same time, surveyors should have certain construction experience, the lining center line and elevation should be well controlled, and the distance between the two sides of the formwork trolley should be properly controlled to prevent excessive and small influences from affecting the next set of trolleys in place;

3. The lining concrete is constructed strictly according to the designed mix ratio. Pumping concrete and workability requirements should be considered when designing the mix ratio. At the same time, the formwork trolley should be coated with a mold release agent. It is best to use a special mold release agent for uniform application. Moderate dosage can improve the quality of lining surface;

4. When placing the lining, it should be layered symmetrically on both sides, and the self-fall height of the concrete should be controlled within 2m to prevent segregation;

5. If there is some concrete on the formwork trolley, remove it before the next pouring, and then apply mold release agent, otherwise it will affect the surface finish of the next group of linings;

6. Due to problems such as the pressure of the cast-in-place concrete at the foot of the side wall will rise, and the end pressure will move longitudinally, the template-bed trolley is strengthened firmly before the lining construction. The lead screw is reinforced again to prevent the trolley from being displaced due to the loosened part of the lead screw.

Cause analysis of insufficient lining thickness

1. The contractor’s quality awareness is not strict, and the process monitoring is not in place;

2. Or the reserved settlement is insufficient;

3. The undercut site is not treated.

Measures to ensure lining thickness

1. The thickness of the lining should be ensured, and the initial support section should be inspected before the lining construction.

2. For some tunnels with large settlements, it is necessary to pay attention to the settlement observations. If the designed settlements do not meet the requirements, the reserve can be appropriately enlarged according to the actual situation, but it cannot be too large to prevent artificial overdigging. Waste lining hoe.

Cause analysis of lining leakage

1. Cracking of the lining;

2.Insufficient waterproofing, drainage and diversion facilities;

3. There are quality defects in the treatment of circumferential construction joints and deformation joints, and the installation of water stop strips and water stop zones is not standardized;

4. The waterproof board is damaged, perforated, and the weld is not tight

5. The lining is not compacted and there are holes or honeycombs;

6.The waterproof material is unqualified;

7. Insufficient number of drain holes or inaccessible drainage.

Double-track railway lining trolley

Prevention measures for lining seepage

The lining seepage is generally caused by the inadequate drainage and drainage construction and the lining itself is not dense. To strengthen the on-site management to ensure that the drainage and drainage measures are in place and the lining concrete is compacted, the following aspects should be done:

1. The blind pipe is installed in place. Before construction of the waterproof board, it is necessary to ensure that the blind pipe is installed according to the design requirements. The local section has a large amount of water to increase the number of blind pipes. The blind pipe and the vertical drainage pipe are well connected to ensure the drainage effect.

2. Waterproof board construction is the key link of lining waterproofing. At present, there are many types of waterproof boards on the market, and the waterproof boards must be qualified. The waterproof board connection is best to be welded. During the construction process, a quality supervisor will inspect the site and find the problem in time. deal with. Strengthen inspections on some uneven areas to prevent leakage; for reinforced concrete linings to prevent damage to the waterproofing board during the construction of the steel bar, if there is any damage, notify the waterproofing board builder to repair it; if the waterproofing board is installed, it must be close to the rock surface. , Moderate tightness to prevent tearing of the waterproof board due to pressure during pouring;

3. Treatment of construction joints and settlement joints: General construction joints and settlement joints are designed with pre-buried and buried buried waterstops or waterstops, and some have back-attached waterstops. The waterproof board can be fixed with a baffle board. When the middle-buried water-proof strip is used for construction, a small-sized cao (half the thickness of the water-stop) must be reserved in the middle of the lining end. In, fixed firmly. The construction of the middle buried waterstop requires the layered construction of the headboard, which is divided into two layers from the position of the waterstop to ensure that the waterstop is reserved and cannot be destroyed. This seriously affects the construction of the headboard, so it is often not in place. Strengthen the management on site to ensure the construction of the middle buried waterstop;

4. The horizontal drainage pipe shall be reserved according to the design, and a three-way connection shall be used to ensure that the drainage can smoothly flow into the ditch; the vertical drainage pipe is generally a perforated corrugated pipe, which is wrapped with geotextile to prevent the sediment from entering and affecting the drainage effect;

5. The lining concrete can not be stopped for a long time during the pouring process, so the site materials and generators must be fully prepared to prevent stoppages because the concrete poured twice is prone to gaps, causing the lining to leak; the only solution is to punch and grout. Water, but the holes should be shallow to prevent damage to the waterproof board;

6. The lining concrete must have a waterproof effect. Generally, it is designed as a waterproof concrete. When cooperating with the design, it must be considered from multiple aspects. It must ensure the workability and water resistance.

7. Control the self-falling height of the concrete when pouring the lining concrete, ensure the layered pouring, the layer vibration is in place, the formwork trolley window template is closed tightly to prevent slurry leakage, etc., to ensure that the concrete lining is dense and the construction concrete is waterproof.

Cause analysis of lining cracking

1. Temperature difference and dry shrinkage;

2. Alkali aggregate chemical reaction;

3.The side wall foundation sinks;

4.Body bias;

5.Cracking of the arch and side wall due to stress concentration;

6.Cracking caused by difficulty or interrupted pouring of concrete in the arch;

7. The demolding time is too early, the lining strength is not enough to support its own weight and crack.

Crack prevention measures

1. High-grade concrete hydration heat is increased, and water conservation should be carried out after construction, not less than 14d, to prevent the surface from drying and causing cracks;

2. Select qualified materials for lining concrete, and strictly follow the mix ratio construction;

3. The lining generally does not crack. Generally, the lining cracks due to bias or topographical movement at the entrance of the cave. Therefore, when backfilling the cave top, pay attention to symmetrical backfilling on both sides. For tunnels with bias, strengthen the lining strength or decompress;

4. The joint of the overhead arch and the side wall is prone to stress concentration. During the construction, ensure that the side wall foot excavation is in place, and there must be no under-excavation, which causes the lining to crack;

5. Control the lining demolding time, and formulate the corresponding demolding time and curing time according to the tunnel temperature in different seasons, to prevent the occurrence of cracking and cracking;

6. The lining concrete is guaranteed to be put in place at one time, and it cannot be stopped halfway, which is not conducive to waterproofing and easy to cause cracks and reduce the strength of the lining. Therefore, sufficient material reserves and good equipment and equipment are available before construction. Deformation, loose bolts, welding off, etc., prevent problems during the construction process, resulting in the lining cannot be properly constructed.

Cause analysis of poor appearance quality of cable trenches

1. The vertical mold is not detailed and not firm, and the outer edge of the groove is not controlled according to the center line of the line;

2.The cover plate is prefabricated and the installation quality is poor;

3. Construction in other processes, which was broken by repeated lifting, moving and collision.

Appearance quality control measures

The cable trench of the ditch is the surface engineering of the tunnel. The quality of the surface construction affects the overall image of the tunnel. Therefore, the linearity and straightness must be ensured, and there must be no wrong platforms and smooth surfaces.

1. The cable trench of the ditch is controlled for measuring and laying out, the curve is controlled according to the radius, 10m or 20m center line elevation control, and the straight line 50m control. The template adopts the overall steel template to ensure one-time pouring molding, and the template is coated with a mold release agent to ensure the appearance quality. After the template is installed, the technician checks the installation of the template, whether the linearity is up to standard, and whether the reinforcement is firm;

2. The prefabrication of the cover plate is centralized prefabrication in the prefabrication field, and the shaped steel-plastic template is used, with marks on the top and bottom for easy installation.

3. After the prefabricated cover is prefabricated, store it in the prefabricated yard. After the tunnel trench construction is completed, it will be placed in a concentrated way when there are no other processes affected. Mortar is used to fill the gap between the cover and the foundation.

Cause analysis of poor drainage ditch

1. The vertical slope of the ditch bottom is not standardized, there are deviations, and the control is not accurate. The bottom of the ditch is “wavy”;

2. The longitudinal slope of the ditch bottom is small;

3. There are debris in the ditch, and the flow path is blocked;

4. The groove bottom is uneven.

Prevention and control measures for poor drainage of drainage ditch

1. Trench excavation is in place, to ensure linearity and straightness when pouring concrete, to ensure smooth trench and prevent water accumulation;

2. There are many sundries in the hole during working hours, and it is easy to block the trench. It must be cleaned regularly to facilitate drainage in the hole.

3. Drainage Because the formwork is installed straight during the ditch pouring, the reinforcement is firm, and the compaction is used when pouring the concrete.

What are the effects of tunnel lining grouting?

Tunnel lining grouting is to improve the lining stress conditions and meet the waterproof requirements. The construction gap behind the lining ring is filled with cement and other materials. In the soft soil layer, the part disturbed by the tunnel digging has a weakened stability, and the gap needs to be filled in time to prevent or limit ground subsidence. The actual void value is approximately 130% to 180% of the theoretical void value. Commonly used grouting materials are made of cement, bentonite, fly ash and other additives. The injection pressure is controlled between 10 ~ 30N / cm2, and the filling effect must be guaranteed by a reliable shield tail sealing device. The relationship between the pressing time and the shield advancement can be divided into two types: synchronous pressing and delayed pressing.

1. Prevent surface deformation

The diameter of the shield is larger than the outer diameter of the tunnel lining. When the shield is advanced forward, an annular gap is formed between the lining of the shield tail and the soil layer. After a certain period of time, the soil layer will deform to fill the gap and cause the ground to settle. If the gaps are filled in time with suitable materials, and the stratum is supported, it will not be easy to produce settlement deformation. Therefore, grouting is an effective measure to prevent ground deformation.

Concrete diversion groove

2. Reduce the settlement of the tunnel

As mentioned above, the segment emerges from the shield tail, and a gap is created between the segment and the soil, which causes the lower portion of the segment to lose support. Due to the segment’s own weight, sinking occurs, which will affect the original well-looped axis. After the grouting, the segment can lie on the grouting material, as if the tunnel has a cushion layer, which prevents or reduces the settlement of the tunnel, guarantees the quality of the tunnel axis, and meets the engineering requirements.

3.Increase the waterproof performance of lining seams

The tunnel is assembled by prefabricated segments, so there are many longitudinal and circumferential gaps, and these gaps are the weak link of waterproofing. It is envisaged that if a certain thickness of waterproof material is evenly laid on the outer wall of the lining, it will improve the overall The waterproof effect of the tunnel is conceivable, and the grouting is playing this role.

Concrete diversion groove

4.Improving the force of the lining

After the grouting, the formation deformation and the formation pressure are prevented, and the slurry is attached to the outer periphery of the lining ring, so that the two are deformed together, thereby improving the stress condition of the lining.

5.Conducive to shield advancement

The effect of the rectifying shield’s advancement and correction has a greater relationship with the relative position of the segments. Sometimes the poor position of the segment restricts the shield’s corrective motion, which is not only unfavorable for the advancement of the effect of correction, but also may damage the segment. If the relative position of the segment and the shield is adjusted by the pressure of the grout, the shield will have an optimal correction condition. If the shield is to be corrected to the right, the grout on the right side can be selected so that the outer periphery of the segment is unilateral. Pressure forces the lining to move to the right, leaning on the left shield tail, and the gap between the inner shield tail and the shield shell on the right side increases, and the shield has more margin to the right. Therefore, the reasonable selection of the grouting position can help the shield to advance and correct the deviation, control the shield’s construction axis, and thereby ensure the overall axis of the tunnel.

Installation instructions for tunnel lining formwork trolley

In order to make the formwork trolley properly use its performance, the installation work instruction is specially formulated. This instruction is based on the factory and field installation. Installation in the cave should be guided according to specific conditions and facilities, and site conditions with reference to these measures.

First, technical equipment

1. Familiar with the design drawings and relevant technical information of the trolley, and have a clear and accurate knowledge of the structural dimensions, connection methods, and related part numbers of the trolley.

2. First of all, inspect the site and determine the installation plan, and carry out the necessary design and calculation of the main lifting equipment and auxiliary facilities, such as the installation space of the trolley, lifting equipment, floor space and activity space. The hoisting ring equipment and trolley parts installed in the cave are placed and placed.

3. Prepare the installation worksheet, determine the technical requirements for the installation schedule, and determine the operating personnel and the person in charge of the project (cooperating personnel of the construction party).

The tunnel concrete maintenance formwork

Second, equipment and tools preparation

1. Determine the feasible location of the lifting equipment on site, and the construction can be carried out under the condition that the lifting height and lifting tonnage are satisfied.

2. Strictly check the lifting equipment, such as the specifications, length, quantity of the wire rope, the condition of the rope ring, the wear condition, the condition of the wire rope card, the ring and other tools. If any problems are found, replace them in time.

Third, check the installation of trolley components

1. Whether there is collision deformation, loss, or mishandling of steel structural components during transportation.

2. Whether all kinds of accessories of hydraulic walking and supporting parts are complete.

3. Whether the specifications and quantity of the bolts used for fastening are complete. If there are problems, corresponding measures and methods should be taken to deal with them in a timely manner.

Fourth, the safety inspection and protection of the installation site

1. Reasonable placement of various equipment, materials and trolley components.

2. The installation of power, voltage, circuit is in line with the requirements of safe power consumption, whether centralized control.

3. The safety distance of the oxygen and acetylene tanks is 6 meters and the line has no leakage. Check the oxygen and acetylene pipes for leakage and maintain a safe operating distance.

Warning signs or guards shall be set up at the installation site. Unemployed persons and vehicles are strictly prohibited from entering the installation site. Installation personnel who enter the site must wear safety helmets and must wear safety ropes. Installation technicians must conduct safety talks before installation and during installation. Safety supervision and inspection.

Tunnel formwork channel

Fifth, when the trolley is installed

First of all, it is necessary to ensure the level of the rail surface, and the contact surface at the bottom of the rail should be rigid to prevent the trolley from sinking after installation and causing the trolley’s diagonal error.

Sixth, install walking beam

1. Determine the walking box assembly on the rail, make the lifting box axis of the walking box perpendicular to the center line of the rail, and support the four sides of the walking box firmly. Hang a walking beam vertically down above the two walking boxes, so that the axes of the lifting ears at both ends of the walking beam coincide with the axes of the active and passive box lifting ears respectively, penetrate the connecting pin and the anti-channeling cotter pin, and Triangular supports are reinforced on both sides to keep the upper plane of the walking beam perpendicular to the centerline of the rail.

2. Repeat the above operation to install another walking beam. The diagonal error of the two walking beams is ± 1.5cm, and the center distance is 1cm.

Seventh, the connection between the gantry

Connect each product door frame to columns, beams, diagonal braces, and small beams as sticks, and place them in sequence according to the serial number.Bundle the upper beam of the door frame with steel wire ropes, and hang vertically between the two walking beams. Install the door frame to the walking beam in order, and then tighten all the connection screws of the door frame.

Eighth, installation of lifting cylinders and translation trolleys

When installing the lifting cylinder and translation trolley, pay attention to the lifting cylinder can be fastened to the cross beam on the mast by the number, and then the 90-degree plywood can be tightened with screws. Then connect the translation beam to the lifting cylinder with a locking pin.After this work is completed, the diagonal error of the four lifting cylinders is ± 1.5cm and the center distance is ± 1cm.

Tunnel formwork channel

Ninth, the installation of the upper longitudinal beam

Hang the upper longitudinal beam to the lifting cylinder according to the number, and connect it with the flange of the lifting cylinder with screws. After this work is completed, it is required to check the diagonal again, and after the center distance is qualified, place the hydraulic station in the designated place on the drawing. And tighten the bottom connecting bolts.

Tenth, the installation of the vault transverse plate

When lifting the main arch template, first check whether the lifting ears are welded firmly before lifting. Hang each template to the upper beam according to the serial number, and connect with the upper beam with bolts. Adjust the formwork joints and the wrong table, fasten all bolts, and complete the vault formwork installation in turn. (Note: The joints of the arch template are ± 1mm, and the staggered ± 0.5mm. All bolts must be tightened in the same direction, spring pads. Flat pads must be worn.

Eleventh, installation of side formwork

The side wall template is hoisted upright according to the number, the hinged ear hole of the vault template coincides with the axis of the hinged ear of the side template, penetrates the hinge pin, and locks with the lock pin. Note that it cannot be installed on one side at a time, and the two sides must be installed separately. A maximum of three side walls can be hung on one side, in order to maintain the upper vault balance, and then the hoisting is completed according to the serial number. It is required that after the installation of the side wall template is completed, the gap adjustment can be performed. It is required that the wrong platform cannot be greater than ± 0.5mm, and the side wall template is +0.00 below the waistline.

Twelfth, installation of trolley accessories

1. Install working platforms and escalators at both ends.

2. Connect and install side mold longitudinal joint, side mold cylinder and translation cylinder.

3. Connect the hydraulic pipeline, pay attention to the direction of the oil pipe, and it should be horizontal and vertical. When installing the operation valve, pay attention to the control sequence of the oil cylinder, and install from the two sides to the middle. After the oil pipe installation is completed, the inlet and return pipes can be tested and flushed with hydraulic oil. After completion, it can be connected with the oil cylinder to ensure that the oil circuit is unblocked.

4. Hang all mechanical support rod assemblies. Pay attention to the positive and negative wire buckle, which is convenient to use.

Thirteenth, inspection and confirmation

After the above work is completed as required, all the panel lifting ears can be cut off, and then polished, until it is qualified and meets the requirements. Then the trolley is adjusted to the lining state according to the requirements of the drawing, and then it is tested and improved until it is submitted to the construction party for inspection and passed, and is given a signature.

Fourteenth, the construction of formwork concrete lining

The construction time of the moulded concrete lining is arranged according to the construction procedures. In principle, the distance from the excavation surface is no more than 40 meters. In the shallow buried and broken zone of the cave entrance, appropriate points are placed for monitoring and measurement. The measurement items are the sinking of the vault and the surrounding convergence values, and the lining is guided based on this.

The concrete lining is poured by factory-made lining trolleys, concrete pumps, and concrete mixer trucks. A total of one concrete pump and one lining trolley are prepared for the tunnel, which are entered from the tunnel exit.

The formwork lining trolley adopted by the concrete lining is driven by external force and supported in place. The main body is a truss type. When designing the trolley, ensure that its abdominal cavity can pass through the transport machinery. The trolley is 9.1 meters long and the length of each pouring is 9 meters. Before pouring the concrete, various inspection records should be made according to regulations to remove debris on the formwork and rebar.砼 Special persons shall be set up to inspect the state of the formwork, plugs, waterproof plates, hoses, water stop and reserved caves during the pouring construction. The pouring concrete is poured from bottom to top, and the uniformity of the load on the formwork trolley is paid attention to. The pouring height of the concrete on one side must not exceed 1 meter on the other side.

The end plug of the formwork trolley door adopts a rubber injection plate to make the surface smooth and beautiful. The block plug in the hole is assembled with 4 forms. The trolley side wall formwork is provided with 2 rows of windows, and the vault is provided with a row of windows for pumps and vibrations. The windows are closed as the concrete is poured, and when the concrete is poured into the vault, the top windows are closed from both sides to the middle, and finally A hole is left in the middle form of the vault, and the conveying pipe is pushed into the concrete until the end plug emerges from the concrete to ensure that the concrete fills the vault.


Gaofei Tunnel Epidemic Prevention and Control Orderly Resumption and Production Resumption

In the New Year of the Rat in 2020, a new crown virus swept across the land of China. Suddenly, the epidemic was an order! A nationwide rapid battle to “resolutely win the new crown virus epidemic prevention and control fight” this smoke-free smoke war, come on Wuhan! Come on China! Everyone sent a sincere cry from the bottom of my heart, and I believe that under the strong leadership of the Party Central Committee and the State Council with Comrade Xi Jinping at the core, Wuhan and China will definitely win the battle against the smokeless epidemic prevention and control!

The Gaofei Tunnel resolutely responds to the requirements of the Luoyang City Coronavirus Prevention and Control Headquarters and municipal, district, and township departments at all levels, publicizes the knowledge of epidemic prevention and control, stabilizes employees’ emotions, and isolates themselves at home to ensure the health of themselves and their families. Seek medical treatment in a timely manner if you have fever, cough, etc., and report to the management department and file with the company to protect yourself during the epidemic. The Gaofeiqiao Tunnel has always taken the lives and health of the people as the starting point, effectively safeguarded the fundamental interests of the majority of employees, fulfilled the company’s obligations and assumed social responsibilities. Under the leadership of the superior department, it tried to postpone the resumption and resumption of work as much as possible to protect employees to the greatest extent Healthy body.

Before the resumption of work, the Gaofei Tunnel actively prepared various anti-epidemic materials in accordance with the requirements of the Municipal Prevention and Control Headquarters and higher authorities, formulated various systems, programs, regulations, emergency measures and various record books according to requirements, and produced a new type of coronavirus epidemic prevention. Control publicity exhibition boards, banners, manuals for employees ‘epidemic prevention and control, set up a company’s epidemic prevention and control command team, set up special isolation rooms, emergency prevention and control emergency vehicles and other measures to maximize the protection of employees’ epidemic prevention materials.


On February 23, under the on-site acceptance of the superior department, the company procedures and materials passed the acceptance. At the request of the superior department, the Gaofeiqiao Tunnel will do a good job of registration before resuming work. “Must”, “Five in place”, “Four insists”, strictly implement the zero-report system, rigorously clarify all disciplines, increase publicity and guidance, and prevent effectively. Resolutely do a good job of safety inspection of facilities and equipment in the factory area, disinfection three times a day, temperature detection twice, entering personnel, workshop and other detection registration, do not get together or eat together, ventilate the dormitory, do not pass through the store, focus on disinfection in key locations, etc. The superior reports and reports the company’s situation and the newly added returnees roster and employee health certification materials. The company should fulfill its duties and obligations to ensure the physical and mental health of employees.


“Employees are the treasures of the company”. Only if the interests of employees are truly protected and everything is considered for the employees, the company can stand firmly, go for a long time and run fast, and finally serve our customers well. The epidemic took some time, but the employees who resumed production and resumed work remained enthusiastic, and the new purpose of serving customers completely remained unchanged. The epidemic is an order! I believe that under the wise leadership of the state and higher authorities, and with the unremitting efforts of the returnees of the Gaofei Tunnel, the country and our company will surely win the battle against the smokeless epidemic prevention and control!

Come on in Wuhan! Go China!

Make up for lost time! A new high in 2020!

Gaofei Qiao Tunnel Spring Festival Holiday Notice

About “Spring Festival Holiday Arrangement in 2020”

Sue client

To: Dear Customers


Thank you very much for your long-term attention and support to our company. At the coming of the new year 2020, Luoyang Gaofeiqiao Tunnel Machinery Co., Ltd. wishes our customers and the Chinese people a happy Chinese New Year!

Our Spring Festival holiday is scheduled to start on January 20, 2020 (December 26th of the lunar calendar) and end on January 29, 2020 (the fifth day of the first lunar month), and start on January 30, 2020 (the sixth day of the first lunar month) I apologize for any inconvenience this may cause you.

Congratulations once again to our customers and people across the country for their smooth work, good health and a happy Chinese New Year! Special thanks for your support and understanding.
Thank you!

Luoyang Gaofeiqiao Tunnel Machinery Co., Ltd.
January 19, 2010

Gaofei Qiao Tunnel Annual Promotion Video 2020

In 2019, we spared no effort to chase the established goals and successfully completed the first five-year plan. Looking back on this year, we have vivid memories and fresh memories.

In 2019, Henan Gaofei Machinery Equipment Group Co., Ltd. was established. Since then, Luoyang Gaofei has a new look. The transformation of the Gaofei Bridge tunnel to the Gaofei Group is a rebirth after a nirvana and a cocoon into a butterfly after a storm It is the general trend, logical, and a milestone in the history of Goofy.

In 2019, with the joint efforts of all of us, we moved to a new location. Since then, we have a more standard and spacious factory building, and we have a brighter and brighter office building. We are working harder and working harder.

2019 is the year of “Quality Year”, “Reshaping Customer Image Year” and “A Year of Transformation from Extensive Management to Standardization and Institutionalization”. This year, we continued to innovate and make great strides forward.

2019 is a year in which our product quality has improved by leaps and bounds, and a year in which our scientific research has “exploded”. This year, we cooperated with Professor Hu’s team at the School of Mechanical and Electrical Engineering of Central South University to actively carry out various product development and upgrades. This has significantly improved our product quality and equipment performance, and has received unanimous praise from our customers.

In 2019, we will continue to deepen reforms, seek benefits from management and the system, improve various related systems, improve various work processes, carry out different learning activities, enhance technical exchanges between industries, listen to customer feedback, and continuously self-check and correct. To escort the company’s formal development.

In 2019, our business is advancing rapidly and blooming everywhere. We have all newly opened domestic highways, railways, subways and other lines. We have participated in all major projects. At the same time, we have also expanded our international business, lining trolleys, waterproofing Pallet trolleys are exported to Indonesia; multi-section lining trolleys are exported to Saudi Arabia, etc., and contribute their own power to the Belt and Road Initiative advocated by the country.

In 2019, our business personnel traveled across five lakes and mountains, famous mountains and rivers, because there will be bridges when there are large rivers, and tunnels when there are mountains. In this way, the sheep intestines in the mountains have become highways and railways! This year, our after-sales personnel also traveled in all directions, all over the world, because with them, our equipment can operate better and link the great country of the motherland. This year, our workers and masters, fighting the extreme cold and extreme heat, have always fought on the front line of production. It is you who created the Gao Feiqiao Tunnel, and you have also achieved the Gao Fei brand.

2019 is also a year when our patents are “harvest.” In 2019, we won 1 invention patent, 13 utility model patents, and more than 20 patents in the process of application. These patents are a weapon for our market competition. It is our magic weapon to defeat the enemy.

2019 is a year in which we received significant rewards. In 2019, our “Luoyang Bridge and Tunnel Trolley Engineering Technology Research Center” award; “Henan Province Science and Technology Giant Cultivation Enterprise” award; our “Henan Province technology type” “Small and medium-sized enterprises” awards; invention patent awards, utility model patent awards, and these awards are the result of the continuous hard work of all of us.

2019 is also a year when our company has become more formal. Our company has become the vice president unit of Luoyang Bridge and Tunnel Complete Equipment Industry Association. In 2019, our company’s corporate credit rating was 3A. Our company also successfully passed the GJB9001C-2017 weapon. Equipment quality management system certification; GB / T 29490-2013 intellectual property management system certification; the company’s dual prevention system has been completed, and the annual environmental protection acceptance of 300 sets of bridge and tunnel complete equipment projects has been announced. Stronger evidence.

We are striding forward in 2019, and we are full of confidence in 2020. 2020 is the first year of our second five-year plan. In this year, we will pay close attention to quality, maintain safety, and comprehensively advance the standardization and standardization process; increase research and development, and focus on innovation Highlight humanity and differentiation, and further improve the core competitiveness of the product; continuously improve various rules and regulations, create a simple and smooth workflow, continue to increase 7S on-site management, people-oriented, and create a rigorous, efficient, tolerant and loving work environment for The company will continue to take off in 2020 to help fuel.

In 2020, Soaring Goofy will surely base itself on China and look globally, making our products more diversified, technology more advanced, and service more perfect. We will spare no effort to increase scientific and technological research and development, for the enterprise, for the industry, for the bridge and tunnel business of the whole world, for the travel and welfare of the people, build the Goofy brand, shoulder the backbone of China, and write national pride.

At the beginning of the new year of 2020, Huang Gaofei, Chairman of Luoyang Gaofeiqiao Tunnel Machinery Co., Ltd., with all staff, wishes everyone from all walks of life, good work, good health, happy family and good luck!

Gaofei Qiao Tunnel New Year 2020 Annual Conference and Awards Ceremony

Singing resigned to the old year, dancing to celebrate the New Year, on January 117, 2020, the 23rd lunar month of the lunar calendar, Luoyang Gaofeiqiao Tunnel Machinery Co., Ltd. “2020 New Year’s Party and Awards Ceremony” was grandly held. Years are like songs, and Huaguang is like a dream; the past year is like water, and time is passing. The year 2019 that has just passed is a year of the company’s succession and success. The company is accompanied by hardships and harvests with sweat. In each busy day, we Don’t be afraid to challenge before you start! Singing resigned to the old year, dancing to celebrate the New Year, on January 117, 2020, the 23rd lunar month of the lunar calendar, Luoyang Gaofeiqiao Tunnel Machinery Co., Ltd. “2020 New Year’s Party and Awards Ceremony” was grandly held. Years are like songs, and Huaguang is like a dream; the past year is like water, and time is passing. The year 2019 that has just passed is a year of the company’s succession and success. The company is accompanied by hardships and harvests with sweat. In each busy day, we Don’t be afraid to challenge before you start!

The company’s leaders, all employees and their families, as well as customers and suppliers attended the event. At the meeting, the company’s chairman Huang Gaofei, general manager Cheng Chaoliang and manager Yang Xuan made annual detailed reports, reviewing the first five years. Climbing, struggling to start a business, all the way to Triumph, with sales of over 100 million, praised all employees for their hard work and high-spirited dedication, and planned the company’s second five-year plan and goals for the entire staff and society All circles conveyed strong development momentum and determination, and won applause and applause from the scene.

The conference began in our company with a group of young and energetic young girls. The modern dance “Born in the Daejeon” brought out that youthful appearance, cute face, light steps, uniform movements, all show youth Vitality and hope for the company’s future.

A “Sunshine Road” sang the magnificent blueprint of the Gaofeiqiao Tunnel, letting us feel the footsteps of the Gaofeiqiao Tunnel. We will face the rising sun, roll out colorful scrolls, and look forward to the future. Gorgeous chapter.

We have faith in our hearts, dreams ahead, down-to-earth, perseverance, and any difficulties can not stop the pace of progress. We will continue to innovate, surpass ourselves, and strive for excellence in the future! This is our consistent “Goofyman” self. Our three regional managers expressed the feeling of high flying in their minds by reading “Joining High Flying, Leading the Future”.

“Unity is strength” is the eternal subject of development. When we sing it, we are full of strength. This strength allows difficulties to recede and relieve tiredness. This strength allows us to hold our arms up, persevere, and work hard, in confidence. Creating the future will make our company endless and will be passed down from generation to generation.

Technology research and development is always at the core of enterprise development. The people in the technology department are those who dare to fight, drill, and public relations, dare to break through, and challenge themselves. The performance of the sketch “Thief Company” is easy and vivid.

We are the best supplier of complete tunnel equipment. Satisfying our customers is our ultimate goal. We take it as our responsibility to cross the heavens and build tunnel bridges. We are rigorous, efficient, tolerant, and loving. A hundred years of flying and having me all the way, interpretation of our company song-“Building Dreams Going High”! We are the best supplier of complete tunnel equipment. Satisfying our customers is our ultimate goal. We take it as our responsibility to cross the heavens and build tunnel bridges. We are rigorous, efficient, tolerant, and loving. A hundred years of flying and having me all the way, interpretation of our company song-“Building Dreams Going High”!

Youth is synonymous with surging blood, overflowing enthusiasm, hard work, and endless attempts. Youth is able to withstand but not wither away, and withstand development but cannot afford to splurge. A song “Wan” sang the voice of our frontline employees.Youth is synonymous with surging blood, overflowing enthusiasm, hard work, and endless attempts. Youth is able to withstand but not wither away, and withstand development but cannot afford to splurge. A song “Wan” sang the voice of our frontline employees.

We not only have songs, we also have operas. Operas are one of our famous local operas in Henan. They have beautiful melodies and heart-warming plots, and “Kill the Pig to the Moonrise Mountain” is a very declarative sing in the opera.

In the warm sun, I welcome the fragrance, who is the girl, and I walked on that bridge, and you were sorrowful. The little girl singing near the bridge, the corner of your eyes is flowing, you say that one person is stubborn, and one person is studying in his hometown.

The vicissitudes of years will not destroy your immature face, the burden of life will not crush your strong backbone, it looks like a fierce appearance can’t cover your good heart, “The Wolf in Sheep’s Clothing” is cold but kind.

The financial staff are daring, and I wish our motherland prosperous; second, the Gaofeiqiao Tunnel Company won the jackpot high school champion in the industry; three wish everyone is auspicious, every family spends a full moon, using Huangmei opera “Who is the emperor list” “Champion No. 1” is an interpretation of Qing Qingzi, my heart …

In the early morning, we look forward to the daylight into the day; in the evening, we bathe in the sunset and think about the gains of the day. The dream of the blue sky lifted the wings of take-off, the dancing youth raised the sails of struggle, and the song “We Will Create Miracles” expressed our firm confidence.

The classmates are very young and handsome, and the book business slams Fang Yan. The smile of a teenager is the most innocent, and the smile of a teenager is the best! You laugh so good, Huang Leyi, Huang Linhan, Zhao Yating’s dance “You laugh really good”.

The dark sky hangs low, and the bright stars follow. In the summer sky, cicadas tweet and worms fly. A small figure of fireflies, a faint and shining firelight, emits light with the power of love. The insect has no wings, but can fly with dreams. The beautiful melody in the keyboard …

The water source, the tree has roots, and the descendants of Yan and Huang are descendants of the dragon. The yellow skin and black eyes cannot change our Chinese heart even when they are in another country! After growing up, we will be the descendants of the dragon, forever and ever.

We also conducted a lottery on-site, the atmosphere was warm, and the first, second and third prizes were held. At the meeting, ten “advanced workers”, “technical elites”, “dedication to work” and business elites of the company were also held at the meeting , “Outstanding Regional Manager”, “Service Star” and “Excellent Management” were awarded.

Tomorrow is wonderful. Our singing will fly to higher mountains, to rivers, to oceans, and to all parts of the world. Your dreams will come true! In the end, we sang a song called “Family and Family”.

I believe that every happy note tonight will turn into a star, inspiring us to fly higher and go further. I believe that every sweet smile tonight will become eternal, inspiring us to open a new chapter and continue to write new glories. I believe that everyone tonight will be aggressive and grow in the miles of the New Year. I believe that a hundred years of flying will definitely come true!

Bless Gao Fei, all staff, and I wish you a Happy New Year, good health and happiness to your family

What are the stages of tunnel survey

The purpose of tunnel survey is to ascertain the engineering and hydrogeological conditions of the location of the tunnel, and the impact of tunnel construction and operation on environmental protection. Provide the necessary survey data for planning, design, and construction, and analyze and evaluate the existing geotechnical engineering problems and environmental problems to propose reasonable design plans and construction measures, so as to make the tunnel engineering economically reasonable and safe and reliable.

Several stages of tunnel survey

The division of the tunnel survey phase should be compatible with the highway design phase, and is generally divided into: feasibility study survey, preliminary survey, detailed survey.

1. Feasibility study survey

Highway feasibility studies are divided into pre-feasibility studies and engineering feasibility studies according to their working depth. The survey in the pre-feasibility study mainly focuses on collecting and studying the existing literature; in the engineering feasibility study, based on the analysis of the existing data, it is necessary to conduct on-site surveys of each possible scheme through surveys and Make necessary explorations at important sites such as bad geological sites, and roughly determine the geological situation.

Tunnel waterproof board laying formwork

2. Preliminary survey

The preliminary survey is based on the approved construction feasibility study report recommending the construction plan, and the survey is conducted in the initially selected route. Its task is to meet the preliminary design requirements for data. According to the engineering geological conditions, the route plan is preferred. Within the basic direction of the route, an initial survey is conducted on the section that may be used as the tunnel line position. The survey will focus on the unfavorable geological sites to determine whether the tunnel can pass or how to pass. Provide all engineering geological data needed to compile the preliminary design.

The preliminary survey work can be carried out in the order of collecting data, selecting tunnel locations for engineering geology, engineering geological mapping, exploration, testing, and data collation.

(1) Collecting information

The preliminary survey should also collect the existing data, including the feasibility study report, obtain the preliminary topographic layout map of the location of the tunnel, and documents about the nature and scale of the project.

(2) Tunnel location selected by engineering geology

The task of the preliminary survey is to choose the optimal tunnel location scheme that is economically reasonable and technically feasible. When the engineering geological conditions in the survey area are relatively complicated, such as poor regional geological stability conditions, and adverse geological phenomena, special attention should be paid to engineering geological route selection.

Firstly, the approximate route position of the tunnel line should be selected from the perspective of engineering geology, and then the engineering geological conditions along the line should be fully researched and mastered, and as far as possible, a more valuable solution should be proposed for comparison, and the tunnel should be selected in a section with better geological conditions. To avoid major program changes due to engineering geological problems during detailed surveys.

(3) Sorting of preliminary survey data

The original data of engineering geological survey, including survey, surveying, mapping, exploration, testing, etc., should be filled in according to relevant regulations, and reviewed and inspected. The submitted materials include drawings, texts, and other materials, which are required to be clear and correct, and to comply with the relevant regulations and the design method of design documents.

Two-lane highway lining trolley

3. Detailed survey

The purpose of detailed survey is to provide complete engineering geological data for line layout and construction drawing design through detailed engineering geological survey in accordance with design information such as construction principles, design schemes, and technical indicators identified in approved preliminary design documents.

The task of detailed survey is to carry out supplementary proofreading on the basis of preliminary survey, to further identify the engineering geological conditions along the line, and the engineering geological characteristics of key projects and bad geological sections, and to obtain the necessary engineering geological data. The construction drawing design of the location provides detailed engineering geological information.

Detailed survey work can be carried out in the order of preparation work, engineering geological mapping along the line, exploration, testing, and data compilation. As the detailed survey work needs to further find out the engineering geological conditions on both sides of the tunnel centerline and the major engineering geological problems of the unfavorable geological section on the basis of the preliminary survey, the detailed survey work is more detailed and in-depth. The depth should meet the needs of the tunnel lining design.

Tunnel Type Summary

Tunnel classification is distinguished from different angles, and different classification methods can be derived. According to the stratum, they can be divided into rock tunnels and earthy tunnels. According to their location, they can be divided into mountain tunnels, urban tunnels, and underwater tunnels. According to construction methods, they can be divided into mining methods, cut-out methods, and shield methods. According to the buried depth, it can be divided into shallow and deep buried tunnels; according to the section form, it can be divided into circular, horseshoe-shaped, rectangular tunnels, etc .; common tunnel types are mainly traffic tunnels, hydraulic tunnels, municipal tunnels, etc. Mining tunnels, let’s take a closer look at these types of tunnels.

Traffic tunnel

A traffic tunnel is the most widely used type of tunnel. Its role is to provide passages for transportation and pedestrians to meet the requirements of smooth traffic lines. Generally, it includes the following types.

(1) Highway tunnel

A road tunnel is a passage dedicated to automobile transportation. With the development of social economy and production, a large number of highways have appeared, and higher standards for road construction technology have been proposed. Straight lines, gentle slopes, and spacious roads are required. Therefore, when roads cross mountain areas, a large number of roads appear. Tunnel scheme. The construction of the tunnel plays an important role in improving the technical status of the highway, shortening the running distance, increasing transportation capacity, and reducing accidents.

(2) Railway tunnel

A railway tunnel is a passage dedicated to train transportation. When the railway passes through mountainous areas, it is necessary to overcome the elevation obstacles. Due to the gentle slope limitation of the railway, the maximum slope limit is less than 2.4% (dual-machine traction). These mountainous areas cannot be bypassed due to the terrain and often cannot obtain the required elevation through the exhibition line. At this time, excavating a tunnel across a mountain is a reasonable choice, and its effect can shorten the line, reduce the slope, improve operating conditions, and increase the traction number.

(3) Underwater tunnel

Underwater tunnels are tunnels built on rivers, rivers, lakes, seas, and oceans, and are used by cars and trains for transportation. The options available are bridges, ferries and tunnels. Underwater tunnels are a good solution. Their advantages are that they are not affected by climate, do not affect navigation, occupy less land, and do not expose traffic facilities during wartime. More and more people are favored, the disadvantage of underwater tunnels is the higher cost.

(4) Subway

The subway is a passageway for train transportation built in urban strata to solve urban traffic problems. The subway is one of the effective ways to solve traffic congestion and vehicle congestion in big cities. As the subway can transport a large number of passengers quickly, safely, and on time, it has become a powerful means to resolve traffic contradictions in large cities. Can improve the city’s traffic conditions and reduce traffic accidents played an important role.

(5) Shipping tunnel

A shipping tunnel is a passage built specifically for shipping transportation. When the canal needs to cross the watershed, a powerful way to overcome the elevation is to build a canal tunnel, which has the advantages of shortening the voyage, reducing operating costs, straightening the river, and greatly improving shipping conditions.

(6) Pedestrian tunnel

Pedestrian tunnels are passages dedicated to pedestrians. It is generally built in the downtown area, crossing streets, or crossing railways, highways, and other pedestrians, crossing traffic, dense vehicles, and occasional accidents. The role of the pedestrian tunnel is to relieve the pressure on the ground, reduce traffic accidents, and facilitate pedestrians.

The tunnel concrete maintenance formwork

Hydraulic tunnel

Hydraulic tunnels are an important part of hydraulic engineering and hydropower hub groups. Hydraulic tunnels include the following:

(1) Water diversion tunnel

A water diversion tunnel is a tunnel constructed by introducing water into the generating set of a hydropower station or mobilizing water resources. The water introduced by a diversion tunnel is the power resource of the generating set of a hydropower station. Therefore, as a diversion construction project, the pressure of the inner wall is generally required, but sometimes it is only partially passing through. Water pressure and diversion tunnels can be divided into pressure tunnels and non-pressure tunnels.

(2) Tail water tunnel

The tail water tunnel is a tunnel constructed by sending out the waste water discharged from the hydropower generating units.

(3) Diversion tunnel or flood discharge tunnel

A diversion tunnel or a spillway tunnel is a tunnel constructed to divert water from a water conservancy project and supplement the spillway after the spillway flow exceeds its limit. It is an important building for water conservancy projects, and its role is mainly to release floods.

(4) Sand drainage tunnel

Desilting tunnels are tunnels built to wash away silt in reservoirs. It is an integral part of the reservoir building, and its role is to use sand-draining tunnels to carry the sand wrapped out of the reservoir. It is also used to empty the water in the reservoir during inspection or repair.

Tunnel formwork channel

Municipal tunnel

In urban construction and planning, underground tunnels are constructed by making full use of the underground space and placing various municipal facilities under the ground, called municipal tunnels. Municipal tunnels are closely related to people’s life, work and production in the city, and play an important role in ensuring the normal operation of the city. The main types are:

(1) Water supply tunnel

The water supply tunnel is a tunnel built for the laying system of urban water pipe network. In cities, orderly and rational planning and layout of water supply pipelines that are closely related to people’s lives and production is an important task of urban municipal infrastructure. It is required not to damage the urban landscape, occupy the ground, and avoid human damage. Therefore, it is a reasonable choice to construct underground tunnels to accommodate these pipes.

(2) Sewage tunnel

Sewage tunnels are tunnels built for urban sewage drainage systems. Except for the part of urban sewage that is seriously polluted and reused or discharged, most of the sewage needs to be discharged into rivers outside the city, which requires underground sewage tunnels. This type of tunnel usually uses its own diversion and drainage. At this time, the shape of the tunnel is mostly oval. It may also be that a sewage pipe is placed in the tunnel to discharge sewage. At the entrance of the sewage tunnel, there are mostly slag blocking barriers to block floating debris out of the tunnel so as not to cause blockage due to influx.

(3) Pipeline tunnel

Pipe tunnels are tunnels built for urban energy supply (gas, heating, hot water, etc.) systems. The pipeline tunnel in the city is to place the pipeline that transports energy in the constructed underground tunnel. After leakage prevention and thermal insulation treatment, the energy can be safely transported to the production and home destination.

(4) Line tunnel

Line tunnels are tunnels built for power and communication systems. In the city, in order to ensure that power cables and communication cables are not damaged or damaged by people’s activities, and to avoid the impact of high altitudes on the urban landscape, special underground tunnels are built to house them: In modern cities, the above four common characteristics According to the city’s layout and planning, a municipal tunnel is built into a common tunnel, called a “common pipe trench.” The common pipe trench is a symbol of the scientific management and planning of modern urban infrastructure, and a scientific method for the rational use of urban underground space. It is also the direction for the planning and construction of urban municipal tunnels.

(5) Civil defense tunnel

Civil air defense tunnels are air defense evacuation tunnels built for wartime air defense purposes. Civil air defense works were built in cities to prevent the need for war air strikes. Civil air defense works are used for shelter in emergency situations. Therefore, the general requirements of people on the living environment should be considered during construction. In addition to drainage, ventilation, lighting and communication equipment, storage of drinking water, food and Necessary ambulance equipment. Explosion-proof and anti-shock wave devices need to be set at the entrance of the cave.

The tunnel concrete maintenance formwork

Mine tunnel

In mining, the tunnels from the outside of the mountain to the ore deposit and transporting the mined ore are realized through the construction of tunnels. Their functions are mainly for mining, and there are the following.

(1) Transportation laneway

Tunnels to the mountains lead to the ore deposits, and roadways are gradually opened to the various mining faces. The former is called the main roadway, which is the main entrance and exit of the underground mining area and the main transportation trunk road; the latter is distributed like a tree shape and is distributed to each mining face. Such a roadway is usually supported temporarily and is only needed for the operator’s mining work.

(2) Water supply tunnel

The clean water sent is used by mining machinery, and the waste water and standing water are pumped out of the cave.

(3) Ventilation tunnel

Underground mine tunnels usually pass through the ground with harmful gases, exhaust gas from mining machinery, and gas exhaled by workers, making the air in the tunnels dirty. If the gas in the formation contains gas, it will endanger human safety. Therefore, to purify the air in the roadway and create a good working environment, a ventilation roadway must be set up to remove harmful gases and replenish fresh air.

In summary, tunnel engineering has been applied in many fields and has become an important component of national construction, people’s life and production. In recent years, there have been considerable developments in tunnel technology, but there are still many problems and areas to be studied and improved.