Tunnel invert construction has always been an important factor affecting construction progress and quality control. In order to reduce the interference of invert construction on slag loading and slagging machine and tunnel lining trolley, and to achieve the goal of accelerating the construction progress of mechanized parallel operation, high The fully-automatically controlled and fully hydraulic inverted arch trestle produced by GaoFei company has the following characteristics.
1) Modular assembly structure: The hydraulic inverted arch trestle adopts a plate-beam structure, which can be assembled quickly and modularly, and realizes the characteristics of variable span and convenient transportation.
2) Cantilever mobile structure: The trestle has a front cantilever, and the whole machine can be cantilevered. It has the function of retreating across the pit, effectively avoiding the impact of the face of the tunnel and the inverted blasting flying rocks. The trestle bridge can be crossed or withdrawn from the invert construction area at any time according to the technological requirements of the tunnel construction operation.
3) Full hydraulic drive mode: The whole machine of the trestle bridge adopts hydraulic drive or crawler walking. It has the characteristics of flexible control, simple structure, low noise, stable and reliable performance, and convenient maintenance and repair.
4) Sliding shoe walking method: The trestle adopts a sliding shoe walking method, which has the advantages of compact structure, small footprint, no noise, and stable and reliable walking. Among them, the selected high-performance wear-resistant materials have long service life. , Maintenance and repair are simple and other features. Of course, the crawler chassis is even more advanced.
5) Fully automatic control system: The trestle introduces a fully automatic PLC control system, which uses microcomputer operation to realize fully automated walking, which greatly facilitates driving operations.
6) High construction safety: The overall structure of the hydraulic inverted arch trestle is novel and reasonable in design, with large bearing capacity, stable structure and safety and reliability, which provides safety guarantee for construction vehicles and operators.
Hoisting sequence and preparation of tunnel invert trestle
1. Preparations for the trestle:
1) Clean the concrete on the foundation to meet the construction conditions;
2) Use theodolite to find the positioning axis, and use the ink fountain to flick the line;
3) Measure the elevation of the steel column foundation with a spirit level, and organize the data for installation;
4) Transport the manufactured steel column to the designated location and place it;
5) Before hoisting, prepare various construction tools and equipment, and the construction machinery is in place, and can be put into use after passing the inspection;
2. Transportation and hoisting of tunnel hydraulic invert trestle:
According to the tunnel invert hydraulic trestle and steel column transportation route and transportation conditions, flatbed trucks are used for transportation. In order to ensure the safe transportation of the trestle bridge and steel columns to the construction site, the following points must be done:
1. The loading of the trestle on the vehicle should be balanced to avoid unbalanced load.
2. Before transportation, the total weight and axle load of the vehicle should be checked, and the error between the two should be within 5%.
3. Trestle transport vehicles and anchor-spraying trolleys should run at a low speed with a speed limit of 5km/h. At the same time, shifting, braking and shaking from side to side are strictly prohibited.
4. It is strictly forbidden to brake suddenly during transportation of the drilling trolley, crawler slag raking machine, and spray anchor trolley to prevent relative sliding. A red light should be set up at night to warn, and a dedicated guard should be set up.
3. Hoisting sequence of tunnel invert trestle:
Hoisting of hydraulic trestle bridge for tunnel inverted arch: mark the axis and elevation in advance, indicate the axis recheck size, measure the top surface with a spirit level and level with the pad, do a good job of leveling and layout of the construction site, and maintain the power and road of the construction site Unblocked and shelf erection work. Use two cranes to lift the hydraulic trestle bridge of the tunnel invert that has been assembled on site to the concrete that has been constructed, use the inverted chain and the pry bar to assist in positioning, and then carry out the calibration according to the axis and elevation. After the review is correct, the formal fixation is carried out.
According to the site conditions and construction plan, the two-piece column is now hoisted. Before hoisting, clean the concrete on the concrete foundation until the construction conditions are met, find out the axis and elevation, and use two cranes to hoist the two columns. After hoisting, use the backing plate, jack, level, and theodolite to check the axis, horizontal elevation, and verticality of the steel column. After the organized tunnel invert hydraulic trestle bridge does not need to be hoisted, it will just move forward with the excavation.
4. Construction of the tunnel invert hydraulic trestle:
Invert construction process: tunnel invert hydraulic trestle in place → invert arch excavation → initial support construction of invert arch → invert arch reinforcement binding → invert lining concrete pouring → invert arch filling concrete pouring → concrete maintenance → enter the next cycle .
The specific arrangements are as follows: The first cycle invert construction: excavation and pouring of the 1# invert trough on the 1st to 3rd days, and the excavation and pouring of the 2# invert trough on the 3rd to 6th days. During this period, the inverted arch trestle bridges above the two inverted arch trough sections are kept in traffic, that is, all trestle bridges above the inverted arch trough will not be removed during the first cycle (1 to 6 days).
On the 7th day of the second cycle invert construction, you can move the trestle bridge originally erected above the l# invert trough to the 3# invert trough, and start the construction of the 3# invert trough. At that time, l# invert concrete has reached strength requirements, vehicles can pass, and so on to complete the construction of other inverts.
There are mainly six construction methods: inverted arch splitting construction method, invert arch trestle construction method, parallel pilot pit transportation inverted arch construction method, buttress construction method, invert precast construction method, and invert sequential construction method.
Transverse movement of hydraulic tunnel invert trestle:
1. Operate the approach bridge lifting cylinder to retract the front and rear approach bridges;
2. Operate the horizontal movement cylinder to drive the main bridge and track to move horizontally;
3. Operate the lifting cylinder, the lifting cylinder is supported on the concrete surface through the walking frame and track, and the trestle bridge is raised, and the trestle bridge lifts the underframe through the slide rail and the chute;
4. Operate the lateral movement cylinder to move the underframe laterally;
5. Operate the lifting cylinder, lower the trestle and underframe, and lift the walking frame and track;
6. Operate the traverse cylinder to move the trestle bridge laterally. This reciprocating movement causes the trestle bridge to move laterally to the opposite side.
Front (rear) movement of hydraulic trestle bridge for tunnel inverted arch:
1. Operate the drive motor, the drive motor passes through the sprocket, and the chain pulls the trestle to move 3.5 meters on the track;
2. Operate the lifting cylinder, lower the trestle bridge and lift the walking frame and track;
3. Operate the drive motor, the drive motor moves forward 3.5 meters through the sprocket and the chain traction track;
4. Operate the lifting cylinder, raise the trestle bridge and lower the walking frame and track;
5. Operate the drive motor, the drive motor passes through the sprocket, and the chain pulls the trestle to move 3.5 meters on the track. This repetition drives the trestle bridge to move longitudinally to the next station.
Preliminary preparations for slipform construction:
1. First advance one station to excavate the bottom of the half-side tunnel, remove ballast, tie up steel bars and other lining preparations;
2. Set up the trestle bridge (traverse and move forward through the trestle bridge), and lower the trestle bridge before and after the approach bridge;
3. Carry out the lining preparation work such as excavation at the bottom of the tunnel on the other side, ballast removal and reinforcement.
Slipform construction of tunnel invert hydraulic trestle bridge:
1. Move the trestle bridge to the middle of the tunnel where concrete needs to be poured, and adjust the long approach bridge to level;
2. Operate the sliding mold traction hoist to adjust the sliding mold to the desired position in the longitudinal direction;
3. Operate the sliding mold to raise the hoist level and adjust the sliding mold to the required height;
4. Pour concrete along the slipform and vibrate;
5. According to the concrete solidification status, use the sliding sliding form of the traction hoist, and the speed of 1-1.5 meters/hour is appropriate, until the concrete construction of the warehouse is completed;
6. Pouring invert backfill concrete;
7. Separate the traction and lifting hoist from the sliding form, and move the trestle forward after the invert backfill concrete reaches the strength of 5mpa.