Construction process and precautions for grouting with tunnel lining
The lining grouting construction technology of tunnel lining is suitable for the grouting construction of lining belt mould of passenger dedicated railway line. The radial grouting pipe is pre-buried on the trolley, and the grouting is carried out through the grouting pipe in time after the construction of the second liner is completed 2h.
The grouting can be operated by a special integrated grouting and grouting machine. The grouting material has the characteristics of micro-expansion, high fluidity, early strength, no bleeding, slow setting, etc. It not only plays the role of cavity filling, but also can make up for Or repair the defect of the second liner concrete.
Technical requirements for grouting construction with tunnel lining
1. The vertical grouting holes and exhaust holes are set on the secondary lining trolley template. Before pouring concrete, install the SM-RPC grouting pipe on the grouting hole of the bottom mold of the trolley. The grouting timing is 2h after the completion of the vault concrete pouring. Start grouting before demoulding, and finish the grouting until the thick slurry flows out of the vent hole and the end mold.
2. Micro-expansive cement mortar should be used for grouting with molds, and self-leveling cement mortar with high strength and good fluidity can be used in sections with special requirements.
3. During the grouting process, if the grouting pressure exceeds 1.0MPa and no thick slurry is produced, the grouting hole is replaced and the grouting is replaced until the grouting meets the requirements. Each board lining is required to be backfilled with grouting inside the waterproof layer, and the grouting pressure is strictly controlled during the grouting process.
4. The grouting effect can be checked by non-destructive testing method. For the section that does not meet the requirements, the hole grouting must be carried out.
The tunnel lining with mold grouting construction procedures
Waterproof board construction → install RPC grouting pipe → lining concrete construction → backfill grouting → demolding → grouting effect inspection → end
Tunnel lining grouting construction process flow
(1) Lining trolley roof plate mounting flange (first time);
(2) Install RPC grouting pipe and exhaust pipe against the waterproof board;
(3) Record the purchase length of the RPC tube on the record board;
(4) Pouring concrete and observing the slurry from the embedded pipe;
(5) Preparation of grouting fluid and grouting with mold;
(6) Observe the pressure gauge and exhaust hole slurry;
(7) Determine whether thick slurry is discharged from the exhaust hole. Yes, after the grouting is finished, remove the grouting machine hose, remove the positioning flange after the initial setting of the slurry; if the thick slurry is not discharged, it is necessary to judge whether the pressure is less than 1.0MPa, if yes, go to step 5, if not, go to step 4 .
The advantages of tunnel lining with grouting construction technology
1. The grouting pipe and grouting vent hole are reserved on the top of the second lining formwork, and at the same time as an observation hole for checking whether the vault concrete is full.
2. Adopting SM-RPC grouting pipe for short, RPC pipe, micro-expansion retarding early-strength early-strength filling mortar, grouting and grouting all-in-one machine, etc. The equipment is simple, easy to walk and operate.
3. The operation is simple and convenient. The grouting of one board and two linings only takes about 2 hours, and does not occupy the normal construction time of the second lining.
4. Grouting with mold can start grouting when the concrete is initially set, and the grouting pressure is much higher than the grouting pressure after demoulding, improve the integrity of the lining concrete and grouting treatment slurry, and repair various concrete defects.
5. During grouting with mold, the second liner concrete will not be damaged due to the protection of the trolley template. Generally, the pouring pressure of concrete exceeds 6MPa, and the pressure of grouting slurry generally does not exceed 1.0MPa.
Precautions for grouting construction with tunnel lining
1. Before laying the waterproof layer of the arch, it is necessary to focus on the treatment of the initial surface of the sprayed concrete in the arch of the tunnel to ensure that the flatness meets the design requirements; and to ensure that the waterproof layer of the arch is laid appropriately and tightly, to avoid being too tight or too loose Make the waterproof board form pull-down hollow or fold bulge; at the same time ensure that the welding point welding of the waterproof layer of the arch is firm and reliable.
2. During the grouting process, if the grouting pressure exceeds 1.0 MPa and no thick slurry is produced, the grouting hole is replaced for grouting until the grouting meets the requirements. The backfill grouting is required for each shift of lining, and the grouting pressure must be strictly controlled during the grouting process.