water seepage

The tunnel water seepage

time:2018-12-06 source:维特编辑部browse:196

隧道渗水

The tunnel water seepage
Tunnel seepage

1. Cause analysis of leakage

Based on the analysis of seepage site and field investigation, it is concluded that seepage may occur for the following reasons:
1. Geological reasons: the geological condition of the tunnel seepage area is joint crack development, groundwater development, seepage water is bedrock crack water, local distribution of crack joint development zone, groundwater seepage to crack, before shotcrete, no treatment of crack water, leakage is more serious.
2, smooth blasting effect is not good, resulting in uneven tunnel excavation outline, some areas of shotcrete thickness and compactness can not meet the requirements of the specification leakage phenomenon.
3. When installing drainage blind pipe, the seepage position cannot be checked clearly, or the blind pipe is not fixed, and the deviation occurs when shotcrete is sprayed, which cannot achieve a good drainage effect.
4. There are many calcium materials in the cracked water around the tunnel, which results in the blockage of the tunnel anti-drainage system, especially the water diversion blind pipe.


Ii. Seepage and water leakage treatment plan

Tunnel leakage treatment, should be based on the leakage of water sources, types, parts and leakage water, determine the treatment scheme and the choice of materials.
According to the results of field investigation, the principle of tunnel seepage control is determined as follows: the main principle is drainage, and the combination of blocking and drainage in areas with large local water volume.
1. Gouge drainage: this method is mainly applicable to the leakage of large amount of water such as single point, strand flow and jet water of arch wall.
According to the actual leakage site location to determine the drainage location.
The construction steps are as follows:
(1) seepage point search: clean the concrete surface around seepage and find the location of cracks and water source, especially if there are multiple seepage points in one water source;
(2) determine the drainage path: after finding the seepage point, determine the path for convenient drainage, and prepare for trenching;
(3) gouge: according to the size of the drainage pipe, manually gouge out the groove with a depth of 5cm. Generally, gouge out the inverted trapezoid groove with a large inside and a small outside to ensure that the external cement mortar is 2~3cm thick;
Buried pipes (4) : buried in the bottom of a tank Φ 40 spring at the bottom of the tube until the arch wall, with zinc iron or iron wire fixation;
(5) sealing: use waterproof mortar for sealing. If water seepage appears in the cracks after gouging, first use water-swelling rubber water-stop to insert the cracks, and then seal and fill the waterproof mortar;
Waterproof mortar proportion: 425# ordinary Portland cement: br-enhanced water-proofing agent: br-2 special powder: sand: water =1:0.14:0.03:1:0.35.
2. Grouting: this method is mainly applicable to small water flow at single point or gap of arch wall.
According to the actual situation, the main choice of grouting radial small pipe grouting, materials are mainly used in ultra-fine cement-sodium silicate double liquid grouting, but also according to the leakage point for drilling, embedded grouting needle, injection epoxy resin grouting plugging.
After sealing, brush 1:2 ordinary mortar.
3, laying waterproof plate: this method is mainly applicable to arch wall multi-point regional leakage.
After tunnel excavation, the leakage point can be blocked in the area with larger water flow. If the sealing effect is not good, and the drainage blind pipe cannot achieve good drainage effect, waterproof board can be laid for drainage.
If larger water flow is not found before shotcrete, and multiple leakage points occur after the initial support is completed, waterproof plates can be laid on the initial support concrete for drainage.

Three, prevent leakage measures

1. Ensure smooth blasting excavation surface.
Smooth blasting is the key to ensure the construction quality of subsequent initial support and drainage board.
In smooth blasting, it is especially necessary to control the surrounding eye spacing and ensure that the surrounding eye spacing is within 40~50cm, so as to improve the flatness of the side wall and play a key role.
2. Grouting reinforcement shall be carried out in the water-rich section first.
Grouting reinforcement is required water area, especially the rich water area, broken surrounding rock area, should first grouting seal, carry out "in case is given priority to, row combining prevention, comprehensive management" principle, to ensure the quality of grouting waterproof stop-water effect, achieve a basic implementation grouting period of wireless flow, preliminary formed the o-ring seal outside support, create conditions for safe excavation, create conditions for tunnel waterproofing.
3, strict water diversion pipe buried close.
Water diversion blind pipe should be according to the actual situation of the penetration of the hole, water arrangement according to the design requirements, rich water should be equally spaced along the longitudinal setting form dark bury and permanent drainage channel system, in the absence of leakage location when necessary, every certain distance, under the spray layer on the surface, playing a drain, and installation of drainage tube or linear drain, prevent seepage of the rainy season.
After installing the water diversion blind pipe, it is necessary to ensure that the hole body does not have a large seepage point before concrete injection.
4, strictly spray concrete waterproof off.
Injection raw materials are prepared in strict accordance with the proportion, the allowable weight deviation (according to the weight ratio) : cement, accelerator plus or minus 2%, sand plus or minus 3%.
Shotcrete adopts the method of multiple shotcrete. It is strictly prohibited to put the shotcrete in place at one time. After the completion of the shotcrete, check whether the thickness of the shotcrete conforms to the design requirements.


Key words: tunnel water seepage tunnel water seepage protection tunnel water seepage construction
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