Water-rich stratum structure with soft upper part and hard lower part and construction method

Abstract

The invention discloses a water-rich stratum structure with a soft upper part and a hard lower part and a construction method. The structure comprises continuous walls, wherein the continuous walls comprise a transverse continuous wall and a vertical continuous wall; the transverse continuous wall and the vertical continuous wall are used for dividing a water-rich stratum plane with the soft upper part and the hard lower part into cabins; the transverse continuous wall is a certain distance away from a primary support outer contour; the vertical continuous wall enters a waterproof medium-micro weathered rock stratum to separate underground water; a plurality of dewatering wells are arranged in a cabin dividing enclosing range of the continuous walls; after the continuous walls are constructed and closed, continuous dewatering is carried out in the cabins; and after the continuous walls are subjected to cabin dividing dewatering, grouting reinforcement is carried out to form a grouting layer. According to the water-rich stratum structure with the soft upper part and the hard lower part and the construction method, water interception, dewatering, reinforcement and mining method tunnel excavation can be realized in a limited range, the influence on the surrounding environment is reduced, the problems of large excavation depth, high manufacturing cost and high risk of an open excavation method of a deep-buried structure of the water-rich stratum with the soft upper part and the hard lower part are effectively solved, and the water-rich stratum structure with the soft upper part and the hard lower part and the construction method are successfully applied in practical engineering.

Description

technical field [0001] The invention belongs to the field of tunnel construction, and specifically relates to a water-rich stratum structure with upper softness and lower hardness and a construction method. Background technique [0002] At present, the tunnel engineering design and construction measures for the upper soft and lower hard water-rich strata mainly include the following schemes: [0003] Option 1. Use ground precipitation and curtain grouting inside the cave; [0004] Option 2: Precipitation in the cave with drainage as the main method combined with pumping and drainage; [0005] Option 3: Set up precipitation guide tunnels or drainage ditches in the catchment direction; [0006] Option 4: Adopt the combination of surface precipitation and precipitation in the cave. [0007] The above schemes have actual cases in actual projects, but there are also shortcomings: [0008] 1. For strata with high water permeability such as pebbles, the water supply is sufficie...

AI Technical Summary

Problems solved by technology

There is no water cut-off curtain on the ground or in the cave, the water supply is continuous, the water pumping is very large, the water level is very small, and the expected precipitation effect cannot be achieved

In addition, a large amount of precipitation will cause the surrounding strata to subside, which will have a great impact on the surrounding environment.

[0009] 2. For the upper soft and lower hard strata, blasting is required for the excavation of the lower rock mass. The blasting will disturb the upper soft soil. In the state of rich water, water leakage will form, causing sudden surge and collapse

Even if the advanced curtain grouting in the cave is used, the diffusion resistance of the grout is relatively large in the water-rich state, and the grout is lost, and the effect of grouting reinforcement and water-stopping is often not ideal

[0010] To sum up, the current design and construction measures for tunnels in upper-soft and lower-hard water-rich strata have difficulties in dewatering, poor grouting effects, and high excavation risks.

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