Gravity type foundation pit supporting system under vacuum effect and construction method

Abstract

The invention discloses a gravity type foundation pit supporting system under a vacuum effect and a construction method. The system comprises a peripheral vertical sealed curtain, a pit top horizontal sealing layer, a transverse drainage body, a slope surface sealing layer, a slope bottom vertical sealed curtain, a pit top vertical drainage body and a slope surface vertical drainage body. The peripheral vertical sealed curtain is downward vertically installed from an outside boundary of a setting range of the pit top horizontal sealing layer; the pit top vertical drainage body is arranged in foundation soil of the setting range of the pit top horizontal sealing layer; the transverse drainage body is arranged on the surface of the foundation soil at a top end of the pit top vertical drainage body; the pit top horizontal sealing layer is formed on the surface of the transverse drainage body; the slope surface vertical drainage body is arranged in the foundation soil inside the pit top vertical drainage body; the slope surface sealing layer is formed on the slope surface vertical drainage body; the slope bottom vertical sealed curtain is formed in a slope foot of a pit bottom. In the gravity type foundation pit supporting system under the vacuum effect and the construction method provided by the invention, a side wall is not arranged to solidify a wall body and a curtain shielding body, a greater cutting depth requirement can be met, construction cost is low and construction period is shorter.

Description

technical field [0001] The invention belongs to the technical field of civil construction foundation pit support, and in particular relates to a vacuum action gravity type foundation pit support system and a construction method. Background technique [0002] Chinese invention patent No. 200810236142.3 discloses a method for excavating a deep foundation pit with vacuum curtain water stop and atmospheric pressure support (hereinafter referred to as "vacuum curtain method"). It is used to support the foundation pit, and the construction is safer, and there is no need for support structures in the foundation pit, and no need for dewatering well points inside and outside the foundation pit. It has obvious advantages in terms of safety, reliability, construction period saving, and investment saving. [0003] The vacuum curtain method mainly includes the following steps: [0004] The first step is to level the site required for excavation of the foundation pit, and plan the vacuum...

AI Technical Summary

Problems solved by technology

[0015] 4. The way of laying the sealing film on the top of the pit by the vacuum curtain method is similar to the traditional vacuum preloading foundation treatment method. The outer boundary of the sealing film is simply buried in the soil body shallowly, so that the vacuum pressure in the vacuum curtain is easy to spread to the outside. On the one hand, the diffusion of vacuum pressure will reduce the vacuum degree within the curtain range, thereby reducing the stability and safety factor of the pit wall; on the other hand, it will cause shrinkage, cracking and subsidence of the foundation within a certain range in the adjacent area, causing adverse effects on the surrounding environment

Moreover, since the water-stopping effect of this method is realized by vacuum pumping, it will actually have a precipitation effect on the foundation around the foundation pit. When the surrounding environment is sensitive to the precipitation of the foundation, this method is not applicable

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