CN-121976569-A - Foundation pit three-dimensional blocking system for polluted soil field and construction method

CN121976569ACN 121976569 ACN121976569 ACN 121976569ACN-121976569-A

Abstract

The application relates to a foundation pit three-dimensional blocking system and a construction method for a polluted soil field, wherein the foundation pit three-dimensional blocking system comprises a foundation pit supporting and vertical blocking structure, a bottom horizontal blocking structure and a peripheral auxiliary blocking structure, wherein the foundation pit supporting and vertical blocking structure is a diaphragm wall arranged around a foundation pit, the bottom horizontal blocking structure is a basement structure bottom plate rigidly connected with the bottom of the diaphragm wall, the peripheral auxiliary blocking structure is an L-shaped concrete retaining wall arranged on the outer side of the diaphragm wall, and the foundation pit three-dimensional blocking system is formed by the diaphragm wall, the basement structure bottom plate and the peripheral L-shaped concrete retaining wall.

Inventors

TENG FEI
Wei nianda
WANG JIANQIU
Luo shuang
BAI XIAOLING
MA XINGMIN
KONG WEI

Assignees

中国建筑第八工程局有限公司

Dates

Publication Date: 20260505
Application Date: 20260130

Claims (10)

1. A foundation pit three-dimensional blocking system for a contaminated site, comprising: The foundation pit support and vertical barrier structure is an underground continuous wall arranged around the foundation pit; the bottom horizontal blocking structure is a basement structure bottom plate which is rigidly connected with the bottom of the underground diaphragm wall; The peripheral auxiliary blocking structure is an L-shaped concrete retaining wall arranged on the outer side of the underground diaphragm wall; the underground diaphragm wall, the basement structure bottom plate and the L-shaped concrete retaining wall form a three-dimensional closed system for isolating polluted soil inside and outside the foundation pit.
2. The foundation pit stereoscopic barrier system for a contaminated site of claim 1, wherein the depth of the underground diaphragm wall penetrates the contaminated soil layer and into the underlying stable formation.
3. The foundation pit three-dimensional blocking system for a polluted soil field of claim 1, wherein an impermeable layer is arranged in the basement structure bottom plate, and steel bars of the basement structure bottom plate are rigidly connected with the underground diaphragm wall through embedded steel bars or connectors.
4. The foundation pit stereoscopic barrier system for a contaminated site of claim 1, wherein the L-shaped concrete retaining wall comprises a vertical wall section and a horizontal wall section which are connected; A gap is formed between the vertical wall section and the underground diaphragm wall, and drainage materials are filled in the gap; the horizontal wall section extends to the lower part of the clean backfill area outside the foundation pit.
5. The foundation pit three-dimensional blocking system for a contaminated soil site of claim 4, wherein the corner of the L-shaped concrete retaining wall is provided with an oblique reinforcing steel bar, and the surface of the side facing the contaminated soil is coated with a waterproof coating.
6. A method of constructing a foundation pit three-dimensional barrier system for a contaminated site according to any one of claims 1 to 5, comprising the steps of: s1, constructing a foundation pit support and vertical blocking structure, namely constructing an underground continuous wall around the foundation pit, and synchronously forming a foundation pit support body and a vertical pollution blocking body; S2, constructing a bottom horizontal blocking structure, namely, after a foundation pit is excavated to a designed elevation, constructing a basement structure bottom plate, and rigidly connecting the basement structure bottom plate with the bottom of the underground continuous wall to form a horizontal pollution blocking surface; S3, constructing a peripheral auxiliary blocking structure, namely constructing an L-shaped concrete retaining wall on the outer side of the underground diaphragm wall to form a blocking line for preventing external polluted soil from entering.
7. The method according to claim 6, wherein in step S1, the construction of the underground diaphragm wall comprises grooving, hanging reinforcement cages, casting concrete, and providing a water stop structure at the joints of the groove sections.
8. The construction method of the foundation pit three-dimensional blocking system for the polluted soil field of claim 6, wherein in the step S2, a cushion layer and a composite impermeable film are paved on the foundation pit bottom before the basement structure bottom plate is constructed; And after the steel bars of the basement structure bottom plate are reliably connected with the pre-buried steel bars in the underground continuous wall, concrete is poured.
9. The construction method of a foundation pit three-dimensional blocking system for a contaminated soil site according to claim 6, wherein in step S3, a gravel drainage layer is laid at a basic position of the L-shaped concrete retaining wall before the L-shaped concrete retaining wall is constructed; The steel bars of the L-shaped concrete retaining wall are connected with the underground diaphragm wall in a bar planting mode.
10. The construction method of the foundation pit three-dimensional blocking system for the polluted soil field of claim 6, wherein the steps S1, S2 and S3 are matched with the foundation pit earthwork excavation procedure to form a segmented construction flow; in the foundation pit section where the three-dimensional barrier system is completed, the repair operation of the polluted soil can be synchronously performed.

Description

Foundation pit three-dimensional blocking system for polluted soil field and construction method Technical Field The invention relates to the technical field of geotechnical engineering and environmental protection, in particular to a foundation pit three-dimensional blocking system for a polluted soil field and a construction method. Background When a foundation pit engineering construction is carried out on a site containing polluted soil, the traditional method generally requires that the polluted soil is completely repaired, and foundation pit excavation and supporting construction are carried out after the polluted soil is to be repaired to reach standards. This "repair first, construction then" mode results in a severely extended overall construction period, especially for construction projects with stringent construction period requirements. Disclosure of Invention The invention aims to provide a foundation pit three-dimensional blocking system for a polluted soil field and a construction method, and overcomes the defect of serious delay in construction period caused by a 'first repair and then construction' mode in the prior art. To achieve the above object, the present invention provides a foundation pit three-dimensional blocking system for a contaminated land, comprising: The foundation pit support and vertical barrier structure is an underground continuous wall arranged around the foundation pit; the bottom horizontal blocking structure is a basement structure bottom plate which is rigidly connected with the bottom of the underground diaphragm wall; The peripheral auxiliary blocking structure is an L-shaped concrete retaining wall arranged on the outer side of the underground diaphragm wall; the underground diaphragm wall, the basement structure bottom plate and the L-shaped concrete retaining wall form a three-dimensional closed system for isolating polluted soil inside and outside the foundation pit. By adopting the technical scheme, the underground diaphragm wall, the basement structural bottom plate and the L-shaped concrete retaining wall jointly form a three-dimensional closed system, the foundation pit supporting function and the pollutant blocking function are integrated, a physical isolation barrier is constructed in the construction stage of foundation pit engineering, and a structural foundation is fundamentally provided for realizing the simultaneous construction and the simultaneous repair in an isolated area, so that the problem of construction period delay caused by the traditional first-repair-later construction mode is solved. Further, the depth of the underground diaphragm wall penetrates the polluted soil layer and enters the stable stratum below. By adopting the technical scheme, the depth of the underground diaphragm wall is limited, so that the pollutant needs to penetrate through a polluted soil layer and enter a stable stratum, the integrity and reliability of vertical blocking are ensured, the pollutant can be effectively prevented from migrating or flowing around through an unimpeded soil body below the wall bottom of the underground diaphragm wall, and the sealing performance of the whole three-dimensional blocking system in the vertical direction is enhanced. Furthermore, an impermeable layer is arranged in the basement structure bottom plate, and the steel bars of the basement structure bottom plate and the underground continuous wall are rigidly connected through embedded steel bars or connectors. According to the technical scheme, on one hand, the impermeable performance of the base plate serving as the horizontal blocking surface is enhanced by arranging the impermeable layer in the base plate of the basement structure, and on the other hand, the rigid connection is realized by limiting the base plate steel bars and the underground diaphragm wall by adopting the embedded steel bars or the connector, so that the connection strength and the integrity between the horizontal blocking surface and the vertical blocking body are ensured, and the risk of leakage of pollutants from the connection position due to gaps caused by weak connection is avoided. Further, the L-shaped concrete retaining wall comprises a vertical wall section and a horizontal wall section which are connected; A gap is formed between the vertical wall section and the underground diaphragm wall, and drainage materials are filled in the gap; the horizontal wall section extends to the lower part of the clean backfill area outside the foundation pit. By adopting the technical scheme, the drainage gap between the vertical wall section and the underground continuous wall can effectively collect and dredge water seepage possibly existing, reduce adverse effect of water pressure on a blocking system, extend the horizontal wall section to the lower side of a clean backfill soil area, effectively block migration of outside polluted soil in the horizontal direction and provide a clean foundation for the backfil