Processing method of large-thickness collapsible loess foundation of subway station

Abstract

The invention relates to a processing method of a large-thickness collapsible loess foundation of a subway station. The method includes the steps that an underground continuous wall (3) is arranged on the periphery of the foundation of the subway station (1); a collapsible loess layer (5) can conduct self-weight collapsible sedimentation in a pre-soaking manner, and reinforcement processing is conducted on soil mass on the upper layer of the foundation after sedimentation deformation is stable; a waterproof cushion layer (11) is arranged on a backfilled soil layer (10) in a filing manner; water guide wells (4) are perpendicularly formed outside the underground continuous wall (3); a water guide cushion layer (12) is arranged on the waterproof cushion layer (11) and the water guide wells (4) in a filling manner, and a horizontal water drainage pipe (2) communicating with the water guide wells (4) is arranged in the water guide cushion layer (12); and a water blocking cushion layer (13) is arranged on the water guide cushion layer (12) in a filling manner. According to the processing method, three aspects of soaking, water blocking and water drainage are comprehensively considered, influences of later-period rainfall, underground water and other factors on the collapsible loess layer in the foundation are reduced, and the possibility that collapsibility is caused to the collapsible loess layer again is effectively lowered.

Description

technical field [0001] The invention relates to the technical field of large-thickness collapsible loess foundation treatment, in particular to a treatment method for large-thickness collapsible loess foundation of a subway station. Background technique [0002] As we all know, collapsible loess is a special geological soil with relatively uniform soil quality, loose structure, developed pores, and high water sensitivity. When not soaked by water, the general strength is high and the compressibility is small. When soaked by water under a certain pressure, the soil structure will be destroyed rapidly, resulting in a large additional subsidence, and the strength will decrease rapidly. [0003] my country's loess covers an area of ​​640,000 square kilometers, accounting for about 6.6% of my country's territory. Northwest China is the main distribution area of ​​my country's loess. The thickness of loess ranges from a few meters to more than 400 meters, generally about 100m. In...

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Problems solved by technology

High energy level dynamic compaction method, DDC method (deep dynamic compaction method in hole), compaction method and pre-soaking water method are all effective methods for dealing with large-thickness collapsible loess foundations, but these methods also have poor treatment effects , difficulty in construction or high project cost, etc. In this regard, Wang Jizhong proposed a treatment method for large-thickness collapsible loess (CN 105970911A): first, the loess layer enters the collapsible state in advance by using the method of water injection in the pile, so that The loess layer undergoes self-weight collapsible settlement. After the settlement deformation of the loess layer is determined to be stable, the soil on the upper layer of the foundation is reinforced by the packing compaction method or the strong method.

This is actually a treatment method that considers "pre-soaking water". However, this treatment method cannot guarantee that the collapsibility of the collapsible loess layer has been completely eliminated. The subsidence loess layer may re-collapse, resulting in the destruction of the structure

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