Foundation pit microbial soil gravity type enclosure structure and construction method thereof

Abstract

The invention provides a foundation pit microbial soil gravity type enclosure structure and a construction method thereof. According to the microbial soil gravity type enclosure structure, a stirring pile machine or a high-pressure jet grouting machine stirs and solidifies a composite bacteria solution, a cementation solution and an immobilization material with a soil body to form a continuously-lapped microbial soil columnar reinforced body retaining wall; the immobilization material is formed by mixing straw fiber powder and expanded perlite powder according to the mass ratio of (5-8) : (1-3); and the cementation solution is a cementation solution containing 0.05-0.1 mol / L of a sodium phosphate buffer solution, and the pH value of the sodium phosphate buffer solution is 5.5-6.8. According to the enclosure structure and the construction method thereof, the composite bacteria solution, the cementation solution and the immobilization material are stirred and solidified with the soil body, so that the cementation reaction rate induced by microorganisms can be effectively improved, and the uniformity and durability of the solidified soil body are improved.

Description

technical field [0001] The invention relates to the technical field of building foundation pit support engineering, in particular to a microbial soil gravity type enclosure structure for foundation pits and a construction method thereof. Background technique [0002] Reasonable selection of foundation pit enclosure structure is the primary work of foundation pit support design, which should be comprehensively determined according to geological conditions, requirements of surrounding environment, characteristics and cost of different support forms, etc. At present, the commonly used forms of row piles or underground diaphragm walls mainly include bored piles + cement-soil mixing piles for water stop, reinforced concrete underground diaphragm walls, steel sheet piles, SMW piles, etc. Among them, the material of bored piles + cement-soil mixing piles for water stop and reinforced concrete underground diaphragm wall is mainly reinforced concrete, which consumes a lot of material...

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Problems solved by technology

The existing microbial soil reinforcement technology often uses a step-by-step method to separately inject the bacterial solution and the cementing solution into the soil, such as patent 201510900093.8, a microbial soil-fixing CFG pile composite foundation and its construction method, and patent 201610933803.1, a shield tunnel end In the microbial reinforcement area construction in the microbial reinforcement structure and its construction method, the soil solidification method is carried out in two steps, so that the bacteria liquid, the cement solution and the soil are mixed and solidified to obtain the microbial soil reinforcement enclosure structure; but the existing microbial soil Soil solidification is easily induced by microorganisms, the controllability of the cementation reaction rate is poor, and the uniformity of the solidified soil is low, especially the soil solidified on soft soil foundations has poor durability and low compressive and shear strength; therefore, it is urgent to find A foundation pit microbial soil gravity enclosure structure and construction method to improve the uniformity and durability of solidified soil and improve the performance of microbial soil gravity enclosure structure

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