Laboratory test method for forming artificial hard crust by microbiologically solidified silt and fine sand

Abstract

The invention discloses an indoor test method forming an artificial hard shell layer by microbial curing silty-fine sand. Silty-fine sand is paved on slurry which is thick enough, the slurry is separated from the silty-fine sand by a seepage-proofing thin film, liquid is injected into the left side by a liquid injecting peristaltic pump until a sand layer is saturated, liquid on the right side is extracted by a liquid extracting peristaltic pump to form horizontal laminar flow, the flow velocity of liquid injection and extraction is controlled, so that liquid injection and extraction are balanced, and silty-fine sand layers are cemented and cured by MICP (microbial induced calcium carbonate precipitation) technology to form the hard shell layer. The hard shell layer has high rigidity and strength, the carrying capacity of a soft soil foundation can be multiply improved, sand consumption is greatly decreased, the hard shell layer is resistant to liquefaction, and the requirement of basic carrying capacity can be met.

Description

technical field [0001] The invention relates to a test method for solidifying sandy soil, in particular to an indoor test method for forming an artificial hard shell layer by using microorganisms to solidify silt and fine sand. Background technique [0002] In recent years, a new soil stabilization technology is gradually attracting the attention of more and more people in the field of geotechnical engineering. This stabilization technology is Microbial Induced Calcium Carbonate Precipitation (MICP). This technology originates from the discovery of natural phenomena. Some microorganisms can react with chemical substances in the surrounding environment through the enzymes produced by their own life activities, such as Bacillus pasteurianus, which can hydrolyze urea and calcium salts. Mineralization forms calcite, which, unlike pure calcite, has a cementing effect, which is manifested in the ability to cement loose detrital material into rock over a prolonged period of time. ...

AI Technical Summary

Problems solved by technology

[0003] The methods used in traditional foundation treatment are: 1) Use man-made materials such as cement, epoxy resin and sodium silicate to solidify the soil by grouting or direct mixing. These substances generally contain toxicity and will cause great harm to the environment and human life. big hazard

2) Physical foundation treatment methods, such as vibration compaction, will greatly disturb the foundation and cause damage to the original structure of the foundation soil

If traditional solidification technology is used to treat silt and fine sand, such as cement mixing to harden sandy soil, although the strength can meet the construction requirements, the hard shell formed will have a great impact on the environment and will hinder the later construction

Images