Large direct shear test sample preparation device for microorganism reinforced coarse-grained soil and use method thereof

Abstract

The invention discloses a large direct shear test sample preparation device for microorganism reinforced coarse-grained soil and a use method thereof. The large direct shear test sample preparation device comprises a device base, a mold cylinder, sleeves, grouting pipes and bending element sensors. The device base is installed on a direct shear apparatus, and the mold cylinder is installed on thedevice base. A plurality of bending element sensors are arranged on the outer wall of the mold cylinder, and a plurality of drain pipes penetrating the side wall of the mold cylinder are arranged at the lower end of the mold cylinder. A plurality of sleeves are vertically arranged in the mold cylinder, a plurality of through holes are formed in the sleeves, and the space between the sleeves and the mold cylinder is filled with coarse-grained soil. The lower ends of a plurality of grouting pipes are inserted into the corresponding sleeves, the upper ends of the grouting pipes are connected withliquid guide pipes, and the liquid guide pipes are connected with a microbial solution pool and a reaction liquid pool. The device is convenient to assemble and separate, can be used for preparing coarse-grained soil with a large particle size range and has strong operability; the utilization rate of reaction liquid is increased by adopting a method of combining saturated grouting and standing reaction.

Description

technical field [0001] The invention relates to the technical field of foundation treatment, in particular to a large-scale direct shear test sample preparation device and a use method for microbial reinforcement of coarse-grained soil. Background technique [0002] Coarse-grained soil is widely distributed in my country, and its particle size range is generally 0.075-60mm. The coarse-grained soil foundation or slope has loose particles, large particle size, poor erosion resistance, and poor physical and mechanical properties. Coarse-grained soils are prone to instability under complex stress conditions, causing landslides, debris flows and other disasters. In engineering construction, it is necessary to evaluate the shear strength of coarse-grained soil. Conventional shear strength tests such as triaxial, torsional shear, and direct shear have relatively high requirements for the maximum particle size of the particles due to the small size of the sample (generally speaking ...

AI Technical Summary

Problems solved by technology

However, the bonding strength of microbial reinforcement is much lower than that of cement mixture, and it is difficult to sample on site

According to the conventional thinking, microbial reinforcement is carried out in the large-scale direct shear sample box first, and the strength of the cemented body is sheared after the reinforcement is completed. However, due to microbial reinforcement, by-products of corroding metal will be produced, which will damage the sample box, and the generated rust will be filled in the The determination of the shear strength is affected by the relationship between the soil sample and the sample, resulting in deviations in the field reinforcement design

In addition, the degree of microbial reinforcement needs to be evaluated before the test, and the traditional direct shear test sample preparation device cannot be used for large-scale direct shear tests on microbial cements, nor can it evaluate the degree of reinforcement. Sample preparation device for direct shear test

Images