Method and device for testing relationship between dynamic modulus and permeability of nano sol reinforced sand soil

Abstract

The invention discloses a method and a device for testing a relationship between dynamic modulus and permeability of nano sol reinforced sand soil. The device comprises a data acquisition and control system, a nano sol injection device, a dynamic modulus testing device and a liquid collection container. The nano sol injection device comprises a peristaltic pump and a nano silicon sol container; the dynamic modulus testing device comprises dynamic triaxial equipment and a longitudinal wave velocity testing system; the data acquisition and control system is connected with the nano sol injection device and the dynamic modulus testing device, and the nano sol injection device, the dynamic modulus testing device and the liquid collection container are in sequential connection. By direct permeation and solidification of a sample in the dynamic modulus testing device, problems of difficulty in moving of weakly-solidified loose samples into the dynamic modulus testing device and disturbance of the samples in moving by adoption of a conventional method are solved. A functional relationship between the dynamic modulus and permeability coefficient can be obtained, and the problem of difficulty in estimation of a dynamic modulus attenuation curve from the permeability coefficient in a process of sand soil reinforcement with nano sol is solved.

Description

technical field [0001] The invention belongs to the field of geotechnical engineering research, in particular to a device and method for testing the relationship between permeability and dynamic modulus of sand reinforced by nano-sol. Background technique [0002] The saturated loose sandy soil foundation will liquefy under the action of earthquake load. Macroscopically, the pore water pressure in the soil increases, and the effective contact stress of the solid phase of the soil is zero. At this time, the soil properties are similar to fluids and lose shear resistance. strength. Earthquake liquefaction causes the following hazards: such as house tilting, foundation settlement, subway tunnel uplift, road subgrade slippage, etc. Therefore, it can be considered to prevent liquefaction by reinforcing the soil. For example, a silica sol solution is introduced into the liquefiable soil. Nanoparticles are suspended in the silica sol solution. These nanoparticles first gradually c...

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Problems solved by technology

The effect of on-site silica sol reinforcement soil can be evaluated by the dynamic modulus of the soil. The unique property of the dynamic modulus of the soil is that it attenuates with the increase of the dynamic strain. However, the soil permeability coefficient is directly measured on site, so it is necessary to Take the reinforced soil samples back to the laboratory for dynamic modulus test to obtain the dynamic modulus attenuation curve. At present, it is impossible to directly obtain the dynamic modulus from the permeability coefficient on site to evaluate the reinforcement effect.

At the same time, on-site sampling often encounters weakly reinforced soil samples that are loose and difficult to shape, and the sample is disturbed during the sampling process. Therefore, a test device suitable for loose solidified samples with little disturbance to the sample is developed, and the permeability coefficient is obtained. The method of dynamic modulus decay curve is particularly important

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