A Substrate Suction Control Method for Subgrade Wet-dry Cycle Test

Abstract

The invention relates to the technical field of civil engineering, in particular to a matrix suction force control method for substrate dry-wet cycling test. The invention provides a substrate dry-wet cycle test device which comprises a hollow pressure chamber composed of a pressure chamber base and a lower opening type pressure chamber cover; a hollow sample device is arranged in the hollow pressure chamber and is positioned on the pressure chamber base, a sample device base is arranged at the bottom of the sample device, a rubber film is arranged on the side wall of the sample device, a sample upper cap is arranged at the top of the sample device, a high-air intake value pottery clay plate is arranged on the upper surface of the sample device base, and permeable stone is arranged on the lower surface of the sample upper cap. The substrate dry-wet cycle test device further comprises a back pressure sensor, a pore water pressure sensor, an air pressure sensor and a confining pressure sensor. The matrix suction force control method has the benefits that an instrument used in the test method provided by the invention is simple to manufacture, the test result accuracy is high, the use is convenient, the sample dry-wet cycling test control requirements are met, and the dry-wet cycle test of various porous media including sand, sandy soil, silt and clay can be directly carried out.

Description

technical field [0001] The invention relates to the technical field of civil (geotechnical) engineering, and further relates to a geotechnical testing method, in particular to a matrix suction control method for roadbed dry-wet cycle test. Background technique [0002] During the operation period of the road, due to slope seepage, groundwater level rise and fall, surface water evaporation and plant absorption, etc., the humidity of the roadbed will change repeatedly, especially the side slope of the roadbed is prone to such dry-wet cycles. Previous studies have shown that the mechanical properties of unsaturated soil will undergo irreversible changes after the stress path of repeated dry-wet cycles. Therefore, research on subgrade performance after dry-wet cycles is the basis for ensuring subgrade stability and improving road performance, and indoor simulation of subgrade dry-wet cycles is the first step and a key step in such research. At present, the indoor dry-wet cycle ...

AI Technical Summary

Problems solved by technology

Conventional methods have no effective control measures for changes in moisture content, and insufficient prevention of expansion damage may occur in the sample during water absorption, and the methods are rough, with many human factors and large errors

The chemical analysis method has many test steps, complex solution preparation, high technical requirements for users, and difficult operation

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