Multi-loading-mode unsaturated soil frost heaving instrument and frost heaving amount testing method

Abstract

The invention discloses a multi-loading-mode unsaturated soil frost heaving instrument and a frost heaving amount testing method. The frost heaving instrument comprises a sample storage system, a loadcontrol system, a humidity control system, a temperature control system and a thermostat, the sample storage system comprises a sample cylinder and a temperature disc, an air inlet is formed in the bottom end of the sample cylinder, a cavity is formed in the temperature disc, a water-proof and air-proof film is arranged outside the cavity bottom, a liquid inlet and a liquid outlet are formed in the cavity top, the temperature disc is arranged in the top end of the sample cylinder, and the sample cylinder is arranged in the constant-temperature box; the load control system comprises a counter-force frame and a load control mechanism, the load control mechanism is arranged in the counter-force frame, the counter-force frame is erected in the thermostat, and the load control mechanism is arranged in the counter-force frame and connected with the temperature disc; the humidity control system is communicated with an air inlet of the sample cylinder; an output port of the temperature control system is communicated with a liquid inlet in the temperature disc, and an outlet of the temperature control system is communicated with a liquid outlet in the temperature disc. Frost heaving testsin multiple loading modes can be carried out, gaseous water supply can be achieved, and frost heaving of coarse-grained soil is induced.

Description

technical field [0001] The invention belongs to the technical field of geotechnical engineering, in particular to a multi-loading mode unsaturated soil frost heave meter and a test method for frost heave. Background technique [0002] Subgrade frost heaving is the main disease of engineering in cold regions, especially for highways and high-speed railways in cold regions. Experimental simulation is an important means to study the frost heave performance of subgrade filler. When the ambient temperature in the cold area reaches negative temperature, the temperature of the pore water in the soil reaches the freezing point and freezes. The frost heave of the subgrade requires water supply. The latest research results show that the migration of gaseous water is the core factor that induces frost heave of unsaturated coarse-grained soil and other rock materials. For example, unsaturated coarse-grained soil filler is the main material of high-speed railway foundation, but in the ...

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Problems solved by technology

[0004] A variety of frost heave instruments have been launched at home and abroad, but none of them can realize the supply of gaseous water, and at the same time, the pressure on the top of the soil sample cannot be eliminated (provided by the temperature plate and the self-weight of the freezing liquid, and the friction between the temperature plate and the sample cylinder)

Frost heave instruments that cannot realize gaseous water recharge cannot be used to study the frost heave characteristics of subgrade fillings such as unsaturated coarse-grained soils

The pressure on the top of the soil sample cannot be eliminated, and the measured frost heave has a large error, which can no longer meet the higher requirements of scientific research at this stage

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