Automatic monitoring system for high-precision soil frost heaving process

Abstract

The invention discloses an automatic monitoring system for high-precision soil frost heaving process, comprising a sample body, a temperature control mechanism, a water supply mechanism, a measuring mechanism, a data collecting mechanism and a seismic isolation bearing, wherein the sample body comprises an organic glass cylinder and a soil sample, the soil sample is placed inside the organic glasscylinder, and the seismic isolation bearing is connected to the bottom of the organic glass cylinder; the temperature control mechanism comprises an incubator, the organic glass cylinder is placed inthe incubator, and a temperature control top plate and a temperature control bottom plate are respectively set on upper and lower sides of the soil sample; the water supply mechanism comprises a water pump, the water outlet of the water pump is connected with a water filling pipe, and the water filling pipe extends through the temperature control bottom plate to the inside of the organic glass cylinder; the measuring mechanism comprises a temperature sensor spirally connected to the side wall of the organic glass cylinder, and a displacement meter disposed above the soil sample, and the temperature sensor and the displacement meter are connected to the data acquisition mechanism. The invention eliminates the influence of mechanical vibration and human reading error on the monitoring result, and deeply reveals the frost heaving mechanism of the soil, and the monitoring result is accurate and reliable.

Description

technical field [0001] The invention belongs to the field of geotechnical low-temperature tests, and in particular relates to an automatic monitoring system for a high-precision soil frost heaving process. Background technique [0002] The coldest month with an average temperature of <-3°C and no more than four months with a monthly average temperature of >10°C is the earliest definition of a cold region in my country, where soil frost heaving is a common natural phenomenon. There are two main reasons for soil frost heaving. One is that the temperature drops below the freezing point, and the pore water in the soil freezes into ice. When the ice crystals fill the pores, the soil particles will be squeezed to meet the needs of their continued expansion, causing the soil particles to wriggle. Scatter outward, resulting in macroscopic deformation. On the other hand, under the joint action of temperature gradient and matric potential, the water in the lower unfrozen soil l...

AI Technical Summary

Problems solved by technology

The primary key to study the mechanism of soil frost heaving is to understand the process of soil frost heaving. At present, the indoor simulation research technology for soil frost heaving is relatively mature, but it has not yet achieved dynamic, automatic and refined, and cannot be targeted. Simulation of soil frost heave in different engineering contexts

[0004] The current test system can only read the final displacement value and water supply at the end of the frost heave, which is obviously satisfactory for the simple test of the final frost heave results under different conditions or soil conditions, but it cannot deeply reveal the soil frost heave mechanism

Moreover, due to the lack of process data, the dynamic phenomena such as the initial drainage consolidation, the advancement of the freezing front, and the whole process of frost heaving and deformation cannot be reversed and analyzed.

Traditional soil frost heave displacements are mostly measured by dial gauges. Compared with high-speed railway foundation coarse and fine granular materials, it is impossible to capture the slight frost heave deformation of this material accurately and stably. Moreover, the accidental error of artificial readings is enough to affect the experimental results.

In addition, the mechanical vibration caused by the cold bath compressor itself to the soil sample cavity is not taken into account. Whether the frost heave finally displayed by the dial indicator can accurately reflect the freezing degree of the soil remains to be verified.

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