Soil body dry-wet cycle effect simulation experiment instrument based on quality threshold value control

Abstract

The invention discloses a soil body dry-wet cycle effect simulation experiment instrument based on quality threshold value control. The soil body dry-wet cycle effect simulation experiment instrument comprises an automatic water supplementing system, an infrared distance measuring system, a quality monitoring and measuring system, a heating system and a data collecting system. A soil sample mass threshold value is preset through the mass monitoring and measuring system, and the soil sample is humidified or heated according to the range of the soil sample mass and the preset mass threshold value, that is, when the soil sample mass is reduced to the lower limit of the preset mass threshold value, the automatic water supplementing system is started to humidify the soil sample; when the mass of the soil sample is increased to the upper limit of the set mass threshold value, a heating system is started according to a preset interval time. When the soil sample is continuously heated and humidified once, a dry-wet cycle period is formed. Meanwhile, in the humidifying and heating process, the quality of the soil sample is continuously acquired through a quality monitoring and measuring system and a data acquisition system; the deformation condition of the soil sample is measured through the infrared distance measuring system, and the axial deformation and the radial deformation of the soil sample are collected continuously or according to the collection frequency set manually.

Description

technical field [0001] The invention belongs to the field of soil property testing, and in particular relates to a soil dry-wet cycle effect simulation experiment instrument based on quality threshold control. Background technique [0002] In engineering practice, during the service period of engineering soil, there will inevitably be seasonal fluctuations in the internal humidity state. In actual engineering, if there is a change in humidity in the soil, it will inevitably lead to corresponding changes in its physical, strength, deformation and other characteristics, thus greatly increasing the risk of engineering diseases. [0003] At present, most of the existing literature adopts the dry-wet cycle method of repeated "drying-soaking", that is, after the sample is dried to constant weight, it is then immersed in water to saturation, which is a dry-wet cycle. However, in engineering practice, engineering soil may be in saturated state, unsaturated state or supersaturated s...

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Problems solved by technology

This experimental method neither considers the influence of the dry-wet cycle range on the properties of the soil, nor does it consider the influence of the excessively high drying temperature on the properties of the sample during the drying process, and does not consider the external environment in which the engineering soil is located.

[0004] However, an existing instrument, a roadbed soil temperature and humidity monitoring experimental device and experimental method with controllable dry and wet thresholds (CN111239036A), is to start the dry and wet circulation system by burying a hygrometer in the soil or the sample and monitoring the soil humidity. The main problem of this method is that there is a humidity gradient in the process of water infiltration from outside to inside or from inside to outside in the soil. The humidity after the final balance and stability inside the body will exceed the preset threshold, and it is impossible to accurately control the equilibrium humidity; if multiple humidity monitors are deployed, although relatively accurate control of soil humidity can be achieved, but multiple humidity meters buried in the soil In fact, it is equivalent to forming a reinforcement effect on the sample, which seriously affects the monitoring results of the deformation law of the soil during the dry-wet cycle process.

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