Multifunctional integrated type soil body freezing and thawing test system

Abstract

The invention relates to a multifunctional integrated type soil body freezing and thawing test system which comprises five parts including a model bearing system, a temperature controlling system, a water replenishing system, an atmospheric environment simulation system and a data acquisition system. Temperatures of an upper temperature controlling plate and a lower temperature controlling plate in a model box are respectively controlled by a cold bath, a fan and a rotatable sprinkler head are arranged at the top of a box body, and thus simulation of atmosphere rainfall and field wind is realized. the water replenishing system is arranged at the bottom of the box body, a soil sample test section is provided with a temperature sensor, a volume unfrozen-water content sensor, a soil water potential sensor, a heat flux sensor, a deformation sensor and the like, which are used for effectively testing physical mechanical factors such as temperature, volume unfrozen-water content, soil water potential, a heat flux and deformation of a soil sample in a freeze-thawing process, thus measurement precision and range are greatly improved. The defect and the deficiency of size effect caused by small size of an existing freezing-thawing test system are overcome. The multifunctional integrated type soil body freezing and thawing test system is simple in structure, easy to operate, accurate in measurement, low in requirement of a working environment condition, and stable to work.

Description

technical field [0001] The invention relates to a test and test system, in particular to a multifunctional integrated soil freeze-thaw test system. It can effectively measure the changes of physical and mechanical elements such as temperature, volume unfrozen water content, soil water potential, heat flux and deformation during the freezing and thawing process of soil under open and closed system conditions. The process of hydrothermal change and the law of freeze-thaw deformation provide an effective way. Background technique [0002] The freeze-thaw test is a process of simulating the freezing and thawing process of a specified sample and measuring its physical, chemical and mechanical properties through artificial refrigeration and heating technology. Freeze-thaw test technology has been widely used in the fields of material science, cold area engineering and medicine, such as the durability of concrete materials, the study of physical and mechanical properties of soil f...

AI Technical Summary

Problems solved by technology

At present, domestic frost heaving and thawing tests generally use cylindrical samples, with diameters ranging from 6.18cm to 20cm, and corresponding heights between 10cm and 20cm (Xu Xiangtian, Lai Yuanming, Liu Feng, Chang Xiaoxiao, Dong Yuanhong. Discussion on several types of mechanical test methods[J]. Glaciology and Permafrost, 2011, 33(5): 1132-1138; Yuanming Lai, Wansheng Pei, Mingyi Zhang, Jiazuo Zhou. Study on theory model of hydro-thermal–mechanical interaction process in saturated freezing silky soil [J]. International Journal of Heat and Mass Transfer, 2014, 78: 805–819), the cylindrical sample was placed in a plexiglass barrel equipped with a temperature sensor, and placed in an incubator together , to control the temperature of the upper and lower ends of the sample, and to monitor the temperature change inside the sample and the overall deformation of the outside. The characteristics of these test models are that the soil sample is small in size and easy to operate. The influence of macroscopic factors such as water volume and soil type on the freeze-thaw characteristics of the soil cannot monitor the change process of the internal micro-elements of the soil during the freeze-thaw process, such as: the dynamic changes of the volume of unfrozen water content, soil water potential, etc.; The actual conditions faced are the characteristics of long water migration route, wide range of temperature field distribution, and large growth space of frost heave.

Therefore, due to the small size of the soil sample, the limited function of the test system, and the susceptibility to interference from the environment, it is very difficult to accurately measure the internal moisture migration, temperature change and deformation in the current model test.

[0004] Facing the problems of single measurement elements (internal temperature and overall external deformation of the sample) and difficult measurement of small samples, in order to comprehensively consider the effects of many freeze-thaw tests more realistically simulate field environmental conditions, give full play to the advantages of low cost and high efficiency of indoor testing, and effectively test multiple factors (internal temperature of the sample, unfrozen volume content, soil water potential changes, and external deformation, etc.) It is very necessary to design a reasonable and effective indoor multifunctional integrated freeze-thaw test device for large-scale soil samples to complete the effective testing of the physical and mechanical properties of soil samples during the freeze-thaw process

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