System and method for testing comprehensive heat conductivity coefficient and specific heat capacity of rock-soil body

Abstract

The invention relates to a system for testing the comprehensive heat conductivity coefficient and specific heat capacity of a rock-soil body. The system comprises a heating device and a measuring device, wherein the heating device comprises a heat preservation water tank, an electrical heating rod, a water pump, a heat preservation water inlet pipe, a heat preservation water return pipe, a heat exchanger tube and a balance valve, and the measuring device comprises a rock-soil body temperature sensor, a fluid temperature sensor and a flowmeter. The electrical heating rod is arranged in the heat preservation water tank, the water pump is arranged on the water inlet pipe, the flowmeter and the balance valve are arranged on the water return pipe, and the two ends of the heat exchanger tube are respectively connected with the water inlet pipe and the water return pipe. The invention simultaneously discloses a testing method of the system for testing. With the system, the disturbance and damage which are caused by a laboratory test method to the original structure of the rock-soil body are overcome; the defect that a heat probe method is not long enough is overcome; and the defect that the convention vertical buried pipe rock-soil thermal response test cannot test the thermal-physical characteristic parameters of all the layers of the rock-soil bodies is made up. The system is simple and easy to operate during field tests, and is low in cost. The thermal-physical characteristic parameters which are obtained through utilizing the theory to invert are accurate and reliable.

Description

technical field [0001] The invention relates to a testing system, specifically a testing system for thermal physical parameters of rock and soil mass, and simultaneously the invention discloses a testing method of the testing system. Background technique [0002] The thermophysical parameters of rock and soil are the basic parameters required for the design calculation of soil source heat pump system and energy underground engineering heat exchanger and the calculation of underground engineering temperature field. The selection of this parameter directly affects the reliability and accuracy of calculation. The thermal conductivity and specific heat capacity of rock and soil at any depth are inverted based on the composite medium line heat source theory by embedding temperature sensors on site to monitor the time-varying curve of the soil temperature field under the rock-soil thermal response test. The thermophysical parameters obtained from the inversion can comprehensively ...

AI Technical Summary

Problems solved by technology

The preparation of indoor test samples destroys the original structure and state of the rock and soil mass, and the obtained thermophysical parameters cannot faithfully reflect the heat transfer characteristics of the rock and soil mass

The thermophysical parameters of rock and soil at a certain depth below the surface can be measured by using the thermal probe method, but due to the limited length of the thermal probe, the test depth is limited, and the thermophysical parameters of deep buried soil cannot be measured

Based on the geotechnical thermal response test of the vertical buried pipe ground source heat pump heat exchanger, the comprehensive thermophysical parameters of the geotechnical mass can be obtained, but this parameter is a comprehensive reflection of the heat transfer characteristics of all the soil layers traversed by the vertical borehole, and cannot be obtained. It reflects the heat transfer characteristics of a certain layer of soil or rock and soil at any depth. This method cannot obtain the thermophysical parameters of rock and soil at any depth.

The existing theoretical basis for the inversion of thermal physical parameters of rock and soil based on the thermal response test of rock and soil is the semi-infinite general line heat source theory. Same heat transfer medium as soil

There is a large deviation between the test results and the actual situation

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