In-situ thermal response testing method of stratified thermal properties of underground rock and soil

Abstract

The invention relates to an in-situ thermal response testing method of stratified thermal properties of underground rock and soil. The invention relates to an in-situ thermal response testing device of the stratified thermal properties of the underground rock and soil. According to the in-situ thermal response testing device disclosed by the invention, a U-shaped pipe is buried, an optical fiber temperature sensor is inserted into two branch pipes of the U-shaped pipe, the U-shaped pipe is connected with an inlet and outlet of a circulating water pipeline of a ground testing device, water temperatures in the two branch pipes, namely the water inlet branch pipe and the water outlet branch pipe of the U-shaped pipe in different depth layers are respectively measured, the power of a heater is kept constant, and measured data of the water temperatures and the flow rates of circulating water in the two branch pipes of the U-shaped pipe in different depth layers at different times, as well as the corresponding heating power of the heater is recorded, so that a heat conduction coefficient, volume specific heat and a drilling thermal resistance value of soil in each layer can be obtained. According to the in-situ thermal response testing device disclosed by the invention, the defects that the distribution of the thermal properties of the rock and soil in different depths can not be obtained, the testing precision can not be improved, an optimal design method of the underground buried pipe can not be improved and the like in the prior art can be solved; furthermore, values of the thermal properties of the underground rock and soil, the types of the rock and soil, the contents of underground water and the seepage situations in the different depths can be obtained, and the in-situ thermal response testing device further has the advantages of high sensitivity, strong anti-interference property, corrosion resistance, small installation size, no requirements on a power supply and low testing cost.

Description

technical field [0001] The invention belongs to the technical field of ground source heat pump air-conditioning utilization, and in particular relates to an on-site thermal response test method for thermal physical properties of underground rock and soil layered at different depths. Background technique [0002] Before the present invention, the existing on-site thermal response test method of thermal physical properties of underground rock and soil is usually under the condition of constant heat flow, the temperature, flow rate and heating power of the circulating fluid in the test hole buried pipe are measured, and the temperature is measured by a certain heat transfer model. The test data is inverted to obtain the average geotechnical physical property value of the buried pipe site. However, the actual situation is that due to the deep buried pipes, the distribution of rock and soil types in this depth range is usually uneven, and the soil moisture content and groundwater...

AI Technical Summary

Problems solved by technology

However, the actual situation is that due to the deep buried pipes, the distribution of rock and soil types in this depth range is usually uneven, and the soil moisture content and groundwater seepage velocity at different depths are also different, resulting in the thermal properties of the soil along the depth. Large changes in direction, which have a great influence on the precise determination of the depth of the buried pipe

Therefore, the current test method cannot obtain the distribution of thermal and physical properties of rock and soil at different depths, and it is impossible to improve the test accuracy and improve the optimal design method of buried pipes.

Images