The Analysis And Correlation Study Of Rock And Soil Thermal Physical Properties In The Harbin Area

It is very significant that shallow geothermal energy resources is developed andutilized in the benefits of energy saving and environmental protection. It is not onlyrestricted by the heat of the hidden from underground rock and soil, but also affectedby thermo-physical properties of geotechnical in the process of the development andutilization of shallow geothermal energy resources. Thermo-physical parameters ofrock and soil have a direct effect on the number and depth of the hole and utilized costin the development of shallow geothermal energy. Therefore, the process of shallowgeothermal energy resource development and utilization would always beaccompanied by the study of the thermo-physical properties of rock and soil, it hasguiding significance for the development and utilization of the shallow geothermalenergy to strengthen the study of thermo-physical properties of the shallow rock andsoil. With the support of the national natural science foundation project”water sourceheat pump underground THCB coupled transport mechanism”(NO.40972172) andcooperation of Hydrogeology and Engineering Geology Exploration Institute ofHeilongjiang Province, the paper analyzed the characteristic of rock and soil thermalproperties of Harbin area according to the studied of thermal physical tests inlaboratory and field of the region and study the correlation of thermal physical tests inlaboratory and field using the analytic hierarchy process(AHP) and the numericalsimulation technology.The article firstly described thermal physical tests in laboratory and field ofHarbin area and studied their characteristic in detail, obtaining thermo-physicalparameters of the research area, and then drew the thermal conductivity distributionschematic diagram of the study area. What is more, combining with AHP, the paperstudied the discrepancy of laboratory and field tests and chose primary factors thataffected two tests. Finally, the paper modified primary affecting factors and performedverification using numerical simulation techniques. Therefore, the study of the paperis divided into the following three parts:The first part: two region was chose in the northeast China central area, that isHarbin area and the northern region of Changchun, then performing thethermo-physical test of rock and soil, and measuring temperature for the differentlocations of reconnaissance holes in the region, and analyzing distributing conditionof the horizontal and vertical underground temperature field in the region. The paper studied thermal physical properties of rock and soil through the indoor thermalproperties test and in-site thermal response test.The second part: based on the research and analysis of the first part andcombined data of geotechnical thermo-physical parameters collected, analyzingthermal physical properties of rock and soil in the study region. Focus on analyzingand contrasting geotechnical thermo-physical parameters of different depth, testingresults of the indoor and outdoor, the whole condition of the shallow geotechnicalthermal conductivity in the region, single and double U tests and units heat exchange.Analyzing and comparing with the shallow geotechnical thermo-physical parametersof Changchun and Harbin City, it has a basic grasp for the overall distributingsituation of the northeast central region of rock and soil thermal physical properties.The third part: studying thermal physical tests in laboratory and field, it is key todesign ground-source heat pump (GSHP) system that tests thermal physicalparameters of underground rock and soil，testing these parameters mainly finishthrough laboratory and field thermal response tests. Based on difference of testingresults of indoor and outdoor experiments，formation thickness，water ratio，densityand osmotic coefficient were chosen as primary factors that affected both testingdiscrepancy of thermal physical parameters，and computed weighted values of everyfactor using AHP，then amending testing results of thermal physical parameters oflaboratory according to weighted values. Finally，choosing outdoor and amendingindoor thermal physical parameters simulates thermal effects of geotechnical systemby using numerical method，validating difference and homology of heat conduction oftwo methods, and providing a new train of thought of thermal physical parametersdetermination for designing GSHP system.Finally, the paper summarized study results and limitations, and proposedrecommendation on development and utilization of the shallow geothermal resources.