Abstract:Abstract: At present, energy and environmental issues have become one of the most principal factors affecting the development of modern society. Energy conservation, exploitation of green renewable energy and environment protection has become urgent tasks in China. With the utilization of renewable energy sources and protection of environment, more and more researchers in the world pay attentions to the thermal environment of the geotechnical engineering. Some environment protection and energy saving technologies can cause the changes of soil temperature or even chemical contaminants diffusion, such as the development and utilization of shallow geothermal energy, nuclear waste disposal, landfill construction, thermal storage. Changes in the mechanical properties of the soil that caused by soil temperature field may lead to soil deformation, falling of ground stability and bearing capacity. Therefore, the research on heat transfer characteristics of rock and soil media has important theoretical values and practical significance in the development of geothermal resources, nuclear waste disposal, energy storage, landfill, heating pipe design and other aspects. The ground-source heat pump (GCHP) technology, as a clean and efficient renewable energy, has developed rapidly in recent decade. The distribution characteristics of the excess temperature in the soil medium were studied with the infinite line source heat transfer model in this paper. The results showed that the temperatures response at the surface of the borehole wall was the biggest in the soil medium around the ground, and heat exchanger which decayed exponentially with distance from the wall of the borehole, increased with operating time of the system. The heat transfer area also increased along with the thermal diffusion of medium and running time of the system. For the group of ground heat exchangers in the engineering, the temperature on the borehole wall of the group buried pipe was calculated according to the superposition principle, it was defined that the thermal response radius of the ground heat exchangers was the vertical distance between the adjacent borehole center when the excess temperature impact factor caused by other boreholes was less than or equal to 5%. With numerical analysis, the calculation method of the thermal response radius of the vertical ground heat exchangers was proposed. The calculating results showed that this method had better precision. The thermal response radius of the vertical ground heat exchanger increased along with the growth of the thermal diffusivity of the ground, duration of working time, borehole row numbers and borehole diameter, and was influenced significantly by the layout of the ground heat exchangers, and less by the borehole diameter under the same layout of the ground heat exchangers. In the case of common borehole diameter in the engineering, such as 115 and 135 mm, the graph of thermal response radius along with running time could be presented with different soil media of a single row, double rows and more than three rows drilling layout in this paper. The engineering examples showed that the method was simple and convenient for engineering design.