Influence mechanism of ancient buried hill geothermal development on land subsidence

Ancient buried hill is a main rich area of hydro-geothermal in China, which has the characteristics of wide distribution, great potential and good development and utilization conditions, and it is also the area with relatively serious land subsidence. Therefore, clarifying the influence mechanism of ground subsidence in the buried hill area is the basis for the reasonable planning, development and utilization of regional groundwater resources and geothermal resources. Based on the mechanism of land subsidence, with Xiong'an district as an example, combined with analysis on the Quaternary thickness, clayey soil content, water level change, soil consolidation, groundwater recharge and its withdrawal, the influence on land subsidence by development of geothermal was studied, which indicates that the occurrence of land subsidence in Xiong'an new area is mainly affected by two factors:over-extraction of groundwater in Quaternary and unbalance of sandstone thermal reservoir. Among them, the overexploitation of groundwater is the main factor of land subsidence and the disordered development of sandstone thermal reservoir is the secondary one. Although the development of carbonate reservoir will cause the decrease of reservoir pressure, the reservoir will not produce obvious compression deformation under the influence of the compression performance of carbonate. As a result, the research can provide support for land subsidence prevention and energy planning in Xiong'an new area.