基于GPS的江阴市地面沉降规律及机理研究

根据GPS监测结果及已有水准测量成果,并结合地下水开采活动和地面沉降分层标的监测资料,系统而深入地研究了江阴市地面沉降时空演化规律及成因机理,发现江阴市地面沉降主要发生在南部,向北、向东沉降量逐渐减小,在时空上与地下水开采密切相关,并具有滞后性及不可逆性;江阴市地面沉降的发生主要受内外两种因素控制,本身具备沉降特性的地质环境条件,包括基岩起伏特征、第四纪土层结构和水文地质条件等,是必备的内在因素,而长期超量开采地下水则是导致地面沉降的主要外因,地面沉降的形成主要是含水砂层的压密和顶底板粘性土层的固结。

GPS BASED STUDY ON REGULARITY AND MECHANISM OF LAND SUBSIDENCE IN JIANGYIN CITY AREA

Based on the data of GPS monitoring and the existing results of leveling, the evolutionary characteristics and regularity of the land subsidence in Jiangyin city were studied systematically and thoroughly. The reasons for the land subsidence were analyzed by integrating the observation data of groundwater activity and slice indicators of land subsidence. It was indicated that land subsidence took place mostly in the south of Jiangyin city, and the subsidence value decreased gradually from the south to the north and east. Land subsidence correlated with the exploitation of groundwater closely in Jiangyin city. It was retardant and irreversible. Land subsidence was controlled mainly by two factors in Jiangyin city. The geological environment with subsidence characteristics was the necessary intrinsic factor, including the discrepancies in the forms of bedrock. The aggradation structure of Quaternary period and hydro-geological conditions, and the super-pumping groundwater is the extrinsic factor. The land subsidence was caused by compression of aquiferous sand strata and concretion of clay soil of roof and bottom plate.