Cause analysis of land subsidence in Haimen area of Jiangsu Province

Based on the hydrogeological and engineering geological data of Haimen area in Jiangsu Province, through field investigation and relevant literature, the development process of land subsidence in this area in recent years has been systematically sorted out. The subsidence genesis were explored by analyzing the development characteristics and distribution law of land subsidence. The results show that the groundwater in the confined aquifer Ⅲ in Haimen area was over-exploited in the early stage, leading to overall subsidence of the area. However, with the implementation of planned extraction of groundwater, the subsidence area has changed from the whole to part the local, focusing in the areas with soft soil distribution and dense building load. The main compression layers are the phreatic aquifer, the first cohesive soil aquitard and the first confined aquifer. The distribution of soft soil in the area is closely related to land subsidence, and the area with dense building load is highly correlated with the area of frequent land subsidence, that is, the distribution of soft soil and building load are the influencing factors of land subsidence.