Comprehensive monitoring of land subsidence and ground fissures in Songzhuang, Beijing, based on distributed optical fiber sensing technology

Traditional point−based monitoring techniques are insufficient for continuous monitoring of geological deformation related to land subsidence and ground fissures. Moreover, they cannot quantitatively analyze the relationship between land subsidence and ground fissures through comprehensive monitoring. Based on distributed fiber optic monitoring technology along the full section of boreholes, simultaneous monitoring of land subsidence and ground fissures was achieved. A case analysis of the relationship between groundwater, land subsidence, and ground fissures located in the Songzhuang area of Beijing city was conducted based on the monitoring results. The results indicate that land subsidence located in Songzhuang is mainly influenced by groundwater extraction, resulting in compression deformation of the aquiferous sand layer. Significant land subsidence occurs on both sides of ground fissures, with noticeable differential subsidence. Both the amount of differential subsidence and the deformation of ground fissures continue to increase, albeit at a slower rate. Synchronous monitoring of land subsidence and ground fissures reveals that ground fissure development in the area is primarily influenced by differential subsidence of strata.