Comprehensive Monitoring of Land Subsidence and Ground Fissures in Songzhuang, Beijing Based on Distributed Optical Fiber Sensing Technology

For land subsidence and ground fissures, it is difficult for traditional point measurement to realize monitoring of the deformation of the strata, and the relationship between land subsidence and ground fissures cannot be quantitatively analyzed through comprehensive monitoring. Based on the full-section optical fiber monitoring technology of borehole and distributed optical fiber monitoring technology, this paper realized the synchronous monitoring of land subsidence and ground fissures. Based on the monitoring results, the relationship between groundwater, land subsidence and ground fissures in Songzhuang is analyzed .The monitoring results show that the land subsidence in Songzhuang is mainly affected by groundwater exploitation. The pumping of the water-bearing sand layer is compressed and the land subsidence is obvious on both sides of the ground fissures, and uneven subsidence is obvious on both sides of the ground fissures. Both the uneven subsidence and ground fissures deformation increase continuously, but the increase rate slows down. The synchronous monitoring results of land subsidence and ground fissures show that the development of ground fissures in this area is mainly affected by the differential subsidence of strata.