Study On Monitoring Experiment Of Water Level And Strain In Huge Unconsolidated Soil Layer

With overexploitation of groundwater or rapid development of city infrastructure, and large scale exploitation of underground resources causing surface subsidence has been widespread domestic and overseas, and has emerged in many cities in China. Water loss and settlement in deep unconsolidated soil layer cause shaft lining breakage that have been ubiquity in East Area of China. As development of information sensor and advanced sensing technology, it is very important significance to analysis the principles of water loss and settlement in unconsolidated soil layer as well as to master deformation states due to it.Starting from water loss and compression theory in loose layer, the characteristics of losing water and compressive deformation in different layers of the deep soil layer is analyzed, base on many calculation methods of settlement due to water loss in loose layer, a methods of how to calculate deformation of soil layer due to water loss by water level or strain change conditions is obtained, and provide the basis for the implementation of the monitoring in different losse layers.According to water levels and strain information by long-term real-time monitoring in No.3 Jinning Coal Mine, the characteristics of water level in different layers of the deep soil layer is summarized, with comparsion of water level and strain in different layers, the relationship between water levels and strain is analyzed by the regression formula. Thus the compressions of loose layer are calculated buy the result of strain monitoring information with Fiber Bragg Grating, as well as the cumulative change of surface subsidence.In order to verify the relationship between water injection and strain in losse layer, a water injection test in loose layers were implemented, the injection parameters and strain states during water injection and after it is analzed, the theoretical model of water injection and strain during test is initially established, and the relationship between them and the strain variation in losse layer are summarized, proved the accuracy of montoring method for strain in losse layer, The result shows that the main water loss occurs in the deep losse layers in East Area of China, nonlinear relation between water level and strain, the compression mainly in gravel layer and thick clay layer nearby bedrock, the strain increase as injection water aslo shows nonlinear relation, long-term water injiection is expected to improve the compression after water loss in the deep losse layers and provide new basis to prevent it.