Abstract:
In order to scientifically prevent and control land subsidence, taking the key area of land subsidence in shanmozi village, Xiaoshan District, Hangzhou as the research object, based on the systematic analysis of the mechanism of the local land subsidence, a demonstration site for automatic monitoring of land subsidence with multi-parameter optical fiber in full cross section of borehole was established. And the variation characteristics of subsidence at different soil depths and the primary subsidence layers were identified, and the deformation characteristics of aquitard and sand aquifer were explored under the different modes of water level changes. The results show that the current primary subsidence layers at the demonstration site are concentrated in the second aquitard and the I
2 confined aquifer, and the average subsidence accounts for 29.59% and 33.21% respectively, and showing an increasing trend. Moreover, during the monitoring period, the I
2 confined aquifer mainly shows elastic deformation, and there is small residual deformation with the continuous rise of groundwater level. The deformation of the second aquitard obviously lags behind the change of pore water pressure, and has the characteristics of plastic deformation and creep. The practice shows that the established monitoring demonstration site could accurately obtain high-precision, multi parameter data in the process of land subsidence, and provide data support for study of land subsidence mechanism and model prediction.