Dynamic variation characteristics of layered monitored land subsidence near a fast railway line

摘要

The fast railway line B is a high-speed railway passengerpassageway in Beijing, with a total length of 40.75 km. In the plain area,the railway passes through the land subsidence area of Beijing from south tonorth, which poses a certain threat to the normal operation of a high-speedrailway. Using layered monitoring data for the period 2009–2014 fromstation A, this paper analyses dynamic changes in the annual subsidence rateand the rate and percentage of soil deformation at different depths, as wellas the compression deformation law of soil with different lithology anddepth with the change of the water level. The results show that (1) since2012, the proportion of shallow-layer (≤82 m) compression andsettlement contribution has gradually decreased, while the proportion ofdeep-layer (> 82 m) compression has significantly increased; (2) during the deformation process of layered soil, the amount of compression isclosely related to the change of groundwater level; and (3) the shallow, middleand deep strata show obvious viscoelastic–plastic deformationcharacteristics on the whole.