运营高铁车站黄土路基沉降特征及原因分析

针对黄土地区某高铁车站路基沉降病害问题,选取典型区域,采用PS-InSRA技术对变形区域进行监测,获取2017年2月至2019年6月的Sentinel-1A卫星影像数据并与现场勘测结果相结合,分析形变特征和趋势,以指导后续病害治理。结果表明:研究区域路基沉降主要发生在2017年5月至9月和2018年4月至8月两个时间段,春夏季沉降速率较大,秋冬季相对平稳;地基土含水率在13%~26%之间,在地下2 m和4 m为含水率增加速率临界深度,0~2 m范围内的含水率增加较快,2~4 m范围内的含水率增加速率减缓,4~10 m范围内含水率基本稳定;路基部位地基处理影响范围有限,路基侧沟外侧地基土干密度偏小,渗透系数偏大,路基沉降的主要原因为车站场坪地表汇水渗入地基引起路基黄土层湿化变形。

Analysis on Settlement Characteristics and Causes of Loess Subgrade in High-Speed Railway Station

In order to solve the problem of subgrade settlement of a high-speed railway station in loess area,a typical area was selected and the PS-InSRA technology was used to monitor the deformation area,and the results of field investigation from Sentinel-1 A satellite image data from February 2017 to June 2019 were combined,analysis of deformation characteristics and trends was carried out to guide the follow-up treatment of diseases.The results show that the settlement of subgrade mainly occurred in May to September 2017 and April to August 2018 in the study area,the settlement rate is higher in spring and summer,and is relatively stable in autumn and winter,the water content of subgrade soil is between 13%and 26%,in the range of 0~2 m,the critical depth of water cut increase rate is 2 m and 4 m underground,the increase rate of water cut in the range of 2~4 m is slowed down,and the water cut in the range of 4~10 m is basically stable.The influence range of subgrade treatment is limited,the dry density of subgrade outside ditch of subgrade side is small,the coefficient of permeability is large,and the main reason of subgrade settlement is the wetting deformation of loess layer of subgrade caused by the infiltration of ground surface water of station yard.