高速铁路软土路基沉降计算方法探讨

根据某高速铁路试验段搅拌桩复合地基和真空预压软土地基路堤,在预压期及轨道结构荷载作用下的实测沉降数据,探讨了路堤荷载的实用简化方法、预压荷载及轨道结构荷载作用下复合地基下卧层不同沉降计算方法以及真空预压地基再加载条件下模量的取值范围。分析结果表明:路堤荷载按高度进行等效,与实际情况更接近;利用实测数据反算了真空预压处理过的软土地基再加载条件下,沉降计算中模量的取值为原压缩模量的2.5~3.2倍;在预压荷载作用下采用Boussinesq法计算的下卧层沉降较采用应力扩散角法计算的下卧层沉降小,采用后者计算的复合地基总沉降与实测数据更接近;在计算轨道结构荷载引起的沉降时,分别采用附加应力从路基面和地基面扩散两种方式进行计算时,所得结果差异较大,前者的计算结果与实测沉降更接近。

Calculation Methods for Settlement of Soft Soil beneath High Speed Railway

Settlement data measured in site of soft soil improved by mixing pile and vacuum preloading was employed to discuss the applicability of different calculation methods under preloading and track structure load and the practical simplified method of the embankment load was discussed also. The scope of modulus of vacuum preloading subgrade under reloading was investigated. The result shows that the embankment load simplified according to the height agrees well with the measured data; and the back analytical method was adopted to analyze the scope of modulus in settlement calculation under the vacuum preloading, and the reasonable scope was 2.5-3.2 times of the original modulus; and the calculated settlement by Boussinesq method is less than that by the method of stress diffusion Angle under preloading load, result of the later agrees with the settlement data more; while calculating the settlement due to the track, the stress distribution from subgrade surface and basement surface was employed respectively, however, the calculating result shows to be quite different, the former agrees with measured data better.