真空预压软土压缩变形计算参数研究

Parameters used for the prediction of soft-soil compressive deformation under vacuum preloading

变形经验系数和排水固结参数的合理选取是计算真空预压下软土地基压缩量是否可靠的关键。结合某大面积真空预压地基处理施工的现场监测数据,对上海浅部的淤泥质黏性土层压缩变形计算的参数取值进行了研究。结果表明,该工程的淤泥质黏性土层变形经验系数远高于目前相关技术规范的建议值,可能与排水板施工扰动造成压缩模量降低有关;根据现场实测数据反算的排水固结参数,与按照涂抹作用较弱条件下的计算值较为接近。此可为上海地区真空预压软土压缩变形计算中参数的合理选取提供有益参考。

The selection of accurate experimental coefifcients of deformation as wel as the choice of watering consolidation parameters is the key to properly estimating the compression of soft soil under vacuum preloading. Using ifeld monitoring data for large-area vacuum preloading on foundations, this paper discusses the selection of parameters for calculating the compressive deformation of shallow sludge clay in Shanghai. The results show that the experimental coefifcients of deformation for sludge clay are far higher than the suggested values in the applicable technical speciifcations. This may be related to disturbance cause by drainage construction work, which reduces the compression modulus. According to inverse calculations, the drainage consolidation parameters of ifeld data are quite close to the calculated values of the weak daub effect condition. These results provide a valuable reference for selecting the proper parameters for calculations of soft-soil compressive deformation under vacuum preloading in Shanghai.