黄土基坑卸荷影响深度的试验研究及工程应用

Experimental study and engrineering application of loess-pit excavation

通过不同固结压力的常规固结回弹试验模拟了黄土基坑大面积卸荷回弹,分析了不同深度土体的卸荷回弹特征,分别得到了卸荷比与回弹率、卸荷比与回弹模量的关系曲线,并由此得出了西安黄土的临界卸荷比和极限卸荷比,间接确定了回弹变形的最大影响深度和强回弹区范围,为计算黄土基坑底回弹变形量提供了理论依据.最后,综合西安某黄土基坑的现场实测数据及理论计算结果,证明了本文研究结论的可行性.

Large area rebound deformation due to excavation of loess foundation pit was modeled through conventional consolidation-rebound test in this paper,and deformation characteristics of soil in different depth were studied.The critical unloading ratio and ultimate unloading ratio were derived according to the unloading ratio-rebound ratio and unloading ratio-resilience modulus relationship,and the maximum depth of unloading influence area and strong rebound area could be estimated using these two ratios,which would provide theoretical basis for determining the rebound displacement of loess foundation pit.Finally,based on the former research,the maximum rebound depth,strong rebound area and total rebound displacement of a foundation pit in Xi′an was calculated,which were similar to the in-situ test results.This verified that the method given in this paper was feasible.