基于弹性地基梁法的深基坑软土抗剪指标优选

Optimization of shear strength parameters of soft soil in deep foundation pit based on elastic foundation beam

软土地区的岩土抗剪强度指标取值问题一直是深基坑工程设计中的重要研究重点。由于受到复杂水文地质条件的影响,武汉地区深基坑工程面临的软土抗剪强度指标取值问题更为复杂。以武汉市某典型深基坑工程基坑土样为试验对象,以弹性地基梁作为主要理论,研究了武汉地区软土抗剪强度指标取值问题。结论如下:采用弹性地基梁理论可以较好地分析深基坑支护结构内力以及变形;对于武汉地区类似基坑进行支护设计时,采用固结不排水的强度指标是较为合适的;采用基于弹性地基梁理论的天汉软件进行深基坑稳定性分析时,若采用原始试验值,结果是偏于危险的,因此存在一个使得指标选取更符合实际情况的修正系数。

The value determination of shear strength parameters in soft soil area has always been the core of research and de-sign of deep foundation pit. Because of the local complicated geological condition in Wuhan, the value determination problem of shear strength parameters in deep excavation projects would be more complicated. Taking a typical deep foundation pit in Wuhan as an example, we carried out soil sampling from this pit to study the shear strength values by elastic foundation beam method. The results show that the elastic foundation beam theory can analyze the forces and deformation of supporting structure of the deep pit ; for similar design in the Wuhan area, the strength index of consolidated undrained shear test is more appropriate ; if Tianhan software based on elastic foundation beam theory is used for deep foundation stability analysis, the result would be dangerous if the original shear test value is adopted, so a correcting coefficient for the shear strength values is needed to make the value deter-mination more suitable for practical condition.