利用十字板强度推算软土抗剪强度指标方法的探讨

Discussion on the Method of Calculating the Shear Strength Index of Soft Soil by Using the Vane-Shear Strength

软土结构性强,灵敏度高,常规室内试验测得强度参数偏小,而十字板剪切试验对土体扰动小,测定结果较为准确,但是十字板剪切试验无法直接得到土体的c,φ值,需要使用一定的方法进行转换。该文结合某一工程案例,探讨了目前常用的几种根据十字板剪切试验推算软土抗剪强度指标的方法,发现几种方法对于软土内摩擦角φ的推算均能达到较好的效果,但是粘聚力c偏大。最后,提出一种基于地基承载力公式修正c值的方法,对规范方法进行粘聚力修正,结果较为合理。

Soft soil structure is strong,and the sensitivity is high. The conventional indoor test measured the strength parameter is small,while the vane-shear test on the soil disturbance is small,so the determination result is more accurate,but the vane-shear test cannot directly get the soil's c,φ value,so the need to use a certain method of conversion. In this paper,several methods of calculating the shear strength of soft soil are discussed according to the vane-shear test. It is found that several methods can achieve good effect for the calculation of friction angle φ in soft soil,but the cohesion c is too large. Finally,a method of modifying the c value based on the bearing capacity of the foundation is proposed,and the cohesive force is modified by the method and the result is reasonable.