基于能量法则计算黏性土不排水抗剪强度的方法

摘要

基于Bolton & Whittle建议的能量法则表达来推求土体不排水抗剪强度力学参数,结合孟加拉某工程场地的剑桥型自钻旁压试验成果,计算不同深度的黏性土的不排水抗剪强度值.采用Marsland & Randolph提出的分析方法获取该值,对比可知2种方法的计算结果极其相近,验证了基于能量法则的表达推求土体不排水抗剪强度指标的可靠性,且可认为旁压试验成果曲线扩孔压力-对数剪切应变曲线塑性部分的拟合直线斜率即为不排水抗剪强度,截距即为极限压力值.通过基于剑桥型自钻旁压试验和不排水抗剪强度理论计算表明,剑桥型旁压试验及该理论计算方法适宜于用作确定黏性土的不排水抗剪强度.%The Bolton & Whittle resenting theory of energy law,in combination with the results of project SBPT in Bangladesh,is used to calculate the undrained shear strength (Cu) value of clay.Also,Marsland & Randolph method is adopted to calculate the value of undrained shear strength.It shows that result calculated by these two methods is very similar and reliable for calculation of Cu.It reveals that the Cu and limit pressure (pL) can be obtained from the plastic part gradient and intercept of the curve of total expanding pressure versus the logarithmic plane shear strain.In practical,the SBPT and the theory are suitable for the confirmation of undrained shear strength of clay soil.