【摘要】 为了研究十字板剪切速率对粉质黏土不排水抗剪强度的影响,首先,应用5种转速的十字板对3种含水率的粉质黏土进行剪切试验,得到不同剪切速率和含水率条件下的土体峰值抗剪强度和残余抗剪强度;其次,对十字板速率和归一化峰值抗剪强度、归一化残余抗剪强度的关系分别进行拟合;最后,基于拟合结果,改进Bjerrum提出的十字板剪切速率修正系数。研究结果表明:随着剪切速率增大,土体峰值抗剪强度和残余抗剪强度均显著增大;在高含水率条件下,剪切速率对土体抗剪强度的影响更显著,且土体残余抗剪强度对剪切速率变化更敏感;半对数函数和幂函数均能对归一化抗剪强度与剪切速率的关系进行较好拟合,半对数函数拟合参数α和幂函数拟合参数β与土体含水率之间均有良好的线性递增关系。由α和β与含水率的线性关系,推导得到了剪切速率修正系数与土体含水率的经验公式。更多还原

【Abstract】 In order to study the influence of shear rate on undrained shear strength of silty clay, firstly, a series of vane shear tests were carried out on silty clay samples with three moisture ratios and five shear rates. The peak and residual shear strength at different shear rates and soil moisture ratio were obtained. Secondly, the relationships between normalized peak shear strength, normalized residual shear strength and vane rate were fitted. Finally, the vane shear rate correction coefficient proposed by Bjerrum was modified based on fitting results. The results show that with the increase of shear rate, the soil peak and residual shear strengths increase markedly. Under the condition of high moisture ratio, the effect of shear rate on soil shear strength is more significant, and the residual shear strength is more sensitive to the change of shear rate. The relationship between the normalized shear strength and shear rate could be well fitted by both Semi-logarithmic function and power function. The semi-logarithmic law fitting parameters α and power law fitting parameters β have a good linear increasing relationship with soil moisture ratio. Considering the relationship between α, β and soil moisture ratio, the empirical equation between the rate correction coefficient and soil moisture ratio is obtained.更多还原