中文摘要：

落锥试验作为一种黏性土不排水强度的测试方法，常常因为经验公式（cu=KW／d^2）中参数K值的不确定性，使得预测的不排水强度与实测值不符。为了提高落锥试验在黏性土不排水强度预测中的准确性，探讨K值的影响因素和确定其合理的变化范围，设计加工了6种不同规格的圆锥，对4种不同种类的黏性土进行落锥试验，探讨了圆锥质量和锥角对圆锥贯入深度的影响，结合无侧限抗压强度试验实测的不排水强度确定参数K值，并对K值的影响因素进行分析。结果表明，圆锥锥角对K值的影响较大，而圆锥的质量和黏性土的种类对足值的影响较小，在进行不排水强度预测时，可以简单取K30°=0．69，K45°=0．39，K60°=0．17，已有的试验数据验证预测公式的有效性。

英文摘要：

The fall-cone tests are used to determine the undrained shear strength of clays. However, owing to the uncertainty of K in the empirical formula cu=KW/d^2, the calculated undrained shear strength is always different from the measured shear strength. For achieving a better application of fall-cone tests on the prediction of shear strength and the impacts on parameter K, six distinct types of cones are introduced on four different clays in fall-cone tests. The effect of cone mass and angle on cone penetration is discussed. And the results of fall-cone tests performed with cones of different angles and weights are correlated together with the results of unconfined shear strength tests for four different clays in order to determine the parameter K. The test results indicate that the effect of cone angles is much greater than that of the cone weights and the clay types. It is convenient to predict the undrained shear strength by a constant K with cone angles as K30°=0.69, K45°=0.39, K60°=0.17. The validity of the method in predicting the shear strength is verified by comparing the existing experimental results.