上海软黏土结构屈服特性的试验研究

Experimental Study on Structure Yielding Character of Shanghai Soft Clay

结构性与各向异性是天然沉积软黏土的两个重要特性。为研究其结构屈服特征,对上海软黏土进行了一系列相关试验,包括灵敏度试验、一维固结试验、K0固结试验、三轴排水应力路径试验。灵敏度试验研究表明,天然沉积上海软黏土在结构破坏前后的不排水抗剪强度存在明显差异,灵敏度为4.86,属高灵敏性土。一维压缩试验结果表明,原状上海软黏土在结构屈服前后压缩特性存在明显的差别,具有结构性土所特有的分段特征。不同应力路径下三轴排水剪切试验表明,上海软黏土具有显著的塑性各向异性,其初始屈服面在p'-q平面上呈倾斜的椭圆形状,但其对称轴略低于K0线。

ing character, Both structure and anisotropy are important characters of natural soft clay. To study structural yielda series of tests were carried out for Shanghai sional consolidation tests and K0 ty show that the Shanghai soft c soft clay including to sensitivity test and one-dimenconsolidation test along with drained stress probe tests. The test results of sensitivilay is high sensitivity with s, = 4.86, and the undrained shear strength is different obviously before and after the structure is destroyed. The test results from oedometer show that the compression curve is divided two parts, the compression properties is different before and after structural yielding. The test reuits from stress paths drained triaxial tests show that the anisotropy is significant for Shanghai soft clay. The initial yielding surface can be described by an inclined ellipse on the p＇-q plane, and the yielding surface is symmetrical with respect to some line below the K0 line.