营口软土的固结不排水剪切蠕变特性

Creep Characteristics for Consolidated-Undrained Triaxial Compression of Yingkou Soft Soil

利用自行改装后的三轴蠕变仪对海相沉积的营口软土进行蠕变试验，获得了在不同围压、不同偏应力条件下的剪切应变与时间关系数据。分析表明：（1）固结不排水蠕变中没有体积变化，不同偏应力下剪切蠕变可用对数形式表达；（2）固结不排水剪切蠕变在低应力水平下表现为线性粘弹性，而高应力水平时则具非线性的特性。由此，提出了描述软土蠕变规律的Singh-Mitchell经验模型和五参数的广义Kelvin模型，并确定了相应的模型参数。与试验数据拟合发现：Singh-Mitchell经验模型对应力水平为20％-80％时具有较高的拟合精度；Kelvin模型中的变形模量和粘滞系数均不为常数。

A creep test of marine deposit soft soil of Yingkou has been carried on the refitted triaxial shear creep apparatus. The relationship between shear strain and time of Yingkou soft soil is obtained under a series of different cell pressures and different deviator stresses. The analysis of the results show as follow： （1）The consolidated-undrained creep, which doesn＇t include the volume strain, can be ex- pressed by logarithmic functions as a type of under a different deviator stress. （2）The shear creep be- haves in a linear elastic character in a lower stress level, and it is a nonlinear behavior in a higher stress level. Therefore, a Singh- Mitchell experimental model and a generalized Kelvin model with five param- eters are suggested, which can describe the shear creep character of Yingkou soft soil, and a method for model parameters determination is also put forward. It is found, fitted with data, that the Singh- Mitchell model has a higher precise in the stress level between 20% and 80%, and the deformation modulus and viscosity coefficient of Kelvin model all vary with stress level.