天津滨海地区两种典型软黏土蠕变特性试验研究

通过三轴蠕变试验，研究了天津滨海地区两种典型淤泥质黏土和粉质黏土的非线性蠕变特性。蠕变试验采用分级加载的方式进行，利用“陈氏法”对实测数据进行处理后得到两种软黏土在不同应力状态下的蠕变试验曲线。在此基础上，提取相关数据得到两种软黏土的应力–应变等时曲线，根据该曲线的变化规律，采用 Merchant 模型对两种软黏土的蠕变曲线进行拟合，确定模型参数，建立了适用于天津滨海地区两种典型软黏土的非线性蠕变模型。最后，对两种软黏土蠕变模型参数的变化规律进行了对比分析得出： Merchant 模型中虎克弹簧的弹性模量 E _H 随主应力差增大呈负指数规律变化， Kelvin 体的弹性模量 E _K 随主应力差增大呈线性规律变化的经验公式。

Experimental research on creep properties of two typical soft clays in coastal region of Tianjin

The non-linear creep characteristics of two typical clays,which are muddy clay and silt clay in the coastal region of Tianjin,are studied by means of triaxial creep tests.The tests are carried out by the step loading method,and the creep curves of the soft clays under different stress states are got from the raw data by Mr.Chen’s method.Considering with the change law of the stress-strain isochronal curves,the results of the creep tests are fitted by the Merchant model based on the creep curves.The model parameters are confirmed,and then a non-linear rheological model suitable for these soft clays in the coastal region of Tianjin is established.Based on the comparative analysis of the change law of model parameters,the empirical formulas for the relation of these main parameters with the stress are confirmed finally.It is shown that the modulus of Hooke spring’s elasticity with stress difference increases in a negative exponent way;and the modulus of Kelvin component’s elasticity with stress difference increases in a linear way at the same time.