不同温度应力路径下饱和黏土剪切特性

在精准温控动三轴试验系统上开展了不同温度及不同升温路径饱和黏土剪切试验研究，探讨了不同温度对饱和软黏土不排水剪切特性的影响,分析不同升温固结方式对饱和软黏土孔压发展、体变、强度以及模量的影响规律。试验结果显示：在4～76 ℃试验研究范围内，环境温度升高导致饱和软黏土的不排水剪切强度有所减少，但温度升高对土体模量增加影响明显，温度T和模量ET关系可用ET = 2.69T 0.3表达；升温变化时正常固结黏土产生超孔隙水压力并随着温度增大而增大，升温热固结后土的剪切强度将明显提高，且排水状态下升温固结对土剪切强度增长小于升温完成后再固结情况；土体从26 ℃分别升高20、40 ℃时，升温引起的超孔压比分别为0.41、0.61，剪切峰值强度分别增加8.23%、22.37%。研究表明：升温幅值增大会使土体热固结程度越大，升温分级越多，热固结也越充分，其对应的体变、强度增长率则越大；同时最终温度及热固结路径对其剪切相转换特征存在影响，升温越高、热固结路径越多其剪胀性越明显，但温度变化范围、固结分级、热固结路径总体上对孔隙水压力的发展基本不产生影响。

Shear characteristics of saturated clay under different temperature stress path

The shear test of saturated clay with different temperatures and different heating paths was performed with the precise temperature-controlled dynamic triaxial test system. Effect of temperature on the undrained shear characteristics of saturated soft clay is explored, and the influence of different heating and consolidation methods on the pore pressure development, volume change, strength and modulus of saturated soft clay is analyzed. The results show that the undrained shear strength of saturated soft clay decreases when the ambient temperature increases from 4 ℃ to 76 ℃, but the increase in temperature has a significant effect on the increase of the soil modulus, and the relationship between them can be well fitted with the function of ET = 26.92T0.3. The excess pore water pressure of the normal consolidated clay increases with the increase of temperature, and the shear strength of the soil increases obviously after thermal consolidation, and the increase of the shear strength of the soil under the condition of drainage is less than that after the completion of thermal consolidation. When the soil mass increases from 26 ℃ by 20 and 40 ℃, the heating induced excess pore water pressure ratio is 0.41 and 0.61, and the shear peak strength increases by 8.23% and 22.37%, respectively . Studies reveal that the increase of heating amplitude will increase the degree of reconsolidation of the soil perturbation, and the more the thermal consolidation grading is, the more sufficient thermal consolidation is, and the corresponding volume change and strength growth rate are larger. At the same time, the final temperature and thermal consolidation path have an impact on the shear phase transition characteristics. The higher the temperature is, the more the thermal consolidation path is, and the more obvious the dilatancy is. However, the temperature range, consolidation classification and thermal consolidation path generally have little influence on the development of pore water pressure in general.