软土初始损伤门槛值的真三轴试验研究

Study on initial damage threshold of soft soil by true triaxial tests

对上海淤泥质软土进行真三轴试验 ,用损伤观点研究土在三维应力状态下的特性 ,认为软土的受力过程就是受损伤的过程。试验表明 ,中主应力及固结压力对上海软土的初始损伤点的出现有影响。初始损伤应力门槛值随中主应力比和固结压力的增大而增大 ,初始损伤应变门槛值随固结压力的增大而增大 ,但随中主应力比的增大而减小。最后 ,提出了确定土在三维应力状态下的初始损伤门槛值的经验方法。

The consolidated undrained true triaxial shear test for soft soil is carried out and the characteristics of this soil under 3 D stress state are investigated.It is revealed that consolidation pressure and the intermediate principal stress remarkably affect the damage threshold of the soil.Damage threshold of deviator stress increases with the increases in consolidation pressure and principal stress.Damage threshold of strain increases with the increase in consolidation pressure,but decreases with the increase in intermediate principal stress.An empirical method for determining the initial damage threshold of soil under 3 D stress state is proposed.