应变速率对天津海积软土力学性能的影响

Effect of Strain Rate on the Mechanical Properties of Marine Soft Soil in Tianjin

采用WF应力路径三轴仪,对天津滨海海积软土进行了不同围压、不同应变速率的三轴固结不排水剪切试验(CU),分析了不同应变速率对海积软土试样的应力-应变关系、有效应力及试样破坏形态的影响.结果表明:CU试验应力-应变关系呈硬化特征,剪应力峰值随着应变速率的增大而增大,而孔压变化值则随着应变速率的增大而逐渐减小;不同应变速率的有效应力路径在相同固结压力下基本一致,因而正常固结黏土的有效应力路径具有唯一性;同时,应变速率对总应力强度有所影响,总应力的内摩擦角随着应变速率的增大而增大.

Consolidation undrained triaxial shear test of marine soft soil of Tianjin Binhai test specimen under different confining pressure and different strain rate was conducted by using WF stress path triaxial instrument. And the influence on marine soft soil＇s stress-strain relationship, effective stress and fracture morphology was analyzed based on different strain rates. The results showed that the CU experiment＇s stress-strain relationship had hardening characteristics and that the peak shear stress increased with the increase of strain rate while pore water press decreased. Under the same consolidation pres- sure, strain rate had little effect on effective stress path. Therefore the effective stress path of normal consolidated clay was unique. The strain rate influenced the total stress strength whose internal frictional angle increased with the increase of strain rate.