含软弱面膨胀土三轴试验结果的校正问题

Calibration Triaxial Test of Expansive Soil with Weak Plane

针对现行规程对三轴试验数据的处理方法适用于普通试样,而未考虑试样中部含有软弱面的情况,通过3组含30°、45°、60°不同倾角软弱面的膨胀土三轴试验,得到软弱面上、下盘沿轴向错动位移与试样轴向变形的关系,进而对三轴试验结果进行校正。研究表明:软弱面上、下盘沿轴向错动位移与试样轴向变形的比值不随围压而改变,但随软弱面倾角的增大而增大;校正后,(σ1-σ3)f的增加随软弱面倾角的增大而增大,c、φ值也有不同程度的增加,且c值的增加幅度比φ值大。

The method of processing the triaxial test data by current rules is applied in ordinary sample,without weak plane.Different triaxial compression tests of expansive soil with weak plane are done in different angles of 30°,45°,60° to obtain the relationship between the axial dip offset of the hanging and lower walls and the axial displacement of the remolded samples,and the axial compression test result of expansive soil with weak plane.The results reveal that there is no ratio change between the axial dip offset of the hanging and lower walls of weak plane and the axial displacement of the remolded samples with the change of confined pressures.But there are increases with the increasing of weak plane angle.After the calibration,the amplitude of the（σ1 σ3） f increases with the increasing of weak surfaces angle,meanwhile both the cohesive strength c and the friction angle φ increase.The amplitude of the former is bigger than that of the latter.