土工合成材料加筋粘性土的三轴试验研究

TRIAXIAL SHEAR TESTS ON CLAYEY SOIL REINFORCE WITH GEOSYNTHETICS

采用固结排水三轴剪切试验,研究土工合成材料加筋对粘性土体的体变、强度以及应力应变特性的影响。结果表明,加筋可以明显抑制土体的剪胀体变,但对土体的剪缩体变影响不大,加筋有利于增强高压实度土体的体积稳定性;轴向应变较低时,加筋试件的强度低于素土试件,仅当轴向应变增大到一定程度后,加筋试件的强度才逐渐高于素土试件,加筋对土体强度的增强作用存在滞后现象,且随筋材拉伸模量和加筋层数的提高,滞后现象更明显。试验结果同时表明筋材拉伸模量较低时,增加加筋层数,虽然可以一定程度提高土体的峰值强度,但对峰值后的强度提高不明显;相比而言,采用较高拉伸模量的筋材,加筋对土体残余强度的提高幅度明显高于峰值强度,对土体应力应变特性的改变也相对较大。

The consolidated-drained triaxial tests were carried out on clayey soil reinforced with geosynthetics to investigate the influences of reinforcement on the performances of the volume strain, the strength and the stress-strain characteristics in the paper. Results showed that reinforcement had restrained remarkablely the volume swell of soil with high compactness, but influenced on the volume shrinkage insignificantly. At lower axial strain levels, the strengths of reinforced soil were even smaller than that of the unreinforced. Only when increasing the axial strain, the strengths of reinforced soil exceeded gradually, the reinforcement contributions to the strength is delayed. Results also showed that when the reinforcement modulus was too low, although the increasing layers might increase a little the peak strength of soil, the post-peak strength was improved insignificantly. By comparision, the increasing modulus enhanced the residual strengths more significantly than the peak strengths of soil, and the stress-strain behaviors of clayey soil were improved remarkablely.