不同土工合成材料与再生混凝土骨料界面动剪切特性研究

Dynamic shear characteristics of interface between different geosynthetics and recycled concrete aggregate

针对研究5种不同土工合成材料与再生混凝土骨料(RCA)之间的界面循环剪切及后直剪特性,在不同法向应力与循环剪切幅值条件下进行了一系列单调直剪(MDS)、循环直剪(CDS)、后循环直剪(PCDS)试验,并综合对比分析了后循环直剪与单调直剪试验结果。试验结果表明,在循环直剪作用下,5种筋-土界面呈现出明显的剪切硬化现象,剪切刚度随循环次数增加而逐渐增大,而界面阻尼比随循环次数增加而减小。在该试验中的3种不同循环剪切位移条件下的加筋界面所引起的收缩量随剪切幅值的增大而显著增加,收缩量的增幅分别为18.6%,22.2%。在后循环直剪试验中,5种加筋界面的应力-位移曲线表现出明显的峰后软化现象,界面似黏聚力与内摩擦角随循环剪切作用而明显增大,后循环直剪试验的峰值、残余似黏聚力和内摩擦角的结果均大于单调直剪试验的相应结果。

Here,to study interfacial cyclic shear and post direct shear characteristics between five different geosynthetics and recycled concrete aggregate(RCA),a series of monotonic direct shear(MDS),cyclic direct shear(CDS)and post cyclic direct shear(PCDS)tests were conducted under different normal stresses and cyclic shear amplitudes.PCDS and MDS test results were comprehensively and contrastively analyzed.The test results showed that under the action of cyclic direct shear,the 5 reinforcement-soil interfaces reveal obvious shear hardening phenomenon,interface shear stiffness increases gradually with increase in number of cycles,and interface damping ratio decreases with increase in number of cycles;in tests,the shrinkage caused by the reinforced interface under 3 different cyclic shear displacement conditions increases significantly with increase in shear amplitude,and the increase of shrinkage is 18.6%and 22.2%,respectively;in PCDS tests,the stress-displacement curves of the 5 reinforced interfaces reveal obvious post peak softening phenomenon,and the interface quasi-cohesion and internal friction angle increase obviously with cyclic shear action;the results of peak value,residual quasi-cohesion and internal friction angle of PCDS tests are larger than those of MDS tests.