循环荷载特征对筋土界面剪切特性的影响试验

Experiment of Influence of Cyclic Load Characteristics on Shear Properties of Geogrid-soil Interface

采用大型结构面剪切仪进行了循环荷载作用下土工格栅与砂土的直剪试验,研究了法向循环荷载特征对土工格栅与石英砂界面剪切特性的影响。循环荷载的波形取余弦波、三角波、方形波3种,频率分别为0.01、0.05、0.1、0.5 Hz,振幅选择25、50、75、100 kPa四种。分析结果表明:法向循环荷载波形控制了剪应力的变化规律,但对界面的峰值剪应力影响不大;频率和振幅对界面剪应力有显著的影响,峰值剪应力随频率的增大而减小,随振幅的增大而增大;频率和振幅对砂土体积应变的影响明显,随着频率和振幅的增加,石英砂的体积应变由剪胀向剪缩过渡。

Using large-scale interfacial shear apparatus,a series of direct shear tests between geogrid and sand were performed under cyclic load.The influence of normal cyclic load characteristic on shear property of geogrid-quartz sand interface was studied.Cyclic load waveforms were cosine wave,triangle wave,square wave,the frequencies were 0.01,0.05,0.1,0.5 Hz respectively,and amplitudes were 25,50,75,100 kPa in the tests.The test results show that the variational rule of the interface shear stress is controlled by the waveform of normal cyclic load,while the waveform has little influence on the peak shear stress.The interface shear stress is dramatically influenced by frequency and amplitude,the peak shear stress decreases with the increasing of the frequency and increases with increasing of amplitude.The volume strain of sand during the interface shearing progress is obviously affected by frequency and amplitude.The sand volume strain experiences a transition from dilatation to compression with the increase of frequency and amplitude.