错缝堆叠土工袋层间界面的循环剪切特性试验研究

Experiments on the cyclic shear behavior of the interface between staggered stacking soilbags

土工袋层间界面的循环剪切特性对其结构动力稳定性有着重要影响。为了研究错缝堆叠土工袋层间界面的循环剪切特性及循环剪切作用对其层间剪切强度的影响,采用大型室内循环剪切试验仪,对错缝堆叠土工袋进行一系列单调直剪试验和循环剪切试验。探究循环剪切次数、竖向应力、剪切位移幅值等因素对错缝堆叠土工袋层间动力变形特性及抗剪强度的影响。结果表明:土工袋层间界面的剪切破坏规律在循环剪切前后均基本符合莫尔-库仑破坏准则,并且在经过循环剪切作用后其层间抗剪强度有所增强;在低压应力范围内,错缝堆叠土工袋层间界面阻尼比随剪切位移幅值的增大而增大,而与循环次数和竖向应力基本无关;错缝堆叠土工袋层间可以形成良好的嵌固作用,使得其在循环剪切过程中表现出与层叠橡胶支座相类似的可恢复性。

The cyclic shear behavior of the interface between soilbags has an important influence on the dynamic stability of soilbags-built structures. In order to study the cyclic shear behavior of the staggered stacking soilbags and the effect of cyclic shear on the interlayer shear strength of the soilbags,a series of large-scale direct shear tests and cyclic shear tests were conducted on the staggered stacking soilbags. The focus is on the effects of the number of cyclic shears,vertical stress,and amplitude of shear displacement during the cyclic shearing process on the dynamic deformation characteristics and shear strength of the staggered stacking soilbags. The results show that the shear failure of the staggered stacking soilbags’ interface before and after the cyclic shear follows the Mohr-Coulomb failure criterion. The shear strength of the staggered stacking soilbags′ interface increases after cyclic shear. In the low stress range,the damping ratio of the staggered stacking soilbags′ interface increase with the shear displacement amplitude,and is basically independent of the number of cycles and the vertical stress. Due to the internal embedding effect of the staggered stacking soilbags,the soilbags exhibit recoverability similar to that of laminated rubber bearings during cyclic shearing.