1.Department of Civil Engineering,Shanghai University;2.College of Civil Engineering and Architecture, Wenzhou University
The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan)
为研究颗粒形状对粗粒土-格栅界面剪切行为的影响，选择碎石和具有相同粒径分布的玻璃珠作为试验材料，利用动态直剪仪对碎石-格栅和玻璃珠-格栅界面进行了一系列单调直剪试验、循环剪切试验和循环后单调直剪试验，分析了竖向应力分别为30、60和90 kPa下加筋碎石和加筋玻璃珠界面的单调直剪特性；接着，研究了位移幅值分别为1、3、6、9、12和15 mm的循环加载作用下两种加筋界面的循环剪切特性，并对比分析了循环剪切前、后两种加筋界面单调剪切特性的异同点。结果表明：单调直剪试验中，3种竖向应力下碎石-格栅界面的抗剪强度和最大剪胀量均大于玻璃珠-格栅界面的相应值。循环剪切试验中，不同剪切幅值的循环加载作用下碎石-格栅和玻璃珠-格栅界面的循环剪切行为存在差异。循环后单调直剪试验中，碎石-格栅界面循环后的界面抗剪强度较未经受循环加载的界面抗剪强度有所提高，幅值为15 mm的界面除外；而所有幅值下玻璃珠-格栅界面循环后的抗剪强度均发生了退化。
In order to study the effect of particle shape on shear behaviors of interface between coarse-grained soil and geogrid, the gravel and glass beads with the same particle size distribution were selected as test materials, and a series of monotonic direct shear, cyclic shear and post-cyclic direct shear tests were carried out using a dynamic direct shear machine. The monotonic direct shear characteristics of reinforced gravel and reinforced glass beads interface at normal stresses of 30, 60, and 90 kPa were analyzed. Then, the cyclic shear behaviors of two reinforced interfaces under cyclic loading with displacement amplitudes of 1, 3, 6, 9, 12, and 15 mm were discussed, and the similarities and differences of monotonic shear characteristics of two reinforced interfaces before and after cyclic shear were compared and analyzed. In the monotonic shear tests, the shear strength and maximum dilation of gravel-geogrid interface at each normal stress are greater than those of glass beads-geogrid interface. In the cyclic shear tests, the cyclic shear behaviors of gravel-geogrid and glass beads-geogrid interfaces under the effect of cyclic loading with different shear amplitudes are not exactly the same. In the post-cyclic direct shear tests, the interfacial shear strength of gravel-geogrid interface after cycling is greater than that of the interface with no cyclic loading, except for the interface at amplitude of 15 mm, while the corresponding value of glass beads-geogrid interface at all amplitudes is degraded.