土工织物-砂土界面的叠环式剪切试验

针对土工合成材料界面特性试验易受试验装置影响的特点，采用大型叠环式剪切仪进行土工织物与砂土的界面剪切试验。对比砂土本身、土工织物与砂土的两种剪切试验结果发现，土工织物-砂土剪切引起的叠环位移较小；叠环的水平位移变化规律与土体的剪胀性具有密切联系，土工织物限制了下剪切盒内土颗粒的运动，对达到峰值强度时的土体剪胀也具有抑制作用。由试验结果可知，筋-土界面的剪切带远小于剪切的影响范围，土工织物在界面剪切中的作用不能仅通过剪切带反映，还应考虑土工织物的屏蔽作用和对于土体剪切带形成的影响。

Laminated shear test of geotextile-sand interface

Considering that the measured interface properties between soils and geosynthetics are prone to being influenced by experimental apparatus, authors applied large-scale laminated shear apparatus to conduct the shear tests on interface between geotextile and sand instead of common direct shear apparatus. The comparative analysis of the results from laminated shear tests shows that the displacements of laminated rings of sand with geotextile are smaller than those in shear tests of sand. The horizontal displacement of each ring is closely related to the dilatancy of sand. The geotextile limits the movement of soil particles in lower shear box and reduces the dilatancy ratio of sand at the peak interface shear strength. It can be inferred from the experimental results that the shear band caused by the interface shear between geotextile and soil is much narrower than its influencing range. The effect of geotextile in the interface shear test cannot be reflected only by the size of shear band, but also by the shielding function of geotextile from shear and its influence on the development of shear band in soil.