砂土颗粒级配对筋土界面抗剪特性的影响

为了研究砂土与土工合成材料相互作用时筋土界面的抗剪强度以及剪胀特性，采用3种不同级配的砂土分别与土工格栅和土工织物进行室内大型直剪试验，研究不同颗粒级配、密实度、筋材种类以及竖向应力对界面剪切特性的影响，并对界面剪胀系数进行分析。试验结果表明：粗砂和细砂与筋材的界面剪切强度要明显大于粗细混合砂；松砂剪切过程中只有剪缩效应的存在，但密实砂土呈现出明显的剪胀过程；当竖向应力较大时，筋土界面达到峰值剪切强度所需的剪切位移比低应力时大；粗砂与土工格栅作用时达到峰值剪切强度所需的剪切位移比与土工织物作用时大，而细砂则相反。

INFLUENCE OF PARTICLE-SIZE GRADATION ON SHEAR BEHAVIOR OF GEOSYNTHETICS AND SAND INTERFACE

A series of large scale direct shear tests，involved three different particle-size gradations of sands with geogrids and geotextiles，were performed to investigate the interface shear strength and dilatancy of soil against geosynthetics. The effect of particle-size gradation，dense degree，types of geosynthetics and vertical stress on interface shear strength and dilatancy coefficient were investigated. The test results show that coarse sand and fine sand/geosynthetics interface have significantly higher shear strength than their mixed sand. Loose sand-geosynthetics interface displays only shear contraction during the shear process；while dense sand-geosynthetics interface presents obvious dilatancy. At the high stress level，sand-geosynthetics interface has larger shear displacement when it reaches peak shear strength than that of low stress. Coarse sand-geogrids interface has larger shear displacement when reaching peak strength than that of coarse sand-geotextile；while fine sand-geosynthetics interface shows the opposite results.