土工格栅与土的界面摩擦特性试验研究

Testing study on soil interface characteristics of geosynthetics

土工格栅是一种新型的加筋材料,目前有关土工格栅机理的研究较少,处于理论落后于工程实际的状态。通过直剪摩擦试验和拉拔摩擦试验对土工格栅(包括塑料格栅和经编格栅)与粗粒土(砂砾、砂和残积土)之间的界面摩擦特性进行了研究,同时还采用有纺土工布进行了对比试验。试验结果表明,与早期普遍采用的有纺土工布加筋材料相比,无论是强度、延伸率、界面摩擦系数,土工格栅都具有明显的优点,尤以土工格栅配合碎石类填料的效果最好,它可以产生摩擦、咬合、嵌锁等综合作用。

Geogrid is one of the new materials for reinforcing soils. However, the reinforcement mechanism of geogrid is not very clear and lack of testing study up to now. It means that the theoretical work is far backward to the engineering practice. The interface characteristics between geosynthetic and soil are studied with direct shear friction test and pull?out friction test. Two kinds of geogrids (plastic geogrid and warp?knitting geogrid) are used as the reinforcing materials to strengthen the granular soils (sand, gravel and residual soil). Meanwhile, for comparison purpose, another kind of material—woven geotextile, which is early used in engineering, is also selected to reinforce those granular soils. The test results show that the geogrid is much better than woven geotextile in aspects of shear strength, elongation ratio, and interface friction coefficient, especially for the composition of geogrid and granular soil owing to the synthetic action of friction, interlock and built?in effects between them. Finally, comparing with direct shear test, the pull?out test seems to be a better way to reflect the comprehensive effect above mentioned.