带加强肋单向土工格栅的拉拔试验

Pull-out test of uniaxial geogrid with strengthening ribs

在水平-垂直加筋体系研究的基础上,对单向土工格栅设置了加强肋,使其具备立体加筋效果。通过大量的拉拔试验,研究了带加强肋土工格栅加筋的筋-土界面特性。通过对汇总得到的36组拉拔试验数据进行分析,探讨了肋间距与肋厚对极限拉拔阻力的影响情况。试验结果表明:在相同法向应力作用下,带加强肋土工格栅的极限拉拔阻力明显高于普通土工格栅,其极限拉拔阻力随着加强肋肋厚的增加而显著增加,并随着加强肋肋距的增加而逐渐减小。在试验基础上,进一步分析了带加强肋土工格栅与砂土的相互作用机制,探讨了极限拉拔阻力的影响因素,建立了拉拔阻力理论公式,并将试验结果与理论值比较,二者基本吻合。

A new reinforced materials as to strengthen the rib of conventional geogrid is proposed on the basis of horizontal-vertical reinforced soil, which has the effect of three-dimensional reinforcement. A series of pull-out tests of geogrid with strengthening ribs are performed to investigate the interface behavior between sand and strengthening rib geogrid inclusions in terms of different forms of reinforcements. 36 groups of pull-out test data are received by a large number of tests. The impacts of tooth height and tooth spacing of reinforcement on ultimate pull-out resistance are discussed. Test results show that the ultimate pull-out force of strengthening rib geogrid significantly larger than ordinary ones in the same normal stress. Ultimate pull-out resistance increased as the increase of the height of strengthening rib; while it decreased when increased the rib spacing under the same degree of rib height. From the test results, the coefficient of apparent pull-out friction is evaluated. The interaction mechanism between soil and geogrid with strengthening ribs is fi,u＇ther analyzed. The influencing factors of ultimate pull-out resistance are discussed; and a new theoretical formula is proposed to determine the pull-out resistance. The comparison between theoretical values and experimental results is in good agreement.