塑料土工格栅加筋土抗拉拔特性试验研究

Experimental Study on Interface Friction of Plastic Geogrid Reinforced Earth

塑料土工格栅的加筋效果好于其它筋材的原因在于其表面结构特性,它与土之间不仅存在表面摩擦力,而且还存在着镶嵌咬合力,从而增强两者的相互联系,提高接触效率。通过筋材拉出行为试验,进行塑料土工格栅受拉时表面摩擦力分布特征的研究。提出将塑料土工格栅与土体之间摩擦应力的发展过程分为四个阶段的观点,即起始阶段、发展阶段、局部屈服和完全屈服阶段。指出在高围压或长埋深的情况下,筋材会出现拉断破坏,这时的摩擦应力至多经历前三个阶段,而不具备完整的四阶段应力发展模式。

Plastic geogrid reinforcement is more effective than others because of its geometry character. Besides friction force, there exists enchasing force that enhances the interaction and the contacting efficiency between soil and geogrid reinforcements. Through geogrid pull-out experiments, study of friction stress distribution is carried out, and a four-stage mode of the development of friction stress is presented-starting stage, developing stage, partial yielding stage and complete yielding stage. It is found that when the surrounding pressure is high or it is embedded for a great depth, the reinforcements will be subject to tensile failure. The friction stress has just passed the first three stages at most and has not completed the whole development mode of the complete four stages.