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现有关于格栅与土的筋-土界面特性研究多以单、双向格栅为研究对象,而对三向土工格栅筋-土界面特性开展的试验研究较少。以三向土工格栅为研究对象并考虑0°和90°两种拉拔方向的影响(记为TX_0工况和TX_90工况),开展了一系列室内拉拔试验,通过对三向土工格栅沿拉拔方向4个断面的位移进行量测,分析了格栅拉伸应变、筋-土相对位移、界面摩阻力分布及格栅变形与破坏模式,并分别从峰值剪切强度和残余剪切强度两个方面对筋-土界面强度参数和表观摩擦系数的变化规律进行了探讨。研究结果表明:由于平面外挠曲变形的影响,TX_0工况下横肋的嵌锁作用随法向应力增大而增强,从而使TX_0工况的拉拔性能逐渐优于TX_90工况;拉拔过程中,筋-土界面摩阻力的发挥是一个渐进的过程,其分布形式不断发生调整,筋-土界面呈弹塑性-软化特征;TX_0工况的筋-土界面摩擦角显著大于TX_90工况,黏聚力则刚好相反,法向应力较高时TX_0工况的筋-土界面强度更高,更有利于材料性能的发挥。
The existing research on the characteristics of tendon-soil interface between grille and soil mostly focuses on single and bidirectional grids, but few studies on the characteristics of the three-direction geogrid tendons and soil interface. Taking a three-direction geogrid as the research object and considering the effects of 0 ° and 90 ° drawing directions (denoted as TX_0 and TX_90 conditions), a series of indoor pull-out tests were carried out. The displacements of the four sections along the drawing direction of the grid were measured, and the tensile strain of the grid, the relative displacement of the tendons and the soil, the distribution of frictional resistance of the grid and the modes of deformation and failure of the grid were analyzed. From the peak shear strength and the residual shear Shear strength of the two aspects of the tendons - soil interface strength parameters and apparent friction coefficient of the law were discussed. The results show that the latching effect of transverse ribs under TX_0 condition increases with the increase of normal stress due to the out-of-plane flexural deformation, so that the drawing performance of TX_0 condition is gradually better than that of TX_90 condition. During the process, the frictional resistance of tendon-soil interface is a gradual process, its distribution forms are continuously adjusted, and the elasto-plasticity-softening characteristics of tendon-soil interface is exhibited. The friction angle of the tendon-soil interface in TX_0 condition is significantly greater than that of TX_90 , Cohesion is just the opposite, higher normal stress TX_0 conditions tendons - soil interface strength is higher, more conducive to the performance of materials.