含水率对土工格栅与膨胀土界面拉拔性状的影响

含水率对土工格栅加筋膨胀土结构的运行具有直接影响,而国内外对其作用机制少有研究。为此,采用填土尺寸为600mm×600mm×600mm的大型叠环式剪切仪进行一系列拉拔试验,研究了含水率对土工格栅与膨胀土界面拉拔性状的影响。试验结果表明,含水率对拉拔力与土工格栅位移特征、界面应力变形特征、界面强度参数等具有显著影响。含水率较高,土工格栅发生刚体平动的时间较早,刚体平动时的单宽拉拔力更接近峰值,界面更偏于理想刚塑性特征;含水率较低,界面似黏聚力较大;而含水率对界面似摩擦角的影响不显著。

Effect of water content on pull-out behavior of interface between geogrid and compacted expansive soil

The mechanical characters of expansive soil structure reinforced with geogrids are directly affected by the water content, whereas the mechanism is rarely studied before. So, the filling with dimension of 600 mm×600 mm×600 mm laminated shear test apparatus is adopted to carry out a series of pull-out tests to investigate the effect of water content on pull-out behavior of the interface between geogrid and compacted expansive soil. The results show that the water content has a notable effect on the pull-out force and geogrid’s displacement, the characteristics of the interface stress and strain, and the strength parameters of the interface. When the water content is higher, the rigid motion of geogrid occurs earlier, and the pull-out force per width when rigid motion more approaches the peak value; and relation of friction and relative displacement of the interface tends to be more ideal rigid-plastic. The interface quasi-cohesion increases with decrease of water content, whereas water content has little effect on the quasi-friction angle of the interface.