粘土与筋带直剪试验与拉拔试验对比分析

在土工合成材料加筋土工程中,土工合成材料与填土的界面作用特性直接决定加筋土工程的内部稳定性,所以土工合成材料与填料的界面作用特性指标是最关键的技术指标。对两种加筋材料与高液限粘土之间分别进行了直剪试验和拉拔试验,通过分析可得筋土之间的剪应力随着垂直压力的增大而增加,但随着垂直压力的增大筋土之间剪应力增长率减小,即随着垂直压力的增加,筋土之间的剪应力收敛于某一上限值;由于加筋材料在试样制作过程中不可避免地在土中发生凹凸变形使土体对筋带产生一定的锚固作用,拉拔试验所测得的似摩擦系数及似粘聚力均大于直剪试验所测得的似摩擦系数及似粘聚力。因此,实际加筋土工程中,拉拔试验更能较好地反映其真实的工作状态。

Research on direct shear test and pullout test between clay and geotextile

In geopolymer reinforced soil structure, the behavior between the soil and geopolymer is very important to inner stabilization of reinforced soil structure, so the index between the soil and geopolymer is a crucial index. In this paper, systematic directtests and pullout tests were carried out between high liquid limit clay and two kinds of geopolymers. Based on the test result, stress-strain relationship is studied. Some useful conclusions and opinions which can be used to supervise the research and design are also presented. That is, the shear stress between the clay and the geopolymer increases with the normal stress increase, but the increase is not unlimited, and the increase ratio of shear stress will decreases. So the high-point of shear stress exists between clay and geopolymer. Due to sample preparation for pullout test, the scraggy interface between clay and geopolymer will generate anchor effect which leads to the friction coefficient and cohesion gained from pullout test more larger than that gained from direct shear test. But in practical engineering, the pullout test can better reflect the truth.