复合土工膜砂砾料界面摩擦特性研究

复合土工膜与粗粒砂砾料垫层的界面摩擦特性对工程结构稳定性十分重要。现有的试验研究多集中在粒径较小的土料与土工织物接触, 对于由粒径较大的砂砾料与土工膜界面特性的研究较少。利用大型土工合成材料直剪仪开展了砂砾料与土工膜界面直剪摩擦试验研究, 讨论了砂砾料级配以及相对密度对界面摩擦特性的影响。试验结果表明:相对密度一定时, 粗颗粒含量越大, 摩擦因子越大;相同级配条件下, 相对密度越高, 摩擦因子越大。最后探讨了土工膜与剪切下盒基座间的固定方式对界面摩擦参数的影响, 求得不同的固定方式导致界面摩擦角相差可达1倍以上。

Friction Characteristic of the Interface Between Composite Geomembrane and Coarse Sand-Gravel

The friction characteristic of the interface between composite geomembrane and coarse sand-gravel is of great importance to the structural stability. Most of the present experimental studies focus on the contact between soil of finer particles and geotextile, but research on the characteristics of interface between gravel of coarse soil particles and geomembrane is rarely seen. In this paper, direct shear friction tests were conducted for the interface by using large-scale direct shear apparatus. The influence of gradation and relative density on the friction characteristics are discussed. Results show that in the presence of equal relative density, the friction factor increases with the increase of coarse particle content, and in the presence of equal gradation, the friction factor increases with the increase of relative density. Furthermore, the influence of the fixation pattern between geomembrane and the lower base of shear box are analyzed. Test results reveal that the discrepancy of interface friction angle in different fixation patterns could be as great as 2 times.