格栅反包生态袋挡土面层界面特性试验研究

Interface Properties of Geogrid Reversely Packaging Retaining Wall Surface Layer Made by Ecological Bags

通过袋装黏土的袋-袋直剪试验和对两种相同网格尺寸不同强度经编涤纶土工格栅材料反包生态袋(袋装黏土)挡土结构面层进行拉拔试验,研究了不同格栅反包生态袋挡土面层的界面特性。试验结果表明:袋装黏土生态袋界面之间的剪切摩擦强度和加筋格栅反包生态袋的拉拔试验强度均随法向应力的增加而增加,强度包线均是一条直线;加筋格栅反包生态袋的试验强度比袋装黏土生态袋界面之间的剪切摩擦强度要高,反包拉拔试验的平均摩擦系数和黏聚力比袋装黏土生态袋直剪试验大,但是摩擦角大小却相反,而拉拔强度-位移曲线并不一定出现峰值;强格栅反包拉拔试验强度比弱格栅的拉拔试验强度高,无论是黏聚力、摩擦角还是摩擦系数指标均是强格栅试验组比弱格栅试验组大。在工程中,尽量选择强度大的格栅有利于加筋挡土结构面层的稳定。

Through the ecological bag interface direct shear test and the drawing test by choosing two kinds of warp knitted polyester geogrid with the same grid size and different strength reversely package retaining wall surface layer made by ecological bags, the interface properties of different kinds of geogrid reversely packaging retaining wall surface layer made by ecological bags was studied. The test results show that： the shear friction strength between ecological bags bagged with clay and the drawing test strength of geogrid reversely packaging ecological bags both increase with the normal stress increasing, and both of their strength envelopes are straight lines ; the reverse drawing test strength is greater than the shear friction strength ; the average friction coefficient and cohesion of reverse package drawing test are greater than the shear test, but the friction angle is opposite; and the peak value may not appear in drawing strength-displacement curve; the strong geogrid reverse drawing test strength is stronger than the weak geogrid reverse drawing test, and the cohesion, friction angle and the average friction coefficient have the same rules. In the engineering construction, it is recommended to choose high-strength geogrid to stiffen the stability of earth-retaining wall surface.