不同角度土工格栅加筋剪切特性的试验研究

Study on Shear Strength Characteristics of Geogrid Reinforcement with Different Angles Based on Direct Shear Test

研究土工合成材料与砂土之间的界面剪切特性的试验通常将土工合成材料水平放置在上下盒之间,但是在加筋体结构中,加筋土的潜在破坏面常常与加筋材料呈一定角度,因此探究加筋材料与剪切面成一定角度时的剪切界面特性有着十分重要的意义。为了探究土工格栅加筋角度对抗剪强度的影响,采用HM-5780大型直剪仪开展了一系列的土工格栅多角度加筋的直剪试验,对比了不加筋状态下的剪切特性,并结合了剪后土工格栅变形特点进行分析。试验表明,在60°加筋时,抗剪强度最大,筋材在剪切过程中主要呈受拉状态,120°和150°加筋时反而削弱了土体的抗剪强度,筋材主要呈受压状态。筋材布置角度越接近剪切过程中最大拉伸应变的方向,则其抗剪强度增加得越多。

The tests for studying the shear characteristics of the interface between geosynthetics and sand are mostly focused on situations where geogrid is put horizontally on the shear plane.However,when it comes to reinforced soil structure,the potential damage plane will usually form an angle with the reinforcing materials.Therefore,it is of great significance to conduct a study on shear characteristics of interface between geogrids and sand in cases where the geogrid and shear plane form an angle.In order to study the effect of reinforcement angle on shear behavior,multi-angle reinforcement direct shear tests are carried out using the HM-5780 large-scale direct shear machine.Comparison is made between the stress of sand with multi-angle reinforcement direct shear test,and the deformation characteristics of the geogrid after shearing is analyzed.The results show that,compared to non-reinforced specimen,the 60-degree-reinforeced specimen have greatest shear strength and the geogrid are mainly in tension,while the 120-degree and 150-degree weaken the shear strength and the geogrid are mainly in compression.The closer setting angle of geogrid is to the direction of maximum extensional strain during shearing process,the stronger of shear strength of soil structure will be.