关于土工格栅合理网孔尺寸的研究

Study on the reasonable size of geo-grid meshes

土工格栅与土之间的界面参数是表征土工格栅加筋作用的重要参数,对土工格栅加筋土结构的稳定和变形破坏特征有显著影响。目前各类规范或标准关于格栅-土界面参数的取值均未考虑土工格栅特有的网孔结构尺寸的影响,致使实际工程中土工格栅的选用存在较大的人为性。针对这一问题,首先通过室内试验和数值方法的对比分析,建立了土工格栅界面特性研究的数值模型,并验证了数值方法研究土工格栅界面特性的可行性。以土工格栅界面特性研究的数值模型为基础,进一步开展了不同网孔尺寸条件下土工格栅界面特性的研究。研究结果表明,土工格栅网孔结构的网孔尺寸对格栅-土的界面特性有显著影响。通过分析不同网孔尺寸对界面特性影响的规律发现,为了更直观地揭示土工格栅的加筋作用,应该将格栅-土界面的摩擦作用从界面综合的摩擦作用中剥离出来。同时,土工格栅的合理网孔尺寸应保证格栅-土之间的有效接触面积占整个界面面积的1/3左右。

The interracial properties between geo-grid and soil are important for representing the reinforcement of the geo-grid and are of great influences on the stability and the deformation-failure characteristics of gee-grid structures. At present, various specifications and standards fail to consider the influences of mesh sizes on the parameters selection of geo-grid soil interface, leading to artificial selection of geo-gdd in practical engineering. In this paper, the numerical model studies the characters of geo-grid interface through comparative analysis between indoor experiments and numerical methods. The results show that the mesh size of geo-gird has dramatic influences on the characteristics of geo-grid interface. Through analyzing the principles of the influences of different mesh sizes on the interface characters, it shows that the friction effects of geo-gfid interface should be excluded .from the comprehensive friction on the interface to explore the effects of reinforcement more directly. Meanwhile, the reasonable mesh size of geo-grid should ensure that the effective contact between geo-grid and soil should be one-third of the whole interface.