基于不同路堤加筋形式的土拱效应离散元

基于室内Trapdoor模型试验，采用MatDEM离散元软件将双向土工格栅二维化，从土拱率、位移、力链和加筋体受力的角度对不同加筋形式下土体内土拱效应和拉膜效应作用进行了宏微观分析。结果表明:设置加筋可以有效提升土体内的荷载转移效率，减少土体表面的差异沉降，且土工布比土工格栅更能保持土体内部土拱结构的稳定；采用土工格栅加筋时，拱脚处为受力薄弱点，易发生土体垮塌，对土拱结构的稳定性造成影响；随着活动门的下移，加筋层以上土体内形成半圆形的土拱结构，土拱效应和拉膜效应共同工作。为衡量拉膜效应对荷载转移的贡献情况，定义了拉膜效应贡献率，最终状态时土工格栅和土工布的拉膜效应贡献率分别为40.78%和30.32%,说明加筋情况下土拱效应在荷载转移中发挥主要作用，加筋体为土工格栅时，拉膜效应转移的荷载占比更大。

Discrete element study of soil arching effect based on different reinforcing types on piled embankment

Based on the Trapdoor model test, two dimensionalization of the biaxial geogrid by MatDEM discrete element software was used to conduct a macro-microscopic analysis of the piled embankment. In the paper, the soil arching effect and the tension membrane effect generated in the soil under different reinforcing types are invsetigated from the perspectives of soil arching ratio, displacement, force chain and geogrid force. The results show that the reinforcement can effectively improve the load transfer efficiency of the soil and reduce the differential settlement at the soil surface. More observed is that the geotextile can maintain the stability of the soil arch structure better than the geogrid. When the geogrid reinforcement is used, the foot of the arching is the weak point of force, which is prone to soil collapse and affects the stability of the soil arch structure; as the trapdoor moves down, a semi-circular soil arching is formed in the soil above the reinforcement layer, in which the soil arching effect and the tension membrane effect work together. The contribution of tension membrane effect is also defined to quantiatively assess its effect on the load transfer. The contribution of the tension membrane effect of the geogrid and geotextile in the final state is found to be 40.78% and 30.32%, respectively. The results indicated that the soil arching effect plays a major role in the load transfer, and the load transferred by the geogrid is greater than that of the geotextile.