土工格室在处治路基不均匀沉降中的应用研究

Application study of treating differential settlement of subgrade with geocell

结合广州北二环高速公路路基不均匀沉降处治工程,应用MARC软件,采用基于直接约束的接触迭代算法和COULOMB摩擦模型模拟半填半挖路基挖方段和填方段的非线性接触,对土工格室处治方法进行了数值仿真;并通过土工格室复合体的承载板试验及实体工程的现场沉降观测,对该处治方法的作用机理进行了研究。结果表明:土工格室复合体具有较大的弯拉刚度与抗剪强度,此复合体能够部分隔离应力和位移的传递,从而柔性过渡和协调了半填半挖路基顶面的沉降;它对局部荷载具有网兜效应,使荷载的分布更为均匀;土工格室的加筋作用减小了土中的竖向应力和剪应力,增强了路基的稳定性,从而达到消除路基不均匀沉降的目的。实体工程表明:土工格室是一种有效解决路基不均匀沉降的方法。

Based on the treated engineering against the differential settlement of subgrade at the northern second-loop freeway in Guangzhou,with the help of the MARC program,authors use the contact iterative computing method based on the direct restriction and COULOMB friction model for simulating the nonlinear contact between cutting and filling of part-cut-part-fill subgrade.Numerical simulation is done for the method treated by geocell.Through the laboratory bearing plate test against the geocell composite body and the field settlement observation,the mechanism of action is researched for the treating method.The result shows that the geocell composite body has the property of flexural tensile stiffness and shearing strength and it can separate partially the transfer of stress and displacement,so the settlement of subgrade top surface is transited and coordinated.Through tuck net effect,the load is distributed uniformly. Because of the reinforced action of geocell,the vertical stress and shearing strength is decreased and the subgrade stability is increased.As a result,the differential settlement of subgrade is eliminated.The solid engineering is proved that it is effective for treating the differential settlement of subgrade with geocell.