土工格栅防护下埋地管道的力学性能及变形分析

Mechanical Properties and Deformation Analysis of Buried Pipelines under Geogrid Protection

为研究荷载作用下路基和管道的破坏机理,建立并验证了三向土工格栅加筋路基中埋置地下管道的三维有限元模型。通过考虑土-土工格栅互锁作用对土工格栅加筋土结构的影响,对土工格栅的几何厚度和孔径进行精确建模,以模拟土工格栅层网孔内颗粒互锁的荷载传递机制,并对于三种土工格栅埋置深度、土工格栅层数和不同加载区域对地下管道的影响进行分析。研究结果显示:土工格栅加筋可以有效减小管道和基础沉降量,随着土工格栅埋置深度增加,管道和基础沉降总体呈下降趋势,土工格栅埋置深度与基础宽度的比值为0.3时管道和基础的沉降最小;随着加筋层数的增加,埋地管道和基础的沉降会显著降低,但降低幅度会随着层数的增加而降低;比较荷载垂直管道加载和平行管道加载的情况,管道管周环向最大应变值一致,但管道底部应变显著减小,同时路基内高应力区朝着加载的偏移方向发生移动;土工格栅层的加入有助于加筋路基形成刚性层,重新分配在此层上传递的应力,分散土体应力分布,降低应力集中现象。

To study the failure mechanisms of subgrades and pipelines under load action,a three-dimensional finite element model of a geogrid-reinforced subgrade with underground pipelines was developed and validated.The effect of soil-geogrid interlocking on the geogrid-reinforced soil structure was considered,and the geometric thickness and aperture of the geogrids were accurately modeled.This aimed to simulate the load transfer mechanism of particle interlocking within the geogrid mesh.The effects of three types of geogrid burial depths,geogrid layers,and different loading areas on the underground pipelines was analyzed.The results show that geogrid reinforcement effectively reduces the settlement of pipelines and foundations.As the burial depth of the geogrid increases,the overall settlement of pipelines and foundations shows a decreasing trend,with the minimum settlement occurring when the ratio of the geogrid burial depth to foundation width is 0.3.Increasing the number of reinforcement layers significantly reduces the settlement of buried pipelines and foundations,although the reduction rate decreases with more layers.Comparing cases of load applied vertically and parallel to the pipelines,the maximum circumferential strain around the pipelines remains consistent,but the strain at the bottom of the pipelines significantly decreases.Additionally,the high-stress area within the subgrade moves towards the direction of loading.The inclusion of a geogrid layer helps to form a rigid layer in the reinforced subgrade,redistributing the stress transferred through this layer,dispersing the soil stress distribution,and reducing stress concentration.