软岩填筑路基在外部因素影响下沉降变形作用机理分析

Analysis of the Mechanism of Settlement Deformation of Soft Rock Filling Subgrade under the Influence of External Factors

在修建穿山掘岭的高速公路过程中,遇到大量软岩路基,因此,对软岩路基的研究尤为重要。本文通过Plaxis软件,建立数值模型,分析不同施工进度和不同上部荷载作用下的路基沉降变形,结果表明:随着填土高度的增加,沉降变形由线性增加逐渐转为非线性增加,顶部土体在重力作用下向下挤压,路堤底部出现拉应力;随着荷载增大,最终沉降值出现均匀增大,但当外载荷达到土体极限承载能力时,沉降幅度会突然增大。在实际工程中,应减小每层填筑高度,且控制上部荷载小于填料承载能力。

many subgrades of highways through mountain areas are filled with soft rock.Therefore,the research on soft rock subgrades is particularly important.In this paper,a numerical model is established by Plaxis software to analyze the settlement deformation of subgrade under different construction schedules and different upper loads.The results show that with the increase of filling height,the settlement deformation gradually changes from linear increase to nonlinear increase.The top soil is squeezed downward under the action of gravity,and tensile stress appear at the bottom of the embankment.As the load increases,the final settlement value increases uniformly,but when the external load reaches the ultimate bearing capacity of the soil,the settlement amplitude will suddenly increase.In practical engineering,the filling height of each layer should be reduced,and the upper load should be controlled within the bearing capacity of the filling material.