黄渭高速公路过湿黄土路基变形特性分析

Research on Over-wet Loess Subgrade Deformation Characteristics of Huangwei Highway

过湿黄土具有明显的压缩性和湿陷性,其抗剪强度低,力学性质差,相对于一般黄土,过湿黄土在自重应力和车辆荷载的循环作用下会产生更明显的塑性变形。结合黄渭高速公路过湿黄土特性,采用ABAQUS有限元软件对过湿黄土路基压实度在0.87~0.94、含水率在18%~22%内的应变及位移规律进行研究。结果表明:过湿黄土路基变形集中在路基顶面2m深度范围内,中心线不同深度及路基顶面各位置随着压实度的增加而减少,但当压实度过高时,影响效果逐渐减小;并且随着含水率的增加,路基的沉降变形会显著增大。实际工程在黄土场地填筑路基时,应关注黄土的含水率,并结合地基土性质和场地条件,对过湿黄土地基采取合理的处治加固。

The over-wet loess has obvious compressibility and collapsibility.It is low shear strength and poor mechanical properties,so in the weight stress and vehicle load under the action of the cycle will produce significant plastic deformation.Combined with the characteristics of over-wet loess of Huangwei Highway,we had adopted ABAQUS finite element software to study on the strain and displacement of over-wet loess subgrade(compaction degree in 0.87 ~ 0.94,the moisture content within18% ~ 22%).The results showed that the deformation of the overcritical loess roadbed is concentrated within the depth of 2 meters of the roadbed,and the position of the top of the roadbed decrease with the increase of the degree of compaction.But when the compaction is too high,the effect is gradually reduced.With the increase of water content the settlement deformation of subgrade will increase significantly.So the actual engineering should be combined with the nature of the foundation soil and site conditions,to take a reasonable treatment and reinforcement.