基于FLAC3D的路基拓宽差异沉降研究

以延安北过境线路基拓宽项目为研究对象,采用现场监测、室内试验及FLAC3D有限差分法相结合的方法对新旧路基拓宽差异沉降特性进行研究。监测数据表明,由路基土体在外荷载作用下产生的黏滞蠕变只占总沉降的很小一部分。通过室内直剪试验,得出黏聚力值为21 kPa,内摩擦角值为38°;当最大差异沉降量达到最小值时,拓宽侧路基填筑高度为6 m;当新路基的沉降开始增加时,拓宽高度大于6 m;当旧路基高度不变时,新旧路基顶面和最大沉降点向外移动。在工程实际中,新旧路基的拓宽宽度增加对旧路基的影响较小。

Study on Differential Settlement of Subgrade Widening Based on FLAC3D

Taking the subgrade widening project of the highway across northern Yan an as the research object,a method that combined field monitoring,laboratory test and FLAC3D s finite difference method was applied to study the characteristics of differential settlement of the widened subgrade.The monitoring data show that the viscous creep caused by the subgrade soil under external load only accounts for a small part of the total settlement.According to the direct shear test in laboratory,the cohesion value is 21 kPa and the internal friction angle is 38°.When the maximum differential settlement reaches the minimum value,the filling height of the widened subgrade is 6 m.When the settlement of the new subgrade begins to increase,the widened height is greater than 6 m.When the height of the existing subgrade remains unchanged,the top surface and the maximum settlement spot move outward.In practical projects,the increase in the widened width has little impact on existing subgrade.