改扩建工程纵坡抬高段路基拼宽方式与变形分析

以惠盐高速深圳段改扩建工程为例，分析了主线纵坡抬高段路基的改扩建难点，提出了采用半幅先抬高、半幅保通的拼宽方式。通过对4种抬高方案的适用性论证，提出在中分带设置挡土墙支护半幅先抬高路基。结合三维有限差分程序分析了分幅抬高工况下路基的变形特性。结果表明:在先抬高道路的荷载作用下，保通一侧道路发生沉降，沉降量呈抛物线形变化，使路拱原有的横向坡度减小；在后抬高道路的荷载作用下，先抬高部分道路发生了二次沉降，沉降量呈抛物线形变化。

Study on Widening and Deformation of Longitudinal Slope Heightened Subgrade in Reconstruction and Extension Project

Taking the reconstruction and extension project of Huizhou-Yantian highway (Shenzhen section) as an example, the difficulties in the reconstruction and extension of longitudinal slope heightened subgrade of the main line are analyzed. The reconstruction mode of heighten widening road were proposed as one half of the road could be first heightened and another half of the road as passing passage. By analyzing the applicability of the four heightening schemes, it is proposed to set up retaining wall at middle strip to support the first heightened half of road. The deformation characteristics of subgrade under such working condition are analyzed with a three-dimensional finite difference program. The results show that under the loading action of the first heightened half of road, the settlement occurred on another half of road, making the original transverse slope decrease, and the settlement takes a parabolic shape. Under the action of the post heightened half of road, the secondary settlement occurred on the first heightened half of road and the settlement also takes a parabolic shape.