单侧道路加宽工程中软弱路基加固范围的研究

Research of Reinforcement Range of Weak Subgrade in One-side Road Widening Project

目前,水泥搅拌桩已经成为道路加宽工程中常用的软基加固方式,但对于单侧道路加宽工程中加固范围的确定缺乏明确的依据。本文以某道路单侧加宽工程为背景,针对典型的软弱路基加宽断面,采用现场取样及室内试验的方法确定了土层参数。然后采用数值分析方法,研究了不同的水平和竖向加固范围对道路加宽工程变形和稳定性的影响,从而确定出合理的加固范围。研究成果表明:在桩底进入最底层土层的前提下,增加桩长对减小竖向位移影响不大;仅在老路坡面线下布桩对减小竖向位移影响不大;增大水平布桩范围对减小竖向位移有显著效果;随着布桩范围向路中心延伸,最大沉降的发生位置由新路中心变为老路肩处等。本文的研究可为同类加宽工程的设计和施工起到参考作用。

At present,cement mixing pile has been a common approach for soft foundation consolidation in road widening project. Unfortunately,how to determine reinforcement range lacks a definite basis. In this paper,according to the typical weak-subgrade widening section,the soil parameter is determined by the methods of field sampling and laboratory tests on the background of one-side road widening project. Through the numerical simulation,under the circumstance of different vertical and horizontal reinforcement range,the deformation features and the stability of the widening road are analyzed. On this basis,reasonable reinforce ment range is given. Research results show that: under the premise of that the pile bottom is in the lowest layer,the increase in pile length has less influence to decrease the vertical displacement; only laying piles under the line of the old road slope also has less influence on the decrease of the vertical displacement; the enlargement in horizontal reinforcement range can reduce evidently the vertical displacement. The position of the maximum settlement will be changed from the center of new embankment to the shoulder of old embankment as the reinforcement range extends to the center of new embankment.The idea and method given in this paper can provide reference for design and construction of similar projects.