摘要
软土地基在公路工程中难以避免,填方路堤穿越软土地基时应采取适当的地基处理措施。深层软土地基处置难度大风险高,现有技术多采用复合地基进行加固。有限元计算将连续结构体离散化,通过对每个离散的单元的计算进而得到连续整体的结果,相对于规范法在复合地基计算中具有更大的优势。以贵州某高速公路深层软土路堤为研究对象,通过外业调查、钻探及试验确定了研究区软弱土的分布情况和物理力学性质,选择典型路基横断面建立15节点高精度三角形网格模型,分别计算软土地基在有无水泥搅拌桩复合地基处理的工况下,路堤填筑施工的稳定性及地基沉降变形,同时分析了路堤施工对附近的高压电塔的环境影响。结果表明:路堤填筑过程,路堤范围内以固结沉降变形为主,两侧主要发生挤出隆起现象;随着填筑高度增加,稳定性系数非线性降低,沉降及水平位移非线性增大。采用水泥搅拌桩复合地基处理后,路堤稳定性从0.775上升至1.9,地基沉降控制在0.244m,电塔基础水平位移由1.554m减少至0.037m。计算结果说明水泥搅拌桩复合地基可有效的解决本项目深层软弱土问题,对下一步指导生产具有积极意义。
Soft soil foundation is common in highway engineering.Appropriate foundation treatment measures should be taken when filling embankment crosses soft soil foundation.The disposal of deep soft soil foundation is difficult and high risk.The existing technology adopts composite foundation for reinforcement.The finite element numerical calculation discretizes the continuous structure,and obtains the continuous overall results through the calculation of each discrete element.Compared with the code method,the finite element method has greater advantages in the calculation of composite foundation.The deep soft soil embankment of an expressway in Guizhou is taken as the research object.The distribution and physical and mechanical properties of soft soil are determined through investigation,drilling and test.The typical cross section is selected to establish a 15 node high-precision triangular mesh model to calculate the stability of embankment and foundation settlement of soft soil foundation with or without cement mixing pile composite foundation treatment.At the same time,the environmental impact of construction on nearby high-voltage power tower is analyzed.The results show that consolidation settlement deformation is the main deformation within the embankment during construction,and extrusion uplift mainly occurs on both sides.With the increase of filling height,the stability coefficient decreases nonlinearly,and the settlement and displacement increase nonlinearly.Using cement mixing pile composite foundation treatment,the embankment stability increases from 0.775 to 1.9,the foundation settlement is controlled at 0.244m,and the horizontal displacement of tower foundation is reduced from 1.554m to 0.037m.The calculation results show that the cement mixing pile composite foundation can effectively solve the deep soft soil problem,which is of positive significance to guide the production in the next step.
作者
杨永刚
YANG Yonggang(China Railway SIYUAN Survey and Design Group Co.,Ltd,Wuhan 430063)
出处
《铁道勘测与设计》
2022年第1期98-102,共5页
Railway Survey and Design
关键词
路堤
软土
有限元
沉降
稳定性系数
Embankment
Soft soil
Finite element method
Settlement
Stability coefficient
