斜坡软土地基拼接式道路拓宽变形控制措施分析  

Numerical Analysis of Deformation-Controlling Measures for Spliced Widening Embankment on Slope Weak Ground

作　　者：李肖华 肖卓琦 史金录 陈志军 王立勇 蒋良潍[2] LI Xiao-hua;XIAO Zhuo-qi;SHI Jin-lu;CHEN Zhi-jun;WANG Li-yong;JIANG Liang-wei(CITIC Construction Co.Ltd.,Beijing 100027,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Central&Southern China Municipal Engineering Design and Research Institute Co.Ltd.,Wuhan 430010,China)

机构地区：[1]中信建设有限责任公司,北京市100027 [2]西南交通大学土木工程学院,成都市610031 [3]中国市政工程中南设计研究总院有限公司,武汉市430010

出　　处：《公路》2024年第10期45-52,共8页Highway

基　　金：四川省自然科学基金项目,项目编号2023NSFSC0380。

摘　　要：软土地基道路拓宽工程的新路堤通常会产生较大变形,水平软土地基桩网结构加固效果得到广泛证实,但缺乏针对斜坡软土的地基加固工程措施研究。针对原状地基、桩网结构处治及与边坡桩组合方案3种工况,建立倾斜软土地基上路基拼接式拓宽PLAXIS 2D有限元模型,对比分析了填筑期及工后5年内的路基变形、应力响应与路堤稳定性变化规律。结果表明,原状地基条件的新路堤将出现明显沉降及水平位移;拓宽体底部采用桩网结构处治,路基顶面最大沉降及水平位移减小约63%、75%,但不能满足路面不均匀沉降小于0.4%的功能性要求;在老路基边坡处增设边坡桩,路基面最大沉降和侧向位移为原状地基工况的8.8%、6.4%,路面不均匀沉降仅为0.3%,桩体荷载分担可大幅降低桩周软土超孔隙水压,固结时间缩短73%,明显提高路堤在填筑期及工后阶段的整体稳定性。Due to the additional stress caused by the road widening,the embankment will occur obvious deformation.The treatment by pile-net structure on the horizontal weak foundation has manifested good reinforcing effect,but the reinforcing measures on slope weak ground need further researches.For original foundation and two construction schemes,treatment by pile-net structure and combination with slope piles,PLAXIS 2D finite element models of spliced widening on slope weak ground are established,the subgrade deformation,stress response and overall stability during construction and five years thereafter are compared and analyzed.The results show that obvious settlement and horizontal displacement at the top of subgrade will occur on original foundation.Treated by pile-net structure under the widened section,the maximum settlement at the top of subgrade and horizontal displacement can reduce by approximately 63%and 75%respectively,but it exceeds the differential settlement limiting value of 0.4%.Adding piles on the slope of existing subgrade,the maximum settlement and horizontal displacement is 8.8%and 6.4%of the condition without treatment and the differential settlement of the pavement only is 0.3%.The excess pore water pressure of soft soil around piles has significantly dropping and the consolidation time reduces by 73%due to load sharing effects of piles,which cause the overall stability of the subgrade is greatly enhanced in entire construction phase.

关 键 词：斜坡软土地基 拼接式拓宽 复合地基 变形控制 整体稳定性 

分 类 号：U418.8[交通运输工程—道路与铁道工程]