换填硬壳层对软土区水泥土搅拌桩影响分析  

Analysis on the Influence of Replacing Hard Shell Layer on the Cement-soil Mixing Piles in Soft Soil Area

作　　者：黄志华 曹雄 李蒙杰 HUANG Zhi-hua;CAO Xiong;LI Meng-jie(Zhuhai Institute of Urban Planning&Design,Zhuhai 519000,China;Guangdong Coastal Area Disaster Prevention and Mitigation Engineering Technology Research Center,Zhuhai 519000,China)

机构地区：[1]珠海市规划设计研究院,珠海市519000 [2]广东省滨海地区防灾减灾工程技术研究中心,珠海市519000

出　　处：《公路》2023年第10期124-132,共9页Highway

基　　金：珠海市产学研合作项目,项目编号ZH22017001200149PWC;广东省住房和城乡建设厅科技创新计划项目,项目编号2021-K4-021299。

摘　　要：针对桩顶与桩间换填硬壳层的滨海软土区水泥土搅拌桩,开展施工阶段和工后道路运营阶段的数值计算分析,探讨换填硬壳层材料参数、厚度等因素对软土区水泥搅拌桩受力变形的影响规律。结果表明:桩间换填硬壳层能够有效提高桩间淤泥的地基承载力,换填材料推荐可选用性质良好的含石类土,换填厚度建议0.5 m及以上;施工机械应避免行驶在复合地基边桩桩间土,且控制接地压力不大于90 kPa。软土区水泥土搅拌桩复合地基采用0.5 m厚石屑垫层+0.8 m厚路基填土,能够有效控制路基顶面的差异沉降;对桩间淤泥进行厚度0.5 m的换填,能够有效改善复合地基浅层部位及上方路基填土受力变形状态,显著减小道路运营期车辆荷载作用下桩间土的沉陷,促进应力横向扩散,减小桩土差异沉降。For cement soil mixing piles in coastal soft soil areas where hard shell layers are replaced between piles,numerical calculation and analysis are carried out during the construction phase and post construction road operation phase to explore the influence of factors such as material parameters and thickness of the replaced hard shell layer on the mechanical deformation of cement mixing piles in soft soil areas.The results show that replacing the hard shell layer between piles can effectively improve the bearing capacity of the mud foundation between piles.It is recommended to use stone-bearing soil with good properties as the replacement material,and the recommended replacement thickness is 0.5 m or more.Construction machinery should avoid driving in the soil between the composite foundation piles,and the grounding pressure should be controlled to not exceed 90 kPa.For cement soil mixing pile composite foundation in soft soil areas,0.5 m thick stone chip cushion+0.8 m thick roadbed filling can effectively control differential settlement on the top surface of the roadbed.Replacing the silt between piles with a thickness of o.5 m can effectively improve the stress and deformation state of the shallow part of the composite foundation and the roadbed filling above it,and significantly reduce the settlement of the soil between piles under the action of vehicle loads during road operation,promote lateral stress diffusion,and reduce differential settlement between piles and soil.

关 键 词：路基工程 软土地基 水泥土搅拌桩 硬壳层 换填 桩土应力比 

分 类 号：U416.166[交通运输工程—道路与铁道工程] TU472.36[建筑科学—结构工程]