公路路基下穿公铁合建桥梁影响分析及处置措施  

The Impact Analysis of Highway Subgrade Passing Through the Highway-railway Bridge and Treatment Measures

作　　者：王子挺 WANG Ziting(China Railway First Survey and Design Institute Group Co.,Ltd.,Xi'an 710043,China)

机构地区：[1]中铁第一勘察设计院集团有限公司,西安710043

出　　处：《铁道勘察》2023年第6期76-81,共6页Railway Investigation and Surveying

基　　金：中国铁建股份有限公司科研计划重点课题(2019-40)。

摘　　要：以珠海某新建公路路基下穿既有公铁合建桥梁为工程背景,基于三维有限元法采用Molar-coulomb模型分析了两处路基下穿工程对公铁合建桥梁的影响,提出淤泥就地固化和采用桩板结构下穿既有桥梁2种处置措施,并重点分析了处置后的下穿工程对桥梁的影响。研究表明,下穿点①的路基下穿会对公铁合建桥梁产生影响,下穿点②的路基下穿对既有桥梁影响较小,需对下穿点①进行处置。研究结果表明,对于刚构桥墩,墩身位移呈现出非线性变化的规律,除需要关注墩顶外,墩身位移也需要进行重点监测,两种处置措施均可以减小桥梁墩顶位移。淤泥就地固化可减少墩顶位移85.02%,桩板结构可减少墩顶位移58.15%,经比选,就地固化能较好地处理路基下穿带来的影响,且有更好的经济性,故予以推荐。Taking the construction of a bridge under the roadbed of a newly built highway in Zhuhai that crosses existing highways and railways as the engineering background,the impact of the two subgrade undercrossing projects on the highway-railway bridge was analyzed using the three-dimensional finite element method and the Molar-coulomb model.Two disposal measures were proposed:on-site solidification of sludge and using pile plate structure to pass existing bridges.The impact of the undercrossing project after disposal on the bridge was then emphasized.Research shows that the subgrade crossing point①will have an impact on the highway-railway bridge,while the subgrade crossing point②has a smaller impact on the existing bridge.Therefore,the subgrade crossing point①needs to be treated.The result of the study shows that,for rigid frame bridge piers,the displacement of the pier body exhibits a nonlinear variation pattern.In addition to paying attention to the top of the pier,the displacement of the pier body also needs to be monitored.Both disposal measures can reduce the displacement of the bridge pier top.In-situ solidification of silt can reduce the displacement of the pier top by 85.02%,and the pile-plate structure can reduce the displacement of the pier top by 58.15%.After comparison,in-situ solidification can better handle the impact of subgrade crossing,and has better economic efficiency,so it is recommended.

关 键 词：城际铁路 公铁两用桥 有限元法 墩顶位移 沉降 

分 类 号：U239.5[交通运输工程—道路与铁道工程] U448.2[建筑科学—桥梁与隧道工程] U213.1