紧邻既有高速公路偏压地铁深基坑围护结构变形监测与数值模拟研究

Study on field monitoring and numerical simulation of deformation of deep foundation pit retaining structure under unsymmetrical load condition adjacent to existing highway

以合肥地铁车站6号风井深基坑为研究背景,结合现场施工监测和数值模拟计算,对既有紧邻合宁高速公路偏压作用下的深基坑开展其开挖过程中围护桩水平位移、围护桩竖向位移及其相邻路基沉降规律的研究。结果表明:路基偏压对于围护桩水平位移影响很大,偏压侧最大水平位移约为非偏压侧的3倍左右;而路基偏压对围护桩顶竖向位移影响不大,路基偏压侧和非偏压侧围护桩顶的竖向位移量基本相同;深基坑开挖对既有合宁高速路基沉降影响很大,路基两侧沉降变形趋势大致相同,且紧邻基坑侧路基最大沉降量约为偏离基坑侧路基沉降量的2倍。

Taking No. 6 air shaft deep foundation pit of Hefei subway station as the research background,combined with the field monitoring and numerical simulation calculation,the rule of deep horizontal displacement,vertical displacement of the retaining pile and its adjacent subgrade settlement were studied in the process of the deep foundation pit excavation under unsymmetrical loads of the He-Ning highway. The results show that the roadbed unsymmetrical load affects horizontal displacement of retaining pile greatly,and the biggest horizontal displacement of unsymmetrically loaded side is about three times of symmetrically loaded side. The roadbed unsymmetrical load has little effect on vertical displacement of the pile,and the vertical displacements of the pile of unsymmetrically loaded side and symmetrically loaded side are basically the same. Deep foundation pit excavation has great influence on the He-Ning highway roadbed settlement. On both sides of subgrade,settlement deformation trend is roughly same and the subgrade settlement close to the foundation pit is about 2times of that deviating from the foundation pit.