基坑开挖对横穿坑壁管线稳定性的影响分析  

Influence of Deep Excavation on Stability of Utility Pipes Penetrating the Supporting Walls

作　　者：杨庆光[1] 柳雄 邓方根 YANG Qingguang;LIU Xiong;DENG Fanggen(School of Civil Engineering,Hunan University of Technology,Zhuzhou 412000)

机构地区：[1]湖南工业大学土木工程学院,湖南株洲412000

出　　处：《土工基础》2020年第6期675-680,共6页Soil Engineering and Foundation

基　　金：湖南省大学生创新项目(2018652);湖南省研究生创新项目(CX20190856)。

摘　　要：为研究基坑开挖对不同角度横穿坑壁的地下管线稳定性的影响,采用flac3d建立了围护结构-土-地下管线相互作用的三维数值模型,考虑不同的夹角和开挖深度,对管线稳定性具有重要影响的管线竖向位移、竖向应力、轴力问题展开研究。研究结果表明:当基坑开挖为1-3阶段,不同角度的管线竖向位移曲线均呈对称分布,而处于4-6阶段时,管线竖向位移表现为非对称,且夹角越小,竖向位移曲线不均匀性越明显,且随着基坑的开挖,坑内管线出现明显的下沉现象。当夹角为90°时,基坑范围内的管线竖向应力曲线接近水平,管线的轴力分布为"山峰"型,是否考虑管线与基坑正交情况得到的轴力曲线有着很大的差异。当夹角为60°、74.74°、80°时,坑壁附近出现较大的应力集中现象,坑内的管线中部位置也出现应力集中,整条管线的轴力分布呈尖锐的"山谷"型,最大的正轴力出现在坑壁附近,最大的负轴力出现在坑内中部附近。In order to study the influence of deep excavation on the stability of underground utility pipelines that penetrating the supporting wall with different intersection angles,a three-dimensional numerical model of the structure-soil-underground pipeline interaction was established by using FLAC3 D commercial software that considering different intersection angles and various excavation depths.The vertical displacement,vertical stress,and axial force in pipelines,which have an important impact on the pipeline stability,are investigated.The results show that when the excavation is in stages 1-3,the vertical displacement curves of the pipelines at different intersection angles are symmetrically distributed,while in the stages 4-6,the vertical displacement of the pipelines is asymmetric,and the smaller the intersection angle is,the more obvious the non-uniformity of the vertical displacement curve.With increase of the excavation depth,an apparent dipping of the pipeline inside the excavated area was observed.When the included angle is 90°,the vertical stress curve of the pipeline within the range of the excavated area is close to horizontal,and the axial force distribution of the pipeline is"mountain peak".Whether the axial force curve obtained by considering the orthogonality between the pipeline and the excavated area has a large value of difference.When the included angle is 60°,74.74°and 80°,a large stress concentration occurs near the supported wall,and a stress concentration also occurs in the middle of the pipeline inside the excavated area.The axial force distribution of the entire pipeline is a sharp"valley"shape.The largest positive axial force appeared near the pit wall,and the largest negative axial force appeared near the middle of the excavated area.

关 键 词：基坑开挖 地下管线 数值模拟 稳定性 

分 类 号：TU472[建筑科学—结构工程]