岩质基坑开挖对临近地埋管线影响研究

Study on Influence of Rock Foundation Pit Excavation on Adjacent Buried Pipelines

以青岛轨道交通L8胶大区间风井的基坑工程为例,探讨岩质基坑施工过程中选择有效支护方式减小基坑开挖产生的地面沉降和管线位移,避免对临近地埋管线产生不良影响。该基坑临近高压燃气管线(二者距离最近处只有5.5 m),属于重大安全风险源。由于各种客观条件限制,管线位置无法进行迁改。因此,选择预应力锚索+钻孔灌注桩的基坑支护方案,并通过三维数值分析软件3DEC的数值模拟结果和现场实际监测数据的分析,结果证明此支护方案的合理性。工程实际经验对临近重要管线的岩质基坑支护方式的选择具有重要的参考价值和意义。

Taking the foundation pit project of L8Jiaozhou section of Qingdao rail transit as an example,this paper discusses how to select effective supporting methods to reduce ground settlement and pipeline displacement caused by foundation pit excavation in the process of construction of rock foundation pit,to avoid adverse effects on buried pipelines nearby.The foundation pit is close to the high-pressure gas pipeline(the closest distance between them is only5.5m),which belongs to the major safety risk source.Due to the limitation of various objective conditions,the location of pipeline cannot be changed.Therefore,the foundation pit supporting scheme of pre-stressed anchor cable+bored cast-in-place pile is selected.The numerical simulation results of3D numerical analysis software3DEC and the analysis of field monitoring data prove the rationality of the supporting scheme.Practical engineering experience has important reference value and significance for the selection of supporting methods for rock foundation pits near important pipelines.