浅埋油气管道隧道施工对潜在滑体稳定性影响分析

Landslide stability analysis of potential slope caused by the construction of shallow oil and gas pipeline tunnel

结合中缅油气管道某隧道洞口边坡的工程特征,采用现场调查、数值计算和原位监测等方法系统研究浅埋油气管道隧道施工对潜在滑坡体稳定性影响,详细分析了隧道开挖前后坡体塑性区的分布特征,提出加固措施并对施工期及工后坡体表层和深部位移进行长期监测.结果表明:隧道开挖导致塑性区的分布向边坡中下部转移,最大剪切应变增至开挖前4倍,坡体滑动风险增大;提出了拆迁坡脚房屋、修筑截排水沟、封堵地表裂缝和优化隧道施工工艺的加固方案;位移监测结果表明,坡体在施工期间呈蠕动变形状态,工后水平累积位移逐渐收敛,坡体基本稳定.

According to the engineering features of one slope located in tunnel entrance which belongs to China-Burma oil and gas pipeline,we applied several types of methods such as field investigating,numerical calculation and in-situ monitoring to systematically study the influence to the stability of landslide during the period of shallow buried pipeline construction.Meanwhile,a detailed analysis was conducted to find the distribution features of plasticity area of the slope before and after the tunnel was excavated.Then reinforcement measures were proposed and a long term displacement monitoring was adopted in the surface and the deep layer of the slope during and after the construction.Results indicate that,the distribution of plasticity area turns into lower part of the slope due to the tunnel excavation and the maximum shear strain quadrupled than before,which leads to increase the risk of slope failure.A strengthening project is proposed to relocate the houses in the toe of the slope,build drain and intercepting drain,plug surface cracks and optimize the tunnel construction technology.The results of displacement monitoring show that the slope is in a creep deformation during the construction and the cumulative displacement is going to be convergent gradually after construction and the slope is stable basically.