盾构井深基坑围护结构变形规律及信息化施工研究

Research on Displacements Law of Shield Shaft Enclosure Structure and the Informatization Construction Analysis

深基坑工程围护结构受力变形的现场监测对保证基坑的安全稳定至关重要。以北京地铁10号线某盾构竖井深基坑工程为背景,阐述了地铁盾构井的监测方案,对桩体水平位移、钢支撑轴力、桩身弯矩及桩侧土压力等项目进行了现场监测,并分析了施工开挖过程对桩体水平位移、钢支撑轴力、桩身弯矩及桩侧土压力的影响。分析结果表明:基坑开挖过程中,围护桩的最大水平位移的发生位置逐渐下移,在顶板完成后,位于距离顶板8 m的位置处;第二道钢支撑在基坑开挖过程中受力始终最大;桩体最大弯矩值约为设计值的50%;桩侧土压力层状分布较为明显。

Field monitoring for enclosure structure subject to deformation in deep pit engineering is essential to ensure the security and stability of deep pit.Based on the shield shaft deep pit engineering of Beijing Subway Line 10,the monitoring alternatives of subway shield shaft are described in this paper.The enclosur structure of horizontal displacement,the steel support axial force,the bending moment of piles and the earth pressures affecting the piles are measured on site.And the relationships among enclosur structure of horizontal displacement,steel support axial force,bending moment of piles,earth pressures affecting the piles in the construction excavation process are estimated.The results show that： the location of maximum horizontal deformation of the pile is gradually downward during excavation,and the location is from the roof 8 m after the roof completion;the second steel support force is always the largest in the excavation process;the maximum bending moment value of piles is about 50% of the design value;the distribution of earth pressure is laminar obviously.