摘要
为维持顶管施工开挖面稳定,支护压力的设定必须小于被动极限支护压力。文章根据开挖面极限平衡,提出了超大直径泥水平衡顶管在粘性土中适用的开挖面被动极限支护压力计算方法。依照数值模拟计算方法,研究了超大直径顶管的被动破坏模式;再基于破坏模式,给出了被动极限支护压力的计算思路;对实际工程进行数值模拟并与所提方法进行对照,初步验证了所提方法的合理性;最后与其它理论方法进行了比较,并对提出方法的影响因素进行了分析。研究结果表明:水平圆柱体破坏模式为超大直径泥水平衡顶管的被动破坏模式,该被动模式与埋深无关;提出的方法具有合理性,而且计算过程相对简单,在实际工程中适用;水平圆柱体模式计算方法能够用于层状、均质粘性土中,应用条件是顶管开挖面只处在一个土层内;其得到的计算结果合理地低于其它方法,且偏安全;得到的被动极限支护压力随埋深直径比增大而增大,随内摩擦角和粘聚力的增大而增大。
Considering that the support pressure of a pipe-jacking machine must be lower than the passive limit support pressure to ensure stability of the working face, this paper proposes a calculation method for the passive limit support pressure of an extra-large diameter slurry balance pipe-jacking machine in clay based on the ultimate equilibrium of the working face. First, the jacking pipe＇s passive failure model was studied using a numerical simulation, then a relevant calculation concept was established based on the results and finally the method＇s rationality was preliminarily verified by the numerical simulation of a practical case. Compared with other methods and based on the analysis of its influence factors, it is indicated that：1） the horizontal cylinder failure mode, which is a passive failure mode and independent of buried depth, is appropriate for the slurry jacking pipe; 2） the proposed method is applicable to the practice for its rationality and simple calculations, of which the application condition for the layered and homogeneous clay simply requires that the working face being kept in a single stratum; 3） the method is more conservative than others, with reasonable lower values; and 4） the obtained passive support pressure increases with an increase of the depth-diameter ratio, internal friction angle and cohesion.
出处
《现代隧道技术》
EI
CSCD
北大核心
2015年第3期127-136,共10页
Modern Tunnelling Technology
基金
十二五国家科技支撑计划课题(编号:2012BAJ01B02)
上海城建集团科技攻关项目(编号:11231202400)
中国博士后科学基金项目(编号:2014M551452)
关键词
泥水平衡
超大直径顶管
被动极限支护压力
破坏模式
极限平衡
Slurry balance
Jacking pipe with extra-large diameter
Passive limit support pressure
Failure mode
Ultimate equilibrium
