摘要
基于极限平衡思想,提出黏土中超大直径顶管开挖面主动极限支护压力的计算方法。通过数值模拟,对超大直径顶管的破坏模式进行研究;基于破坏模式,推导提出极限支护压力的计算方法;根据实际工程的数值计算结果,验证提出方法的合理性;最后对提出方法的影响因素进行分析,并与其他理论方法进行比较,得到深埋和浅埋的临界深度。研究结果表明,超大直径顶管深埋主动破坏模式为水平圆锥体破坏模式,浅埋主动破坏模式为楔形体破坏模式;1.5倍直径为深埋顶管和浅埋顶管的临界埋深;提出的方法是合理的,而且过程相对简单,适用于实际工程;新方法适用于均质或者层状黏性土中,并且顶管还需在同一土层中顶进;新方法得到的主动极限支护压力值大于极限分析方法,但当内摩擦角接近40°时,得到的结果很接近。
Based on the method of limit equilibrium, an approach for calculating the active limit support pressure of tunnel face in cohesive soils is proposed. First, the failure mechanism of pipe jacking is studied by employing the numerical simulation. Then, an approach for the limit support pressure is derived and presented according to the failure mechanism. After that, the rationality of the approach obtained is verified by a numerical example of an actual project. Finally, influencing factors of the proposed approach are analyzed. Meanwhile the new method is compared with other methods, and the critical depth for deep and shallow pipe jacking is determined. The research results show that the failure mechanism of deep pipe jacking is horizontal cone mechanism, while that of the shallow one is wedge mechanism. The critical depth to distinguish deep pipe jacking from shallow one is 1.5 times the diameter. The proposed approach is rational and the calculation process is relatively simple, and it is suitable to actual projects. It can be used in homogeneous and layered soils, requiring the pipe jacking advancing in the same stratum. The limit pressure calculated by the new approach is larger than that by the limit analysis methods, however, it is almost the same when internal friction angle is close to 40 degrees.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2013年第11期2060-2067,共8页
Chinese Journal of Geotechnical Engineering
基金
"十二五"国家科技支撑计划课题(2012BAJ01B02)
上海城建集团科技攻关项目
关键词
超大直径顶管
主动极限支护压力
破坏模式
数值模拟
极限平衡
large-diameter pipe jacking
active limit support pressure
failure mechanism
numerical simulation
limitequilibrium
