研究目的:地层抗力系数的合理取值对于盾构隧道管片衬砌结构的设计的合理性、安全性至关重要。鉴于此,本文从既有的盾构隧道地层抗力计算方法出发,通过引入荷载修正和断面不同位置修正的系数∈,考虑地层中隧道结构与地层的相互作用,推导出基于简化二向不等地应力场假定的地层抗力系数的修正计算公式,并与既有地层抗力系数的计算方法及现场实测数据进行对比分析,对该修正计算方法进行验证。 研究结论:(1)采用本文得到的地层抗力系数修正计算方法与Muir Wood方法、Plizzari—Tiberti方法等三种地层抗力理论算法下管片衬砌结构受力分布规律基本相同,但内力的量值有所差异;(2)三种算法下最大正负弯矩对应轴力均与现场实测结果相差不大,采用本文方法管片结构弯矩偏差明显小于其他两种方法;(3)本研究成果可为盾构隧道结构分析中地层抗力系数的合理取值提供有益参考。
Research purposes: Reasonable value of the ground resistance coefficient is important for rational design, construction and long - term structure safety of a shield tunnel lining structure. In view of this, the paper based on the existing ground resistance calculation method of shield tunnel, using a modified factor to consider the effect of load and ground resistance distribution on the value of ground resistance coefficient, and considering the interaction between lining structure and ground, the modified calculation formula of ground resistance coefficient is deduced based on the simplified twodirection unequal stress field hypothesis. Furthermore, by analyzing and comparing with the existing ground resistance calculation method and field test, the modified calculation method is verified. Research conclusions: ( 1 ) The segment lining structure stress distribution rules obtained by using modified calculation method of ground resistance coefficient deduced by this paper, Muir Wood Method and Plizzari - Tiberti Method are same as each other, but the magnitude of the inner force are different. (2) The axial force acquired by using the three methods almost the same with the field test results. However, the deviation of segments bending moment calculated by using the method proposed by this paper is much smaller than the other two methods. (3) The research results can beused for reasonable value of the ground resistance coefficient in the design of shield tunnel lining structure.