武汉长江隧道管片衬砌结构受幅宽影响的力学分布特征研究

 以武汉长江盾构隧道为工程背景，通过引入管片接头的弯矩–轴力–转角非线性曲线参数的三维壳–非线性弹簧计算模型对幅宽为1～10 m的管片衬砌结构的三维力学分布特征进行系统研究，并与传统梁–非线性弹簧模型的内力结果进行比较，得出管片衬砌结构受管片幅宽影响的内力分布规律。最后通过大比尺相似结构模型试验对计算成果进行验证。研究结果表明：三维管片衬砌结构的最大正、负弯矩一般发生于幅宽边缘部位；就幅宽边缘的最大弯矩而言，在偏安全地假定环间剪切刚度无穷大的情况下，梁–弹簧模型的最大值和三维结构最大值基本相等，表明采用梁–弹簧模型的计算结果用于结构分析是可以确保安全的；就幅宽中央的最大弯矩而言，梁–弹簧模型的最大值比三维结构相应结果明显偏大，说明采用梁–弹簧模型计算结果进行管片配筋会使幅宽中部区域结构配筋率偏大，造成不必要浪费；大幅宽管片的环间接头径向剪力值比梁–弹簧模型的计算结果小，并且幅宽越大两者差值越大。该研究成果对于类似大型越江和海底盾构隧道优化管片结构配筋和分析管片结构安全具有重要的参考价值。

STUDY ON MECHANICAL DISTRIBUTION CHARACTERISTIC OF LINING STRUCTURE INFLUENCED BY SEGMENT WIDTH FOR WUHAN YANGTZE RIVER TUNNEL

Taking the Wuhan Yangtze River tunnel as an engineering background，the 3D mechanical distribution characteristic of lining whose segment width ranges from 1 to 10 m is analyzed by establishing a 3D shell-nonlinear spring model which needs to input the nonlinear data about bending moment，axial force and rotating angle of segment joint. The analytical results about internal forces are contrasted with those calculated by traditional beam-nonlinear spring model. In addition，the internal force distribution rules of segment lining structure influenced by segment width are achieved. Finally，the rules are validated primarily by large-scale similar model test. The study shows that：(1) both the positive and the negative maximum bending moments of the 3D lining structure always occur on the edge of segment；(2) the maximum bending moment calculated by the beam-nonlinear spring model equals to that calculated by 3D shell-spring model on the edge of segment when it is assumed that the shear stiffness between rings is infinite，which indicates that using the results obtained by beam-nonlinear spring model to analyze lining structure is safe；(3) in the middle of the segment，the maximum bending moment calculated by the beam-nonlinear spring model is greater than that calculated by 3D shell-nonlinear model，so the reinforcement ratio of reinforced concrete in the middle of segment obtained by the beam-nonlinear spring model is greater than that by 3D shell-nonlinear spring model；and (4) the radial shear force on the ring joint calculated by the 3D shell-nonlinear spring model is less than that induced by the beam-nonlinear spring model，the larger the segment width is，the bigger the margin between them is. The study results can provide valuable references to reinforcement design of segment structure in the shield tunnel under the big river or sea and security appraisal of segment lining.