【摘要】 以大型水下盾构隧道工程为背景,首先采用壳-弹簧计算模型分析运营期间管片衬砌结构的三维力学分布特征,并用相似模型试验对结论做初步验证,提出主筋优化分布的配筋措施,然后采用三维管片组合体模型分析施工期间在千斤顶推力作用下的管片内部应力分布规律,并与施工现场调查统计的管片裂缝进行印证,提出管片局部配筋措施。研究表明,大幅宽条件下,幅宽边缘部位的最大弯矩值明显大于幅宽中央,建议主筋沿幅宽采用中疏边密的阶梯状分布配筋率;施工期间的管片应力集中主要发生在靠近管片环缝边缘部位,建议将此区域设置成刚性较大的钢筋整体梁式骨架;千斤顶推力作用下,管片平均应力集中部位呈八字形分布而剪切应力集中部位呈剪刀状,建议按照应力走向配置局部加强钢筋。研究结论可为分析管片结构安全和合理优化管片结构配筋提供有实用价值的参考。更多还原

【Abstract】 With a large-scale underwater shield tunnel as the background,the mechanical distribution characteristics of the segment lining structure in the stage of operation is analyzed by establishing a 3D shell-spring model,and the rules are verified primarily by an analogy model test,and so the reinforcement optimization measures of major steel are proposed.Then,the stress distribution in the segment structure under the jack thrust action during construction is analyzed by the 3D segment combination model,and the laws are testified by statistics of the segment cracks counted on the construction site,and so partial reinforcement measures for segment lining is derived.The study shows as follows: The maximum bending moments on the edge of the segment width are bigger than those in the middle of the segment width,so we suggest that the reinforcement ratio of major steel changes gradually in ladder-like distribution along the direction of the segment width;the stress concentration of the segment during construction mainly occurs on the edge of the segment,and we propose that the whole steel skeleton with large stiffness be added here;under the jack thrust action,the average stress concentration of the segment is like slope-shaped,but the shearing stress concentration is like shear-shaped,so we advise that partial reinforcement bars will be determined by the stress direction.The paper can provide valuable preference to reinforcement design of the segment structure and security appraisal of segment lining for the shield tunnel.更多还原