纵向裂纹对盾构隧道衬砌管片力学特性的影响

Influence of Longitudinal Cracks on Mechanical Behaviors of Shield Tunnel Lining Segments

盾构隧道衬砌管片在施工与运营过程中容易产生纵向裂纹,对管片的承载能力有较大影响。本文依托成都地铁2号线牛王庙—牛市口区间盾构隧道,应用有限差分软件建立裂损管片壳-弹簧计算模型,分析裂纹数量与裂损程度对管片力学特性的影响。结果表明:纵向裂纹会导致其附近管片的内力比无裂纹时明显减小;存在多条裂纹(单一分块仅出现单条裂纹)时,裂纹对管片弯矩影响较大区域的范围并未产生叠加,在同一裂纹影响区单条裂纹与多条裂纹作用效果相近;随着裂损程度的增加,裂纹附近管片的内力逐渐降低,裂纹对管片弯矩影响较大区域的范围有所增加。

Longitudinal cracks easily occur in the lining segment of shield tunnel during construction and operation,which has a great influence on the bearing capacity of segment.Based on the shield tunnel in Niuwangmiao-Niushikou section of Chengdu metro line 2,the finite difference software was used to establish the shell-spring calculation model of cracked segment,and the effects of crack number and damage degree on the mechanical behaviors of segment were analyzed in this paper.The results show that the internal force of the segment near the longitudinal crack decreases obviously compared with that without crack.When there are multiple cracks(single crack in a single block),the ranges of areas where the bending moments of the segments are greatly affected by the cracks do not overlap,and the effect of single crack is similar to that of multiple cracks in the same crack area.With the increase of damage degree,the internal force of the segment near the crack decreases gradually,the range of area where the crack has a great influence on the segment bending moment increases.