组合推力下管片裂损形成机理及优化控制研究

Research on Formation Mechanism and Optimization Control of Segment Crack Damage under Combined Thrust

针对施工过程中千斤顶推力作用下管片损伤问题开展研究。以苏州某地铁线路实际情况为基础,建立多环三维有限元模型,对千斤顶推力过大及推力不均综合作用下管片裂损形成、演化规律及损伤分布等进行分析,并提出相应的工程控制措施。研究结果表明:不同推力作用下,管片损伤主要沿着螺栓孔均匀分布,且内弧面损伤大于外弧面,管片的最大损伤因子呈近似线性增大,损伤面积呈非线性增加。当推力均匀分布时,管片损伤主要集中于第1环管片,当出现不均匀推力时,管片损伤会向推力较大侧转移,并逐渐向第2环和第3环管片发展,推力不均使得相同推力下管片裂缝出现的荷载提前约11%。设计施工中可以通过严格控制千斤顶不均匀推力、优化管片设计、实行分段控制等工程控制措施,减少盾构施工阶段管片裂损的形成。

The damage of segment under the thrust of jacks during construction was studied.Based on the actual situation of a subway line in Suzhou,a multi-ring three-dimensional finite element model was established to analyze the formation,evolution and distribution of shield segment fracture under the combined action of excessive and uneven thrust of jacks,and the corresponding engineering control measures were put forward.The results show that the segment damage is mainly distributed uniformly along the bolt hole under different thrust,and the damage on the inner cambered surface is larger than that on the outer cambered surface.The maximum damage factor of the segment increases approximately linearly,and the damage area increases nonlinearly.When thrust is evenly distributed,segment damage is mainly concentrated in the first ring segment,while when thrust is not uniform,segment damage will transfer to the side with larger thrust,and gradually develop to the second and third ring segment.The uneven thrust forces advance the loading of segment cracks by about 11%under the same thrust.The formation of segment crack damage during shield construction can be reduced by adopting engineering control measures such as strictly controlling uneven thrust of jacks,optimizing segment design and implementing segment control.