(3.3.8)--软土地区侧压损失对盾构隧道受力及变形的影响.pdf

软土地区侧压损失对盾构隧道受力及变形的影响 摘 要：针对软土地区地铁沿线工程活动导致盾构隧道收敛变形增大的问题，采用 1 ∶10 相似模型试验和精细化 3D 有限元模拟相结合的方法，研究了侧向压力损失对盾构隧道结构处于弹性阶段与塑性阶段的受力及变形的影 响规律。研究结果表明：当侧向压力损失较小时，侧向压力损失与盾构隧道径向变形之间呈线性关系，盾构隧道 结构处于弹性阶段；当侧向压力损失增大时，侧向压力损失与盾构隧道径向变形之间呈指数型关系，盾构隧道结 构进入塑性阶段；增大管片厚度能有效提升管片的抗变形能力，但抗变形能力会随厚度增大而趋于平缓；从混凝 土结构偏心受力的角度分析，盾隧道管片厚度增大会导致结构从小偏心受压向大偏心受压转变，但从结构应力/ 应变的角度分析，管片的最大应变值减小，从而使盾构隧道结构处于更安全的受力状态。 关键词：盾构隧道；侧向卸载；相似模型试验；有限元方法；管片厚度 中图分类号：U455.43 ；U451 文献标志码：A doi: 10.6052/j.issn.1000-4750.2018.04.0216 INFLUENCE OF LATERAL PRESSURE LOSS ON THE FORCE AND DEFORMATION OF SHIELD TUNNEL IN SOFT SOIL AREA LIANG Dong , JIN Hao , XIAO Jun-hua , ZHOU Shun-hua (1. Key Laboratory of Road and Traffic Engineering of Ministry of Education, Tongji University, Shanghai 201804, China; 2. Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety, Tongji University, Shanghai 201804, China) Abstract: To study the problem that construction activities adjacent to metro tunnels in soft soil area could lead to increasement of segment deformation, a combination approach of model test and finite element simulation is adopted to study the force and deformation of shield tunnel structure at both elastic stage and plastic stage induced by lateral pressure loss. The results showed that: when the lateral pressure loss of shield tunnel is small, the segment deformation increases linearly, shield tunnel structure is still at elastic stage; when the lateral pressure loss becomes large, the segment deformation increases exponentially, and the shield tunnel structure changes into the range of plasticity. Increasing the thickness of segment can effectively improve the anti-deformation capacity of shield tunnel, but the improvement will become