砂卵石地层盾构开挖面极限支护压力计算模型研究

摘要

Chengdu Metro Line No.1 and Line No.2 were taken as the background of research.On the basis of analyzing the collapse pattern of shield face in the sandy cobble stratum,the trapezoid wedge model was proposed to calculate the limit supporting pressure of the excavating face.The formula for calculating the limit supporting pressure of the excavating face was re-deduced.In the process of re-deduction,the forces of triangular sides and top surface of sliding block with outside soil were considered.Through numerical simulation with the particle discrete element method,the Terzaghi loosening earth pressure formula was modified in the 3-dimensin space.Combining with numerical simulation of the shield face stability,the problem of model parameter selection was discussed.The modified trapezoid wedge model of the limit support pressure suitable for the sandy cobble stratum was proposed.Comparison and verification were made with the calculation formula.%以成都地铁1、2号线为背景,在分析砂卵石地层盾构施工开挖面破坏模式基础上,提出使用梯形楔形体模型计算开挖面极限支护压力；对开挖面极限支护压力计算公式进行重新推导,推导过程中考虑滑动块侧面三角形和滑动块顶部与外部土体相互作用力.通过颗粒离散元数值计算,在三维空间修正太沙基松动土压力计算公式；结合开挖面稳定性数值计算成果,分析计算模型中主要参数的选取；提出适用于砂卵石地层的修正梯形楔形体模型极限支护压力公式；对计算公式进行对比分析和验证分析.