上海大学学报(自然科学版) ›› 2021, Vol. 27 ›› Issue (6): 1094-1105.doi: 10.12066/j.issn.1007-2861.2228

• 研究论文 • 上一篇    下一篇

盾构穿越软硬复合地层开挖面稳定性分析

周立基1, 张孟喜1(), 王维2, 加武荣2, 张晓清1   

  1. 1.上海大学 土木工程系, 上海 200444
    2.中铁二十局集团有限公司 广州分公司, 广州 511400
  • 收稿日期:2019-12-21 出版日期:2021-12-31 发布日期:2022-01-06
  • 通讯作者: 张孟喜 E-mail:mxzhang@i.shu.edu.cn
  • 作者简介:张孟喜(1963—), 男, 教授, 博士生导师, 博士, 研究方向为隧道工程及地下结构等. E-mail: mxzhang@i.shu.edu.cn
  • 基金资助:
    国家自然科学基金资助项目(41172238);中铁二十局集团有限公司技术开发课题资助项目

Stability mechanism of the excavation face for shield tunneling in soft and hard composite ground

ZHOU Liji1, ZHANG Mengxi1(), WANG Wei2, JIA Wurong2, ZHANG Xiaoqing1   

  1. 1. Department of Civil Engineering, Shanghai University, Shanghai 200444, China
    2. Guangzhou Branch, China Railway 20th Bureau Group Co., Ltd., Guangzhou 511400, China
  • Received:2019-12-21 Online:2021-12-31 Published:2022-01-06
  • Contact: ZHANG Mengxi E-mail:mxzhang@i.shu.edu.cn

摘要:

盾构穿越复合地层尤其是上软下硬地层时, 开挖面失稳形式多样、受力机理复杂, 由于开挖面失稳而导致的工程灾害时有发生. 依托佛莞城际铁路隧道工程, 构建三维有限元数值模型并引入参数地层复合比对部分楔形体理论进行改进, 分析盾构穿越上软下硬地层时不同地层复合比和软土内摩擦角对开挖面稳定性的影响. 研究结果表明: 盾构开挖面最大变形出现在软土区域中某个特定位置, 与软土比例有关;开挖面位移随着支护压力的减小可分为缓慢增长、急剧增大、失稳破坏三个阶段, 当支护压力比接近极限支护压力比时, 开挖面变形将急剧增大;改进的部分楔形体模型理论解与数值模拟结果相吻合, 该理论具有一定的合理性. 研究成果可为类似地层隧道盾构施工提供一定的理论指导.

关键词: 盾构隧道, 上软下硬地层, 开挖面稳定性, 支护压力比, 极限平衡

Abstract:

When the shield passes through composite strata, especially the upper soft and lower hard strata, instability of the excavation surface is variable and the stress mechanism is complex. Consequently, engineering disasters caused by instability of the excavation surface can occasionally occur. Based on the Fo-Guan intercity railway tunnel project, a three-dimensional finite element numerical model is constructed and a stratum composite ratio parameter is introduced to improve the wedge theory of earth pressure. The effects of different stratum composite ratios and soft soil internal friction angles on the stability of the excavation surface when the shield passes through the upper-soft and lower-hard strata are analyzed. The results indicate that the maximum deformation of the shield excavation face appears at a specific position in the soft soil area, which is related to the proportion of soft soil. The displacement of the excavation face can be divided into three stages: slow growth, sharp increase, and instability failure. When the support pressure ratio is close to the limit support pressure ratio, the excavation face deformation will increase sharply. The theoretical solution of the improved partial wedge model is consistent with the numerical simulation results, and the theory is reasonable. These research results can provide some theoretical guidance for shield construction of similar strata.

Key words: shield tunnel, upper-soft and lower-hard ground, excavation face stability, minimum support pressure ratio, limit equilibrium

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