扰动松散砂层浅埋盾构隧道开挖面失稳破坏特性分析  

Analysis of instability and failure characteristics of shallow bur-ied shield tunnel face in disturbed loose sand stratum

作　　者：黄昌富 赵庾成 孙丹丹 刘中欣[1] 吕玺琳[2,3] Huang Changfu;Zhao Yucheng;Sun Dandan;Liu Zhongxin;LüXilin(China Railway 15th Bureau Group Co.,Ltd.,Shanghai 200070,China;Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China)

机构地区：[1]中铁十五局集团有限公司,上海200070 [2]同济大学地下建筑与工程系,上海200092 [3]同济大学岩土及地下工程教育部重点实验室,上海200092

出　　处：《土木工程学报》2024年第S2期127-132,共6页China Civil Engineering Journal

基　　金：国家自然科学基金(42172300);上海市青年科技启明星计划资助(24QB2708000)。

摘　　要：针对扰动松散砂层中浅埋盾构隧道开挖面失稳特性,开展了物理模型试验和数值模拟研究。模型试验结果表明,随着盾构隧道开挖面处水平变形逐渐增大,土压力从静止土压力降低到一个极限值,开挖面失稳呈现为贯通至地表的整体模式。采用理想弹塑性和应变硬化弹塑性模型,进行浅埋盾构隧道开挖面失稳过程数值模拟,结果表明两种模型得到的极限支护压力值差异较小,应变硬化模型能更准确复现开挖面支护压力随变形演变过程。基于应变硬化模型得到的开挖面失稳破坏模拟结果,针对每个高斯积分点计算二阶功,并通过二阶功变负的材料失稳条件追踪了开挖面失稳区域空间演化过程,模拟结果与模型试验结果吻合。Physical model tests and numerical simulation studies were carried out on the instability characteristics of the shallow buried shield tunnel in disturbed loose sand stratum.The model tests result show that as the horizontal deformation at the tunnel face gradually increases,the earth pressure decreases from the static earth pressure to a limit value,and the tunnel face instability shows an overall mode penetrating to the surface.Both the elastic-perfect plasticity model and strain hardening plasticity model were used to simulate the instability process of the shallowburied shield tunnel face.The results show that the difference between the limit support pressure values obtained by the two models is very small,and the strain hardening model can more accurately reproduce the evolution of the tunnel face support pressure with deformation.Based on the simulated results of the tunnel face instability and failure obtained from the strain hardening model,the second-order work is calculated for each Gauss integral point.The spatial evolution process of the tunnel face instability area is traced through the material instability condition where the second-order work becomes negative.The simulation results are consistent with the test results.

关 键 词：隧道开挖面 松砂 应变硬化 弹塑性 失稳模式 

分 类 号：U455.43[建筑科学—桥梁与隧道工程]