| 基于CDEM的砂卵石地层盾构开挖面稳定性分析 |
| |
| 引用本文： | 薛亚东,张森,李兴,葛嘉诚.基于CDEM的砂卵石地层盾构开挖面稳定性分析[J].西南交通大学学报,2019,54(3):499-506, 586. |
| |
| 作者姓名： | 薛亚东 张森 李兴 葛嘉诚 |
| |
| 作者单位： | 同济大学岩土及地下工程教育部重点实验室;同济大学土木工程学院 |
| |
| 基金项目： | 国家自然科学基金资助项目（41072206） |
| |
| 摘 要： | 为探究砂卵石地层中盾构开挖工作面失稳现象的机理，采用CDEM （continuum-based discrete element method）可变形块体离散元方法，建立准连续介质模型，对砂卵石土三轴压缩试验开展数值模拟，以分析其细观力学特性；基于“颗粒流动”、“土拱效应”、“超挖出土”等特点，通过平面三角块体离散元建立模拟砂卵石地层盾构开挖面超挖出土的二维动态离散元模型，研究土拱效应、空洞区发展等开挖面失稳的渐进演化机制. 研究结果表明:砂卵石土三轴压缩试验宏观应力应变曲线可分为线弹性阶段、弹塑性阶段、理想塑性阶段；卵石作为粗粒相颗粒存在骨架增强作用，砂卵石接触界面对宏观强度具有弱化作用；通过以土拱效应为标定准则的Hopper Flow标定试验可有效得到不同尺度平面三角形离散单元摩擦角的转换关系；土拱效应显著存在于开挖面前方并随着开挖面超挖出土渐进发展，达到极限状态后逐渐破坏消散；空洞区始于螺旋输送机底部，随超挖出土逐步向上方和前方扩展，最终在击穿承载土拱后到达地表，形成“水滴状”空洞区；从不同角度提出了三类超挖量的控制标准.
|
| 关 键 词： | 隧道工程 数值模拟 砂卵石地层 盾构开挖面稳定性 土拱效应 |
| 收稿时间： | 2017-05-24 |
Face Stability of Shield Tunnel in Sandy Cobble Stratum with Continuum-Based Discrete Element Method |
| |
| XUE Yadong,ZHANG Sen,LI Xing,GE Jiacheng.Face Stability of Shield Tunnel in Sandy Cobble Stratum with Continuum-Based Discrete Element Method[J].Journal of Southwest Jiaotong University,2019,54(3):499-506, 586. |
| |
| Authors: | XUE Yadong ZHANG Sen LI Xing GE Jiacheng |
| |
| Abstract: | The instability mechanism of shield tunnel excavation working face in a sandy cobble stratum was explored, and the CDEM (continuum-based discrete element method) was adopted to establish a quasi-continuous numerical model. Triaxial compression tests of sand-cobble soil were carried out numerically to analyse its macro–mesoscopic mechanical characteristics. Based on the features of " particle flow”, " soil arch effect”, and " over-excavation”, a 2D dynamic discrete element model was established to simulate the tunnel working face over-excavation with plane triangular blocks. The progressive instability mechanisms of the tunnel face (such as soil arch effect and cavity zone) were studied. The results show that the macroscopic stress-strain curve of the sandy cobble soil triaxial compression test can be divided into linear elastic, elastoplastic, and ideal plastic stages. The cobble enhances the soil structure as coarse granular particles. The contact surface of the cobble and sand weakens the macroscopic strength. The Hopper flow calibration test with the soil arching effect as the calibration criterion can effectively obtain the friction angle transformation relationships of discrete plane triangles of different scales. The arching effect is notably ahead of the face, develops gradually with over-excavation, and finally dissipates gradually after reaching the limit state. Void regions start from the bottom of the screw conveyor, develop forward and upward gradually with over-excavation and finally cut through the load-bearing arch, reaching the ground surface and forming water-drop shaped void regions. Three types of control standards for over-excavation are proposed based on different strategies. |
| |
| Keywords: | |
| 本文献已被 CNKI 等数据库收录！ |
| 点击此处可从《西南交通大学学报》浏览原始摘要信息 |
|
点击此处可从《西南交通大学学报》下载全文 |
|
