砂卵石地层隧道开挖围岩变形特性及沉降规律研究  

Study on Deformation Characteristics and Settlement Law of Surrounding Rock in Sandy Cobble Stratum Strata

作　　者：冯靖杰 FENG Jingjie(Wuhan Railway Supervision and Administration Bureau,Wuhan 430062,China)

机构地区：[1]武汉铁路监督管理局,武汉430062

出　　处：《广东水利水电》2022年第11期60-65,共6页Guangdong Water Resources and Hydropower

摘　　要：随着城市地下空间开发利用的不断推进,城市隧道工程面临的地质条件也越来越复杂。特别是在砂卵石地层进行隧道开挖时会直接诱发地表塌陷并对周边建筑物稳定性造成潜在威胁。该文通过采用室内三轴实验和数值模拟相结合的研究手段,获得了砂卵石土的细观参数,包括接触模量、摩擦系数、孔隙率、粘结刚度和接触粘结法相刚度。同时基于离散破裂理论,利用离散元模拟在砂卵石地层中开展不同开挖断面情况下地表沉降特性研究,研究得出:马蹄形断面开挖后不仅地表产生沉降槽,同时拱墙周围砂卵石向临空面侵入,拱脚围岩则较为稳定。圆形断面开挖在无支护情况下比马蹄形断面开挖更稳定,地表沉降量也更小。隧道开挖时,隧道拱顶下沉主要由上台阶开挖引起,而下台阶开挖则引起隧道向侵入临空面方向上的水平位移。基于研究成果建立了圆形和马蹄形断面隧道开挖引起的地表沉降预测模型。With the continuous development and utilization of urban underground space,the geological conditions faced by urban tunneling projects are becoming more and more complex.In particular,tunneling in sand-cobble strata can directly induce surface collapse and pose potential threats to the stability of surrounding buildings.In this paper,the mesoscopic parameters of sand and pebble soil,including contact modulus,friction coefficient,porosity,bond stiffness and contact bond normal phase stiffness,are obtained through a combination of indoor triaxial experiments and numerical simulations.Meanwhile,based on the discrete rupture theory,discrete element simulation was used to study the settlement characteristics of the ground surface under different excavation sections in sand-cobble strata.Round section excavation is more stable than horseshoe section excavation without support,and the surface settlement is smaller.During tunnel excavation,the upper step excavation mainly causes tunnel vault subsidence,while the lower step excavation causes horizontal tunnel displacement.Based on the research results,a prediction model for surface settlement caused by tunnel excavation in circular and horseshoe-shaped sections was developed.

关 键 词：砂卵石地层 细观参数 开挖断面 地表沉降 预测模型 

分 类 号：U451.2[建筑科学—桥梁与隧道工程]