大凉山背斜核部区隧道初支大变形机理与控制
Large Deformation Mechanism and Control of Tunnel Initial Support in Anticlinal Core Zone of Daliang Mountain
梁斌 1陈诺 1苗景川 2李文杰1
作者信息
- 1. 河南科技大学 土木建筑学院,河南 洛阳 471023
- 2. 中铁十五局集团 第一工程有限公司,陕西 西安 710018
- 折叠
摘要
针对大凉山 2 号公路隧道穿越高地应力背斜核心区域,隧道易发生初支大变形、坍塌、钢架扭曲等问题,通过现场监控量测、围岩岩性实验、理论分析、数值模拟分析和围岩接触压力监测等综合分析,研究了大凉山2 号隧道背斜核部大变形成因机理.研究表明:背斜核部玄武岩单轴抗压强度为 23.31 MPa,凝灰质泥岩遇水具有一定膨胀性,给围岩变形创造了条件.由于岩层岩性不同,开挖后洞周玄武岩呈独立受弯剪梁状态.相对无水条件下,受地下水补给影响,围岩塑性区面积增加,拱腰部位较为明显.加固前,拱顶沉降量最大达470 mm,拱腰最大收敛值为 844 mm,围岩接触压力为 523.47 kPa.采用双层小导管+中台阶临时支撑+边墙临时支撑的"主动适应+强支撑"的综合处置方式,隧道拱顶变形减少 87.6%,水平收敛变形减少 95%,围岩接触压力最大值降至 128 kPa,隧道变形得到有效控制.
Abstract
As the tunnel of Daliang mountain No.2 highway passes through the core zone of anticline with high in-situ stress,it is prone to large deformation in initial support stage,collapse and steel frame distortion,through the comprehensive analysis of on-site monitoring measurement,surrounding rock lithology experiment,theoretical analysis,numerical simulation analysis and surrounding rock contact pressure monitoring,genetic mechanism of large deformation in anticlinal core zone of Daliang mountain No.2 tunnel was studied.The results show that the uniaxial compressive strength of anticlinal core basalt is 23.31 MPa,tuffaceous mudstone has certain expansibility when exposed to water,it creates conditions for the deformation of surrounding rock.Due to the different lithology of rock strata,the basalt around the tunnel is in the state of independent bending shear beam after excavation.Under the condition of relatively no water,the area of plastic zone of surrounding rock increases due to the influence of groundwater recharge,and the arch waist is more obvious.Before reinforcement,the maximum settlement of the vault is 470 mm,the maximum convergence value of the arch waist is 844 mm,and the contact pressure of surrounding rock is 523.47 KPa.By adopting the comprehensive disposal method of"active adaptation+strong support"of double-layer small conduit+temporary support of middle step+temporary support of side wall,the tunnel vault deformation reduce by 87.6%,the horizontal convergence deformation reduce by 95%,maximum contact pressure of surrounding rock reduce to 128 kPa,the tunnel deformation is effectively controlled.
关键词
隧道工程/背斜核部区/大变形机理/现场监测/岩性实验/数值模拟Key words
tunnel engineering/anticlinal core zone/large deformation mechanism/field monitoring/lithology experiment/numerical modeling引用本文复制引用
基金项目
国家自然科学基金(11502072)
中铁十五局集团有限公司重点科研项目(2020B2)
河南省科技厅产学研合作项目(2015HNCXY011)
出版年
2024
国家科技期刊平台
NSTL
维普
万方数据