复杂地质条件下浅埋大断面隧道开挖台阶参数优化数值模拟研究  

Numerical simulation study on optimization of excavation bench parameters of shallow large section tunnel under complex geological conditions

作　　者：邵顺安 SHAO Shunan

机构地区：[1]福建省建筑科学研究院有限责任公司 [2]福建省建筑工程质量检测中心有限公司,福建福州350108

出　　处：《福建建设科技》2023年第4期58-62,共5页Fujian Construction Science & Technology

摘　　要：本研究以某典型的软弱围岩隧道为工程依托,在隧道穿越软弱复杂地质环境出现塌方灾害时,通过建立数值模型和现场试验的方式,研究了不同台阶工法开挖穿越上软下硬地层时的隧道变形行为和结构力学特性。研究表明隧道上台阶核心岩体开挖后,拱顶、拱肩及拱腰位置处的沉降变形大约占最终稳定值的67%,中台阶左侧岩体开挖之后,上述三位置处的围岩变形大约占总体的20%,隧道最大沉降变形的产生主要是由于上台阶环形部分围岩以及中台阶左侧部分围岩的非对称开挖引起的;当隧道所穿越地层为上部较为松散的塌方围岩段和下部岩体较为坚硬的基岩段,在上台阶部分开挖扰动后,由于隧道开挖部分围岩分空间分布的不连续性,岩体上“软”层和下“硬”层的变形存在时空差异,导致隧道拱顶沉降迅速增加。Based on the typical soft surrounding rock tunnel in certain area,this study proposes the treatment methods and measures for tunnel collapse when the tunnel passes through the soft and complex geological environment.On this basis,the deformation behavior and structural mechanics characteristics of the tunnel when different bench excavation methods pass through the upper soft and lower hard strata are studied by establishing numerical models and field tests.Research has shown that after the excavation of the core rock mass of the upper step of the tunnel,the settlement deformation at the arch crown,arch shoulder,and arch waist positions accounts for approximately 67%of the final stable value.After the excavation of the left rock mass of the middle step,the deformation of the surrounding rock at the above three positions accounts for about 20%of the overall deformation.The maximum settlement deformation of the tunnel is mainly caused by the asymmetric excavation of the annular part of the upper step surrounding rock and the left part of the middle step surrounding rock;When the tunnel passes through a section of loose collapsed surrounding rock in the upper part and a section of hard bedrock in the lower part,after the upper bench is separately excavated and disturbed,due to the discontinuity of the spatial distribution of the surrounding rock in the tunnel excavation section,there is a temporal and spatial difference in the deformation of the"soft"layer and the"hard"layer on the rock mass,leading to a rapid increase in the settlement of the tunnel arch.

关 键 词：隧道工程 分部开挖 参数优化 上软下硬 数值模拟 

分 类 号：U455[建筑科学—桥梁与隧道工程]