The existence of squeezing ground conditions can lead to significant challenges in designing an adequate support system for tunnels.Numerous empirical,observational and analytical methods have been suggested over the ...The existence of squeezing ground conditions can lead to significant challenges in designing an adequate support system for tunnels.Numerous empirical,observational and analytical methods have been suggested over the years to design support systems in squeezing ground conditions,but all of them have some limitations.In this study,a novel experimental setup having physical model for simulating the tunnel boring machine(TBM)excavation and support installation process in squeezing clay-rich rocks is developed.The observations are made to understand better the interaction between the support and the squeezing ground.The physical model included a large true-triaxial cell,a miniature TBM,laboratoryprepared synthetic test specimen with properties similar to natural mudstone,and an instrumented cylindrical aluminum support system.Experiments were conducted at realistic in situ stress levels to study the time-dependent three-dimensional tunnel support convergence.The tunnel was excavated using the miniature TBM in the cubical rock specimen loaded in the true-triaxial cell,after which the support was installed.The confining stress was then increased in stages to values greater than the rock’s unconfined compressive strength.A model for the time-dependent longitudinal displacement profile(LDP)for the supported tunnel was proposed using the tunnel convergence measurements at different times and stress levels.The LDP formulation was then compared with the unsupported model to calculate the squeezing amount carried by the support.The increase in thrust in the support was backcalculated from an analytical solution with the assumption of linear elastic support.Based on the test results and case studies,a recommendation to optimize the support requirement for tunnels in squeezing ground is proposed.展开更多
针对煤矿矩形巷道支护参数设计问题,采用模糊数学对煤巷围岩稳定性的类别进行分析。选择顶板岩石单轴抗压强度、底板岩石单轴抗压强度、煤层单轴抗压强度、巷道埋深、采动影响系数、护巷煤柱宽度、围岩完整程度7个指标作为矩形巷道围岩...针对煤矿矩形巷道支护参数设计问题,采用模糊数学对煤巷围岩稳定性的类别进行分析。选择顶板岩石单轴抗压强度、底板岩石单轴抗压强度、煤层单轴抗压强度、巷道埋深、采动影响系数、护巷煤柱宽度、围岩完整程度7个指标作为矩形巷道围岩稳定性分析指标,并根据不同的围岩稳定性类型选用不同的支护形式;采用(内嵌数值模拟软件优化、CAD)支护设计方法进行设计,并进行合理的支护参数计算,通过数据库中的诸多样本判断类似的样本数据以自动选择合理的支护方案。以Visual Studio 2022为开发工具,利用SQL Sever 2019构建了围岩力学参数、支护参数、围岩稳定性等信息巷道信息数据库,采用C#语言进行计算机编程,实现了巷道参数数据库管理、围岩稳定性分类、支护参数智能设计等功能。展开更多
基金financial support of the University Transportation Center for Underground Transportation Infrastructure(UTC-UTI)at the Colorado School of Mines under Grant No.69A3551747118 from the US Department of Transportation(DOT)。
文摘The existence of squeezing ground conditions can lead to significant challenges in designing an adequate support system for tunnels.Numerous empirical,observational and analytical methods have been suggested over the years to design support systems in squeezing ground conditions,but all of them have some limitations.In this study,a novel experimental setup having physical model for simulating the tunnel boring machine(TBM)excavation and support installation process in squeezing clay-rich rocks is developed.The observations are made to understand better the interaction between the support and the squeezing ground.The physical model included a large true-triaxial cell,a miniature TBM,laboratoryprepared synthetic test specimen with properties similar to natural mudstone,and an instrumented cylindrical aluminum support system.Experiments were conducted at realistic in situ stress levels to study the time-dependent three-dimensional tunnel support convergence.The tunnel was excavated using the miniature TBM in the cubical rock specimen loaded in the true-triaxial cell,after which the support was installed.The confining stress was then increased in stages to values greater than the rock’s unconfined compressive strength.A model for the time-dependent longitudinal displacement profile(LDP)for the supported tunnel was proposed using the tunnel convergence measurements at different times and stress levels.The LDP formulation was then compared with the unsupported model to calculate the squeezing amount carried by the support.The increase in thrust in the support was backcalculated from an analytical solution with the assumption of linear elastic support.Based on the test results and case studies,a recommendation to optimize the support requirement for tunnels in squeezing ground is proposed.
文摘针对煤矿矩形巷道支护参数设计问题,采用模糊数学对煤巷围岩稳定性的类别进行分析。选择顶板岩石单轴抗压强度、底板岩石单轴抗压强度、煤层单轴抗压强度、巷道埋深、采动影响系数、护巷煤柱宽度、围岩完整程度7个指标作为矩形巷道围岩稳定性分析指标,并根据不同的围岩稳定性类型选用不同的支护形式;采用(内嵌数值模拟软件优化、CAD)支护设计方法进行设计,并进行合理的支护参数计算,通过数据库中的诸多样本判断类似的样本数据以自动选择合理的支护方案。以Visual Studio 2022为开发工具,利用SQL Sever 2019构建了围岩力学参数、支护参数、围岩稳定性等信息巷道信息数据库,采用C#语言进行计算机编程,实现了巷道参数数据库管理、围岩稳定性分类、支护参数智能设计等功能。
