滇中引水工程砂化白云岩隧洞围岩地质特征与破坏机制

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中文摘要：砂化白云岩岩体结构破碎,赋存地质环境复杂,因易发塌方、突水涌砂,可能诱发地面塌陷等灾害,在该地层中修建地下工程面临施工难度大、灾害处置难、施工安全风险高等挑战.滇中引水工程玉溪段共有5条输水隧洞穿越砂化白云岩地层,采用地质调查与分析、微观结构测试与分析等方法,研究隧洞沿线砂化白云岩空间分布特征及不同砂化等级白云岩的微观结构;通过施工跟踪、围岩失稳案例统计、理论分析归纳等手段,概括砂化白云岩隧洞围岩失稳的影响因素,探索围岩破坏机制并提出灾害的针对性防控措施.研究结果表明:(1)砂化白云岩空间分布和砂化程度与断裂、断层的发育密切相关,由地表向深部呈剧烈砂化→强烈砂化→弱砂化的分带性;滇中引水工程玉溪段砂化白云岩隧洞的砂化程度以强烈砂化、剧烈砂化为主;(2)砂化白云岩隧洞围岩失稳的影响因素主要包括砂化等级、断层、地下水、施工工艺与管理等因素;(3)无水条件下,砂化白云岩隧洞主要发生重力驱动型、应力-岩体结构复合驱动型的围岩塌方失稳;富水砂化白云岩洞段主要发生强烈、剧烈砂化岩体突水涌砂,其失稳机制主要为渗透失稳;(4)超前地质预报和灾害风险动态评价是砂化白云岩隧洞灾害防控的重要举措,止浆墙施作、围岩固结灌浆是突水涌砂的主要工程处置措施,施工经验仍然需要积累和总结.研究成果对砂化白云岩隧洞围岩灾变防控具有一定的指导价值.

外文标题：Study on geological characteristics and failure mechanism of surrounding rock of sandy dolomite tunnel in water diversion project in central Yunnan

外文摘要：Sandy dolomite often has broken structure,with complex geological environment.It is prone to occur collapse,water inrush and sand gushing,induce the ground collapse and other disasters.Consequently,the construction of underground engineering in this stratum face several problems such as great excavation and supporting difficulties and high safety risk.There are five water conveyance tunnels passing through sandy dolomite strata in Yuxi section of central Yunnan water diversion project.In this paper,geological survey and analysis,microstructure testing and analysis were used to obtain the spatial distribution characteristics of sandy dolomite along the tunnels,with different sandy grades.Through geological survey in the construction period,case statistics of surrounding rock instability,theoretical analysis and induction,the influence factors of surrounding rock instability of sandy dolomite tunnel were summarized,the failure mechanism of surrounding rock was explored,and targeted prevention and controlling measures were put forward.The results show that:(1)The spatial distribution and sandification degree are closely related to the scale and distance of faults.In the vertical zonation,the sandification degree is gradually deepen from the surface to depth.Furthermore,strongly and severely sandy dolomite is the main surrounding rock mass in this project.(2)The influence factors of surrounding rock instability of sandy dolomite tunnel are mainly sandy grade,faults,groundwater condition and excavation disturbance.(3)Under anhydrous conditions,gravity-driven and stress-rock mass structure composite-driven surrounding rock collapse is prone to occur.In addition,under the condition of water-rich section,the failure modes are mainly water inrush and sand gushing,and the mechanism is mainly seepage instability.(4)Advanced geological prediction and dynamic risk evaluation of disaster occurrence are important measures for disaster prevention and controlling of sandy dolomite tunnels.The construction of slurry stop wall and consolidation grouting of surrounding rock are specific measures to deal with water and sand inrush.Construction experience still needs to be accumulated and summarized.The research results have certain guiding value for the disaster prevention and control of surrounding rock of sandy dolomite tunnel.

外文关键词：

rock mechanicswater diversion project in central Yunnansandy dolomitespatial distributionmicrostructurefailure mechanism of surrounding rock mass

作者：

董家兴、周志强、赵永川、米健、李建国、柳晓宁、李超、周伦顺、沈桢洛、沐红元

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作者单位：

昆明理工大学电力工程学院,云南昆明 650500

云南省水利水电勘测设计研究院,云南昆明 650021

关键词：

岩石力学滇中引水工程砂化白云岩空间分布微观结构围岩破坏机制

基金：

云南省重大科技专项计划国家自然科学基金资助项目云南省应用基础研究计划

项目编号：

202002AF08000342162026202201AT070083

出版年：

2024

DOI：

10.13722/j.cnki.jrme.2023.0279

岩石力学与工程学报

中国岩石力学与工程学会

岩石力学与工程学报

CSTPCD北大核心

影响因子：2.589

ISSN：1000-6915

年,卷(期)：2024.43(z1)