首页|近断层砂化白云岩隧洞突水涌砂演化过程及防突岩盘安全厚度研究

近断层砂化白云岩隧洞突水涌砂演化过程及防突岩盘安全厚度研究

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滇中引水工程砂化白云岩隧洞突水涌砂灾害频发,严重制约工程进度并威胁着施工安全.通过施工跟踪、砂化白云岩隧洞突水涌砂案例统计、理论分析等手段,总结富水洞段突水涌砂的成灾条件及灾变特征;基于小扑隧洞典型近断层段的突水涌砂灾害原型,采用FLAC3D模拟突水涌砂过程渗流场、应力场、位移场的演化,确定突水涌砂灾害的防突岩盘安全厚度临界判据,并建立系统、可行的灾害防控体系.研究结果表明:(1)突水涌砂通常发生在断层发育的富水强烈、剧烈砂化洞段;(2)突水涌砂灾变演化过程中,强烈、剧烈砂化白云岩孔隙水压力均存在漏斗效应,剧烈砂化白云岩渗流量变化与强烈砂化白云岩相比存在时滞性,并且剧烈砂化白云岩的渗流量明显比强烈砂化白云岩小;(3)强烈砂化白云岩隧洞开挖至距离断层4m时,隧洞围岩应力出现突变现象,剧烈砂化白云岩隧洞开挖至距离断层8～9m时,呈现出明显的拉应力区域;(4)强烈砂化洞段拱顶最大沉降于开挖至距离断层1m时出现,而剧烈砂化洞段位移场演化无明显规律;(5)确定了富水砂化白云岩隧洞防突岩盘安全厚度临界判据,通过工程实例计算得到的最小安全厚度与实际工程预留接近.结合综合超前地质预报、富水砂化白云岩隧洞突水涌砂演化过程建立的隧洞施工期突水涌砂防控体系,可为富水砂化白云岩地下工程易发频发的突水涌砂灾害防控提供借鉴.
Water and sand inrush evolution and minimum safe thickness of waterproof-resistant slab in sandy dolomite tunnels near the faults
The frequent water and sand inrush disasters in the sandy dolomite tunnels of the water diversion project in central Yunnan seriously restrict the progress of the project and threaten the construction safety.In this paper,the disaster conditions and characteristics of water and sand inrush in water-rich tunnel sections are summarized by means of construction tracking,case statistics and theoretical analysis of water and sand inrush in sandy dolomite tunnels.According to the typical disaster prototype of Xiaopu tunnel,the evolution of seepage field,stress field and displacement field in the process of water inrush and sand gushing is studied by FLAC3D numerical simulation.The critical criterion of safety thickness of rock plate for preventing water and sand inrush disaster is determined by theoretical analysis.In the other hand,systematic and feasible disaster prevention and control system is established.The results show that:(1)water and sand inrush disasters usually occur in the severely completely sandy and water-rich section of the fault development.(2)In the evolution process of water and sand inrush disaster,the pore water pressure of intense and severe sandy dolomite has funnel effect.There is a time lag in the change of seepage flow of severe sandy dolomite compared with that of strong sandy dolomite,the seepage flow of intensely sandy dolomite is obviously smaller than that of intensely sandy dolomite.(3)When the severely sandy dolomite tunnel is excavated to a distance of 4 m from the fault,the stress of the surrounding rock of the tunnel shows a sudden change.When the completely sandy dolomite tunnel is excavated to a distance of 8-9 m from the fault,it shows an obvious tensile stress area.(4)The maximum settlement of the vault of the severely sandy tunnel section occurs when the excavation is 1 m away from the fault,while the evolution of the displacement field of the completely sandy tunnel section has no obvious law.(5)The critical criterion of safe thickness of outburst prevention rock plate in water-rich sandy dolomite tunnel is determined.The minimum safe thickness calculated by engineering example is close to the reserved in practical engineering.On the basis of the above research results,combined with the comprehensive advanced geological prediction and the evolution process of water and sand inrush in water-rich sandy dolomite tunnel,the prevention and control system of water and sand inrush in tunnel can be established,which can provide theoretical basis for the prevention and control of water and sand inrush disasters that are prone to occur in water-rich sandy dolomite underground engineering.

tunnel engineeringwater-rich sandy dolomiteengineering prototypefluid-solid couplingevolution processminimum safe thickness of outburst prevention rock plate

张延杰、董家兴、周志强、周伦顺、米健、刘登学

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云南省滇中引水工程有限公司,云南昆明 650000

昆明理工大学国土资源工程学院,云南昆明 650093

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

长江科学院水利部岩土力学与工程重点实验室,湖北武汉 430010

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隧道工程 富水砂化白云岩 工程原型 流固耦合 演化过程 防突岩盘安全厚度

云南省科技重大专项长江水利委员会长江科学院开放研究基金云南省应用基础研究计划

202002AF080003CKWV2021882/KY202201AT070083

2024

10.13722/j.cnki.jrme.2023.1127

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(3)
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