砂板岩互层隧道掌子面突水灾变发生模型试验研究  

A Model Test Study on the Catastrophic Occurrence of Water Inrush on the Tunnel Face in Sand-slate Interbedded Strata

作　　者：许芃[1,2] 彭鹏 琚国全[3] 赵万强 张志强[1,2] XU Peng;PENG Peng;JU Guoquan;ZHAO Wanqiang;ZHANG Zhiqiang(Key Laboratory of Transportation Tunnel Engineering,Ministry of Education,Southwest Jiaotong University,Chengdu 610031;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031;China Railway Eryuan Engineering Group Co.,Ltd.,Chengdu 610031)

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室,成都610031 [2]西南交通大学土木工程学院,成都610031 [3]中铁二院工程集团有限责任公司,成都610031

出　　处：《现代隧道技术》2023年第2期271-281,共11页Modern Tunnelling Technology

基　　金：高铁联合基金(U1934213)。

摘　　要：为深入研究砂板岩隧道突水灾变机制及规律,以中老铁路新平隧道为工程背景,通过模型试验再现了隔水板岩渐进破坏型突水灾变演化过程,分析了围岩应力-应变特征、渗透压力与流量随隔水层厚度减小的变化规律。结果表明:(1)砂板岩突水灾害经历了渗流、涌突和衰减3个阶段,本质上是在开挖卸荷和应力-渗流耦合作用下,隔水层中薄弱部位裂隙逐步扩展、贯通直至突水通道形成,隔水层稳定性逐渐丧失的渐进过程;(2)围岩的应力-应变曲线及渗透压力和流量的关系均具有明显的前兆特征和阶段性特征,其变化规律反映了灾害的孕育、发展和演化过程;(3)渗透压力和流量变化过程中均存在一个突变点,突变点可作为隔水层阻水能力劣化的特征点,该点所对应的隔水层厚度即为隔水层临界安全厚度。To investigate the catastrophic mechanism and pattern of water inrush in tunnels in sand-slate strata,this paper takes the Xinping Tunnel on China-Laos Railway as the study case,and through model tests,reproduces the catastrophic occurrence and evolution process of the water inrush in the progressive failure of slate aquifuge,so as to analyze the changing pattern of the stress-strain characteristics of surrounding rocks,seepage pressure and flow rate with the decreasing thickness of the aquifuge.The results show that:(1)The water inrush in the sand slate strata would experience three stages:seepage,inrush and attenuation,which is essentially a gradual evolution process where,under the action of excavation unloading and stress and seepage coupling,fractures in the weak parts of the aquifuge gradually expand and break through until inrush channels are formed and the stability of the aquifuge loses gradually;(2)The stress-strain curve of the surrounding rocks and the relationship between the seepage pressure and flow show significant precursor and stage characteristics,and their changing patterns reflect the breeding,devel⁃opment and evolution process of the disaster;(3)A sudden change point exists in the changing process of the seep⁃age pressure and flow rate,and this sudden change point can be seen as the characteristic point of degradation in the water-blocking capacity of the aquifuge.The aquifuge thickness reflected by this point can be seen as the critical safety thickness of the aquifuge.

关 键 词：突水 砂板岩互层 模型试验 灾变过程 隔水层厚度 

分 类 号：U451.5[建筑科学—桥梁与隧道工程]