摘要
突水突泥是隧道穿越岩溶、风化花岗岩等软弱地层常面临的地质灾害之一。在隧道开挖过程中,预留必要的安全厚度是保障岩土体不被高水压击穿,遏制突水突泥灾害的重要措施。为了确定合适的安全厚度,首先基于溶质运移和多孔介质渗流理论,导出可以考虑软弱地层颗粒物迁移的多场耦合突水突泥理论模型;其次依托实际隧道工程,采用Comsol多场耦合系统开展不同安全厚度下的隧道渗流侵蚀特性数值研究。通过分析地层孔隙率、渗透率、涌水及涌泥量发展规律,评定发生潜在突水突泥灾害风险,进而确定合理的安全厚度。结果表明:防突厚度小于4 m时,短时间内掌子面前方颗粒即发生显著流失,极易形成突水通道,涌水涌泥量大大超过开挖设计的标准。当防突厚度大于5 m,地层围岩孔隙率、渗流通道得到有效遏制,掌子面的涌水涌泥均得到有效控制。从安全、经济、技术角度分析,防突厚度建议取4 m~5 m。
Water and mud inrush is the most commonly geological disaster when the tunnel passes through the waterrich soft stratum such as karst and weathered granite.Reserving the necessary safety thickness is an important measure to prevent the rock mass failure induced by high water pressure and water inrush disaster.To determine the safety thickness,a multi-field coupling theoretical model is proposed considering the migration of particles in weak formation based on the theories of solute transport and porous media seepage.Then,a numerical study using the Comsol system is conducted to investigate the seepage erosion characteristics of the tunnel under different safety thickness based on a field case.By analyzing the development law of porosity,permeability,water and mud inrush,the water inrush risk and the reasonable safe thickness are evaluated.The results show that when the thickness is smaller than 4 m,the particles in front of the face will lose significantly in a short time,which is easy to form water inrush channel.Besides,the amount of water and mud gushing greatly exceeds the standard of excavation design.When the thickness is larger than 4 m,especially larger than 5 m,the porosity of surrounding rock and seepage channel are effectively suppressed,and the water and mud gushing on the face are effectively controlled.In terms of safety,economy and technology,it is more suitable to take the thickness of 4 m~5 m.
作者
刘晨
曾冠铭
王松
余来斌
杨涛
田荆涛
梁超恒
卢亚婷
LIU Chen;ZENG Guanming;WANG Song;YU Laibin;YANG Tao;TIAN Jingtao;LIANG Chaoheng;LU Yating(China Construction Eighth Engineering Bureau Co.,Ltd.,Shanghai 200000,China;South Company of China Construction Eighth Engineering Bureau Co.,Ltd.,Nanning,Guangxi 530022,China;School of Civil Engineering,Xijing University,Xi’an,Shaanxi 710123,China)
出处
《水利与建筑工程学报》
2021年第6期57-62,共6页
Journal of Water Resources and Architectural Engineering
关键词
软弱富水地层
隧道工程
突水突泥
安全厚度
water-rich soft formation
tunnel engineering
water and mud inrush
safety thickness
