藏区高速公路高压富水区隧道渗流场特性分析

Analysis of Seepage Field Characteristics in High-pressure and Water-rich Area Tunnel of Tibetan Expressway

高压富水地层隧道施工时往往伴随着突涌水,严重影响施工进度并威胁洞内人员生命安全。依托汶马高速公路某隧道工程,基于流固耦合方法开展数值模拟计算,研究不同水头和围岩渗透系数下施工扰动造成的隧道外侧渗流场变化情况,并通过现场监测进行验证。结果表明,隧道开挖扰动引起孔隙水压呈先降低后升高的变化趋势;隧道拱顶与拱底处渗流集中,拱腰处外水压力最大,需要重点设防;水头高度与渗流场初始孔隙水压呈正相关;围岩渗透系数越大渗流越强烈,衬砌相同位置对应孔隙水压越小。

The construction progress of tunnel in high-pressure water-rich stratum is often seriously affected by water inrush,which also threatens the life safety of people in the tunnel.Based on a tunnel project in Wenchuan-Markang Expressway,this paper carries out numerical simulation calculation based on fluid-solid coupling method to study the changes of seepage field outside the tunnel caused by construction disturbance under different water heads and surrounding rock permeability coefficients,and verifies it through on-site monitoring.The results show that,the pore water pressure decreases and then increases due to tunnel excavation disturbance;The seepage is concentrated in the vault and the bottom of the tunnel,and the water pressure outside the waist of the arch is the largest so it needs to be fortified;The head height is positively correlated with the initial pore water pressure in the seepage field;The larger the permeability coefficient of surrounding rock,the stronger the seepage,and the smaller the corresponding pore water pressure at the same position of lining.