富水全强风化花岗岩隧道突水突泥灾害机制与帷幕注浆技术

Water and Mud Inrush Disaster Mechanism and Curtain Grouting Technology on Granite Tunnel with Rich Water and Strong Weathering

为研究富水全强风化花岗岩隧道突水突泥灾害机制与帷幕注浆技术,以广西均昌隧道富水全强风化花岗岩地段突水突泥灾害处治实践为例,对隧道突水水泥灾害特征、诱发机制及防治措施进行深入研究分析。结果表明:富水全强风化花岗岩隧道突水突泥灾害突发性强,演变速度快,次生灾害严重,影响范围大;隧道突水突泥灾害的孕险环境因素有长条状谷地汇水负地形、水资源丰富、导水通道发育、岩层水稳定性差,而超前勘探工作不充分、注浆效果不到位及施工扰动是主要致灾因子,岩体受地下水浸泡软化,岩层在静水压力作用下被击穿,掌子面发生局部渗流失稳,形成突水通道,渗流转变为管道流,形成突泥通道,在静水压力和动水冲刷的共同作用下迅速演化发展成突水突泥灾害,同时引发地表塌陷、河流断流、池塘干涸等次生灾害;通过修正帷幕注浆参数,隧道注浆治理段开挖面整体稳定性显著增强,稳定渗流量减少53.78%~80.19%,对隧道堵水加固效果明显,能有效防治突水突泥灾害,确保工程施工安全,缩短建设工期,增大工程效益。研究成果对全强风化花岗岩隧道防治突水突泥灾害具有一定指导意义。

In order to study the water inrush and mud inrush mechanism and curtain grouting technology of water-rich fully weathered granite tunnel,the water-rich and strongly weathered granite section of Junchang tunnel in Guangxi was used as an example to make in-depth study on the characteristics of tunnel water-burst cement disaster,induction mechanism,prevention and control mea-sures.Results show that the water and mud inrush disaster in rich water and strong weathering granite tunnel happens suddenly and has strongly destructive influence with high evolution speed.The risk environment factor of water and mud inrush disaster in weathered granite regions includes long valley topography,abundant water resources,interconnected channels of groundwater,and poor formation water stability.Meanwhile,inadequate advance exploration,inadequate grouting effect and construction disturbance are the main disaster factors.The rock mass is softened by static water pressure soaking,and the rock formation is penetrated under the joint action of construction disturbance and static water pressure.Local seepage loss occurs on the palm surface to form a water burst channel and the seepage becomes a pipe flow to form a mud burst channel,which rapidly evolves and causes the tunnel water inrush and mud inrush disaster under the combined action of static water pressure and dynamic water scour.It even causes secondary disasters such as surface collapse,river breakage,and pond drying up.After curtain grouting treatment,the overall stability of tunnel excavation surface is enhanced significantly.The effect of water plugging and seepage prevention is obvious that the steady seepage flow is decreased by 53.78%~80.19%.This shows that curtain grouting can be used to reinforce the fully weathered granite tunnel with rich water and effectively avoid water inrush and mud inrush.It is beneficial to ensure the safety of the construction,shorten the construction period of the tunnel and increase the benefit of the project.The research results have a certain guiding significance for the prevention of water inrush and mud inrush by fully weathered granite tunnel.