摘要
侵入接触带围岩往往风化严重,其内部的渗流通道与地表水系联系紧密,进一步增加了隧道穿越施工时的风险。本文从地下水渗流的致灾机理出发,研究了荆西隧道施工过程中侵入接触带的突水时间以及开挖扰动后围岩受力特征。分析认为隧道地下水的不断渗流会致使围岩孔隙率及渗透性增大,从而导致侵入接触带中潜在滑动面裂隙失稳,渗流过程中在土粒骨架上形成渗透压力,对岩石形成拉曳作用,加剧突水突泥风险;通过理论推导可知,荆西隧道侵入接触破碎带的渗流量突水流量约为3878 m^(3)/d,突水完成时间为12 d,此结果对于确定因突水导致的停工时间以及预测下个阶段施工节点意义重大;利用数值模拟手段可知,在穿越侵入接触带施工过程中,突水突泥溃口处围岩所受应力较大,最大有效应力为207 kPa,最大总应力为4590 kPa,变形均集中在隧道拱顶及拱腰处,及时采取钢拱架、钢筋网片、锚杆和喷射混凝土等措施进行加固,能够有效阻止灾害的进一步发展。
The surrounding rock in the intrusive contact zone is often severely weathered,and the seepage channel inside is closely connected with the surface water system,which further increases the risk of tunnel crossing construction.Based on the disaster causing mechanism of groundwater seepage,this paper studies the water inrush time of the intrusive contact zone and the stress characteristics of surrounding rock after excavation disturbance in Jingxi Tunnel construction.The analysis shows that the continuous seepage of underground water in the tunnel will increase the porosity and permeability of surrounding rock,which will lead to the instability of potential sliding surface cracks in the intrusive contact zone.In the process of seepage,osmotic pressure is formed on the soil grain framework,which forms a drag effect on the rock and aggravates the risk of water and mud inrush.Through theoretical deduction,it can be seen that the seepage flow of the intrusive contact crushing zone of Jingxi Tunnel is about 3878 m^(3)/d,and the completion time of water inrush is 12 days.This result is of great significance for determining the downtime caused by water inrush and predicting the construction node of the next stage.According to the numerical simulation method,during the construction process of crossing the intrusive contact zone,the stress on the surrounding rock at the water burst and mud burst is larger,with the maximum effective stress of 207 kPa and the maximum total stress of 4590 kPa,and the deformation is concentrated at the vault and hance of the tunnel.Timely reinforcement measures such as steel arch,steel mesh,bolt and shotcrete can effectively prevent the further development of the disaster.
作者
王红伟
WANG Hongwei(China Railway 16th Bureau Group Co.Ltd.,Beijing 100018,China)
出处
《铁道建筑技术》
2023年第7期163-166,171,共5页
Railway Construction Technology
基金
中铁十六局集团有限公司科技研究开发计划项目(K2022-8A)。
关键词
隧道工程
垂直侵入带
渗流量
稳定性
tunnel engineering
vertical invaded zone
seepage flow
stability
