针对广西山心隧道屡次发生的突水灾害,采用现场勘探、室内试验与理论分析方法,对全强风化花岗岩隧道突水灾害机制、灾变特征与防治对策进行了深入研究。结果表明:山心隧道突水灾害具有突发性强、灾变演化速度快、次生灾害严重及影响范围大的特点,突水灾害发生的孕险环境因素为地层水稳定性差、导水通道发育、地下水与地表水丰富、带状谷地汇水负地形,而注浆实施不到位、防突岩土体留设厚度不足及施工扰动是隧道突水灾害主要致灾因子,在施工扰动与地下水压力共同作用下,掌子面渗透失稳形成突水通道并迅速演化扩展,继而引起地表塌陷、井塘干涸等次生灾害。综合考虑隧道施工与地表生态环境安全,制定了"以堵为主、排堵结合、分段治理、动态施工"的总体治理原则,优化确定复合帷幕注浆、全断面帷幕注浆及动态施工的协同治理技术体系,应用于山心隧道全强风化花岗岩段突水灾害的防治实践。
Water inrush disaster in weathered granite regions with abundant water does tremendous harm to the construction of tunnels and surrounding environment. Combining with the treatment practice of water inrush disaster of Shanxin tunnel in Guangxi Zhuang Autonomous Region,the water inrush mechanism,character of disaster and countermeasures were studied by conducting geophysical and drilling exploration at field,laboratory experiments and theoretical analysis. It shows that the water inrush disaster happens suddenly and has strongly destructive influence with high evolution speed. The risk environment factor of water inrush disaster in weathered granite regions are disintegration of surrounding soil, interconnected channels of groundwater, abundant groundwater recharge,and banded valley topography. Meanwhile,unsatisfactory of grouting implementation,insufficient of outburst prevention thickness and disturbance of excavation is the dominant inducing factor to cause water inrush disaster. Under the influence of excavation disturbance and groundwater pressure,the advancing face loses stability because of seepage failure and evolves rapidly to form water inrush disaster,even inducing ground collapse and severe water losses, etc. Considering the safety of tunneling construction and ecological environment,general treatment principle of water inrush disaster is proposed,which emphasizes on giving priority to seal water by grouting combining with the drainage work. Further on,according to the different geological conditions caused by water inrush disaster,corresponding treatment scheme should be adopted with dynamic construction principle. In order to seal water and reinforce the completely weathered granite,the synergetic treatment technology is optimised,with composite curtain grouting and full-face curtain grouting. And the proposed synergetic treatment technology is adopted in the design of treatment of water inrush disaster and applied into practice.