CCS水电站输水隧洞工程地质条件分析与处理

Analysis and Treatment of Engineering Geology Conditions at CCS Hydropower Station Headrace Tunnel

为保证CCS水电站输水隧洞双护盾TBM施工正常进行,开展了围岩分类与稳定性评价及隧洞超前地质预报,研究了施工方法,提出了施工技术建议。在双护盾TBM施工过程中,可见的围岩范围较小,无法进行地质素描,根据双护盾TBM施工的技术特点,选择了隧洞掌子面及洞壁小范围的围岩观察、TBM掘进参数分析、局部岩石回弹值测试、岩渣性状分析、地下水特征分析等多种方法获取围岩地质信息,从而对围岩进行分类和稳定性评价。选择了隧洞宏观地质条件分析、施工过程地质条件分析、以地震法和电法为主的物探方法、掌子面超前水平钻探等综合方法对掌子面前方围岩进行探测和预报,根据预报结果有针对性地采取处理措施。针对TBM施工过程中出现的涌水、砂岩砂化、断层破碎带等不良地质条件,建议施工单位采取了超前地质预报及调整掘进参数、堵水、超前灌浆加固围岩等施工方法和技术,TBM顺利通过了不良地质段。

In the TBM construction process of the headrace tunnel of CCS Hydropower Station,the main construction geology work is as follows,classification and stability evaluation of surrounding rock,advance geological prediction,construction method and construction technique suggestions.In the process of double-shield TBM construction,visible surrounding rock is too small to carry out geological sketch.According to the technical characteristics of double shield TBM construction,the surrounding rock observation,TBM tunneling parameter analysis,local rock rebound test,rock muck property analysis,groundwater characteristic analysis and other methods were selected to obtain the surrounding rock geological information,and then surrounding rock classification and stability evaluation were carried out.The comprehensive methods of tunnel macro-geological condition analysis,construction process geological condition analysis,geophysical prospecting method based on seismic method and electrical method,and horizontal drilling were selected to detect and forecast the surrounding rock in front of the tunnel face,and corresponding treatment measures were taken according to the prediction results.According to the water gushing,sandstone,fault zone and other adverse geological conditions,it suggested that the construction company to take the advanced geological forecast,adjust the tunneling parameters,water plugging and advanced grouting reinforcement technique,TBM passed the adverse geological section successfully.