白鹤滩水电站左岸坝基柱状节理开挖松弛特性试验研究

白鹤滩水电站左岸坝基边坡柱状节理玄武岩出露且易松弛,对边坡安全稳定影响较大。为了解坝基柱状节理玄武岩在爆破开挖后松弛深度的变化规律及发展趋势,以坝基650~660 m高程边坡柱状节理试验区为研究对象,利用声波孔检测不同区域、不同支护条件下岩体松弛深度。通过分析检测成果得出如下结论:地质条件对柱状节理玄武岩的松弛深度有影响;预应力锚杆在一定时间内能压密松弛岩体,其防松弛作用好于砂浆锚杆。

Characteristics of Excavation-induced Relaxation of Columnar Jointed Basalt in the Left Bank Dam Foundation of Baihetan Hydropower Station

Columnar jointed basalt rock masses are exposed and easily relaxed on the left bank dam foundation of Baihetan hydropower station,posing large influence on the safety and stability of slope.In the aim of obtaining the variation rule and development trend,the relaxation depth of columnar jointed basalt in different areas under various support conditions was detected using acoustic detection technology.The area at elevation 650-660m of the dam foundation slope was selected as the test area.According to detection results,the relaxation depth of the columnar jointed basalt is affected by geological condition;pre-stressed anchor could prevent the rock mass from relaxation by compacting it,and the effect is better than that of mortar anchor.