洛宁抽水蓄能电站排沙洞出口岩质边坡安全控制研究

Study on Safety Control of Rock Slope at Outlet of Desilting Tunnel of Luoning Hydropower Station

洛宁抽水蓄能电站泄洪排沙洞出口边坡为高陡岩质边坡,该处边坡存在风险主要有:边坡岩体结构面发育、泥化夹层等不良地质风险;爆破开挖加剧岩体结构面扩张的施工风险;下方排沙洞隧道施工对上方边坡的稳定性影响。边坡施工期间出现小范围垮塌,为保证隧道口边坡的安全稳定性,开展了风险分析、边坡稳定性分析、支护优化设计、现场监测相结合的边坡稳定性研究工作。边坡稳定性分析表明:爆破施工引起的振动效应使得边坡的剪应变及位移增大,边坡应力增大有可能超过岩体抗剪强度,导致岩体沿结构面滑出。通过在边坡上埋设以阵列位移计及多点位移计为主的深部位移监测孔,以信息化思路指导边坡运营及隧道施工。目前隧道进尺50余米,边坡阵列位移计的竖向最大位移约为3mm,多点位移计的水平向最大位移约为4mm。现场监测及巡视结果表明:隧道口区域的边坡及隧道均处于安全状态。

The slope at the outlet of the spillway and sand drainage tunnel of luoning pumped storage power station is a high and steep rock slope,and the risks of the slope mainly include:Adverse geological risks such as the well developed of structural plane of rock mass and muddy interlayer in the slope;blasting excavation intensifies the construction risk of rock structure plane expansion;influence of tunnel construction in the lower sand drainage tunnel on the stability of the upper slope.In order to ensure the safety and stability of the tunnel portal slope,the slope stability was studied by risk analysis,slope stability analysis,support optimization design and site monitoring.The slope stability analysis shows that the vibration effect caused by blasting construction makes the shear strain and displacement of the slope increase,and the increase of the slope stress may exceed the shear strength of the rock mass,resulting in the rock mass sliding out along the structural surface.The deep displacement monitoring hole with array displacement meter and multi-point displacement meter is embedded in the slope to guide the slope operation and tunnel construction with the idea of information.At present,the tunnel footage is over 50 meters,the maximum vertical displacement of slope array displacement meter is about 3mm,and the maximum horizontal displacement of multi-point displacement meter is about 4mm.The results of field monitoring and inspection show that the slope and tunnel are in a safe state.