金佛山水库取水口岩质高边坡动力稳定性分析

Dynamic Stability of High Rock Slope Located at Intake of Jinfoshan Reservoir

针对重庆金佛山水库取水口岩质高边坡,采用人工修正的加速度时程作为地震输入条件,运用动力有限元法,分析了地震作用下边坡岩体动力时程响应规律及其变形破坏机制。结果表明:锚喷支护抗震效果显著,有效地约束了地震作用下的边坡变形;地震作用下岩体运动方向主要以水平方向为主,边坡应力分布主要为压应力,并未出现明显的拉应力集中区;边坡整体范围内地震加速度放大系数呈不规则分布,受地震累积效应影响,岩体质点速度响应滞后于地震波普变化;按地震烈度Ⅶ度进行工程抗震设防时边坡整体安全,虽然地震作用下边坡可能发生自上而下的压致拉裂式滑移破坏,但边坡整体大规模惯性滑移失稳可能性较小。

Focusing on the high rocky slope located at intake of Chongqing Jinfoshan reservoir,the dynamic response law and failure mechanism of slope rock mass were analyzed by the dynamic finite element method,adopting the artificially modified acceleration curve as the input condition of earthquake. The results show that the anti-seismic effect of bolt-spray supporting is significant,which effectively constrains the deformation of the slope in earthquake. The movement direction of the rock in earthquake is horizontal,the stress is mainly compressive stress,and there is no obvious tensile stress area. In the whole range,the distribution of acceleration magnification coefficients of earthquake is irregular; the response speed of rock mass lags behind Pope change of earthquake wave,which is affected by the cumulative effect of earthquake. The slope is safe under the design of anti-seismic engineering according to seismic intensity VII. Although it may occur top-down pressure-induced crack damage under earthquake,the slope is unlikely to be large-scale inertial instability.