【摘要】 基于卸荷岩体的理论和方法,对大岗山水电站坝肩边坡进行研究。以大型通用有限元程序ADINA为计算平台,对比分析坝肩边坡卸荷后,不同地震加速度及不同锚固长度和锚固吨位在卸荷条件下关键点的位移和应力以及塑性区的变化规律,认为边坡开挖变形由两部分组成,一部分为卸荷回弹,另一部分是由于大吨位锚索施加后产生的朝向坡内的压缩变形。研究表明,由于锚索穿过V岩体底部界线,在可能的滑坡剪出口形成强大的阻滑键,增加锚索长度或吨位均可有效地减小坝肩塑性区,地震加速度为0.1g和0.15g时,在各加固吨位下均可能形成塑性区的贯通;在不同的地震加速度下,受不同锚固长度和锚固力影响,不同关键点处水平向位移呈现线性变化和非线性变化,非线性关系中的拐点应重点关注;若要减少岩体塑性区,相同比例下增大锚固长度效果更好。为了有效减少在高地震烈度时边坡塑性区的发育,建议采用增加120%的锚固长度。更多还原

【Abstract】 The Dagangshan hydropower station dam abutment slope stability has been studied based on the theory of unloading rock mass.Based on the large-scale universal finite element program ADINA,for the conditions of different earthquake accelerations,different anchoring lengths and tonnages of unloading dam abutment slope,the displacements of key points,stresses and plastic zones change rule are comparatively analyzed;and it is pointed out that the slope deformations are composed of two parts;one part is unloading rebound,the other part is the compressive deformation of inner facing slope induced by applying large tonnage anchors.Research shows that because of the cable through the V-shaped rock bottom line,in the possible shear zone of landslide there formed a strong resistance sliding key,so that increasing cable length or tonnage can effectively reduce the plastic zone of the abutment;for accelerations of 0.1g and 0.15g in the earthquake,in different reinforcements of tonnages,may form transfixion of plastic zone.Under different earthquake accelerations effected by different anchorage length and anchoring force,the horizontal displacements of different key points presented linearly and nonlinearly changing;inflection point in the nonlinear relationship should be paid attention to.To reduce the plastic zone of rock mass,it is better to increase anchorage length in the same proportion.In order to effectively reduce the plastic zone development during strong earthquake,the 120% increase in anchor length is suggested.更多还原