There is intrinsic difficulty in the investigation of the largest volume of rockfalls that is expected in an area, which lies in the small number of large events, in registrable times. The maximum credible rockfall size has been associated with the properties of the rock mass discontinuities, as they delimit detachable rock blocks, and in particular with the penetration of those discontinuities that comprise rockfall sliding planes. In highly fractured rock masses, the evaluation of the penetration remains an issue. A probabilistic methodology is proposed, to measure the penetration of potential sliding planes into the interior of a rocky slope. The main hypothesis of the method is that the sliding plane persistence is interrupted along its two directions, at the intersection with two lateral discontinuity sets, as the latter displaces the former. Due to the displacement, the sliding planes are formed by quasi-planes that contain a maximum number of spacings of the intersecting joints, hence their size is restricted. The methodology requires as an input the spacing of the intersecting joint sets. Its application to a granodiorite slope confirms that for the study site, there is a maximum volume of rockfalls, excluding the possibility of large stepped failures and rupture of rock bridges. The maximum calculated persistence for the two existing sliding planes in the study site is, respectively, 28.0 m and 48.5 m. The maximum calculated sliding plane surfaces are, accordingly, 282.5 m 2 and 289.3 m 2 . These results are compared against the observed scar dimensions at the study site, which have been retrieved alternatively, by processing a LiDAR point cloud. The results from the two alternative sources are similar, indicating that the methodology can be efficiently used to assess the sliding plane persistence and the expected maximum rockfall magnitude at the study site.

中文翻译：

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基于滑面进入斜坡的概率评估的最大落石尺寸评估

在可登记的时间内，由于大型事件的数量很少，因此要调查预计发生在一个地区的最大数量的落石事件存在固有的困难。最大可信的落石尺寸与岩体不连续性的特性有关，因为它们界定了可分离的岩块，特别是与构成落石滑动面的那些不连续性的渗透有关。在高度破碎的岩体中，穿透力的评估仍然是一个问题。提出了一种概率方法，以测量潜在滑动面对岩石斜坡内部的渗透。该方法的主要假设是滑动平面持久性沿其两个方向在与两个横向不连续集的交点处中断，因为后者取代了前者。由于位移，滑动面由包含最大数量的交叉接头间距的准平面形成，因此它们的尺寸受到限制。该方法需要将交叉关节组的间距作为输入。它在花岗闪长岩边坡上的应用证实，对于研究地点，存在最大的落石量，排除了大型阶梯式破坏和岩桥破裂的可能性。研究站点中两个现有滑动平面的最大计算持久性分别为 28.0 m 和 48.5 m。因此，计算出的最大滑动平面为282.5 m 2 和289.3 m 2 。这些结果与在研究地点观察到的疤痕尺寸进行比较，这些疤痕尺寸是通过处理 LiDAR 点云来替代检索的。