The rock instability of granodiorite mountain rock located within a key route for the Mecca city (Al Haram) and Al-Taif (tourist place) was investigated. In this study eight, highly susceptible sites from 22 km road selected for kinematic and rockfall analysis to avoid rockfall consequences. Based on the field investigation, this mountain road is characterized by nearly vertical cut slopes with highly fractured and jointed rocks leading to the occurrences of rock instability. The kinematic results indicated that planar, wedge and toppling failure is the main reason for rock block instability. Furthermore, the rockfall movement trajectory and bounce height were modeled with their corresponding translational velocity and kinetic energy for delineating the dynamics of a falling rock block. The bounce height ranged from approximately 1.3 m to > 8 m. The energies ranged from low (< 30 kJ) to high-intensity zones (> 300 kJ) capable of causing mortality and damaging infrastructure. The present study indicates the study area is at risk of rockfalls and preventive measures are required to minimize the rockfall hazard. Study results can serve as a reference for predicting rockfall areas under similar conditions.

中文翻译：

---

NH-15沿线崩塌危险性分析：以Al-Hada公路为例

调查了位于麦加市（Al Haram）和Al-Taif（旅游胜地）关键路线内的花岗闪长岩的岩石不稳定性。在这项研究中，从22 km的道路上选择了八个高度敏感的地点进行运动和落石分析，以避免落石的后果。根据现场调查，这条山路的特征是近乎垂直的开挖坡度，具有高度破裂和节理的岩石，从而导致岩石失稳的发生。运动学结果表明，平面，楔形和倾覆破坏是造成岩体失稳的主要原因。此外，利用落石运动轨迹和弹跳高度及其相应的平移速度和动能对落石块的动力学进行了建模。弹跳高度约为1.3 m至> 8 m。能量范围从低（<30 kJ）到高强度区域（> 300 kJ），能够导致死亡和破坏基础设施。本研究表明，研究区存在崩塌的危险，需要采取预防措施以最大程度地降低崩塌的危险。研究结果可为预测相似条件下的落石面积提供参考。