基于摄影成像的景观平衡石调查及稳定性分析

Investigation and Stability Analysis of Balanced Rock Based on UAV Photographic Imaging

平衡石在自然状态下大多处于基本稳定或极限平衡状态,在外界扰动下易失稳。为了开展缙云抽蓄工程区典型景观平衡石在爆破荷载下的保护工作,采用无人机航拍和手持相机摄影相结合的摄影测量方法,获得了典型景观平衡石精细三维数字模型;基于数字模型获得了平衡石的几何信息及接触状态,对平衡石的静力平衡状态及静力稳定性开展了分析,获得了滑移失稳和倾倒失稳模型下的安全系数;采用非连续变形分析(DDA)方法,对极限平衡状态下的平衡石开展了动荷载稳定分析,采用大刚度法在模型底部输入速度时程,模拟平衡石基座实测的振动曲线,通过放大输入荷载得到平衡石失稳时基座水平振动速度允许值,并结合爆破安全规程提出了景观平衡石基座的爆破振动安全允许振动速度为0.20~0.40 cm/s。

Most balanced rocks are in limit equilibrium or basically stable state in natural conditions,but are prone to lose stability under external disturbance.The aim of this research is to protect the famous landscape balanced rocks in Jinyun Pumped Storage Power Station project area under blasting load.The fine three-dimensional numerical model of the balanced rocks was established based on unmanned air vehicle(UAV)photography and handheld camera photography.The geometric information and contact state of the balance rocks were obtained by using the numerical model,and the safety factors under sliding instability and toppling instability were acquired by analyzing the static equilibrium state and static stability.Moreover,the Discontinuous Deformation Analysis(DDA)method was employed to analyze the dynamic load stability of the balanced rocks under limit equilibrium state.The large stiffness method was adopted to input the velocity time history at the bottom of the model to simulate the measured vibration curve of the balanced stone base.By amplifying the input load,the allowable value of the horizontal vibration velocity of the base at instability state was obtained.In line with blasting safety standard,the allowable blasting vibration safety standard of balanced stone base is proposed to be within 0.20-0.40 cm/s.