大型节理岩质边坡失稳破坏机理三维DDA方法与试验研究

本项目以经历开挖扰动的大岗山水电站右岸大型节理岩质边坡为工程背景，根据现场调研资料和微震监测数据，建立岩质边坡室内试验平台系统和边坡模型，开展不同结构面分布、界面参数、开挖方量及雨水渗透、水库水位变化等条件下的边坡失稳破坏试验。基于以进入块体模型为核心的接触理论，发展非凸块体接触和角-角局部接触等模型，改进块体大转动、接触界面临界滑动等接触力学模型，提出复杂形态块体间准确接触判断和搜索方法，研发拥有较高接触计算效率的3D DDA方法。结合边坡微震监测及传感器宏观变形监测数据和模型试验结果，验证3D DDA在大型节理岩质边坡模拟方面的有效性。提出一套基于微震监测、模型试验和3D DDA数值模拟的综合研究方法，对岩体内部损伤机理和不同荷载条件下边坡失稳破坏进行研究，揭示大型节理岩质边坡内部岩体损伤、失稳破坏、停积成灾的三维动力学机理、特征及规律，为大型节理岩质边坡稳定性评价与灾害预警提供依据。

This project takes the large jointed rock slope on the right bank of Dagangshan Hydropower Station which has experienced excavation disturbance as the engineering background. According to the field investigation and microseismic monitoring data, the laboratory experimental platform system and slope model of the rock slope are established, and the slope failure experiments are carried out under various conditions, such as various structural plane distributions, interface parameters and excavation volumes, as well as rainwater infiltration and reservoir water level change. Based on the contact theory with the entrance block model as the core, the non-convex block contact and vertex-vertex local contact models are developed, the contact mechanics models such as large rotation of blocks and critical sliding of contact interfaces are improved, the accurate contact judgment and search methods between three-dimensional (3D) blocks of complex shapes are proposed, and the 3D discontinuous deformation analysis (3D DDA) method with high contact calculation efficiency is developed. The effectiveness of 3D DDA in the simulation of large jointed rock slopes is verified by combining the data from microseismic monitoring and macro deformation monitoring by the sensors and the results from laboratory model experiments. A comprehensive research method based on microseismic monitoring, model experiment and 3D DDA numerical simulation is proposed, the damage mechanisms of rock mass and slope failure under different load conditions are studied, and the 3D dynamic mechanisms, characteristics and laws of rock mass damage, instability failure and deposition disaster of large jointed rock slopes are revealed, which provides the basis for the stability evaluation and disaster early-warning of large jointed rock slopes.