旭龙电站尾水调压室洞间岩柱围岩宏细观特性分析

Macro and micro characteristics of surrounding rock of rock pillar between tail-race surge chamber caverns in Xulong Power Station

为了将连续和非连续分析方法耦合用于地下厂房围岩稳定性分析,提出了一种基于软硬混合平行黏结模型的细观参数快速标定法,可根据给定岩石的宏观力学参数快速给出其颗粒流模型细观接触参数;在此基础上,构建了基于颗粒离散元PFC 3D与有限差分FLAC 3D耦合的旭龙地下电站尾水调压室三维离散-连续耦合分析模型,研究了开挖期尾水调压室洞间岩柱围岩变形与破坏宏细观特性,以及检修期间侧向水压力对洞间岩柱稳定性的影响。结果表明:检修期间尾水调压室水压力引起的围岩变形与应力增量变化是极小的,但洞间岩柱上半段22.7 m的高度存在塑形贯通区,局部稳定性较差,有必要在工程建设期开展尾水调压室及尾水支洞岩墩塑性贯通区专项支护方案研究,以确保旭龙地下电站工程的安全建设与运行。

To couple continuous and discontinuous analysis methods for the stability analysis of surrounding rock in underground power stations,a rapid calibration method for mesoscopic parameters based on a soft-hard mixed parallel bond model was implemented.This method can quickly correspond to the given rock macroscopic mechanical parameters to PFC model mesoscopic contact parameters.A three-dimensional discrete continuous coupling analysis model for the tail-race surge chamber of Xulong Power Station based on the coupling of particle discrete element PFC 3D and finite difference FLAC 3D was constructed.The macro-micro deformation and failure characteristics of rock pillars between tail-race surge chamber caverns during excavation were studied,as well as the impact of lateral water pressure on the rock pillar stability.The results showed that the deformation and stress increment of surrounding rock caused by the water pressure in the surge chamber under maintenance condition were minimal,but there was a plastic penetration zone at the height of 22.7 m in the upper half of the rock pillar between the caverns,with poor local stability.Thus it is necessary to carry out a special support scheme study on the plastic penetration zone of the tail-race surge chamber and tail-race branch tunnel rock piers during the construction period to ensure the safe construction and operation of the Xulong Power Station project.