深部地下泵站厂房锚固岩体时效变形特征与加固效应

Time-dependent deformation characteristics and reinforcement effect of anchored rock mass in deep underground pumping stations

预应力锚索支护系统能够有效抑制地下洞室围岩塑性区的扩展。基于原位监测和数值计算分析,对高边墙、大跨度地下洞室开挖过程中顶拱和边墙的变形演化过程以及锚索拉力的时效特征进行分析研究,得出地下洞室顶拱、拱腰、边墙位置预应力锚索拉力分别呈单向增长型、先减后增波动型、单向衰减型的3种变化模式;进一步采用有限差分软件FLAC3D,对锚索支护岩体开挖全过程的变形特性进行分析,并对锚索拉力变化模式及其支护效应进行探讨。结果表明,锚索拉力具有明显的时效特征,拉力演化模式与空间位置密切相关;进水池和主厂房洞室间隔墙内对穿锚索有效减小了岩墙塑性区分布范围。该研究成果具有重要理论价值,并对同类工程的设计和施工具有一定指导意义。

The support system of prestressed anchor cables can effectively reduce the expansion of the plastic zone of the surrounding rock in underground cavers.Based on in-situ monitoring and numerical analysis for the high-wall and long-span underground caverns,the deformation evolution process of the surrounding rock and the time-dependent characteristics of the anchor cable tension are analyzed.Three types of change modes of the anchor cable tension,including monotonically increasing,decreasing firstly and then increasing,and monotonically decreasing respectively at the top arch,arch waist and side wall of the underground cavern,are proposed.The deformation characteristics of the anchored rock during the excavation process are analyzed by using the finite difference software FLAC3D,and the variation mode of the anchor cable tension and the supporting effect are discussed.The results show that the anchor cable tension presents remarkable timedependent characteristics and is closely related to its spatial position;The thru-anchor cable in the middle partition wall effectively reduces the distribution range of the plastic zone of the rock wall.The research conclusion has important theoretical value and guiding significance for the design and construction of similar projects.