摘要
在深部开采工程中,全长粘结锚杆被广泛应用,深入了解全长粘结锚杆在高地应力条件及复杂本构模型条件下的受力特征,对深部巷道支护设计具有重要意义。基于量化GSI围岩评级系统及Hoek-Brown应变软化模型,以FLAC3D数值模拟软件为工具,分析全长粘结锚杆在不同本构模型条件下的受力特点,研究不同长度锚杆对围岩稳定性的影响,对比分析不同剪胀角对锚杆轴力及剪力的影响。研究结果表明:采用理想弹塑性模型与应变软化模型计算所得的锚杆轴力及剪力相差较大;通过现场实际应用可知,应变软化模型能够较为真实的反应围岩的屈服破坏过程,在支护结构设计当中,建议采用应变软化模型进行计算,会得到较为精确的计算结果。
Based on the Hoek-Brown strength criteria and GSI surrounding rock rating system,analysis of rock mass strength weakening behavior,summed to determine the rock peak and the peak strength parameters,proposed a simplified calculation method for the strain-softening model,application of the FLAC3D numerical simulation software tools and Convergence Constraint Method to analysis the stability of surrounding rock and support in buried a large section tunnel, and calculated the safety factor for supporting structure. The results show that： with the release of the rock stress, rock softening parameter decreases and strength weakening behavior severe. Although the high GSI index （GSI =75） rock strength weakening serious, but the deformation is still small. Low GSI index （GSI=25） of the rock showing the perfect elastic-plastic behavior. The proposed simplified Hoek-Brown strain-softening model is suitable for used in the tunnel close to the rock section of the surrounding rock.Application of the Convergence Constraint Method to analysis the stability of surrounding rock and support, which could provide a reference for initial support to optimize the design and safety evaluation in tunnels.
出处
《科技创新导报》
2015年第28期25-27,共3页
Science and Technology Innovation Herald
基金
国家自然科学基金联合资助项目(51174268)
