基于量化GSI系统的破碎岩体应变软化行为研究

松软破碎岩体的复杂力学特性给深部开采工程带来一系列棘手的问题，深入研究破碎岩体峰后力学行为，对于深部巷道围岩稳定性分析及支护结构设计具有重要意义。基于量化GSI围岩评级系统及连续介质理论，建立了考虑围压影响的破碎岩体峰后应变软化力学模型。通过工程应用实例验证了数值模型的可靠性。研究结果表明：通过计算围岩与支护结构相互作用关系可知，理想弹塑性模型和应变软化模型所得计算结果差异较大，采用理想弹塑性模型进行支护设计，可能导致支护结构的安全性偏低，甚至失稳。现场应用结果表明：数值计算结果与现场实际情况吻合；提出的深部破碎岩体应变软化模型能够较为真实地反映破碎岩体的非线性破坏行为，可为硐室围岩稳定性分析及支护结构设计等提供新的思路。

Strain softening behavior of broken rock mass based on a quantitative GSI system

The complex mechanical properties of soft broken rock mass lead to a series of challenging issues in deep mining engineering. In-depth study of the post peak mechanical behavior of broken rock mass is significant for analyzing the stability of surrounding rock and designing support structures in deep roadway. By considering the effect of confining pressure, a mechanical model of the post peak strain softening is established on the basis of a quantitative geological stremth index (GSI) evaluation system of surrounding rock and the continuous media theory. The reliability of the proposed model is verified by comparing numerical results with an application of a field engineering project. By calculating the relationships between surrounding rock and support structure, it is indicated that calculated results by the ideal elastic-plastic model and by the strain softening model are obviously different. The use of ideal elastic-plastic model may lead to a low safety and even instability of the support structure. Field application results are in good agreement with numerical results. The proposed model can reflect the nonlinear failure behavior of broken rock mass and provide new insights into the stability analysis of surrounding rock and the design of support structure.