基于塑性区形态系数的巷道冲击风险性量化评估方法

A quantitative assessment method of roadway rockburst risk based on the plastic zone shape coefficient

采用理论分析、数值模拟、现场案例分析的方法,从巷道围岩塑性区演化扩展与能量释放入手,研究了不同形态塑性区对应力变化的响应规律.建立了一个以塑性区形态系数为量化指标、以塑性区形态特征为评估判定依据、能够对处在一定应力与围岩环境中的巷道进行量化的冲击风险性评估方法.结果表明:圆形、椭圆形塑性区范围小、应力响应迟钝,蝶形塑性区范围大、应力响应敏感;应力改变会引发蝶形塑性区大范围扩展,并释放大量弹性能,随着蝶形形态的发展,塑性区对应力响应程度呈递增趋势;巷道围岩塑性区形态为圆形、椭圆形时冲击风险低,蝶形时冲击风险较高,且随着蝶形形态的发展,冲击风险性不断增大;塑性区形态系数量化表征了塑性区的形态演化规律,可以定量判别巷道围岩塑性区形态类别,同时可以量化塑性区所处的演化阶段,可作为巷道冲击风险性的量化评估指标.

Using the methods of theoretical analysis,numerical simulation field case analysis,and starting with the evolution and expansion of plastic zone and the law of energy release,the dynamic response characteristics of plastic zone with different shapes were studied.A quantitative rockburst risk assessment method was established,which took the shape coefficient of plastic zone as the quantitative index,the shape characteristics of plastic zone as the evaluation criterion,and which could quantify the roadway rockburst risk in a certain stress and surrounding rock environment.The results show that,the circular and elliptical plastic zone have a small range and their stress responses are insensitive,while the butterfly plastic zone has a large range and its stress response is sensitive.Stress variation may cause the butterfly plastic zone to expand in a wide range and release a lot of elastic energy,The response of plastic zone to stress sensitivity is increasing with the development of butterfly shape.When the shape is circular or elliptical,the rockburst risk is low,while it is high when the shape is butterfly,and rockburst risk is increasing with the development of butterfly shape.The shape coefficient of plastic zone quantitatively represents the shape evolution laws of plastic zone,which can quantitatively distinguish the shapes categories and quantify the evolution stage of plastic zone.So the shape coefficient can be taken as the quantitative assessment index of roadway rockburst risk.