The rationality of using strain energy storage index(Wet)for evaluating rockburst proneness was theoretically verified based on linear energy storage(LES)law in this study.The LES law is defined as the linear relation...The rationality of using strain energy storage index(Wet)for evaluating rockburst proneness was theoretically verified based on linear energy storage(LES)law in this study.The LES law is defined as the linear relationship between the elastic strain energy stored inside the solid material and the input strain energy during loading.It is used to determine the elastic strain energy and dissipated strain energy of rock specimens at various loading/unloading stress levels.The results showed that the Wetvalue obtained from experiments was close to the corresponding theoretical one from the LES law.Furthermore,with an increase in the loading/unloading stress level,the ratio of elastic strain energy to dissipated strain energy converged to the peak-strength strain energy storage index(Wp et).This index is stable and can better reflect the relative magnitudes of the stored energy and the dissipated energy of rocks at the whole pre-peak stage than the strain energy storage index.The peak-strength strain energy storage index can replace the conventional strain energy storage index as a new index for evaluating rockburst proneness.展开更多
Fault rockburst is treated as a strain localization problem under dynamicloading condition considering strain gradient and strain rate. As a kind of dynamic fracturephenomena, rockburst has characteristics of strain l...Fault rockburst is treated as a strain localization problem under dynamicloading condition considering strain gradient and strain rate. As a kind of dynamic fracturephenomena, rockburst has characteristics of strain localization, which is considered as aone-dimensional shear problem subjected to normal compressive stress and tangential shear stress.The constitutive relation of rock material is bilinear (elastic and strain softening) and sensitiveto shear strain rate. The solutions proposed based on gradient-dependent plasticity show thatintense plastic strain is concentrated in fault band and the thickness of the band depends on thecharacteristic length of rock material. The post-peak stiffness of the fault band was determinedaccording to the constitutive parameters of rock material and shear strain rate. Fault bandundergoing strain softening and elastic rock mass outside the band constitute a system and theinstability criterion of the system was proposed based on energy theory. The criterion depends onthe constitutive relation of rock material, the structural size and the strain rate. The staticresult regardless of the strain rate is the special case of the present analytical solution. Highstrain rate can lead to instability of the system.展开更多
为探究弹性能指数、应力系数、脆性系数、埋深4种岩爆指标与岩爆等级之间的相关关系,解决复杂机器学习算法的黑盒问题。引入LIME(local interpretable model agnostic explanations)算法,完善岩爆机器学习预测过程中的可解释性。搜集了...为探究弹性能指数、应力系数、脆性系数、埋深4种岩爆指标与岩爆等级之间的相关关系,解决复杂机器学习算法的黑盒问题。引入LIME(local interpretable model agnostic explanations)算法,完善岩爆机器学习预测过程中的可解释性。搜集了中外190组岩爆实例工程构建数据集经过预处理后,通过9种机器学习算法比较获得最优算法并采用贝叶斯优化获得算法最优参数,建立岩爆预测模型。基于LIME可解释性算法,对4种岩爆指标进行相关、回归及阈值分析,最后采用弹性能指数及应力系数两种指标阈值对终南山隧道竖井工程进行岩爆预测。研究结果表明:岩爆等级与弹性能指数、应力系数呈线性相关,且弹性能指数线性关系更明显;岩爆等级与脆性系数、埋深呈非线性相关,且脆性系数非线性关系更明显;4个岩爆指标对岩爆等级影响程度依次为:弹性能指数、应力系数、埋深、脆性系数;LIME算法可以准确地表达岩爆等级与岩爆指标之间的相关关系且得到的两种指标阈值与终南山隧道竖井工程实例具有一致性。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42077244 and 41877272)the Fundamental Research Funds for the Central Universities(Grant No.2242022k30054)。
文摘The rationality of using strain energy storage index(Wet)for evaluating rockburst proneness was theoretically verified based on linear energy storage(LES)law in this study.The LES law is defined as the linear relationship between the elastic strain energy stored inside the solid material and the input strain energy during loading.It is used to determine the elastic strain energy and dissipated strain energy of rock specimens at various loading/unloading stress levels.The results showed that the Wetvalue obtained from experiments was close to the corresponding theoretical one from the LES law.Furthermore,with an increase in the loading/unloading stress level,the ratio of elastic strain energy to dissipated strain energy converged to the peak-strength strain energy storage index(Wp et).This index is stable and can better reflect the relative magnitudes of the stored energy and the dissipated energy of rocks at the whole pre-peak stage than the strain energy storage index.The peak-strength strain energy storage index can replace the conventional strain energy storage index as a new index for evaluating rockburst proneness.
基金This work was financially supported by the National Natural Science Foundation of China (No.50309004) Liaoning Technical University (No. 02-38).
文摘Fault rockburst is treated as a strain localization problem under dynamicloading condition considering strain gradient and strain rate. As a kind of dynamic fracturephenomena, rockburst has characteristics of strain localization, which is considered as aone-dimensional shear problem subjected to normal compressive stress and tangential shear stress.The constitutive relation of rock material is bilinear (elastic and strain softening) and sensitiveto shear strain rate. The solutions proposed based on gradient-dependent plasticity show thatintense plastic strain is concentrated in fault band and the thickness of the band depends on thecharacteristic length of rock material. The post-peak stiffness of the fault band was determinedaccording to the constitutive parameters of rock material and shear strain rate. Fault bandundergoing strain softening and elastic rock mass outside the band constitute a system and theinstability criterion of the system was proposed based on energy theory. The criterion depends onthe constitutive relation of rock material, the structural size and the strain rate. The staticresult regardless of the strain rate is the special case of the present analytical solution. Highstrain rate can lead to instability of the system.
文摘为探究弹性能指数、应力系数、脆性系数、埋深4种岩爆指标与岩爆等级之间的相关关系,解决复杂机器学习算法的黑盒问题。引入LIME(local interpretable model agnostic explanations)算法,完善岩爆机器学习预测过程中的可解释性。搜集了中外190组岩爆实例工程构建数据集经过预处理后,通过9种机器学习算法比较获得最优算法并采用贝叶斯优化获得算法最优参数,建立岩爆预测模型。基于LIME可解释性算法,对4种岩爆指标进行相关、回归及阈值分析,最后采用弹性能指数及应力系数两种指标阈值对终南山隧道竖井工程进行岩爆预测。研究结果表明:岩爆等级与弹性能指数、应力系数呈线性相关,且弹性能指数线性关系更明显;岩爆等级与脆性系数、埋深呈非线性相关,且脆性系数非线性关系更明显;4个岩爆指标对岩爆等级影响程度依次为:弹性能指数、应力系数、埋深、脆性系数;LIME算法可以准确地表达岩爆等级与岩爆指标之间的相关关系且得到的两种指标阈值与终南山隧道竖井工程实例具有一致性。
基金Project(42172317)supported by the National Natural Science Foundation of ChinaProject(2021326)supported by the Youth Innovation Promotion Association of Chinese Academy of Sciences。
