引入梯度应力的岩爆预测方法

New method for introducing gradient stress into rock-burst prediction

地下工程开挖过程中,深部岩体在开挖扰动作用下,洞壁附近围岩所受切向应力呈梯度分布。为探索梯度应力对岩体产生岩爆特性的影响,借助自主研发的YB-A型气液复合岩爆模拟试验装置对大尺寸试件进行不同梯度应力作用下的岩爆试验,且在结合大量工程实例的基础上,引入梯度应力强度比对强度-应力比判据进行优化,建立一种引入梯度应力的岩爆预测方法。结果表明,岩体岩爆烈度与其所受梯度应力存在明显的相关性,考虑梯度应力的岩爆判据克服了传统的强度-应力比指标区间不均匀的问题,预测准确率提高到90.4%,为地下工程岩爆预测提供理论依据。

During the excavation of underground projects,the tangential stress in the surrounding rock near the cave wall is distributed in a gradient because of the disturbance of excavation unloading in the deep rock mass.In order to explore the effects of gradient stress on rock-burst characteristics,the rock-burst tests under the effects of different gradient stresses on large-sized specimens are conducted with the help of the independently developed rock-burst test simulation device.It is found that there is an obvious correlation between the intensity of rock-burst of rock mass and the gradient stress that it is subjected to.On the basis of considering a large number of engineering examples,the intensity ratio of gradient stress is introduced to optimize the intensity stress ratio criterion so as to establish a prediction method for rock-burst with gradient stress.The results show that there is a clear correlation between the intensity of rock-burst of rock mass and the gradient stress it is subjected to.The criterion considering the gradient stress of the rock-burst overcomes the uneven problem of the traditional intensity-stress ratio index,and the prediction accuracy is raised to 90.4%,which provides a theoretical basis for the prediction of rock-burst of underground projects.