节理岩体冲击破坏的数值流形方法模拟

Simulation of impact failure of jointed rock mass by numerical manifold method

节理的存在是岩体明显区别于岩石的一个重要特征,也是导致岩体具有非均质性及各向异性的一个重要因素。节理岩体在爆炸冲击荷载作用下的破坏特征不仅是岩体力学研究的一个热点问题,也是岩石爆破领域经常遇到的一个工程问题。目前,常用的有限元和离散元等数值方法都不能很客观地反映岩体中节理分布的实际规律,而最新出现的数值流形方法则完全能够按照岩体中节理的实际分布规律进行建模,并能够很好地模拟岩体在外力作用下新裂纹的产生及已有节理的开裂。对3种不同节理岩体,即无节理岩体、均布水平节理岩体、均布垂直节理岩体等在均布垂直于圆周方向上的冲击荷载作用下的破坏过程进行了模拟。由模拟结果可以明显看出,节理的存在对岩体的破坏型式起到了关键性的控制作用。对于完整岩体,其破坏型式呈现出了很好的对称性;而对于水平及垂直节理岩体,其破坏型式在很大程度上受到节理分布的控制。研究结果对岩石爆破工程设计具有一定的指导意义。

The existence of the joints is an important characteristic of rock mass distinctly different from rock, and it is also an important factor leading to the heterogeneity and anisotropy of rock mass. The failure characteristic of jointed rock mass under blast impact load is not only a hot subject in study of rock mass mechanics, but also an engineering problem in rock blasting, while such models as those created by finite element method and discrete element method cannot objectively reflect the actual distribution law of joints in rock mass. However, the new kind of numerical method numerical manifold method can create the calculation model completely according to the actual distribution law of the joints in rock mass, and can perfectly simulate the occurrence of the new cracks and opening of the existed joints in the rock mass under the action of external load. By corresponding program of numerical manifold method, the failure process of the rock mass with such three kinds of joints as horizontal joints, vertical joints and no joints under the impact load perpendicular to the circumference is simulated. From the simulation result, it can be evidently seen that the existence of the joints plays a vital role on failure form of rock mass. The failure form of the intact rock mass has good symmetry, while to horizontal jointed and vertical jointed rock mass, their failure forms are controlled by the distribution of the joints to large extent. The study result is of certain meaning in rock blasting engineering design.