دانلود مقاله ترجمه شده شکست های دینامیکی ایجاد شده بر اثر انفجار در سطح تونل ها

Blasting plays an important and active role in mining and rock engineering. At the same time, however, blasting may cause negative effects on mining safety and environment. For example, blasting usually induces dynamic rock fracture in and near the surface of a drift in underground mines as the surface is close to explosive charge. The most typical example of such a dynamic rock fracture is the back break and brow damage in sublevel caving mining, as shown in Fig. 1 [1] that indicates a church-shape roof formed by the back break and brow damage due to blasting (also due to the orientation of rock mass discontinuities and stress redistribution). Fig. 2 shows a serious dynamic rock fracture consisting of back break and brow damage, mainly because of incorrect detonator placement, where the right part of the figure shows the stress distribution as one portion of explosive charge in the blasthole is detonated. Both back break and brow damage endanger field work such as charging and loading operations. Accordingly, some investigations on the back break and brow damage in sublevel caving mining have been made and corresponding measures for reducing them been studied [1,2]. However, note that the dynamic fracture in back break and brow damage is usually very close to blast sources, meaning that the dynamic loads on rock due to blasting are very strong. Therefore, such a dynamic rock fracture is relatively easy to understand