不同静应力和节理条件下岩体爆破破岩机制研究  

Mechanisms of blasting-induced rock fractures under different static stress and joint properties conditions

作　　者：张凤鹏[1] 彭建宇[1] 范光华[1] 李邵军[2] 李元辉[1] 

机构地区：[1]东北大学深部金属矿山安全开采教育部重点实验室,辽宁沈阳110819 [2]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071

出　　处：《岩土力学》2016年第7期1839-1846,1913,共9页Rock and Soil Mechanics

基　　金：国家科技支撑计划课题(No.2013BAB02B01;No.2013BAB02B03);煤矿安全开采技术湖南省重点实验室开放基金资助项目(No.201302)~~

摘　　要：考虑不同应力条件和岩体节理属性,对静应力作用下含有长节理和局部短节理花岗岩的爆破破岩机制进行研究,探讨静应力、节理位置和充填介质物性等因素对爆破效果的影响。在节理间充填弹性弱介质和空气两种情况下研究半无限长节理面反射拉伸破坏效应和端部衍生翼裂纹扩展特性;在不同静应力作用下,改变爆源与节理间的距离,研究长节理面反射效应对爆破裂纹扩展的影响规律;在保持节理近端与爆源距离和节理长度不变的情况下,研究短节理端部衍生翼裂纹产生、扩展的规律。通过比较表明,当节理充填介质时,节理面的反射拉伸破坏作用弱于不充填情况,而前者的端部翼裂纹发育明显比后者充分;长节理阻断了爆破主裂纹的扩展,节理面反射拉伸应力波产生的拉裂纹与爆破主裂纹耦合贯通在爆源与节理之间岩体内产生密集裂纹网,改善了该区域岩体的破碎效果,但随爆源与节理之间距离的增大以及静应力增高,这种破岩效应逐渐消失;入射角对节理端部衍生翼裂纹的产生与扩展影响显著,而静应力对翼裂纹起抑制作用。The aim of this paper is to investigate failure mechanisms of granite with long and local short joints induced by blasting under different static stress conditions. The effect of static stress, location of the joint and filling material properties on blasting results is discussed and analyzed in detail. The extension failure behaviour caused by reflection along the semi-infinite joint plane and wing crack propagation characteristics at the end of the joint are examined by filling the weak elastic material or air. Under different static stress conditions, numerical simulations are performed by changing the distance between blasting source and joint to determine the influence of reflection of stress waves from the long joint plane on blasting crack propagation. Then, we study the generation and expansion laws of wing cracks by diffracted stress wave at short joint tips under different incident angles by maintaining the joint length and the distance between the proximal joint and blasting source. It is indicated that the reflected tensile failure near the surface of joint with filling material is more likely to occur instead of joint without filling. However, wing cracks at the former tip develop are more obvious than the latter. The long joint to great extent blocks the propagation of blasting induced cracks. The dense crack networks produced in the rock mass between blasting source and joints are caused by the coupling coalescence of extension cracks that are induced by the reflected stress wave and main crack. Although it heavily enhances the crushing effect of the rock mass, the effect disappears gradually when the distance between blasting source and joints or the static stress is increased. The generation and propagation of wing cracks are significantly influenced by the incident angle, and the wing cracks are restrained by static stress.

关 键 词：静应力 岩体爆破 节理 LS-DYNA 裂纹扩展 入射角 

分 类 号：O383.1[理学—流体力学] TD853[理学—力学]