【作者】 丁希平；

【导师】 冯叔瑜； 王中黔；

【作者基本信息】 铁道部科学研究院 ， 铁道工程， 2001， 博士

【摘要】 本文通过采用三维动力有限元法和激光全息动光弹试验对半无限介质中柱状药包的应力场、台阶爆破应力场和若干爆破设计参数进行了初步数值分析研究。 首先阐述了三维动力有限元DYNA3D系统的数值计算方法，对有限元计算中的几个关键处理：沙漏控制、应力波与人工体积粘性、接触碰撞仅滑移（Sliding-only）边界、无反射边界等做了说明。为了应用三维动力有限元DYNA3D系统进行模拟计算，本文依据相似原理，采用1:10的几何相似比进行计算模拟。由于单值条件与物理相似条件在模拟上存在具体困难，因此完全满足现象相似的充要条件不太可能。在本文计算中主要应用了几何相似、边界条件相似和部分动力相似条件，在本论文中取C_μ=1，C_ι=10，C_ρ=1，C_Ε=1，C_ε=1，C_σ=1，C_ι=C_ι=10。由于岩体在动载作用下的破坏特征以及塑性特征的研究仍处在十分初浅的百家争鸣的阶段，尚未上升到数学描述阶段，故岩石在爆炸作用下的强动载荷作用特性还不是很清楚，为简化计算，本章将岩石材料假设为线弹性体，采用Mises屈服条件来描述岩石材料的破坏特性。 三维动力有限元数值分析和全息动光弹试验结果表明：半无限介质中柱状药包爆炸应力场在底部点火起爆后，应力波呈水滴状向外扩展，其波阵面与炮孔轴线所形成的角度基本不变，直到爆轰结束。此后有效应力场逐渐呈近似椭球体向四周传播并开始衰减。半无限介质中柱状药包的端部应力场与水平条形药包的应力场都存在着有效应力为零的“应力空洞”区，但是，条形药包端部应力场两端是对称分布的，而柱状药包的上下端部应力场是不对称的，且柱状药包底部零畸变范围要比顶部大，这个现象同样被动光弹试验所证实。双自由面的单孔台阶爆破数值计算表明，在应力波传播的初期，初始应力场的发展规律是和半无限体 铁道部科学研究院博士论文2001 中柱状药包爆炸应力场的发展规律是相似的，在有效应力场的传播过程 中，两端部的无畸变区由炮孔中心线处向最小抵抗线方向偏移。无超深 爆破时，由于底部受到柱状药包端部效应的影响，在炮孔附近距轴线相 等距离上，中部有效应力要比底部大1一2倍。 对深孔台阶爆破若干设计参数（炸药单耗、超深、填塞长度）的数 值计算表明，炸药单耗的变化对应力场有显著的影响，单耗增加42％时， 在抵抗线方向的有效应力相应增加1 ．57一3．1倍。超深改变对台阶爆破时 底部应力场的变化影响很大，台阶爆破最大超深约为0．3倍最小抵抗线 长度。这个结论与深孔台阶爆破的工程实践相吻合。数值计算验证了填 塞长度对深孔台阶爆破破碎效果的影响，虽然无填塞爆破对孔底抵抗线 位置的破坏应力基本没有影响，但对于台阶上部岩体中的应力场影响较 大，在相同条件下无填塞爆破填塞区中有效应力减小约60％，说明无填 塞不利于孔口区的破碎，从理论上证实了无填塞爆破对爆破能量是相当 大的浪费，并且得到最佳填塞长度Ls＝（0一1．0）万，这个结论与工程 实际经验也是相符的。更多还原

【Abstract】 In this paper, Effective stress field distribution of semi-infinite and bench blasting in rock mass and some design parameters of deep hole bench blasting are analyzed by the method of photo-elastic holography and 3-D dynamic element method.Firstly the digital compute method of 3-dimisional dynamic finite element method of DYNA3D system is introduced The typical question of hourglass control, artificial bulk viscosity, contact-impact algorithm and non-reflecting boundary is explained. In order to use DYNA3D system to simulate deep hole bench blasting, the simulation rule is used. The geometry ratio is 1:10. the geometry simulation , boundary simulation and some dynamic simulation rule is used here. In this paper C,~ =1, C,=10,(7~=1, CE=l, C~=1, C,.=l, C1=C1=10. For the reason that thecharacter of rock under dynamic stress is unknown, the rock mass is considered to be lineal elastic and the Mises stress rule is used to descript the breakage of rock mass.The photo-elasticity holographic test and 3-0 dynamic element method shows that the shape of Mises effective stress field of deep hole blasting in the semi-infinite media is water-like (ignition at the bottom of the hole ) and the angle of the face of stress wave and the axle of the hole is not changed in the process. The shape of stress wave is quasi-ellipsoid and the tip effect appears at both ends. The zero distortion energy field appears at the both ends of the hole in the propagation process of stress field which means that the stress field of the ends of cylinder shaped charge can dense the rock. Theinitial stress field of deep hole blasting is quasi-cylinder with hemisphere atboth ends and the stress field at both ends is attenwted quickly. The effectivestress field of deep hole bench blasting propagation is simulate to that ofsemi-finite rock mass. The zero distortion energy field aPpears both in thetip of the charge of bench blasting and linear charge. The difference is tha thedistribution of zero distortion energy field of linear charge is sytnrnetric andthe distribution of the zero distOrtion energy field of bench blasting isunsyrnmetrical. For the affection of the tip effect at the bottom When blastingwith non-sub-drill, the effeetive stress in the model is one hundred to twohundred percent bigger than tha at the bottom.The digital computation of some design parameters(explosiveconsumption, sub-drill and steedng length) of deep hole bench blastingshows that the change of explosive consumPtion is deeply affect the Misesstress field. When 42% of the consumPtion is increased, the effective stressfield in the direction of the least resistant increase l57 to 3l0 percent. Thechange of the sub-drill affect the bottom stress field greatly and the biggestsub-drill is about 30 Percent of the length of the least resiStan. Thisconclusion is accordan tO the engineering experience. The digitalcomputation also shows the affection of the sternrning length to thefragInentaion of deep hole bench blasting. Although the blasting ofnon-StCmming alinost has no thection to the breakage of the rock mass at thebottom, it heavily affect the Stress field in the uPper rock mass in benchblaning. Under the same condition the stress field of the non-stemrningblasting in the stenuning region decrease 60 Percent, which explains that thenon-Sternrning blasting is not advtuge to the fragmentation of the rock atthe collar. It shows that blasting energy of non-stemming blasting is wasted.The optimal stenuning length is (0.9-l .0) of the least resistant, which is alsoaccordan to the experience.更多还原