摘要
在防护和采矿等工程中,洞室围岩常会受到不同形式的冲击载荷作用,从而诱发垮塌和冲击地压等严重灾害。继续完善自主开发的拉格朗日元与变形体离散元耦合的连续-非连续方法,同时引入Ⅰ型和Ⅱ型断裂能,在适于模拟拉裂的基础上,也适于模拟剪裂,从而可对有关灾害的机理分析和预防产生积极意义。利用该方法开展了周期半正弦波冲击下洞室围岩的变形-开裂-垮塌过程的数值模拟研究,着重阐明了应力波反射和叠加导致洞室顶板开裂机理,解释了洞室两帮拉、剪裂相伴现象的原因,探讨了周期冲击载荷幅值的影响规律。研究发现:(1)当由模型的上端面传入的第1个压应力波抵达洞室顶板表面时,压应力波分化成的中间部分发生反射,反射的拉应力波单独自己或与第1和第2个压应力波之间的受拉区叠加导致顶板拉裂;(2)洞室顶板以拉裂为主;洞室两帮以剪裂为主,并形成V形坑。洞室顶板的拉裂区对于后继应力波有吸能作用;(3)在洞室两帮发生剪裂后形成多重V形坑,坑内应力处于低值,而且,压应力波波后会存在一个挤压程度不强烈区甚至受拉区,从而导致坑内发生拉裂,造成拉、剪裂相伴现象;(4)随着冲击载荷幅值的减小,拉、剪裂缝的数目和分布范围减小,V形坑最大深度减小,洞室围岩更易平衡。
In protection and mining engineering,cavern surrounding rock is often subjected to different forms of impact load to cause serious disasters,such as,collapses and rockbursts.Here,the continuous-discontinuous method developed by ourselves for Lagrange element-deformation body discrete element coupling was continuously improved.At the same time,Type-Ⅰ and Type-Ⅱ fracture energy were introduced,on the basis of simulating tensile fracture,they were also suitable for simulating shear fracture,so they were of positive significance to the mechanism analysis and prevention of related disasters.The continuous-discontinuous method was used to perform the numerical simulation of deformation-cracking-collapse process of cavern surrounding rock under periodic half sine wave impact.The mechanism of cavern roof cracking caused by reflection and superposition of stress wave was emphatically studied.The cause of the phenomenon of tensile and shear cracking on both sides of cavern was explained,and the influence law of periodic impact load amplitude was explored.Results showed that(1)when the first compression stress wave reaches cavern roof surface,the middle part of the compression stress wave is reflected,and the reflected tensile stress wave alone or superimposed with the tensile zone between the first and second compression stress waves leads to roof cracking;(2)cavern roof is mainly subjected to tensile cracking,and two sides of cavern are mainly subjected to shear cracking to form V-shaped pits,the tensile cracking zone of cavern roof can absorb energy of subsequent stress wave;(3)multiple V-shaped pits are formed after shear cracking on both sides of cavern,and the stress in pit is low,moreover,there exists a weakly squeezed zone or even a tensile zone behind compression stress wave to cause tensile cracking in pit and phenomenon of tensile cracking and shear cracking accompanying;(4)with decrease in impact load amplitude,the number and distribution range of tensile and shear cracks decrease,the maximum depth of V-shaped pit decreases,and cavern surrounding rock is easier toreach an equilibrium.
作者
王学滨
田锋
钱帅帅
WANG Xuebin;TIAN Feng;QIAN Shuaishuai(Institute of Computational Mechanics,Liaoning Technical University,Fuxin 123000,China;College of Mechanics and Engineering,Liaoning Technical University,Fuxin 123000,China)
出处
《振动与冲击》
EI
CSCD
北大核心
2021年第1期233-242,共10页
Journal of Vibration and Shock
基金
国家自然科学基金项目(51874162)。
关键词
冲击载荷
洞室围岩
应力波
反射
叠加
拉裂
剪裂
连续-非连续方法
impact load
cavern surrounding rock
stress wave
reflection
superposition
tensile cracking
shear cracking
continuous-discontinuous method
