支护失效对岩爆弹射破坏影响的真三轴试验研究

发布时间：2018-04-26 11:19

本文选题：岩石力学 + 岩爆　；参考：《广西大学》2016年硕士论文

【摘要】：岩爆是高地应力条件下的岩体在开挖卸荷后围岩应力状态改变导致围岩的强度和承载能力急剧下降,诱发突然或激烈的弹射破坏并伴随着巨大能量释放的地质灾害,是深部地下工程经常遇到的危害性最大的地质灾害之一。支护是控制岩爆发生的一种重要途径,然而工程实际中,虽然支护对岩爆破坏具有一定的抑制作用,但岩爆仍然常发生在已支护的围岩中,甚至因支护失效诱发强烈岩爆。因此,支护失效对岩爆的影响问题不容忽视,支护失效对岩爆影响的研究对岩爆倾向隧洞的合理支护设计具有重要的现实意义。利用具有单面突然卸载功能的真三轴岩爆试验系统,以灰白色花岗岩为研究对象,根据地下洞室支护失效前后的围岩应力路径变化,通过岩爆过程模拟试验,利用高速摄像系统对岩爆破坏全过程进行追踪与弹射动能测试,详细分析岩爆的弹射过程、岩爆弹射动能、岩爆破坏形态、声发射能量累计数和平均破碎块度等特征,研究不同失效支护力、支护失效时机及支护失效速率对岩爆弹射破坏的影响。研究结果表明：(1)支护力越大,岩样峰前储存的弹性应变能越多,同时支护力抑制了岩样裂缝的发展,岩样损伤小,声发射能量累计数低,支护失效时,突然释放的弹性应变能转化为动能越多,岩爆的弹射动能越大；(2)在不超过岩样真三轴抗压强度的条件下,在轴向应力加载过程中,单面卸除最小主应力的时间越晚,即支护失效时机越迟,峰前储存的弹性应变能越多,岩样破坏时,瞬间释放的弹性应变能转化为动能越多,岩爆的弹射动能越大；(3)岩爆弹射动能随支护失效速率的增大而增大,呈现线性增长趋势。随着支护失效速率的增大,岩样的破坏模式由静态脆性破坏向岩爆动力破坏转变；岩样峰前损伤越少,声发射能量累计数越小,岩爆强度越高。
[Abstract]:Rock burst is a geological disaster that changes the stress state of rock mass under high ground stress condition after excavation and unloading, which leads to the sharp decrease of strength and bearing capacity of surrounding rock, which induces sudden or intense ejection damage and accompanying with huge energy release. It is one of the most harmful geological hazards often encountered in deep underground engineering. Support is an important way to control the occurrence of rockburst. However, in engineering practice, although the rock burst is restrained to some extent, the rockburst still occurs in the supported surrounding rock, even the strong rock burst is induced by the failure of support. Therefore, the influence of support failure on rock burst can not be ignored. The study on the influence of support failure on rock burst is of great practical significance to the reasonable support design of rock burst inclined tunnel. Using the true triaxial rockburst test system with the function of one side sudden unloading, taking gray-white granite as the research object, according to the change of surrounding rock stress path before and after the failure of underground cavern support, the simulation test of rock burst process is carried out. The whole process of rock burst damage was tracked and ejection kinetic energy was measured by high speed camera system, and the characteristics of rock burst ejection process, rock burst ejection kinetic energy, rock burst failure form, acoustic emission energy accumulation and average fragmentation were analyzed in detail. The effects of different failure support forces, failure time and failure rate on the ejection failure of rock burst are studied. The results show that the greater the support force is, the more elastic strain energy is stored in front of the rock sample peak. At the same time, the support force inhibits the development of rock sample fracture, the damage of rock sample is small, the accumulation of acoustic emission energy is low, and the support fails. The more elastic strain energy suddenly released into kinetic energy, the greater the ejection kinetic energy of rock burst is.) under the condition that the true triaxial compressive strength of rock sample is not exceeded, the time of removing the minimum principal stress on one side is later during axial stress loading. That is, the later the failure time of support, the more elastic strain energy stored before peak. When rock sample is destroyed, the more elastic strain energy released instantly is converted into kinetic energy, the larger the ejection kinetic energy of rock burst is, the larger the ejection kinetic energy of rock burst increases with the increase of support failure rate. Showing a linear growth trend. With the increase of the failure rate of support, the failure mode of rock sample changes from static brittle failure to dynamic failure of rock burst, and the less damage in front of rock sample is, the smaller the accumulative energy of acoustic emission is, and the higher the rock burst intensity is.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TV223;TV542

【相似文献】