侧向点扰动下高应力岩石的破坏机制研究

发布时间：2018-07-22 10:48

【摘要】：目前,局部侧向扰动下高应力岩石的破坏机制仍缺乏研究。本文利用自行研制的岩石真三轴电液伺服诱变(扰动)试验系统,开展了高应力岩石侧向扰动试验,研究不同静载条件下岩石的破坏机制与声发射特性；利用PFC3D软件进行数值模拟,验证了试验结果,此外,还分析了不同扰动幅值条件下高应力岩石的裂纹发育规律与破坏机制。本文的研究成果为揭示岩爆机理以及提高深部凿岩效率提供了理论与技术支持。全文主要内容与成果如下： 1、利用岩石真三轴电液伺服诱变(扰动)试验系统,对100mm×100mm×100mm大尺寸花岗岩试样进行不同静载作用下的侧向扰动破坏试验。通过PCI-2型声发射系统监测发现：动力扰动下高应力岩石的声发射最大能量事件一般滞后于扰动峰值,发生在动力卸载段；随着静载的增加,声发射最大能量事件的发生时间有提前的趋势,而且较大能量事件数量增加。 2、对试样进行基于弹性波速变化的损伤评价和声发射RA值(声发射撞击上升时间/幅度)的分析发现,不同静载下岩石的扰动破坏模式不同,较低静载时,扰动仅触发少量剪切裂纹并导致扰动近区岩石的局部剪切破坏；较高静载时,扰动同时触发剪切裂纹和拉伸裂纹,大量拉伸裂纹的出现最终导致岩石发生贯穿式整体溃崩破坏。 3、利用PFC3D首先模拟了相同扰动不同静载作用下的岩石破坏试验,所得结果与试验结果一致；同时还对相同静载不同动力扰动幅值作用下的岩石破坏试验进行模拟。模拟结果表明,高应力岩石在侧向扰动作用下其裂隙的发育速率、裂隙总量与扰动幅值成正比,在裂隙扩展深度发面,虽然提高扰动幅值可以增加裂隙扩展深度,但裂隙主要还是分布在试样受扰动一侧,裂隙贯穿性不强,同时,提高扰动幅值可以增加扰动末期裂隙发育的程度。 4、增大动力扰动幅值对于提高扰动破岩效果有帮助,但其效果有限；持续扰动的破岩效果相对于单次扰动有所提高,而提高静载对于动力扰动破岩效果有显著成效。
[Abstract]:At present, the failure mechanism of high stress rock under local lateral disturbance is still lacking. In this paper, the lateral disturbance test of high stress rock is carried out by using the self developed true triaxial electro-hydraulic servo mutagenesis (disturbance) test system. The failure mechanism and acoustic emission characteristics of rock under different static load conditions are studied. The experimental results are verified by numerical simulation with PFC3D software. In addition, the crack development and failure mechanism of high stress rock under different disturbance amplitude are analyzed. The results of this paper provide theoretical and technical support for revealing the mechanism of rock burst and improving the efficiency of deep rock drilling. The main contents and results are as follows: 1. Using the true triaxial electro-hydraulic servo mutagenesis (disturbance) test system, the lateral disturbance failure tests of 100mm 脳 100mm 脳 100mm large size granite specimens under different static loads are carried out. Through the monitoring of PCI-2 acoustic emission system, it is found that the maximum energy event of acoustic emission of high-stress rock under dynamic disturbance generally lags behind the peak value of disturbance and occurs in the dynamic unloading section, and with the increase of static load, The maximum energy event of acoustic emission has a tendency to occur in advance. And the number of large energy events increased by 0.2. The damage evaluation based on elastic wave velocity variation and the analysis of acoustic emission RA value (acoustic emission impact rise time / amplitude) found that, The disturbed failure modes of rock under different static loads are different. At low static load, the disturbance only triggers a small amount of shear cracks and results in local shear failure of rock near disturbance, and at higher static load, the disturbance triggers both shear cracks and tensile cracks. The appearance of a large number of tensile cracks eventually leads to the whole collapse failure of the rock. 3. PFC3D is used to simulate the rock failure test under the same disturbance and different static loads, and the results are consistent with the test results. At the same time, the rock failure test under the same static load and different amplitude of dynamic disturbance is simulated. The simulation results show that the fracture growth rate of high stress rock under lateral disturbance is proportional to the disturbance amplitude, and the crack propagation depth can be increased by increasing the disturbance amplitude. However, the fracture is mainly distributed on the disturbed side of the specimen, and the fracture penetration is not strong, at the same time, Increasing the amplitude of disturbance can increase the degree of fracture development at the end of disturbance. 4. Increasing the amplitude of dynamic disturbance is helpful to improve the effect of disturbance rock breaking, but its effect is limited, the rock breaking effect of continuous disturbance is higher than that of single disturbance. But improving static load has remarkable effect on dynamic disturbance rock breaking.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU45

【共引文献】