锚杆对岩石力学特性影响规律的试验与数值模拟研究

【作者】 马学斌；

【导师】 李克钢；

【作者基本信息】 昆明理工大学 ， 采矿工程， 2020， 硕士

【摘要】 我国金属矿山多为地下矿山,经过多年开采,浅部资源日益减少并逐步枯竭。因此,向深部采矿进军将成为今后很长一段时间内采矿行业生产的主旋律。与交通隧道、地铁开挖、地下厂房建设等所有地下工程一样,采矿过程中,大量的巷道、硐室、采场等地下空间将被形成,由于可选择性与可调整性较小,除一般性岩石之外,各种复杂地质情况不断出现,致使深部岩体的组织结构、行为特征和工程响应均发生根本性的变化,使得该类岩体具有更加明显的时间效应,更容易出现较大的持续变形进而导致工程结构的失稳或失效,使地下工程变得极不稳定,给工作人员和设备安全构成严重威胁。锚杆作为一种常见的岩体加固手段,虽然在施加时对巷道等工程稳定性的控制起到了一定的促进作用,但锚固结构失效的情况仍然多有发生。因此,对这种所处地质环境复杂、受外部因素影响显著的深部加锚岩石开展理论与试验研究,通过对其加固效果的分析,不仅可以掌握锚杆对其力学特性的影响,还能对该类岩体破坏及锚杆失效时的主要特征有更进一步的了解。本文通过试验及模拟相结合的方法。对加锚岩石进行了系统的分析,主要内容包括以下几点:(1)通过实地考察,以云南省永昌铅锌矿390中段顶板灰岩作为研究对象,通过取样,制备及加工,进行了室内单轴压缩试验,直剪试验,经数据处理及计算,获取到无锚及加锚岩石的力学参数。(2)根据试验结果及图表,分析在单轴压缩下,加锚岩石强度特征、变形规律、破坏形式及裂纹扩展规律;并从不同的锚固方式及不同的锚杆直径出发,进行了交叉对比分析。(3)利用物理试验所得岩石宏观力学参数进行岩石力学参数的宏细观转换,通过RFPA-2D数值模拟软件,进行了细观岩石真实破碎过程的数值计算。主要包括全长锚固下加锚岩石的单轴压缩数值模拟,旨在与物理试验结果形成对比,从细观上分析其力学特性。(4)90°加锚岩石的剪切数值试验,分析锚杆对岩石内聚力和内摩擦角的影响;以及同一应力水平下,不同锚杆角度的剪切数值试验,研究锚杆角度对岩石抗剪特性的影响。(5)结合RFPA软件自带的声发射模拟系统,连续模拟岩石材料可视化破坏过程的声发射活动信息,进行了加锚岩石脆性破坏声发射参数与能量演化特征的模拟及分析。本文的研究成果,不仅掌握了该类岩石锚固后的力学特性及变化规律,阐明锚杆对该类岩石的加固效果及破坏特征的影响,为井巷和硐室等围岩稳定控制提供科学依据,而且有助于指导锚杆支护参数的选取及设计,对保证矿山的正常和安全生产具有重要的意义。更多还原

【Abstract】 Most mines in China are underground mines.After years of mining,shallow resources have been gradually reduced and gradually dried up.Therefore,the march to deep mining will become the main theme of mining industry production for a long time to come.As with all underground projects such as transportation tunnels,subway excavations,and underground powerhouse construction,a large number of underground spaces such as roadways,chambers,and stopes will be formed during the mining process.Due to the small selectivity and adjustability,except for general In addition to rock,various complex geological conditions continue to appear,resulting in fundamental changes in the organizational structure,behavioral characteristics,and engineering response of deep rock masses.This type of rock mass has more obvious time effects and is more likely to appear larger.The continuous deformation of the structure leads to the instability or failure of the engineering structure,making the underground engineering extremely unstable,posing a serious threat to the safety of staff and equipment.However,although the application of the anchor and anchoring system has played a certain role in controlling the stability of the roadway and other projects,anchoring failure and structural instability still occur.Therefore,it is of great significance to carry out theoretical and experimental research on such deep anchored rocks with complex geological environment and significant influence by external factors.This paper uses a combination of theoretical analysis,laboratory test and numerical simulation.A systematic analysis of the anchored rock is conducted,and the main contents include the following:(1)Through field inspection,taking the limestone of the 390 middle section of the Yongchang Lead-Zinc Mine in Yunnan Province as the research object,through sampling,preparation and processing,indoor uniaxial compression test,direct shear test,and data processing and calculation were performed to obtain anchorless And mechanical parameters of the anchored rock.(2)According to the test results and charts,the strength characteristics,deformation law,failure mode and crack propagation law of the anchored rockunder uniaxial compression are analyzed.Based on different anchoring methods and different anchor diameters,a cross-contrast analysis is performed.(3)The macro-mechanical transformation of rock mechanical parameters was performed using the macro-mechanical parameters of rocks obtained from physical tests.The numerical calculation of the true crushing process of meso-rocks was performed by RFPA-2D numerical simulation software.It mainly includes uniaxial compression numerical simulation of anchored rock under full-length anchoring,which aims to contrast with the results of physical tests and analyze its mechanical characteristics from a meso-scale.(4)Shear numerical test of 90°anchored rock to analyze the effect of anchor on the cohesion and internal friction angle of rock;and the shear test of different anchor angles at the same stress level to study the effect of anchor angle on rock shear resistance influences.(5)Combined with the acoustic emission simulation system built into the RFPA software,the acoustic emission activity information of the rock material visualization failure process is continuously simulated,and the acoustic emission parameters and energy evolution characteristics of brittle failure of the anchored rock are simulated and analyzed.The research results in this article not only master the mechanical characteristics and change laws of this type of rock after anchoring,clarify the failure mode of this type of anchor,provide scientific basis for the stability control of surrounding rocks such as wells,tunnels,etc.;and bolt support The selection and design of the parameters are of great significance for ensuring the normal and safe production of the mine.At the same time,for deep mining in the same situation,the study of rock deformation and damage characteristics and stability control have important reference value.更多还原