【作者】 闫长斌；

【导师】 徐国元；

【作者基本信息】 中南大学 ， 岩土工程， 2006， 博士

【摘要】 采用钻爆法进行地下岩体工程建设或矿山采掘生产，频繁爆破作业产生的动荷载，不可避免地对周围岩体产生累积损伤危害，甚至诱发地下工程岩体产生失稳破坏。爆破损伤作用体现在岩体力学性能劣化与完整性降低两个方面，必然造成岩体力学参数指标弱化，从而影响工程稳定性。目前，爆破作用下岩体累积损伤效应及其稳定性缺乏系统研究，在理论与试验方面均有待进一步探索。现有的岩体力学参数取值方法没有充分考虑开挖爆破损伤弱化作用，存在明显不足。针对上述问题，结合国家“十五"科技攻关项目“复杂多空区下强制与诱导耦合大规模落矿采矿综合技术研究”（2003BA612A-10-2）和中南大学博士研究生学位论文创新工程项目“复杂关联空区动力失稳机制及预测预报模型研究”（040109），对爆破作用下岩体累积损伤效应及其稳定性问题进行了系统深入的研究。主要研究内容如下：第一，率先利用声波测试技术，系统研究了多次爆破作用下岩体损伤累积增长规律。通过10次小药量模拟爆破，采用RSM-SY5智能声波测试系统，对厂坝铅锌矿某巷道围岩产生的爆破累积损伤效应进行了现场试验研究。基于大量的现场实测数据，获得了爆破动载作用下岩体累积损伤程度、岩体声波速度，与爆破作用次数之间存在的统计规律。分析了爆心距等因素对岩体爆破累积损伤效应的影响，建立了爆破累积损伤与爆心距之间的非线性递减关系。第二，首次发现了重复爆破作用下，随爆破次数增加，岩体爆破累积损伤程度与声波测试信号波形、主频、能量等频谱参数变化规律之间的内在联系，进一步揭示了岩体爆破损伤累积增长规律及其失稳破坏机理。创造性地运用傅立叶变换与小波（包）分析方法，找出了声波主频、能量及其频带分布随爆破次数增加的变化规律。第三，基于现场声波测试数据，首次建立了岩体爆破疲劳损伤非线性累积预测模型和岩体爆破累积损伤扩展模型。应用损伤力学、断裂动力学理论，系统研究了多次爆破作用下中远区岩体损伤断裂破坏机理；基于疲劳累积损伤理论，探寻了多次爆破作用下岩体损伤非线性累积特性及疲劳裂纹扩展规律。第四，基于爆破作业对岩体质量的损伤弱化效应，对Hoek-Brown经验公式做了进一步改进和完善，提出了爆破损伤作用下岩体力学参数研究方法—BDRMP（Blasting Damaged Rock Mechanical Parameters）法。BDRMP法充分考虑开挖爆破对岩体的损伤弱化程度，建立了爆破累积损伤程度、岩体完整程度与岩体力学参数劣化程度之间的定量关系，可以更好地确定介于破碎岩体和完整岩体之间的岩体力学参数。运用BDRMP法研究得到了厂坝铅锌矿岩体力学参数，为进一步深入开展爆破动荷载作用下地下工程岩体稳定性数值模拟研究和失稳机理的突变理论分析奠定了有力的基础。第五，首次系统分析了多次爆破作用诱发地下工程岩体失稳破坏的临界微扰机制，建立了爆破扰动作用下地下洞室顶板、矩形矿柱失稳的突变模型，分析了其失稳过程的非线性演化规律，导出了其失稳的充分和必要力学条件判据。确定了地下洞室顶板临界安全厚度，分析了临界安全厚度及矩形矿柱动力失稳的主要影响因素。第六，复杂多空区条件下，同时考虑开挖（采）过程和爆破震动作用对采空区稳定性的影响，利用FLAC^3D如对复杂地下采空区稳定性问题进行了系统的三维数值模拟研究。通过对比开挖过程、单次爆破震动作用和两次爆破震动联合作用三种情况对采空区稳定性的影响程度，揭示了爆破动荷载作用下复杂采空区失稳破坏机理以及爆破累积损伤效应对采空区稳定性的影响特征。本文立足于学科前沿，紧密结合工程实践，综合运用数学、力学方法、数值计算工具和先进的试验手段，对爆破作用下岩体累积损伤效应及其稳定性问题进行了深入的研究。为系统研究频繁爆破作业条件下采空区、地下厂房、隧道、边坡等岩体工程稳定性问题奠定了理论和技术基础，具有较为重要的理论意义和工程应用价值。更多还原

【Abstract】 The dynamic loadings generated by recurrent blasting operations will inevitably bring cumulative damage to surrounding rock mass and even induce rock mass of underground engineering to instability, when the drilling and blasting methods are used in the underground rock mass construction engineering and the excavating production in mines. The blasting damage is embodied in two aspects, which are weakness of rock mass mechanical properties and degression of rock mass integrality. So it is certain that the mechanical parameters of rock mass will be weaken and stability of rock mass engineering will be affected accordingly. At present, researches on cumulative damage effects and stability of rock mass under blasting loadings lack systemic study. It is awaited for more researches in theory and experiment further. The weaken effects induced by excavation and blasting can not be considered sufficiently in existing methods to confirm mechanical parameters of rock mass, so there are obvious shortages. Aiming at above questions, the author studied deeply and systematically on the cumulative damage effects and its stability of rock mass under blasting loadings, combining with the two projects: the special performance of the 10th five-year national key technologies R&D subject ’Study on integrated mining technology of large-scale ore avalanche with coupling of force and abduction under complicated mined-out areas’ （No. 2003BA612A-10-2）, and the innovated project of PHD candidate supported by Central South University ’Study on dynamic instability mechanism and forecast models of complicated correlative mined-out areas’ （No.040109）. The main research contents and results in the dissertation are as follows:First of all, the growth laws of rock mass cumulative damage under blasting for many times have been studied systemically, taken the lead in using sonic measurement technology. The experiments were carried out in situ for blasting cumulative damage effects of surrounding rock at some laneway in Changba Lead-zinc Mine with RSM-SY5 intelligent sonic measuring system, through simulating blasting for ten times with little charge. The statistic laws between blasting times and cumulative damage degree, sonic velocity of rock mass under blasting loadings have been obtained based on a lot of measuring data in situ. The influences on rock mass blasting cumulative damage effects brought by some factors, such as the distance from the blasting center, have been analyzed and the nonlinear degression relationship between blasting cumulative damage and the distance from the blasting center has been set up.Secondly, the internal relationship between the blasting cumulative damage degree of rock mass and the change laws of frequency spectral parameters of sonic measuring signals, such as waveform, key frequency and energy, with increasing of blasting times under repetitious blasting have been discovered for the first time. The increasing laws of blasting damage cumulative and instability mechanism of rock mass have been uncovered further. The variation laws of key frequency, energy and its distribution of bands of sonic signals with increasing of blasting times have been found out creatively, with the Fourier transform and the wavelet （wavelet packet） analytical methods.Thirdly, the nonlinear fatigue forecast models and the extension models of rock mass blasting cumulative damage have been established for the first time, based on the abundant sonic measurement data. The damage and fracture mechanism of rock mass subjected to blasting stress wave for many times at moderate or far distance has been studied systemically by damage mechanics and fracture dynamics theory; The nonlinear damage cumulative characters of rock mass and the laws of fatigue cracks propagation under blasting for many times have been searched for, based on the cumulative fatigue damage theory.Fourthly, Hoek-Brown expressions were amended and improved further and research methods of rock mass mechanical parameters damaged by blasting ’BDRMP （Blasting Damaged Rock Mechanical Parameters）’ were taken forward, based on the weaken effects of rock mass quality caused by blasting damage. The method of BDRMP can take disturbed and weaken degree of rock mass caused by blasting into account well, and set up the quantitative relationship among blasting cumulative damage, rock mass integrity degree and weaken degree of rock mass mechanical parameters. It can make certain the mechanical parameters of rock mass between disturbed and undisturbed better. The mechanical, parameters of rock mass at Changba Lead-zinc Mine were obtained by BDRMP method, which laid solid foundation for further numerical simulation in three dimensuions of stability and analysis with catastrophe theory of instability mechanism of underground engineering rock mass under blasting loading.Fifthly, the micro-disturbance mechanisms under critical condition of the instability of rock mass in underground engineering induced by blasting for many times have been analyzed systemically for the first time. The catastrophe models of instability of the roof of underground chambers and rectangle pillars under the blasting disturbance have been set up. The nonlinear evolvement laws of instability process have been analyzed and the necessary and sufficient mechanical conditions of instability have been derived. What’s more, critical safe thickness of the roof of underground chambers has been confirmed and the key influence factors of dynamic instability of critical safe thickness and rectangle pillars have been analyzed.Finally, taken the influence of excavtion （or mining） and blasting vibration on the stability of mined-out areas into account at the same time, numerical simulation in three dimensions was carried out for the stability of complicated mined-out areas with FLAC^3D under group mined-out areas. The instability mechanism of mined-out areas and influenced characters of blasting cumulative damage effects on the stability of mined-out areas were uncovered, through contrasting the influenced degree on the stability of mined-out areas of three different conditions, which were excavation process, individual action of once blasting vibration and combined action of twice blasting vibration.In short, the research in this dissertation is based on the frontal of the subject and combined with engineering practice close. The theories and methods of mathematical and mechanical, numerical simulation software tools and advanced experiment means, are used in studying on rock mass cumulative damage effects and its stability under blasting loading. It founded a theoretical and technological basis for studying on the stability of rock mass, such as mined-out areas, underground power chambers, tunnels and slopes, under the frequent blasting operations systemically. The research in the dissertation is of important theoretical significance and engineering application values.更多还原