【作者】 蒋楠；

【导师】 周传波；

【作者基本信息】 中国地质大学 ， 岩土工程， 2013， 博士

【摘要】 随着矿石资源露天开采不断进行,浅部资源不断减少,国内外露天转地下开采的矿山工程不断涌现。爆破作为矿山开采、岩体开挖等采矿生产与工程建设的必要手段,在提高生产作业效率的同时,其爆破振动动力作用的影响使得矿山露天边坡崩塌、滑移等地质灾害现象屡见不鲜。由此可见,露天转地下开采边坡动力稳定性等相关问题,已成为我国露天转地下开采矿山安全生产的关键科学技术问题。开展露天转地下开采边坡爆破动力特性研究,是边坡爆破动力稳定性问题研究的工作基础,同时也是工程地质学、爆炸力学与岩石动力学等多学科交叉的前沿与热点课题,具有重要的的理论研究价值和重要的工程应用意义。本文采用“现场测试”、“数值模拟”、“理论计算分析”综合研究方法,开展了露天转地下开采边坡爆破振动现场测试分析、边坡爆破振动高程效应、地下开采中深孔爆炸应力波荷载特性、露天转地下开采边坡爆破动力响应、露天转地下开采边坡爆破振动安全判据等一系列的研究工作,论文具体研究内容和成果如下：(1)露天转地下开采边坡爆破振动传播规律研究。采用TC-4850型爆破振动记录仪及其测试系统,对大冶铁矿地下开采爆破振动进行现场监测,获得了一系列露天边坡岩体爆破振动数据,并对监测数据进行频率分布特征及振动速度回归分析。研究结果表明：爆破振动X、Y、Z各方向的主震频率分布并不一致,X方向爆破振动主振频率主要集中在55Hz,而Y、Z方向爆破振动主振频率分布在<45Hz区间内；对比表征爆破振动传播规律的萨道夫斯基公式发现,南北帮边坡爆破振动传播规律因岩体特性及特地质条件不同而存在明显差异性,以大理岩为主的南帮边坡比以闪长岩为主的北帮边坡衰减更快,地下开采爆破振动对露天边坡的影响分析时应对南北帮边坡分别进行。(2)露天转地下开采边坡爆破振动高程效应研究。基于量纲分析原理建立了考虑高程影响的爆破振动速度预测模型,采用改进的预测模型对大冶铁矿地下采矿爆破振动速度传播特征进行了预测分析,并与萨道夫斯基经验公式预测结果进行了对比；同时依托露天采场狮子山北帮边坡采矿工程实际,建立了边坡数值模型计算分析并通过现场实测数据进行了验证,采用已验证模型及参数,分别建立不同坡度边坡模型(坡角依次为15°、30°、45°、60°)进行了爆破动力数值计算,系统探讨了不同坡度边坡爆破振动高程效应。研究结果表明：相比于萨道夫斯基经验公式,改进后的爆破振动速度预测模型对衰减规律的表征更加贴切、误差更小,引入相对坡度的概念爆破振动速度计算模型能更好地表征爆破振动在边坡体上的传播过程中的高程效应；边坡爆破振动速度的放大效应主要以垂直方向振动速度放大为主；对于不同坡度边坡,爆破振动速度以衰减为主,但存在高程放大效应比衰减趋势占主导的现象。(3)露天转地下开采扇形中深孔爆破荷载特性研究。采用动力有限元软件LSDYNA建立扇形中深孔爆破计算模型,计算分析得到爆炸应力波荷载的有效应力、矢量叠加振动速度的分布特征；采用相同材料参数分别建立药包半径为30cm、32cm、34cm、36cm、38cm、40cm、42cm、44cm、46cm、48cm球形药包爆破计算模型,通过两种装药结构爆破荷载的有效应力、矢量叠加振动速度对比分析,得到爆炸应力波荷载的等效球形药包模型。研究结果表明：338kg(半径42cm)球形装药结构的计算模型爆破荷载特性与493kg柱状装药的爆破模型基本一致,等效球形装药结构能够较好地反映扇形中深孔爆破中远区荷载特性,消除数值建模过程中因量级不统一造成的网格划分问题。(4)露天转地下开采边坡爆破动力响应研究。结合大冶铁矿东露天采场特殊的工程地质条件,通过地质模型的概化分析,建立了包括地下采矿巷道、边坡岩体及主要断层破碎带的三维数值计算模型,爆破动力分析得到南北帮边坡岩体、断层破碎带及稳定性条件较差的A区滑体内坡面岩体爆破振动时程曲线及振动主频。分析结果发现：南帮边坡坡面岩体监测点X、Y、Z方向振动速度最大值分别为0.823cm/s、0.727cm/s、0.866cm/s,各监测点Z方向主振频率位于23.14Hz～31.88Hz；北帮边坡坡面岩体监测点X、Y、Z方向振动速度最大值分别为0.877cm/s、0.737cm/s、0.903cm/s,各监测点Z方向主振频率位于13.89Hz～25.17Hz；A区滑体内坡面岩体监测点爆破振动速度位于0.464cm/s-0.176cm/s,各监测点Z方向主振频率38.22Hz～22.83Hz。(5)露天转地下开采边坡爆破振动速度安全判据研究。基于岩石动力学理论及爆破振动荷载作用下岩体的动态强度特征,对大冶铁矿露天边坡主要岩体极限抗拉强度进行了判定；根据边坡爆破动力响应研究成果,建立了各边坡岩体及断层破碎带充填体所受拉应力峰值和振动速度峰值的统计关系,从统计角度近似确定两者的函数方程,结合极限抗拉强度准则并引入重要性修正系数的概念,探讨了基于数值计算的露天转地下开采边坡爆破振动速度安全判据；同时,基于应力波传播理论,对爆炸应力波传播至自由表面、断层交界面处的反射折射进行了理论分析,建立了爆破振动速度判据理论计算模型,并结合大冶铁矿露天边坡工程实际求解分析得到了基于应力波传播理论的爆破振动速度安全判据；最后对理论分析求解结果、数值计算结果及爆破安全规程标准取值进行了对比。根据研究结果得到：基于数值计算方法,南帮边坡爆破振动速度安全判据为9.31cm/s,北帮边坡爆破振动速度安全判据为7.90cm/s；基于应力波传播理论,南帮边坡爆破振动速度安全判据为13.41cm/s,北帮边坡爆破振动速度安全判据为27.79cm/s；数值计算及理论分析结果与爆破安全规程安全允许标准基本相符,理论分析计算结果对于数值计算分析结果相比略微偏大。更多还原

【Abstract】 With the exploiting of surface mining as ore resources, shallow resources declines and mining is turning from open pit to underground mining projects either at home or abroad. Blasting is an inevitable means of mining production and construction projects in mining, rock excavation, underground mining. Surface slope collapse, slip and other geological disasters are common occurrences because of the influence of blasting vibration dynamic action. Therefore, the problem of slope dynamic stability has become a key scientific and technological issue of safe exploiting in open pit to underground mining. Moreover, the dynamic response of open pit to underground mining slope is not only the basis for the work of the slope blasting dynamic stability problems, but also the hot topics in engineering geology, explosion and rock dynamics, which has significant importance in theoretical and engineering applications.In this paper, the field test, combined with numerical simulation, theoretical calculation and analysis were adopted. The analysis of the open pit to underground mining the slope blasting vibration field test, slope altitude effect of blasting vibration velocity, deep hole explosion in underground mining stress Bohol overload characteristics, the dynamic response of the open pit to underground mining blasting, the safety criterion of blasting vibration velocity in open pit to underground mining, etc. were carried out. The main results are listed as followings:(1) Study on rule of blasting vibration propagation on open pit to underground mining slope. Daye Iron Mine underground mining blasting vibrations were monitored applying the TC-4850blasting vibration recorder test system. Then, A series of open-pit slope rock blasting vibration test data were obtained which were analyzed on frequency distribution characteristics and velocity attenuation. The results show that:the main vibration frequencies on X, Y and Z direction are not consistent; the frequency on X direction is mainly concentrate in55Hz, but the frequencies on Y and Z direction are less than45Hz. Due to differences of rock mass characteristics and special geological conditions, there are significant differences of vibration propagations on the north and south slope rock mass by comparing the Sadaovsk formulas. The vibration velocity of the south slope which is made of marble attenuates faster. The influences of blasting vibration on the north and south slope should be analyzed separately.(2) Study on blasting vibration altitude effect of open pit to underground mining slope. A new forecasting model of blasting vibration velocity which considered the altitude effect was established based on the principle of dimensional analysis; then the blasting vibration velocity propagation characteristics were predictive analyzed separately by the forecasting model and Sadaovsk formula. On the basis of north slope mining engineering practice, the numerical model of the slope was established which was improved by field data. Applying the proved model and parameters, this dissertation establish the different degree slopes which contains15°slope,30°slope,45°slope and60°slope, and investigate the blasting vibration altitude effects of the slope. The results show that:the new forecasting model predicts the blasting vibration attenuation rules more accurate than Sadaovsk formula; the PPV’s amplification is obvious, and the vertical PPV plays the main role; The PPVs on the different slope surface attenuate with the slope degree increase, but there is a phenomenon that the amplification effect plays the main role.(3) Study on blasting load characteristics of sector medium-length hole in underground mining. The sector medium-length hole blasting model was established by dynamic finite element software LSDYNA, and the distribution characteristics of effective stress and resultant velocity were calculated and analyzed; Applying the same material parameters, this dissertation established the spherical structure blasting models whose radius were0cm,32cm,34cm,36cm,38cm,40cm,42cm,44cm,46cm,48cm; the equivalent spherical charge model was obtained by comparing effective stress and resultant velocity with sector medium-length hole charge model. The results show that:the blasting load characteristics of338kg (radius is42cm) spherical structure model were similar with493kg sector medium-length hole charge model; the equivalent spherical charge model can reflect the load characteristics of sector medium-length hole which can eliminate the meshing problems caused by size disunion.(4) Study on blasting dynamic response of open pit to underground mining slope. Based on the special engineering geological conditions of Daye Iron Mine, the three-dimensional numerical model including underground mining tunnel, slope rock mass and fault fracture zone was established; then the blasting vibration velocity-time curves and main frequencies of slope rock mass, fault fracture zone and the A-slope rock mass. The results show that:the vibration velocities of south slope rock mass on X, Y, Z direction are0.823cm/s,0.727cm/s and0.866cm/s separately, and the frequencies are between23.14Hz and31.88Hz; the vibration velocities of North slope rock mass on X, Y, Z direction are0.877cm/s0.737cm/s and0.903cm/s separately, and the frequencies are between13.89Hz and25.17Hz; the vibration velocities of A-slope slope rock mass on X, Y, Z direction are from0.464cm/s to0.176cm/s, and the frequencies are from38.22Hz to22.83Hz.(5) Study on blasting vibration velocity safety criterion of open pit to underground mining slope. On the basis of rock dynamic theory and rock dynamic strength characteristics subjected blasting vibration, the dynamic tensile strengths of Daye Iron Mine slope rocks were determined; according previous numerical simulation research on dynamic response of slope rock mass, the relationship models of PPVs and tensile strength of the slope rock mass and fault fractures were established:combined with ultimate tensile strength criterion, the blasting vibration velocity safety criterions based on numerical simulation was calculated by the introduction of the concept of the importance of the correction factor. Meanwhile, based on the theory of stress wave propagation, the reflection and refraction on the free surface and the interface were analyzed, and the blasting vibration velocity criterion theoretical calculation model was established; combined Daye Iron Mine open pit slope engineering practice, the blasting vibration velocity safety criterions based on theoretical analysis was solved. Finally, the numerical analysis results and theoretical analysis compared with the blasting safety standard. The results show that:based on the relationship models of PPVs and tensile strength, the blasting vibration safety criterion of south slope is9.31cm/s, and the blasting vibration safety criterion of north slope is7.90cm/s; based on the theory of stress wave propagation, the blasting vibration safety criterion of south slope is13.41cm/s, and the blasting vibration safety criterion of north slope is27.79cm/s; the blasting vibration safety criterion of numerical calculation and theoretical analysis are both basically consistent with the blasting safety standard, and the theoretical analysis results is slightly larger compared to the results of the analysis for numerical calculation.更多还原