【作者】 孙辉；

【导师】 王在泉；

【作者基本信息】 青岛理工大学 ， 结构工程， 2013， 博士

【摘要】 我国金属矿山资源日渐枯竭，加快复杂地质环境下矿山资源的勘探和开发已成为必然趋势，复杂地质环境条件下的开采将面临前所未有的矿山地质灾害，因此，研究复杂地质条件下的新型采矿方法等成为重要的研究课题。本文以解决复杂大水矿床的铁矿石地下开采为研究背景，运用理论分析、室内及现场试验、数值模拟及现场监测相结合的综合研究方法，对《工程岩体分级标准》的不合理性进行分析并提出修改建议，并结合大量的室内、现场测试及实验分析，研究确定了谷家台铁矿的围岩级别和相关物理力学参数；并引入安全系数作为稳定性评价指标对新型六边形下向进路胶结充填采矿法对控制顶板变形、改善围岩受力、减少对注浆帷幕的扰动机理及规律、参数优化等进行了系统研究，得出了合理的开采参数；探讨了渗流条件下的围岩破坏机理，并据此确定了多水平、多矿块的合理开采方案。通过现场注浆帷幕的变形及受力监测分析，初步验证了理论分析的合理性及可行性。论文主要研究内容及成果如下：(1)对国标《工程岩体分级标准》中存在的各种问题进行了初步探讨，提出了相应的修改建议，并应用于莱芜谷家台铁矿。针对定性判断和定量指标之间不一致的问题，对岩体基本质量指标BQ值评分标准进行了修正；针对初始地应力影响判断公式物理意义并不明确的情况，建议将初始地应力分为自重应力和地质构造应力两部分分开考虑，地质构造应力的部分适用于原有判断公式，自重应力的影响通过不同埋深情况下的安全系数指标来体现，进而对岩体基本质量指标BQ值进行了修正；增加了具有严格力学意义的安全系数作为稳定性评价的定量指标，使围岩分级的表述更具科学性；建立岩体基本质量指标BQ值和岩体分级指数RMR值之间的数学关系，根据RMR值与岩体力学参数之间的经验公式，得到了基于BQ值的岩块到岩体的物理力学参数折减方法。(2)结合《工程岩体分级标准》的修改建议，通过现场点荷载试验、钻孔波速测试、节理裂隙统计，室内三轴试验等手段，对谷家台铁矿不同区段的围岩状况进行了综合评价，确定了不同区段围岩的围岩级别和相应的物理力学参数，并试验确定了不同配比充填体的物理力学参数。(3)通过对注浆帷幕体试样进行瞬态渗透试验研究，揭示了其全应力-应变过程中的渗透特性。整个破坏过程分为三个阶段，平静期，试样内部微裂隙萌生；发展期，试样内微裂隙快速发育、延伸和贯通；完全渗透阶段，试样受压破坏，大量裂隙形成贯通，出现断裂面。应变-渗透系数曲线的峰值滞后于应力-应变曲线的峰值，说明岩石破裂是透水的直接原因，且先于透水而发生。(4)采用解析法对六边形进路回采围岩应力进行求解，利用单位圆外域到一般形状洞孔外域的映射函数，近似求得六边形洞孔外域的映射函数，考虑垂直方向受均布荷载γ H，水平方向受均布荷载λγ H、地面荷载为0时六边形洞周围岩应力分布，发现原岩应力场(λ的大小)对洞周围岩应力分布有很大影响，λ值小于0.2时，洞顶出现拉应力，随着λ值增大，拉应力逐渐消失，开始出现压应力并逐渐增大。利用有限元软件ANSYS模拟了不同侧压力系数λ的情况，模拟结果与解析解基本吻合。(5)结合传统数值分析中围岩应变、变形及塑性区变化，引入安全系数作为稳定性评价指标，系统研究了埋深、围岩参数、宽高比和横截面积等条件对六边形矿房围岩稳定性的影响，并与同等条件下矩形矿房的模拟结果进行了比较，分析了六边形矿房在限制注浆帷幕顶板位移和控制洞周应力转移方面的优越性，并优化确定了合理的开挖矿房间距至少为矿房宽度的2倍，确定了不同矿石参数条件下合理的矿石间柱和矿块尺寸，通过对整个矿块开挖过程的围岩稳定性进行分析，认为在间柱位置最容易发生失稳。(6)对多水平、多矿块开采方案的合理性进行了研究。无渗流条件下，确定单一水平同时开采矿块间距至少为一个矿块+两个间柱的宽度；两水平、多矿块同时开采的间距须大于两个矿块+三个间柱的宽度，且第二水平矿块的顶板须为充填体才可保证安全开采；因为矿体倾角仅为30°左右，第一和第三水平的矿块已不在一个断面内，三水平、多矿块的开采方案可参考两水平的方案进行设计。(7)对无渗流条件下确定的开采方案进行了渗流条件下的围岩稳定性验证，确定渗流条件下单一水平多矿块开采间距至少要两个矿块+三个间柱宽度，两水平多矿块开采至少间隔三个矿块+四个间柱宽度，且第二水平开挖矿块的直接顶板须为充填体。统计各开采方案采场围岩渗流场和应力场可能发生突变点的区域，为后续远程监测系统的安装提供技术支持。(8)基于上述研究确定了注浆顶板围岩渗流场和应力场可能发生突变点的区域，现场实施了顶板注浆围岩应力、变形及空隙水压力监测，初步监测表明，注浆顶板围岩处于安全稳定状态。更多还原

【Abstract】 The resourse of metal mine in our country becomes exhausted day by day, it isbecoming inevitable trend to speed up prospection and exploitation of complexwater-rich mine. The influence of ground water on mining safety, new mining methodbecome important research subjects. The actual project was taken as researchbackground, comprehensive research method of theoretical analysis, indoor and field,numerical simulation and field monitoring were used to revise the unreasonable partsof national standard ‘Standard for Engineering Classification of Rock Mass’. Theresearch findings were applied to Gujiatai iron mine. Roof deformation-controlling,improving surrounding rock stress, decreasing the perturbed mechanism and rule ongrouting curtain, parameter optimization and so on of new hexagon access miningmethod with cemented filling were studied systematically. Safety factor was leadingin as evaluating index of stability. The stability of surrounding rock under seepagecondition was studied to confirm reasonable scheme about multi-level andmulti-block. Based on the deformation and stress monitors of grouting curtain, therationality and feasibility of theory analysis were forecasted and testified to furtherimprove mining technology and provide technical support for mining safety. The maincontents and results are as follows:(1) The various problems of national standard ‘Standard for EngineeringClassification of Rock Mass’ were studied for corresponding methods, and theresearch results had been applied in Gujiatai iron mine. Based on inconsistentproblem of qualitative judgment and quantitative index, the basic quality index ofrock mass BQ was revised. The physical meaning of initial crustal stress formula isindeterminated, initial crustal stress should be divided into gravity stress and tectonicstress. The influence of gravity stress would be reflected by different safety factors indifferent depths to revise basic quality index of rock mass BQ. The safety factorwhich has strict mechanics content was used as quantitative criteria about stabilityestimation in grading standards, which made the surrounding rock classification morescientific. The mathematical relation between basic quality index of rock mass BQ and rock mass classification index RMR were built, the reducing method aboutphysical mechanical parameters based on BQ value was obtained based on theexperience formula between RMR value and rock mechanics parameters.(2) Combined with suggests of ‘Standard for engineering classification of rockmass’, the surrounding rock of different sections in Gujiatai iron mine had been madea comprehensive evaluation by means of field point loading test, wave velocity test,field jointing statistics, three triaxial test. The grades and physical mechanicsparameters of surrounding rock at different sections had been determined. Thephysical mechanics parameters of filling with different ratio were also determined.(3) The permeate characteristics of full stress-strain process had been revealedthrough transient permeability test on samples of grouting curtain. There were threestages in whole destroying process: quiet period, the internal fracture appear.Development period, microcracks grow, extend and link up quickly. Completepermeate stage, samples have compression damage, fracture link up and fractureplane appears. The peak value of strain-permeability coefficient curve lags behind thepeak value of stress-strain curve, which means that the rock failure is the direct causeof gushing water.(4) The analytical method was used to solve surrounding rock stress ofhexagonal tunnel. The mapping function from exterior domain of the unit circle togeneral shape hole was used to obtain mapping function of hexagonal hole. Incondition of uniform load γ Hin vertical direction、 λγ Hin horizontal direction andground load is zero, the in situ stress field (λ value) had great influence on stressdistribution around the hole. When λ is less than0.2, tensile stress appeared in theroof and gradually disappeared with λ value increasing. The finite element softwareANSYS was used to simulate conditions of different lateral pressure coefficient, thenumerical simulation results was consist with analytical solution, which proved thatthe analytic solution could been used in design calculation of mining parameters.(5) Combined with variety of strain, deformation and plastic zone of surroundingrock in traditional numerical analysis, safety factor was leading-in as stability estimating index. The effects of buried depth, surrounding rock parameters, aspectratio and the cross-sectional area had been systematically studied and compared withthe result of rectangular stope room with same conditions. The superiority ofhexagonal stope was summarized in limiting roof displacement and controlling holestress transfer. The reasonable stope spacing should be more than2times of stopewidth, the reasonable size of rib pillar and block under different mineral parameterswere determined. The stability of surrounding rock in whole block excavation hadbeen analyzed. The rib pillar positions were more easy to unstable.(6) The rationality of scheme about multi-level and multi-block had beenresearched. Without seepage conditions, the spacing of mining blocks at the sametime was at least one block plus two rib pillars at single level. When miningmulti-blocks at two levels, the spacing was greater than two blocks plus three ribpillars and the roof of block at second level should be fillings. The dip angle oforebody was only about30degrees, blocks at first and third levels were not in onesection, the mining scheme of three levels and multi-block could refer to the schemeof multi-blocks at two levels.(7) The stability of surrounding rock under seepage condition had been testified,the spacing of mining blocks at the same time was at least two blocks plus two ribpillars at single level. When mining multi-blocks at two levels, the spacing wasgreater than three blocks plus four rib pillars, and the roof of block at second levelshould be fillings. The dangerous locations where seepage field and stress field maychange suddenly have been counted to provide technical support for the follow-upremote monitoring system.(8) Based on above researches, the mutational area of seepage field and stressfield in grouting roof were confirmed, the field monitoring of stress, deformation andpore water pressure put into effect. The initial monitoring results indicated that thegrouting roof was in stable state.更多还原