【作者】 张定邦；

【导师】 周传波；

【作者基本信息】 中国地质大学 ， 地下建筑工程， 2013， 博士

【摘要】 岩体的相似材料物理模型试验主要用来研究与岩土工程相关的天然岩体受力特性及其变形破坏机理,能较为真实的模拟复杂的地下结构、复杂的地质构造及复杂的岩层组合关系等,通过模型试验可以发现一些特殊的规律和现象,并能与理论研究相互印证,但由于模型试验工期长、投资大、难度高,因此物理模型试验在地下建筑工程中的应用较少。露天转地下开采是国内外露天矿山发展的必然趋势。开采过程中,高陡露天边坡与地下开采相互影响和制约,其相互影响机理研究是保证矿山安全生产的基础和理论依据,非常有必要采用相似材料物理模型试验手段,研究露天转地下采动影响下,露天超高陡边坡与地下采场的稳定性及潜在的变形破坏机理。目前,相似材料物理模型试验面临着较多尚未得到解决的技术问题,如模型材料的局限性、断层破碎带模拟的合理性、模型应力应变量测技术等,这些问题的解决是本文研究的重点和难点。本文是国家自然科学基金面上项目“超高陡边坡与崩落法地下开采相互影响机理研究”(41072219)的主要研究内容,以大冶铁矿露天转地下开采条件为依托,在遵循相似原理的基础上,从研究模型试验技术入手,研制了岩矿相似材料,设计完成了高陡边坡与崩落法地下开采相互影响机理的物理模型试验,并用相关数值计算软件进行了模型试验结果的对比分析。主要研究内容和成果如下：(1)现场工程地质性质与地质模型概化研究。①通过资料收集、现场工程地质勘察与室内外测试等方法对大冶铁矿东露天采场的工程地质性质进行了分析。②由于复杂的地质形貌和岩性特征难以在模型试验中完整模拟,因此必须在充分考虑地质特征和工程特性,保证试验结果真实有效的基础上对模型进行概化;本试验选择狮子山矿段26～31#勘探线间的1-2剖面为模型试验研究典型断面,断面岩矿体可概化为闪长岩、大理岩、磁铁矿以及回填体四类,断面地质构造较为发育,概化为最具代表性的两条较大断层F9和F25,分别穿越上下盘边坡体。(2)相似理论分析及岩矿相似材料的研制。①考虑经济合理、技术可行的原则,选择物理模型的几何相似常数为300,并根据相似理论推导出各类岩矿相似材料及整体模型的物理力学性质相似比。②运用正交实验设计的方法,通过大量配比试验及物理力学性质测试,研制出一种以铁矿粉、重晶石粉和石英砂为骨料,不饱和树脂和石膏为胶结材料的矿岩相似材料；该矿岩相似材料解决了现有材料模拟技术中的不足,其制备成本低廉、性质稳定、制作工艺简单、养护周期短、材料来源广泛、价廉且无毒副作用,具有较高的实用性。(3)岩矿相似材料的理化性质研究。①进行了岩矿相似材料的物理力学性质测试。测试结果表明：岩矿相似材料的密度分布在2.37～2.83g/cm3之间,弹性模量分布在11.423～127.935MPa之间,抗压强度分布在0.091～0.884MPa之间,黏聚力分布在2.3～12.01KPa之间,内摩擦角分布在15.93～38.590之间。②运用极差和方差分析法对岩矿相似材料物理力学性质的影响因素进行了敏感性分析。分析结果表明,相似材料中铁矿粉含量对相似材料密度、内摩擦角起主要控制作用,黏结剂含量对试件的抗压强度、弹性模量、黏聚力起主要控制作用,重晶石粉含量对相似材料密度和弹性模量的影响较为明显,石英砂含量对相似材料内摩擦角的影响较为明显。③对岩矿相似材料进行了环境扫描电镜分析,分析结果表明岩矿相似材料颗粒较粗,颗粒形状不规则,球形颗粒较少,磨圆度较差,孔隙连通性不好,颗粒间存在不同程度的胶结。④对岩矿相似材料进行了X射线荧光光谱分析,分析结果表明该岩矿相似材料以氧化铁和氧化钡为主要成分,且两者的含量和大于60%,因此该岩矿相似材料的化学活性较低,相似材料在自然环境中不易发生化学变化而改变其物理力学性质。理化性质研究结果表明,该岩矿相似材料物理力学性质稳定,满足大理岩、闪长岩及铁矿体等岩体物理力学性质的相似比要求。(4)物理模型试验系统研制。①设计了完整的模型试验整体方案,研制出模型砌块生产装置,解决了高重度、低变形模量、低强度岩矿相似材料砌块难以成型及易碎的问题；设计制作了满足相似比要求的整体模型。②充分考虑了扩帮式露天开采和无底柱分段崩落法地下开采的工艺特点,结合现有试验条件设计出试验模拟开采方法和详细开采方案,可以在模型试验过程中较为合理的模拟这二类采矿方法的工况。③将传统的位移和应力应变接触式量测方法和新兴的近景变形测量技术结合起来,克服了接触式量测方法测点布置的局限性和近景测量技术运用尚不普及的缺点,保证了试验全程监测过程中监测点分布的全面性和监测数据的可靠性。采用了百分表、数字照相量测、应变片及土压力盒数据采集等监测手段全程监测模型试验过程。(5)露天转崩落法地下开采模型试验及分析。①露天转地下开采过程中边坡力学特征研究。露天开采时,南北帮边坡坡脚位置出现了回弹现象；废石固体回填至±0m使回弹变形有了较明显的改善；转入地下开采后,南北帮边坡坡面位置的水平位移出现了增长较快;开采-72m至-180m地下矿体的过程中,南北帮边坡的总位移随开采深度增加而近似呈线性增大,北帮边坡总位移值始终大于南帮边坡；北帮边坡顶部产生了最大的竖向位移,量值约为-0.15mm(折合为原型的-45mmm),北帮边坡坡脚产生了最大的水平向位移,量值约为-0.23mm(折合为原型的-69mm)。矿体开采对北帮边坡影响较大,南帮边坡稳定性较好。②露天转地下开采过程中采场围岩力学特征研究。在整个露天转地下开采过程中,矿体围岩测点的位移值随着测点高程的降低和距矿体中心水平距离的增大而减小,地下开采对距矿体南北边界50cm(折合为原型的150m)范围外的岩体不产生影响。在地下开采阶段,随开采深度增加,矿体上下盘围岩的总位移都呈均匀增加的趋势,且上盘围岩总位移始终大于下盘围岩。-60m水平及以下各水平矿体上下盘围岩的最大主应力值呈现出平缓变化→快速下降→平缓变化的特点,即开采到某—水平之前,该水平围岩的最大主应力随着开采深度的增加而近似呈线性缓慢增加；当开采到该水平时,该水平围岩的最大主应力跃升至最大量值；之后在开采该水平以下深部矿体时,该水平围岩的最大主应力随着开采深度的增加而缓慢减小。(6)模型试验中的数字照相测量技术研究。研究表明：当模型的变形大于0.04mm时,数字照相量测的数据适用性较好,数字照相量测技术适用于较大变形与位移的量测,能对露天转地下开采物理模型试验实现全场、全过程的实时动态监测,能够提供不同开采水平下模型的变形特征图像,能够分析模型各部位的变形值和变形趋势,更好的分析崩落法地下开采对高陡边坡变形的影响机理。该研究成果为相似材料物理模型试验研究提供了新的测试技术,将有利于相似材料物理模型试验的应用发展。(7)数值模拟对比分析研究。以物理模型试验选取的典型断面为研究对象,运用FLAC软件开展了数值模拟与物理试验的对比分析,研究结果表明：①露天开采过程中,由于卸荷作用,使得露天高陡边坡坡脚处出现应力集中及位移回弹现象。②受地下采动的影响最为严重,产生竖向位移最大的位置出现在北帮边坡的上部(高程130m以上)及矿坑底部的回填体上。③总体上看,随着铁矿体开采的不断进行,矿体上下盘围岩及高陡边坡的位移值均逐渐增大；最大主应力云图基本沿边坡轮廓以层状的规律分布,自上而下逐渐增大,坡脚及坑底处的应力值最大。④数值模拟反映出的矿体南北帮边坡及采场围岩变形规律和应力分布特征与模型试验结果基本吻合,可以相互验证。更多还原

【Abstract】 Similar model test of rock mass is mainly used to study the mechanical characteristics and deformation mechanism of rock mass related to underground structure, it can really simulate the complicated underground structure, geological structure and stratum combination. Some special rules and phenomenon can be found in the model test, and can be confirmed with the theoretical research, but because of long duration, large investment, high difficulty, therefore the physical model test is rarely used in underground engineering.Open-pit to underground mining is the inevitable trend of the development of domestic and foreign open pit mines. In the process of mining, high steep slope and underground mining influence and restrict each other, their mutual influence mechanism is the guarantee and theoretical basis of safety production. It is necessary to adopt the model test to research the stability and potential mechanism of deformation-failure to high slope and underground stope under the influence of underground mining. At present, the similar material model test is facing many technical problems, such as the limitations of similar material, rationality of fault fracture zone simulation, measurement technology and so on, the solution to these problems is the key point of this research.This article is main contents of the National Natural Science Fund Project "the research of mutual influence mechanism between high-steep slope and underground mining"(41072219), taking Daye iron open-pit to underground mining conditions as the basis, follow the principles of similarity theory, starting from the research of model test technology, developed the rock similar material, completed the design of model test, analysis and compare the model test results with numerical calculation software. The main research contents and results are as follows:(1) The research of engineering geological properties and model generalization.①The engineering geological properties are analyzed through data collection, geological investigation and indoor-outdoor tests of the east open-pit stope of Daye iron mine.②Choosing the1-2profile between26～31#exploration line at the Shizishan mining area as the typical section of model test, the rock mass of the profile can be generalized as diorite, marble, magnetite and backfill, the fault fracture zone can be generalized as F9and F25fault.(2)Similarity theory analysis and the development of similar materials.①Selected geometry’s similar constant as300, the physical and mechanical properties of rock similar material are derived according to the similarity theory.②A new kind of similar material of underground caving mining model test which consists of iron ore powder, barite powder, quartz sand, unsaturated resin, gypsum, etc was developed through a lot of material mechanics test which are high availability.(3) Study on the physicochemical properties of rock similar material.②The test of physical and mechanical properties of similar material show that the density of similar material range from2.37to2.83g/cm3, the elastic modulus range from11.423to127.935MPa, the compressive strength range from0.091to0.884MPa, the cohesion range from2.3to12.01kPa and the friction angle range from15.93°to38.59°②The sensitivity of every factor is analyzed by using variance and range analysis method. It concluded that the weight ratio of iron ore powder has control effect on density and internal friction angle, and the weight ratio of unsaturated resin has control effect on compressive strength, elastic modulus and cohesion.③The analysis results of the rock similar material by using environmental scanning electron microscope show that the particles are irregular shape, spherical less, poor roundness, pore connectivity and containing different degree of cementation.④The analysis results of the rock similar material by using X ray fluorescence spectrometry show that the60%contents of the similar material are ferric oxide and barium oxide. So the chemical activity of similar materials are low, the physical and mechanical properties are stability under natural environment.The physicochemical properties of rock similar materials show that the physical and mechanical properties of similar materials are stability and the materials can meet the the needs of marble, diorite and iron ore for Daye Iron Mine’s underground caving mining model test.(4)Development of physical model experiment system.①The overall scheme of the complete model test is designed. The model block production device is developed to solve the forming problem of rock similar material block which are high gravity, low deformation modulus, low strength.②According to the characteristics of open mining and sublevel caving mining, similarity mining technology and mining plan of model test is designed under the existing experimental conditions.③According to the research need,12dialgage,39strain foil,2soil pressure cell and59photographic objective are arranged in the model surface to monitor the model test process.(5)Model test of open-pit to underground mining.①Study on mechanical characteristics of slope in the process of open-pit to underground mining process. In process of underground mining, the horizontal displacement of slope grow rapidly. The displacement of northern slope is always greater than the total value of the south slope. The largest vertical displacement appears on the top of northern slope, the value of about-0.15mm that is-45mm equivalent to prototype, the largest horizontal displacement appears at the toe of north slope. The value of about-0.23mm that is-69mm equivalent to prototype. The principal stress of slope are pulling stress and parallel to slope surface. The southern slope are more stability than northern slope.②Study on mechanical characteristics of the surrounding rock of stope in the process of open-pit to underground mining process. During the process of open-pit to underground mining, the displacement of surrounding rock decrease with the elevation reduction and horizontal distance from the center. Before mining to a certain level, the rock maximum stress of a level increase slowly with the increase of mining depth, when mining to the level, the rock maximum stress jump to the maximum value, after mining below the level, the rock maximum stress decreases with the increase of mining depth.(6)Research on digital photogrammetry technology in model tests. Research shows that: Digital photographic measurement technology applies to large deformation and displacement measurement, it can dynamically monitor the process of this model test, analysis the deformation trend at each part of model. The results provide the new testing technology for experimental study of model test and will be conducive to the application and development of model test.(7)Study on numerical simulation compare with model test. Choosing the typical cross section of physical model test as the research object, using the FLAC software to analyse the comparison between numerical simulation and physical experiment. The results show that:①Because of the unloading effect in open pit mining process, the phenomenon of displacement and stress rebound appear at the toe of slope.②The largest vertical displacement appears on the top of northern slope.③Displacement of surrounding rock and the slope increase gradually during the underground mining. The maximum principal stress are in layered distribution and gradually increasing from bottle to top of the slope.④The mechanical characteristics of the slope and the surrounding rock of stope in the process of open-pit to underground mining process described in numerical simulation is the same with the results of model test. Both the results studied by model test and numerical simulation can be verified with each other.更多还原