学科：矿业工程,出版时间：2018,导师：许梦国指导,学位授予单位：武汉科技大学,论文作者：王明旭著,
中文
传统充填法重点研究胶结充填体充填井下后自身的强度问题，而忽略了不同龄期所呈现的不同强度胶结充填体对围岩稳定性影响不同。胶结充填体与围岩共同承载能力直接影响井下采场高效安全回采和上覆岩层的变形稳定，并且充填采场受到复杂的多向应力环境，以程潮铁矿为工程背景出现了充填法与无底柱分段崩落法共同开采和确保地表选厂安全的充填采场安全高效回采的要求。为确保矿山高效安全开采，通过胶结充填体与围岩共同承载问题的研究确保接触带的稳定，进而确保无底柱分段崩落法不对充填采区的安全构成不利影响，同时通过胶结充填体与围岩的共同承载确保上覆岩层变形稳定，进而确保地表选厂安全。为此，荷载作用下充填体与围岩复合体的变形演化特征及承载能力是接触带稳定性分析和评判的关键科学问题，故采用岩石力学试验、理论分析、数值模拟试验、物理相似模拟试验和现场监测等研究手段，系统研究不同强度胶结充填体对采场围岩稳定性的影响及胶结充填体与围岩共同承载的变形演化规律问题。 (1)利用安全系数云图定量表征了含随机节理围岩的变形损伤演化规律；建立了基于随机分组函数的围岩随机分布夹石的复合体数值模拟方法。针对充填体与围岩接触区域围岩应力复杂、节理发育、夹石分布较多的特点，开展了接触区域完整围岩、含随机节理和夹石围岩变形损伤的室内试验和数值模拟研究。通过系统描摹法建立了随机节理数值模型，结合色素提取软件，利用安全系数云图定量表征了含随机节理围岩的变形损伤演化规律；建立了基于随机分组函数的围岩随机分布夹石数值模拟方法，结合弹塑性理论，得到了不同节理分布和夹石含量对围岩稳定性的影响规律，为接触区域不同赋存地质条件的围岩稳定性评判提供了理论指导。 (2)提出了蠕变能量积聚法，研究了胶结充填体能量积聚与释放响应，并构建了胶结充填体的失稳判据。依据胶结充填体不同龄期的变形特点，将胶结充填体划分为早期和后期。对早期胶结充填体开展力学加载变形的室内试验和数值模拟研究，结合静水压力理论处理方法，构建早期胶结充填体与围岩相互作用力学模型，得到了早期胶结充填体对围岩稳定性的影响规律。提出了蠕变能量积聚法，通过对本构拟合方程求积分和求导，引入柔化正态张量和应变能张量表征胶结充填体能量变化特点，研究了胶结充填体能量积聚与释放响应，并构建了后期胶结充填体的失稳判据。将后期胶结充填体对围岩作用简化为简支梁的力学模型，结合胶结充填体长期稳定性具有蠕变特性，将其简化为西原体模型，通过挠度计算评判简支梁稳定性。研究结果揭示了不同龄期胶结充填体通过对围岩形成不同程度的变形挤压约束机制，实现能量的传递、积聚与释放，从而影响围岩的稳定。 (3)建立了损伤变量与强度占比系数关系和内部损伤破坏与超声波值衰减之间的对应关系，定量表征了充填体与围岩复合体共同承载的内部损伤规律。利用声发射仪和超声波仪监测胶结充填体与围岩共同承载复合体的变形演化特征。对共同承载复合体开展加载过程中的声发射点定位，监测声发射振铃数、声发射能量值，引入不同时刻振铃计数占全部振铃计数比值的强度占比系数，建立损伤变量与强度占比系数关系表征其内部损伤与整体稳定性的对应关系。同时借助超声波仪测试胶结充填体与围岩共同承载复合体在加载破坏前后的声波值变化，建立内部损伤破坏与声波值衰减之间的对应关系。通过复合体表壁裂纹扩展分形特征评价和软PVC塑料薄片对接触面的破坏形态进行表征和监测，理清了充填体与围岩共同承载复合体的变形演化规律。 (4)研制了充填体与围岩共同承载复合体三轴加载装置，构建了复合体的多向受力模型。研究了充填体与围岩共同承载复合体在轴向加载、双向剪切加载、自研制的类三轴加载方式下的损伤破坏形式和失稳破坏特点。通过电阻应变片和应变计监测充填体与围岩共同承载复合体接触区域的应变变化特点。通过电子显微成像设备监测不同加载形式下复合体表壁裂纹萌生、扩展、汇集及贯通，利用损伤力学和分形理论建立不同破坏面裂纹的分形维数表征方法。同时开展了数值模拟研究，其结果验证了接触区域的应变值变化规律。研究成果揭示了胶结充填体与围岩共同承载时不同受力形式对其整体稳定性产生的不同影响，有利于通过采矿作业调整改变接触区域受力特点，减少对胶结充填体与围岩共同承载的不利影响。 (5)选取程潮铁矿为现场工程研究对象，开展崩落法和充填法共同开采下的接触带稳定性研究。将崩落法和充填法共同开采下的接触带简化为简支梁加弹簧约束的力学模型开展挠度和位移计算，定量分析接触带的变形变化特点。利用数值模拟软件，选择程潮铁矿典型剖面，通过重点监测不同回采顺序作用下的接触带围岩应力分布及安全系数变化规律，开展接触带稳定的崩落法和充填法合理回采顺序优化研究，并结合地表沉降监测和采场地压在线监测，指导矿山安全生产。 关键词：充填体；围岩；变形演化；裂纹扩展；安伞系数；声发射
英文
The traditional filling method focuses on the strength of cemented backfills after filling downholes, while ignoring the different strength cemented backfills present at different ages having different effects on the stability of surrounding rocks. Both the common carrying capacity of cemented backfills and surrounding rock directly affects the downhole. The stope’s high-efficiency and safe mining and stable deformation of the overlying rock strata, and the filling of the stope are subjected to a complex multi-axial stress environment. With Chengchao Iron Mine as the engineering background, the filling method and sub-column-less sublevel caving method have been jointly exploited and ensured that the surface selection plant secure fill stope requirements for safe and efficient recovery. In order to ensure the efficient and safe mining, the stability of the contact zone is ensured through the study of joint bearing problems between the cemented backfill and the surrounding rock, thereby ensuring that the sublevel caving method without bottom pillars does not affect the safety of the filling and mining area, and at the same time, through cemented backfills and enclosures. The common bearing of the rock ensures the stability of the overlying rock formations, which in turn ensures the safety of the surface plant. For this reason, the deformation evolution characteristics and bearing capacity of the backfill body and the surrounding rock mass under load are the key scientific issues for the stability analysis and evaluation of the contact zone. Therefore, the rock mechanics test, theoretical analysis, numerical simulation test and physical similarity simulation test are adopted. And on-site monitoring and other research methods, systematically studied the impact of different strength cemented backfill on the stability of the surrounding rock of the stope, and the problem of the evolution of the deformation of the cemented backfill and the surrounding rock. (1)With the safety factor cloud images, the evolutionary rule of deformation damage of stalactites with stochastic joints was quantitatively characterized. Based on stochastic grouping function, a stochastic numerical simulation method for stochastic ore-rock distribution was established. Aiming at the characteristics of complex stress, tight joint development and large distribution of gravel in the contact area between the filling body and the surrounding rock, laboratory tests and numerical simulations on the deformation damage of the intact ore rock, random joint and gravelly ores in the contact area were carried out. A random joint numerical model was established by systematic tracing method. Combined with pigment extraction software, the evolution law of deformation damage of random jointed ore strata was quantitatively characterized by the cloud graph of safety coefficient. A random distribution function was used to simulate the random distribution of rock strata. With the elasto-plastic theory, the influences of the distribution of different joints and the content of gravel on the stability of surrounding rock was obtained, which provided theoretical guidance for the stability evaluation of surrounding rock under different geological conditions in the contact area. (2)The creep energy accumulation method was proposed, the energy accumulation and release response of cemented filling body was studied, and the instability criterion of cemented filling body is established.The cemented filling body was divided into early and late stages by the deformation characteristics of cemented filling body at different ages. The laboratory tests and numerical simulations on the mechanics and deformation of early cemented filling bodies were carried out. Combined with hydrostatic pressure theory, the mechanical model of interaction between early cemented filling bodies and ore rock was established, and the influence of early cemented filling bodies on the stability of surrounding rock was obtained. The creep energy accumulation method was proposed. By integrating and deriving the constitutive equations, the softening normal tension and strain energy tensor are used to characterize the energy variation of cemented filling body. The energy accumulation and release of cemented filling body was studied. In response, a post-cemented filling body instability criterion was builded. The effect of surrounding cemented backfill on the surrounding rock was simplified as the mechanical model of simply supported beam. The long-term stability of the cemented backfill has the creep property, which was reduced to the model of the Visco-elastoplatic model. The stability of the simply supported beam was evaluated by the deflection calculation. The results revealed that the different time cemented filling bodies can exert energy transfer, accumulation and release to influence the stability of the surrounding rock through different degrees of deformation and squeezing constraints on the surrounding rock. (3)The relationship between the damage variables and the strength proportion coefficient and the corresponding relationship between the damage and the attenuation of the ultrasonic wave value were established, and the internal damage situation co-carried by the filling body and the ore-rock complex was quantitatively characterized. The acoustic emission apparatus and sonicator were used to monitor the deformation, and evolution characteristics of co-supported composite body with cement-bounding and surrounding rock. The acoustic emission point locating during the loading process of the co-bearing complex was monitored. The number of acoustic emission rings and the acoustic emission energy were monitored, and the proportion of the damage variables and intensities count ratios was established to characterized the relationship between the internal damage and the overall stability by introducing the proportion of the ringing counts to the total ringing count ratios at different times. At the same time, the ultrasonic wave instrument was used to test the changes of acoustic wave before and after loading and unloading, and the corresponding relationship between damage and sound attenuation was established. Through the evaluation of the fractal characteristics of crack growth on the surface of the composite wall and the soft PVC plastic sheeting, the failure morphology of the contact surface was characterized and monitored, and the deformation and evolution characteristics of the composite bearing body was clarified. (4)Three-axis loading device was designed to co-carry the composite body with the surrounding rock to construct a multi-directional force model of the composite body. The damage and failure characteristics of the composite bearing body with surrounding rock under axial loading, bidirectional shear loading and self-designed three-axis loading were studied. The strain changes in the contact area of the composite bearing body with the surrounding rock were monitored by the strain gages and strain gauges. The initiation, propagation, pooling and penetration of the surface cracks of the composite under different loading conditions were monitored by the electronic microscope imaging equipment. The fractal dimension characterization method of different fracture surfaces was established by using damage mechanics and fractal theory. At the same time, the variation of strain in the contact area is validated by numerical simulation. The research results revealled different forms of stress on the overall stability when the cemented filling body and the surrounding rock were co-supported, which was beneficial to change the stress characteristics of the contact area through the adjustment of mining operations and reduced the co-bearing of the cemented filling body and the surrounding rock Adverse effects. (5)Chengchao Iron Mine was selected as the research object of the field project, guiding the stability of the contact zone under the common mining of caving and filling method. The contact zone under caving method and filling method was simplified as the mechanical model of simply supported beam with spring constraint to calculate the deflection and displacement, and to quantitatively analyze the deformation characteristics of the contact zone. Numerical simulation software was used to select the typical section of Chengchao Iron Mine to carry out numerical simulation research. The contact zone was stable and the caving method was reasonable optimization of the sequencewas studied to guide mine safety production by focusing on monitoring the stress distribution and safety factor changes of surrounding rock under different sequence of recovery. Keywords: cemented filling body; surrounding rock; contact zone; deformation evolution; crack propagation; safety factor; A
