阶段充填采矿优化设计可靠性分析与稳定性评价

针对充填采矿优化设计中充填体力学参数中诸多因素的不确定性,开展了地表岩移可靠性分析和采场稳定性评价。首先,基于某铁矿山超大采场阶段嗣后充填3种回采模式的优化设计方案,设计了充填强度正交实验,运用FLAC3D软件对矿山充填回采过程进行了数值模拟和岩移计算;其次,应用有限元正交设计算法,分别得出该矿各中段地表岩移的失效概率、可靠度指标和安全系数,开展了不同优化设计的采场稳定性评价。研究结果表明,矿体自下向上3个回采阶段可靠度依次降低,其中-250m中段地表发生剧烈沉降和变形;3个回采方案中,点柱式回采方案采场安全性最好,能满足岩移控制要求,适于工程的长期稳定性开采。     

点柱式上向水平分层充填采矿法结构参数优化研究

鉴于二道河铁矿属于"三下"开采范围,地表有河床、公路、工业场地以及临时性住房等需要保护的单元,确定采用点柱式上向水平分层充填采矿法,以实现安全、经济、高效回采。通过调查分析矿区范围内的水文地质条件,结合岩石力学室内试验以及工程类比得到岩体力学参数,并采用FLAC3D有限差分软件分别对8种采矿方案各分层开挖充填后的采场应力、位移及塑性区的大小及分布规律进行模拟,最后在数值模拟结果的基础上对8种采矿方案进行极差分析。结果表明:矿房长度对顶板最大拉应力、点柱最大压应力、底板最大起鼓量、顶板最终沉降量和塑性区总体积等指标的影响程度最大,点柱尺寸次之,分层高度最小。综合评价得到采矿方案Ⅰ、方案Ⅱ、方案Ⅳ为较优方案,并由此推出最优方案Ⅸ,即采场结构参数选择为矿房长度49.5m,点柱尺寸5m×5m,分层高度5m。     

崩落转充填开采地压显现规律及稳定性监测

露天转地下开采后,在进行崩落法转充填法开采过程中,过渡采场的稳定对维护露天边坡的稳定至关重要。采用FLAC~(3D)对无底柱分段崩落法转分段凿岩阶段空场嗣后充填法开采过程中的采场地压显现规律进行了数值模拟分析,结果表明:崩落法采场底部结构中的应力较开采前增大了2 MPa;充填法二步骤开采矿柱时,采空区两侧及顶板应力突增2 MPa。采用钻孔应力计等仪器对310#矿房回采过程中采场的稳定性进行了为期56d的现场监测,监测期间采场应力变化幅度较小(3.0~4.2 MPa),监测区域平均收敛速率仅为0.086~0.20mm/d,采场整体较稳定,验证了数值模拟结果的准确性。     

胶结充填在二步回采中的应用研究

结合某金矿二步回采,胶结充填工艺,采用有限差分数值软件FLAC3D模拟非线性大变形问题,建立数值模型,模拟矿体的回采和充填过程,为安全开采提供了依据,论证了胶结充填的可行性,保证安全生产。     

某浅埋矿床条带法开采地表沉降与开采强度关系的试验研究

针对上横山浅埋缓倾斜矿床条带嗣后充填回采条件,以物理相似模拟试验为基础,分析了矿床回采地表沉降(陷)变形特征。地表沉降在不同回采时步呈非线性变化,当最大不充填开采1~2个条带时,空区上覆直接顶能有效的控制地表沉陷范围,沉降变形以采空区为中心对称,未形成明显的沉陷区;当最大不充填开采3个条带时,沉降变形从直接顶延伸至松散层,地表沉陷显现,沉降范围约40~50m,但小于地下开采范围;当最大不充填开采为4个条带时,导致了松散层持续垮塌、空区上覆岩层破坏,沉陷范围达100~120m,完全大于地下开采范围。从控制地表沉陷安全范围和提高开采强度考虑,选择最大不充填开采3个条带,盘区生产能力达到1141.96t/d,且能够保证地表沉陷范围小于地下开采范围,实现矿床安全高效开采。     

公路下磷矿开采位移沉降规律分析

贵州省开磷集团用沙坝矿的部分矿体位于金阳公路下,为保护公路而保留的保安矿柱矿石量约2262万t,为矿区储量的50%。采用留竖向矿柱的房柱式分层充填法开采使金阳公路的位移沉降量仅为48.5mm,为公路下矿体开采提供了一种矿石损失率小,位移沉降量小的开采方法。     

基于数值模拟的某铜矿深部采场结构参数优化研究

某铜矿深部矿体品位较高,采场顶板破碎,目前采用分层充填采矿法开采。为保证深部矿体的安全、高效开采,结合该铜矿开采技术条件,提出采场结构参数优化方案,并对-580m水平采用分层充填法的采场结构参数进行分析验证。运用ANSYS软件建立三维模型,并导入有限差分软件FLAC~(3D)中模拟采场的开采,对不同开采方案下采场的应力、位移及塑性区进行对比分析。模拟结果表明:矿房宽度为6m,点柱尺寸为4.0m×4.0m,矿柱间距为5.0m的方案为最优方案。     

国外缓倾斜中厚矿体采矿方法的新发展

本文介绍近年来国外开采缓倾斜中厚矿体新发展的采矿方法:分段房柱采矿法,对角式运输斜巷房柱法,斜交走向推进的房柱法,垂直分条密实充填法,斜分条密实充填法和分段房柱充填法。     

条带式矿柱嗣后充填采矿方法在缓倾斜磷矿开采中的应用

根据湖北杨柳磷矿区的开采技术条件,将普通空场房柱法和条带式矿柱嗣后充填采矿方法进行了对比分析,发现条带式矿柱嗣后充填采矿方法既能保证采矿的安全,又可以提高矿石的回采率,是一种较为适合缓倾斜中厚矿体开采的新方法。     

充填式浮选柱中径向返混及流速分布对浮选效果影响的研究

建立了充填式浮选柱的二维混合模型,并对该模型进行了数值法求解,探讨了径向返混系数和轴向气、液流速沿径向的分布对充填式浮选柱捕集区的回收率的影响.结果表明,增大径向返混系数有助于提高回收率;轴向气、液流速沿径向的分布越均匀越好;气速的不均匀分布将对回收率造成较大影响.分析结果对提高充填式浮选柱的浮选效果具有一定的理论指导意义.     

Numerical simulation of injection mold filling

This paper illustrates a numerical simulation of polymer flow as applied to the injection molding fill process. The simulation model considers heat conduction and viscous heat generation along with the temperature dependence of the flow parameters to predict fill lengths and fill times of thin constant crossection cavities. This simulation is designed for molding situations where fill is difficult, such as thin cavity sections, long flow length requirements, or difficult-to-process materials. The simulation sensitivity is explored by performing experimental molding trials with two different cavity thicknesses. The thinner cavity illustrated a short shot in all cases with the thick cavity completely filling. The simulation accurately distinguishes between the short shot and fill conditions, although significant error is noted for the length prediction of the short shot and the time-to-fill of the full shot condition.     

Optimization of filling process in RTM using a genetic algorithm and experimental design method

In the resin transfer molding (RTM) process, preplaced fiber mat is set up in a mold and thermoset resin is injected into the mold. An important issue in RTM processing is minimizing the cycle time without sacrificing part quality or increasing the cost. In this study, a numerical simulation and optimization process for the filling stage was conducted in order to determine the optimum gate locations. The control volume finite element method (CVFEM), modeled as a 2‐dimensional flow, was used in this numerical analysis along with the coordinate transformation method to analyze a complex 3‐dimensional structure. Experiments were performed to monitor the flow front to validate the simulation results. The results of the numerical simulation corresponded with that of the experimental quite well for every single, simultaneous, and sequential injection procedure. The optimization analysis of the sequential injection procedure was performed to minimize fill time. The complex geometry of an automobile bumper core was chosen. A genetic algorithm was used to determine the optimum gate locations in the 3‐step sequential injection case. Taguchi's experimental design method was also used for determining the pressure contribution of each gate. These results could provide the information on the optimum gate locations and injection pressure in each injection step and predict the filling time and flow front.     

A unified simulation of the filling and postfilling stages in injection molding. Part II: Experimental verification

The unified numerical simulation of the filling/postfilling stages of the injection-molding process described in Part I is compared in the present paper with experimental results obtained with instrumented test molds. Flush-mounted pressure traces in the delivery system as well as in the cavity are favorably compared with corresponding predictions for both an amorphous and a semicrystalline polymer. It is demonstrated that the present unified formulation is well suited to handle complicated molds where compressibility effects can become important even during the filling stage, as portions of the cavity fill and undergo a packing behavior even when other regions of the cavity are still only partially filled.     

充填工作面上覆岩层运移规律数值模拟分析

为了取得邢台矿7623充填工作面开采的充填效果,通过采用UDEC离散元分析软件,模拟分析不同等价采高充填开采时上覆岩层运移特征,得到7623充填工作面上覆岩层运移弯曲下沉及地表变形规律和充填效果。该技术的成功应用,为存在类似问题的充填工作面提供了可借鉴的经验。     

共注成型充模流动数值模拟研究

在共注成型多相分层流动充模成型的机理研究基础上,通过采用通用的Hele-Shaw模型和流体积技术,推导出用于描述共注成型多相分层流动充模过程的理论模型,并提出了一种稳定有效的求解理论模型的数值方法。该数值方法通过使用不连续Galerkin法、上风（upwine)法等稳定性技术来解决数值解的不稳定性问题和数值发散问题,实例数值模拟结果与实验结果基本吻合。     

A phenomenological model for fiber tow saturation of dual scale fabrics in liquid composite molding

Advanced composites are manufactured by liquid composite molding by impregnating a thermoset resin into a stationary woven or stitched preform. For a successful injection, the manufactured part should fill all the empty spaces between the fiber tows and inside the fiber tows with the resin. The fiber tows in such preforms have orders of magnitude lower permeability than the regions between the fiber tows, which makes them difficult to fill and hence susceptible to formation of microvoids. Numerical simulations can address the filling of fiber tows but it is difficult to capture the essential physics of their filling in a model created entirely from first principles due to the complexity of the flow which involves anisotropic permeability of flow along and across a fiber tow, uneven packing, fiber sizing, capillarity and the treatment of entrapped air. Hence, in this article we adopt a phenomenological approach in which we compare some of the possible models with an experimental procedure. The experimental procedure provides a quantitative measure of the filling of fiber tows during the impregnation process. A numerical simulation based on the dual scale flow was developed with different constitutive models that described the filling of the fiber tows. The predictions of the different models are compared with the experimental results under different processing conditions to select the model that most accurately describes the tow filling behavior. POLYM. COMPOS., 31:1881–1889, 2010. © 2010 Society of Plastics Engineers.     

冬瓜山矿床开采方案优化的数值模拟研究

通过正交试验的方法,运用RFPA数值程序研究了不同开挖步骤、充填体刚度、充填接顶情况对铜陵有色金属公司冬瓜山矿挖稳定性的影响。以采场破坏和峰值载荷为评判依据,试验表明,在给定的数值试验条件下,充填接顶对峰值载荷影响最大,而充填体刚度影响最小,这表明,在冬瓜山矿开采过程中,一定要保证充填的接顶质量。     

Numerical simulation of fiber orientation in injection molding of short-fiber-reinforced thermoplastics

The present study develops a numerical simulation program to predict the transient behavior of fiber orientations together with a mold filling simulation for short-fiber-reinforced thermoplastics in arbitrary three-dimensional injection mold cavities. The Dinh-Armstrong model including an additional stress due to the existence of fibers is incorporated into the Hele-Shaw equation to result in a new pressure equation governing the filling process. The mold filling simulation is performed by solving the new pressure equation and energy equation via a finite element/finite difference method as well as evolution equations for the second-order orientation tensor via the fourth-order Runge-Kutta method. The fiber orientation tensor is determined at every layer of each element across the thickness of molded parts with appropriate tensor transformations for arbitrary three-dimensional cavity space.     

某地下矿山采矿方法及参数的数值试验研究

在采场结构稳定的前提下,为了降低矿石二次贫化,利用三维数值分析程序,模拟了乳山市金矿深部分别采 用留矿法和上向不胶结充填分层开采两种采矿方法,得出乳山市金矿在-485m水平以下,上向不胶结充填分层回采 方法是首选方案,并确定了该回采方法的矿房参数。     

破碎带下磷矿开采诱发地表沉陷的离散元数值模拟

探讨了破碎带下矿体开采引起地表沉陷的地质现象和产生机理,并介绍了离散元法的原理和常用离散元软件UDEC的特点及其控制参数的选择方法,利用该软件结合某磷矿山的具体工程地质情况,对破碎带下采矿诱发地表沉陷的地质力学现象进行了数值模拟,验证了该机理的正确性.