Stability and reliability of pit slopes in surface mining combined with underground mining in Tonglushan mine

Slope stability is of critical importance in the process of surface-underground mining combination. The influence of underground mining on pit slope stability was mainly discussed, and the self-stabilization of underground stopes was also studied. The random finite element method was used to analyze the probability of the rock mass stability degree of both pit slopes and underground stopes. Meanwhile, 3D elasto-plastic finite element method was used to research into the stress, strain and rock mass failure resulting from mining. The results of numerical simulation indicate that the mining of the underground test stope has certain influence on the stability of the pit slope, but the influence is not great. The safety factor of pit slope is decreased by 0.06, and the failure probability of the pit slope is increased by 1.84%. In addition, the strata yielding zone exists around the underground test stope. The results basically conform to the information coming from the field monitoring.

Limits to foundation displacement of an extra high voltage transmission tower in a mining subsidence area

Given the background of a transmission tower erected on a particular mining subsidence area,we used finite element modeling to analyze the anti-deformation performance of transmission towers under a number of different load conditions,including horizontal foundation displacement,uneven vertical downward displacement,wind loads and icing conditions.The results show that the failure in stability of a single steel angle iron represents the limit of the tower given ground deformation.We calculated the corresponding limits of foundation displacements.The results indicate that compression displacement of the foundation is more dangerous than tension displacement.Under complex foundation displacement conditions,horizontal foundation displacement is a key factor leading to failure in the stability of towers.Under conditions of compression or tension displacement of the foundation,wind load becomes the key factor.Towers do not fail when foundation displacements are smaller than 1% (under tension) or 0.5% (under horizontal compression or single foundation subsidence) of the distance between two supports.

Constitutive model of disturbed soil-structure interface within mining subsidence areas

The characteristics of a disturbed soil-structure interface were studied based on the variation regularities of the disturbed soil within its mining subsidence area using direct shear tests.The effects of the initial moisture content on the shear strength parameters of the soil-structure interfaces were analyzed.The results indicate that the cohesion of the interface initially increased and then decreased as the initial moisture content increased.In addition,the friction angle of the interface decreased as the initial moisture content increased.A constitutive model of the disturbed soil-structure interface,a rigid-plastic model based on the initial void ratio and saturability(VSRP) model,was established based on the results.In order to validate this model,a finite element analysis of DRS-1 direct shear tests was conducted.The finite element model calculations coincided with the results of the DRS-1 direct shear tests.The proposed model also reflected the nonlinear features of the soil-structure interface.

基于数值模拟的充填采矿地表移动规律研究

通过FLAC3D软件建立的三维数值仿真模型,结合有限元理论,针对某矿露天转地下开采过程中的地表沉降问题进行了研究。结果表明,随着充填率的增加,顶板最大主应力和竖向位移均呈现出降低的趋势。在-40 m首次开采中段回采后及时进行充填的情况下,100%充填率相比于90%充填率,竖向位移最大值降低了45%;当回采至305 m中段时,100%充填率相比于90%充填率,竖向位移值降低了22%。地表监测点的竖向位移和水平位移均随充填率的增加而降低。在保证95%充填率的情况下,地下开采对地表构筑物的影响较小,满足规程允许的地表变形值。研究结果对露天转地下开采地表沉降规律提供了有益参考。

植物根系对赣南矿山边坡的稳定性影响

利用Midas SoilWorks有限元软件,对矿山边坡生态修复工程种植的狗牙根(Cynodondactylon(L.)Pers.)、花木蓝(Indigofera kirilowii Maxim.exPalib.)和榆树(Ulmus pumila L.)的根系,在自然条件和暴雨条件下对矿山边坡的安全稳定性影响进行了研究。结果表明,3种植物根系在各条件下对矿山边坡的安全稳定性都有不同程度的提高。植物根系对矿山边坡稳定性的影响程度与根系的数量及根系对边坡土体的作用范围有密切关系,深浅根系的组合效果最佳。但随着植物根系的深入,边坡安全稳定性系数提高,坡面的水平位移量也会随之增大,所以在实际的矿山边坡修复设计中,应结合安全稳定性系数、应力和变形等综合分析验证坡体的可靠性,选取最佳设计方案。

大型料仓仓壳顶稳定性分析及建议

在料仓仓壳顶厚度的常规计算中,通常只考虑其单位面积上承受的平均载荷,包括基本雪压、仓壳顶自重等,未考虑质量较大的过滤器、管架平台等给仓壳顶局部稳定性带来的影响。这一问题在大直径料仓的计算中更为突出。为此,文章以1台直径15 m的大型料仓为例,对其仓壳顶在过滤器质量和大尺寸管线载荷影响下的稳定性进行了有限元分析,验证了较大的集中载荷对于料仓仓壳顶的稳定性的不利影响,并据此给出了工程设计中的合理化建议。

红岭铅锌矿采场结构参数优化研究

为确定红岭铅锌矿分段凿岩阶段空场嗣后充填采矿法的合理采场结构参数,采用数值模拟的方式对顶板厚度分别为3 m、5 m、7 m和10 m,采场长度分别为20 m、30 m、40 m和60 m的16种工况进行了研究,对比了顶板厚度为3 m情况下各工况的应力、位移和塑性区分布。结果表明:红岭铅锌矿分段凿岩阶段空场嗣后充填采矿法采场顶板厚度3 m,采场长度35 m时,采场稳定性较好。

有限元强度折减法下的岩土边坡稳定分析

岩土边坡稳定性分析是岩土工程中的重要课题,传统的极限平衡法存在一些缺陷和不足,难以准确反映边坡的真实破坏状态。采用有限元强度折减法,对一个节理岩质边坡进行了稳定性分析,通过不断降低边坡的强度参数,直到模型发生破坏,计算出边坡的安全系数,并确定了边坡的滑动面;还采用了不同的稳定判断准则,如计算收敛与否、位移突变、塑性区贯通等,综合评价了边坡的稳定性。结果表明,有限元强度折减法可以有效地模拟岩质边坡的破坏过程,考虑了边坡的复杂几何形状、材料非线性、节理裂隙等影响因素,提高了分析的精度和可靠性,为边坡工程设计和施工提供了参考依据。

关于煤矿液压支架顶梁结构强度的探讨分析

以ZZC8800/20/38充填液压支架后顶梁为研究对象,介绍一种后顶梁多目标优化设计。根据充填液压支架后顶梁基本结构,利用有限元仿真软件构建仿真模型,从静态强度性能和动态强度性能两个角度实施后顶梁结构强度仿真分析。根据分析结果,采用多目标优化设计法,介绍充填液压支架后顶梁优化设计方案,将优化设计应用于工业性试验,确认优化设计可有效提高后顶梁多方面强度性能。

基于Midas/GTS对铜矿破碎机硐室边坡施工的稳定性分析

基于某铜矿破碎机硐室支护施工难度大,围岩稳定性差等特点,采用圆管支撑+锚杆+板桩墙联合支护,利用MIDAS/GTS建立二维有限元数值模型,分析圆管支撑+锚杆+板桩墙联合支护在硐室边坡施工的可行性。研究表明,围护结构变形及整体稳定性满足相关规范要求,整体安全可靠,在不平衡土压力作用下,围护结构产生最大位移位于最下一道钢管支撑至坑底2/3处,后期硐室边坡开挖至硐室底时,应立即施做硐室结构,减少硐室边坡暴露时间。为类似铜矿破碎机硐室边坡设计及施工提供参考。

矿柱回采对空区稳定性影响分析

针对矿柱回收后形成的空区是否稳定,是否对周边主要构(建)构物产生影响的问题。本文通过单轴压缩试验、巴西劈裂试验、三轴压缩实验、纵波波速试验确认空区周边岩石性质,并在此基础上通过采用Madis岩土分析软件进行模型建立和网格划分,采用FLAC3D有限元软件进行数值模拟运算,通过计算该区域矿柱回采后空区是否稳定,能够较好的验证了该项目矿柱回采方案可行性。同时,本文中相关模型及计算结果皆可作为相关矿柱回采的理论借鉴。

宁夏中南部5 m分级黄土边坡稳定性模拟研究

以宁夏已建黄土地区公路资料为基础,通过有限元模拟计算宁夏中南部黄土地区公路路堑边坡,研究单级5 m自然边坡情况下,坡率、平台宽度、中间宽平台等各因素对边坡安全系数的影响,并结合规范、占地、土方等综合因素,提出20 m以下不同开挖深度下推荐的路堑边坡形式,为今后宁夏黄土地区公路路堑边坡设计提供借鉴及参考。

新型脱挂式矿山架空乘人索道迂回轮体结构设计与优化

传统矿山架空乘人索道作为地下矿井、巷道的重要载人设备存在速度慢、安全性低的缺点。据此提出了一种高速、安全的新型脱挂式矿山架空乘人索道方案,并对其迂回轮体进行了结构设计与优化分析。文中应用Ansys Workbench软件对初步设计的迂回轮体进行了强度分析,结果表明该方案安全系数过高,需进行优化设计。通过对腹板厚度为12 mm、16 mm的模型进行分析,确定了较为理想的腹板厚度为16 mm;同时为进一步减轻轮体质量、改善其受力情况,对轮体进行了开孔设计,确定了2孔间连接钢板宽度为180 mm的条件下开孔处内外侧圆角分别为100 mm、180 mm时,轮体结构较为合理。

Lateral bearing characteristics of subsea wellhead assembly in the hydrate trial production engineering

Conductor and suction anchor are the key equipment providing bearing capacity in the field of deep-water drilling or offshore engineering,which have the advantages of high operation efficiency and short construction period.In order to drill a horizontal well in the shallow hydrate reservoir in the deep water,the suction anchor wellhead assembly is employed to undertake the main vertical bearing capacity in the second round of hydrate trial production project,so as to reduce the conductor running depth and heighten the kick-off point position.However,the deformation law of the deep-water suction anchor wellhead assembly under the moving load of the riser is not clear,and it is necessary to understand the lateral bearing characteristics to guide the design of its structural scheme.Based on 3D solid finite element method,the solid finite element model of the suction anchor wellhead assembly is established.In the model,the seabed soil is divided into seven layers,the contact between the wellhead assembly and the soil is simulated,and the vertical load and bending moment are applied to the wellhead node to simulate the riser movement when working in the deep water.The lateral bearing stability of conventional wellhead assembly and suction anchor wellhead assembly under the influence of wellhead load is discussed.The analysis results show that the bending moment is the main factor affecting the lateral deformation of the wellhead string;the anti-bending performance from increasing the outer conductor diameter is better than that from increasing the conductor wall thickness;for the subsea wellhead,the suction anchor obviously improves the lateral bearing capacity and reduces the lateral deformation.The conduct of the suction anchor wellhead assembly still needs to be lowered to a certain depth that below the maximum disturbed depth to ensure the lateral bearing stability,Thus,a method for the minimum conductor running depth for the suction anchor wellhead assembly is developed.The field implementations show that compared with the first round of hydrate trial production project,the conductor running depth is increased by 9.42 m,and there is no risk of wellhead overturning during the trial production.The method for determining the minimum conductor running depth in this paper is feasible and will still play an important role in the subsequent hydrate exploration and development.

基于ANSYS程序下的采场稳定性分析

采用大型有限元分析软件ANSYS对柿竹园矿III矿带矿体典型采场顶板的稳定性及其对采场围岩力学状态的影响进行数值模拟、非线性分析,对9种典型采场结构模型的模拟结果进行了比较分析,根据分析结果结合采掘效率和开采成本等因素确定了采场最优结构参数,并对当前采矿方案提出修正和调整建议,以便更清楚地掌握采场地压发展变化规律,有效地进行地压管理,实现矿体的安全高效开采。

康家湾矿深部难采矿体采场稳定性及结构参数优化研究

采用大型有限元分析软件——ANSYS对康家湾矿深部难采矿体典型采场顶板的稳定性及其对采场围岩力学状态的影响进行数值模拟、非线性分析,对9种典型采场结构模型的模拟结果进行了比较分析,根据分析结果结合采掘效率和开采成本等因素确定了采场最优结构参数,并对当前采矿方案提出修正和调整建议,以便更清楚地掌握深部地压变化规律,有效地进行地压管理,实现深部破碎带矿体及顶板不稳固矿体的安全高效开采.

复杂采空区条件下残矿回收与采区稳定性的有限元数值模拟研究

结合江西省香炉山钨矿的残矿回收工程实践,利用有限元数值分析软件3D-δ建立三维数值模型,对该矿复杂采空区条件下残矿回收与采空区稳定性进行了数值模拟,揭示了残采过程中矿柱及采空区的应力分布规律和位移变形趋势,验证和评价了传统经验方法判断结果的可靠性,模拟结果对矿山安全回收残矿、矿柱加固处理工作有重要的指导意义。

无底柱分段崩落法采场稳定性分析

无底柱分段崩落法是国内外地下矿山广泛采用的采矿方法。长期以来由于受凿岩、装药以及出矿设备的制约,国内矿山大多采用小结构参数的无底柱分段崩落法,所产生的地压问题十分严重,开采效率低。近年来无底柱分段崩落法朝着增大采场结构参数的方向发展,不但有利于改善采场稳定性,同时还降低了生产成本。因此,开展采场稳定性分析有利于实现安全、高效开采。采用三维有限元方法对10 m×10 m、15 m×15 m、15 m×20 m共3种不同结构参数的崩落法采场进行了数值模拟,对进路开挖与矿石回采两个不同过程的巷道顶板竖直位移、主应力进行分析。数值计算结果表明:进路开挖时15 m×20 m与10 m×10 m的结构参数相比较,巷道顶板的竖直位移降低了20.1%,最小主应力下降了约18.8%;开采过程中顶板的竖直位移、主应力值都比进路开挖时小,采场地压得到改善;进路开挖与矿石回采过程巷道顶板的竖直位移和主应力值都随着结构参数的增大而降低。因此,大结构参数能更好地改善采场地压,增强采场稳定性,采用大结构参数的无底柱分段崩落法是安全可行的。

露天开采边坡稳定性分析方法及灾害防治措施研究

研究露天开采边坡的安全稳定对露天矿山的安全生产具有重要意义。在分析边坡滑动破坏影响因素的基础上,总结和分析了边坡稳定性分析方法在露天开采中的应用现状;系统地探讨在露天开采边坡安全评价中常用的3种边坡稳定性分析方法;应用典型的计算算例验证3种方法在露天开采边坡稳定性分析中的适用性;在边坡滑坡破坏机理分析的基础上,探讨了边坡滑动灾害的防治措施。

淮南矿区地应力条件及其对煤层顶底板稳定性的影响

通过现场地应力测量和理论分析以及数值模拟计算，研究了淮南矿区地应力分布规律，探讨了圆形硐室围岩应力分布和不同侧压下回采工作面顶板稳定性分布。研究结果表明：淮南矿区原岩应力主要表现为自重应力场，除局部构造应力集中外，不存在高构造应力；区内侧压力系数A值一般为0．49—1．49，平均为0．92，并且与测点距地表深度有一定的趋向性，表现为在浅部A值较大，变化范围也大，而在深部A值渐小，变化范围也缩小；回采工作面顸底板稳定性与侧压系数A的大小密切相关，且随侧压系数A的增大，顶板垂直位移减小，顶板岩层易于形成结构平衡而保持稳定，但底板垂直位移量增大，且易于形成底鼓破坏。这些认识为研究区煤层顸底板岩层支护控制提供了科学依据。