条带开采煤柱稳定性的试验模拟与数值分析——以山东省济宁市太平煤矿为例

以山东省济宁市太平煤矿为例，采用煤柱模拟试验和数值分析手段，对薄基岩条带开采时所留设煤柱的应力应变状态、煤柱强度结构及煤柱长期稳定性进行了深入的分析与研究，揭示了煤柱稳定性及煤柱应力分布与条采尺寸、采出率、覆岩特征的相互关系，进行了条带煤柱的稳定性评价，为工程实践提供了理论依据。     

基于室内试验的条带煤柱稳定性研究

对建新矿13煤进行了室内力学性质研究,研究了煤岩的尺寸效应,得到了建新矿13煤煤岩体单轴抗压强度为 6.928 MPa;进行三轴压缩试验确定该层煤符合摩尔-库仑弹塑性力学模型。以试验研究结果为基础,结合建新矿的实际情况,在选定采出条带宽度25 m时,应用FLAC3D对条带开采进行煤柱应力和地表最大下沉分析,并研究煤柱稳定性。结果表明选择20 m宽度的煤柱时,可以保持煤柱稳定性。基于室内煤岩试验研究的结果,采用数值模拟的方法,通过多方案条带开采研究煤柱安全性,在减小煤柱尺寸的同时,确保煤柱安全稳定,避免仅仅使用经验公式计算带来的盲目性。     

某尾矿坝扩容抗滑稳定性分析

用瑞典圆弧法对某尾矿坝的抗滑稳定性进行了计算分析,得到了不同坝体高程和不同运行情况下尾矿坝的抗滑稳定性安全系数。结果表明浸润线对坝体稳定性的影响很大,当浸润线位置较高,坝体趋于饱和状态时,坝体稳定性降低很多。同时根据抗滑稳定性的计算分析结果,对尾矿坝的治理提出了一些建议。     

斜坡抗滑结构的地质工程分析

斜坡治理是一项系统工程，如何以合理、有效的手段，获得对斜坡稳定性最为有效的改善，一直为人们所关注。本文将地质环境与处理工程结合起来，提出以显示拉格郎日差分方法对这一体系进行联合分析，从而探讨斜坡变形与抗滑结构之间的最佳运行状态，提出合理的整治处理措施。结合实例，本文采用这一方法和途径，对某斜坡的整治处理进行了具体的地质工程分析。     

有限元分析在尾矿库渗流及抗滑稳定工程实践中的应用

某新建尾矿库初步设计拟采用一次性筑坝,坝型为碾压式土石坝,为评价设计方案的合理性以及尾矿库的安全性,采用有限元方法对尾矿库渗流稳定性和抗滑稳定性分析计算,结果表明,尾矿坝采用的渗控体系能够满足大坝的防渗要求,坝体上游侧的HDPE土工膜起到了较好的截渗效果,库内浸润线分布规律合理,下游设计排渗系统起到了较好的排渗效果;在正常蓄水位、最高洪水位和地震等3种工况下,尾矿坝下游边坡的抗滑稳定性均满足规范要求,设计方案合理可行。     

条带煤柱设计的强度准则效应研究

条带开采广泛应用于深部煤层,合理的条带煤柱尺寸对提高煤炭采出率和保护地表地貌都具有十分重要的意义。通过总结平面应变状态下Wilson准则、Mohr-Coulomb(M-C)准则、广义Matsuoka-Nakai(M-N)准则、广义Lade-Duncan(L-D)准则和外接圆Drucker-Prager(D-P)准则等5种强度准则的统一表达式,进而建立条带煤柱的极限强度、屈服宽度和留设宽度的统一计算公式,探究条带煤柱设计的强度准则效应,并得出煤层黏聚力和内摩擦角的影响特性。研究结果表明：建立的统一计算式涵盖文献已有解,且应用非常方便;条带煤柱设计的强度准则效应显著,Wilson准则和M-C准则的结果过于保守,外接圆D-P准则应用需谨慎,应优先选用广义M-N准则或广义L-D准则;煤层黏聚力和内摩擦角对条带煤柱设计的影响明显,应充分考虑煤层的强度参数变化。该研究结果可为条带煤柱的合理设计与施工提供一定的理论指导。     

某上游法尾矿坝抗滑稳定性浅析

通过某上游法尾矿坝抗滑稳定性分析,对比分析了坝体加高、浸润线条件、排渗系统运行状况和透镜体简化对尾矿坝抗滑稳定性的影响。结果表明该尾矿坝抗滑稳定性随坝体加高而降低;排渗系统运行状况对尾矿坝抗滑稳定性的影响超过坝体加高对尾矿坝抗滑稳定性的影响;根据一定简化原则减少透镜体,从而简化剖面形状和计算复杂程度,是一种能反映工程实际但比较保守的分析方法。拟静力法并非适合于所有的尾矿堆积坝抗震稳定性分析,即便采用其所得结果也可能会出现较大偏差。     

回采巷道煤柱与底板稳定性分析

将老顶和老底视为加载系统,分析了回采巷道煤柱和底板岩层的相互作用及稳定性,并提出了底板岩层产生滑移的条件。认为回采巷道底鼓一般不是底板岩层在垂直应力作用下向巷道内滑移所致。     

用强度折减方法分析重力坝深层抗滑稳定性

目前,对重力坝深层抗滑稳定的分析方法尚无统一和明确的规定。强度折减方法在求解安全系数方面具有不用指定滑面、自动搜索滑裂面等优点。本文基于FLAC软件,采用强度折减方法对分属三种典型地质条件的多个算例进行分析。分析结果表明,无论采用相关联还是非相关联流动法则,采用强度折减方法得到的安全系数与Morgenstern-Price方法求解的安全系数都相差较小,误差小于5%,且采用相关联流动法则时得到的安全系数误差更是小于3.5%。根据在破坏时坝基塑性区的分布,提出了确定滑裂面的方法,该方法确定的滑裂面与M-P方法搜索到的滑裂面有很好的一致性。本文通过多个算例的分析证明基于FLAC软件的强度折减方法是一种可靠、有效的方法,可以应用于分析重力坝深层抗滑稳定性。通过对向家坝水电站泄12坝段的深层抗滑稳定分析表明该方法可以应用到重力坝深层抗滑稳定的工程分析中。     

金沙江阿海水电站混凝土重力坝地震抗滑稳定性的时程法分析

通过动力有限元时程法分析了金沙江阿海混凝土重力坝在设计地震动(0.344g)作用下的动态响应,计算模型考虑了动水压力作用、大坝-岩基相互作用,用黏弹性吸波边界模拟了地震动能量向无限远域逸散的地基“辐射阻尼”效应。通过将坝体惯性力时程极大值与振型分解反应谱法的惯性力极值对比,从而验证了复杂动力数值模拟结果的正确性,为后续分析打下了基础。采用沿滑面的应力积分法得到了大坝沿建基面的瞬态抗滑安全系数时程。计算结果表明：阿海重力坝在设计地震动(0.344g)作用下的安全系数时程的极小值为1.146,大坝整体稳定性良好,可不采取提高整体抗滑     

基于Bishop条分法的边坡稳定分析及支护方案

结合柳州市柳东新区物流港片区在建道路的边坡支护工程实例,分析由于道路工程的路堑设计施工造成的高差约35 m高边坡,基于极限平衡理论的Bishop条分法理论分析,使用理正岩土设计软件对边坡进行滑动面选择,并进行稳定性分析及剩余下滑力计算,探讨锚索桩-墙复合垂直抗滑结构的设计思路;通过承载力极限条件对桩的截面尺寸和配筋进行复合;同时介绍垂直支护结构以上边坡坡面处理、防护、排水方案;为今后在道路工程造成的高边坡类支护、治理工程提供参考。     

Yield pillars for stress control in longwall mines — case study

Summary The demand for increased productivity and the problems associated with mining at greater depths have increased the interest in using the yield pillar concept in the United States. This paper summarizes chain pillar behaviour in a mine that historically experienced coal bumps in both room-and-pillar and longwall sections. Results indicate that, generally, the chain pillars yield as designed, but that yielding occurred either after development or with approach of the longwall face. The Bureau of Mines investigated several yield pillar design approaches to possibly explain observed differences in pillar behaviour. These approaches suggest that very localized conditions, such as coal and rock properties, cover depth, and extraction height, may influence the behaviour of any one pillar. At this mine, yielding chain pillars result in de-stressing of the longwall entries and the transfer of potentially dangerous stress concentrations to adjacent panels. Pre-longwall-mining behaviour indicates the existence of a pressure arch, the width of which increases with depth. Results indicate that use of yield pillars improves stress control, reduces bump potential, and increases resource recovery.     

条形基础在水平力及弯矩作用下的稳定性突变分析

采用尖点突变模型理论,对考虑水平力及弯矩影响黏土地基上条形基础的稳定性进行分析,较好地解释了地基失稳时滑动位移突然增大而破坏的现象,讨论了水平力和弯矩、地基土容重和基础埋深、位移高阶效应、位移场随水平力的变化等对地基稳定性及其突变性质的影响。分析结果表明,当参数变化跨越分叉集时,地基滑动将会发生跳跃式突变而导致地基失稳破坏;不计水平力对位移场的影响时,可能会使分析结果不安全。     

Gate road layout design for two-seam longwall mining

Summary Results of instrumentation, test mining and computer aided stability analyses were combined to design the most stable gate road layout for two-seam longwall mining at the Plateau Mining Company. Five layouts were evaluated; these layouts used a combination of yield and/or large pillars with either three-entry or two-entry development systems.A layout which used a yield pillar within a two-entry development system resulted in the most stable gate roads for two-seam mining. Another layout using a yield and large pillar was shown to be most stable for single-seam mining of the top seam, but it was unsuitable for two-seam mining because of seam interaction problems.The size of the yield pillar was determined by satisfying several design requirements, as well as by limited test mining; test results showed good, medium-term stability for the yield pillars, with a possible need for rib control. It was shown that the yield pillars might be effective in controlling the floor heave, and could minimize interaction problems in two-seam mining.     

The role of sedimentation rate and permeability in the slope stability of the formerly glaciated Norwegian continental margin: the Storegga slide model

Despite the gently dipping slopes (ca 1°), large-scale submarine slope failures have occurred on the mid-Norwegian continental margin (Storegga, Sklinnadjupet, Traenadjupet), suggesting the presence of special conditions predisposing to failure in this formerly glaciated margin. With a volume estimated between 2,400 and 3,200 km³ and an affected area of approximately 95,000 km², the Storegga slide represents one of the largest and best-studied submarine slides of Holocene age known worldwide. Finite element modeling of slope failure indicates that a large (6.5 < Ms < 7.0) seismic triggering mechanism would not be sufficient to cause failure at more than 110 m below the seabed as observed for the slip planes at Storegga (northern sidewall). This implies that other factors (e.g., liquefaction, strain softening, gas charging, rapid burial) are needed to explain the occurrence of the Storegga slide with a deep surface of failure. In this paper, we discuss the importance of the compaction effect of rapidly accumulated sediments in the slide area. During compaction, sediment grains reorganize themselves, thereby, expelling pore water. Consequently, depending on sedimentation rate and permeability, excess pore pressures might result beneath less permeable sediments. Our modeling and cross-checking illustrate how excess pore pressure generation due to high sedimentation rate could explain the development of layers of weakness, and thus, how such a large slide might have been initiated in deep sediments. Using the highest sedimentation rate estimated in the area (36 and 27 m/kyr between 16.2 and 15 kyr BP), 1D modeling shows excess pore pressure values of around 200 kPa at a depth of 100 m below the seafloor 15 kyr BP and 60 kPa at a depth of 100 m at the time of the slide (8 kyr BP). Excess pore pressure apparently drastically reduced the resistance of the sediment (incomplete consolidation). In addition, 2D modeling shows that permeability anisotropies can significantly affect the lateral extent of excess pore pressure dissipation, affecting, that way, normally consolidated sediments far from the excess pore pressure initiation area.     

矿柱稳定性影响因素敏感性分析及其应用研究

为研究矿柱稳定性影响因素的敏感程度,以招金大尹格庄金矿为研究背景,从矿柱载荷、强度、失稳形式及影响因素确定四方面推导出两种矿柱形式的安全系数计算公式,设计采用6因素5水平正交试验对矿柱稳定性影响因素敏感性进行分析,并研究主要影响因素与矿柱安全系数之间的函数关系。研究表明,矿柱宽度、矿体开采深度和矿房宽度3个主要因素对矿柱稳定性影响程度是最为剧烈的;矿柱安全系数随着矿柱宽度地增加呈指数形式递增且递增速率不断加大,随矿体开采深度地增加呈幂函数形式递减且递减速率逐渐变缓,随矿房宽度地增加呈负指数形式递减且降低速率逐渐变慢。利用DPS和Matlab建立的矿柱安全系数回归方程得出保证安全生产的合理矿柱尺寸,矿房宽度应不超过8 m,布置条形矿柱宽度应不小于3.6 m,布置方形矿柱宽度应不小于5.9 m。结合采场矿柱布置实际,应用效果较为理想,可为下中段矿体回采矿块布置提供较好的依据。     

薄基岩条带开采覆岩与地表移动数值模拟研究

通过数值模拟模型，分析了薄基岩条件下条带开采引起的覆岩破坏机理、地表的下沉和水平变形等移动变形值，揭示了薄基岩条带综放开采引起的上覆岩土层的应力场、位移场及地表的移动变形规律，为薄基岩条件下条带开采覆岩与地表移动变形的工程地质机理的研究奠定了基础。     

The stability of underground workings in the soft rocks of the Coal Measures

Summary The characteristics of soft rocks typical of the British Coal Measures are defined and a series of working hypotheses are developed to provide improved design methods for underground roadway and face supports and pillars in coal mines. Proposed design equations are tested against case history data.     

基于加卸载响应比理论的矿柱动力稳定性分析

利用有限差分程序FLAC建立连续和并排的两类非均质矿柱模型,对矿柱在动力载荷循环作用下的破坏过程进行全时程动力分析。将加卸载响应比(LURR)理论引入矿柱动力稳定性分析中,以施加的动力载荷对矿柱作用的周期性变化作为加载量,以矿柱特征点的位移变化和破坏单元的弹性应变能的演化规律作为响应参数,建立矿柱的加卸载响应比模型,确定矿柱在动力载荷作用期间的加卸载响应比时间序列。计算结果表明,矿柱整体上处于稳定状态和趋于失稳时,其加卸载响应比Y值表现出不同的特征,通过对Y值的分析对矿柱的稳定状态进行评价,预测是否临近峰值承载能力,表明在矿柱动力破裂过程数值模拟分析中引入加卸载响应比是矿柱破坏力学行为研究的一种方便而有效的方法。