Fuzzy genetic programming method for analysis of ground movements due to underground mining

The prediction of ground surface movements is an important problem in rock and soil mechanics in the excavation activities especially the coal and metal mining. Based on results of the statistical analysis of a large amount of measured data in underground excavation engineering, the fuzzy genetic programming method (FGPM) of ground surface movements is given by using the theory of fuzzy probability measures and genetic programming (GP). And genetic programming approach is proposed to determine the parameter of ground surface movements due to underground mining of coal in this paper. Genetic programming is trained by used practical mining induced surface movement data. The agreement of the theoretical results with the field measurements shows that the FGPM is satisfactory and the formulae obtained are valid and thus can be effectively used for predicting the ground surface movements due to underground mining, especially the mining of coal and metal.     

辛置煤矿间歇开采岩移机理及沉陷规律研究

为了研究巨厚黄土层下间歇开采岩移机理及地表沉陷规律,基于辛置煤矿的地质采矿条件,对条带开采煤柱的稳定性进行了理论分析,得到了倾斜煤层煤柱稳定性的判别函数;采用UDEC数值分析方法反演了百亩沟村庄下前期条带开采覆岩及地表沉陷特征,揭示了岩层移动的机理,获取了研究区域主断面的地表沉陷值。隔离煤柱回收后,依据现场实测数据,分析了间歇开采地表动态和静态地表沉陷特征,求取了地表移动角值参数和概率积分预计参数。研究结果表明,前期条带开采煤柱能够形成稳定的核区,煤柱安全系数为2.34,关键层不破断,地表最大下沉217 mm,最大水平拉伸变形为0.41 mm/m,小于窑洞的Ⅰ级抗拉伸水平变形的临界值。间隔煤柱回采后,地表移动初始期和活跃期偏短累计219 d,最大下沉点下沉量与下沉时间服从负指数函数关系;地表终态最大下沉1 537 mm,水平拉伸变形为3.98 mm/m,地表建(构)筑物所受的采动损坏程度超过了Ⅱ级。间歇开采后地表沉陷下沉系数为0.74,开采影响传播角系数为0.6。     

Combined prediction model for mining subsidence in coal mining areas covered with thick alluvial soil layer

The entire overburden stratum above a coal mining area is considered to be composed of an alluvial soil layer and a bedrock layer. In underground mining, alluvial soil has a major effect on ground subsidence. This effect is especially significant and not negligible when the alluvial soil accounts for a large proportion in the entire overlying stratum of coal mining areas covered with thick alluvial soil (CMATASs). In this study, the applicability of the most popular probability integral method (PIM) used for CMATASs was analyzed, and it was found that the PIM is not suitable for ground subsidence prediction in CMATASs for two main reasons: (1) the subsidence basin range predicted by the PIM was smaller than the measured range; thus, the predicted basin converged more rapidly than the measured basin at the edges. (2) Poor fitting results were obtained at the subsidence basin edge. The mechanism of mining subsidence in CMATASs and the reasons why the PIM is not suitable for CMATASs were investigated in terms of the internal deformation and crack (void) distribution within the rock mass induced by underground coal mining. The results indicate that the alluvial soil is compacted and then subsides under vertical compression deformation, which increases ground subsidence. The bedrock is subjected to the weight/load of the thick alluvial soil layer. Because of the vertical compression deformation inside the rock, its internal voids (spaces) are compacted; thus, the replaced voids (spaces) are transferred to the ground surface, resulting in an increase in ground subsidence. However, the effect of the alluvial soil on ground subsidence cannot be detected by the PIM; moreover, the PIM is unable to represent the mechanism of the mining subsidence in CMATASs. Thus, the PIM cannot be used for predicting subsidence in CMATASs. To precisely calculate subsidence in CMATASs, we propose a combined prediction model (CPM) for mining subsidence in CMATASs based on soil mechanics and stochastic medium theory. The new CPM was applied to the mining process in the Huainan Coal Mining Area. The calculation results show that subsidence predicted by the CPM better fits the measured subsidence values, with a relative error of 4.9%, and that the fitting accuracy is improved by 18% compared to the relative error of the PIM (6.0%). Thus, the proposed CPM is more suitable for predicting ground subsidence caused by underground coal mining in CMATASs, and can be used to provide more accurate predictions for ground subsidence in similar coal mining areas.     

考虑底板岩层移动的急倾斜煤层开采沉陷预计

分析了急倾斜煤层开采岩层和地表移动特点,总结了急倾斜煤层开采地表下沉盆地的4种类型,并对这4种下沉盆地的形成原因进行揭示。给出了急倾斜煤层开采沉陷预计建模的4条原则,并针对该原则提出了一种基于概率积分法的急倾斜煤层开采沉陷预计模型,该模型能清楚地解释急倾斜煤层开采煤层顶底板岩层移动和地表下沉的相互关系。建立了预计方法的坐标系,分析了预计参数的物理意义,并给出了预计参数的变化规律。编制了基于本文方法的计算机程序,并利用矿区观测站实测数据对本方法进行了验证。实验结果表明,本文方法对于倾角大于70°的急倾斜煤层开采沉陷预计效果较好,能为矿区的环境保护,地表移动预警起到决策支持作用。     

软岩地层深部开采地表下沉分析

针对软岩地层深部地下大面积开采岩体移动变形预测问题,利用弹塑性力学理论建立了相应的预测分析理论模型。用所建立的弹性理论模型对某铁矿地表移动变形进行了计算分析,并将理论预测结果和实测资料进行了对比。文中用弹塑性有限元法分析了不同弹性模量、泊松比、内聚力、内摩擦角等物理力学参数对地表下沉的影响;对软岩地层深部开采地表移动进行了计算分析。结果表明,弹性模量对地表下沉影响较大,而其他参数影响较小。结果表明,弹塑性力学方法适用于分析软岩地层大面积开挖岩体移动预测问题。     

官庄铁矿深埋破碎矿体开采岩体变形测试分析

 以大量实测资料为基础,分析官庄铁矿北区深埋破碎厚矿体开采引起的围岩变形和地表移动规律。实测结果表明,官庄铁矿北区地表下沉属于连续下沉,岩层破坏主要是缓慢型破坏。分析过程中,把几种实测分析方法和数值分析法有机结合在一起,形成岩体移动变形综合研究方法,对地下开采引起的岩体移动机制进行具体分析。分析中所采用的实测分析类方法包括蠕变试验分析、地表移动观测分析、围岩变形监测分析、原岩应力量测分析;数值分析类方法包括ANSYS和FLAC。结合官庄铁矿工程实例,通过具体测试分析,探讨深部开采岩体移动变形规律及特点,即深部开采覆岩移动变形具有均匀、整体压缩变形等特点,地表移动连续且周期较长。实践证明,所采用的综合研究方法是分析岩体移动和地表下沉机制的有效途径。     

Surface subsidence due to underground mining operation under weak geological condition in Indonesia

Subsidence analysis and prediction with measured data have been conducted and applied to local strata and mining conditions worldwide. Underground coal mines chose the most suitable analysis and prediction method for them. However, there was no study based on the measured data of subsidence induced by underground mining operation in Indonesia. This paper describes the condition of underground coal mine in Indonesia and then discusses the subsidence behavior due to longwall mining operation based on measured data in Balikpapan coal-bearing formation in Indonesia.     

厚表土层下采煤对地表及铁路桥的影响分析

以淮南某矿区为例,用有限元分析了厚表土层下煤矿开采引起的地表沉陷、地表倾斜、水平移动及孔隙水压的变化规律,总结了地表移动的基本特征和相关参数;同时分析了位于该矿首采区的铁路桥因地表变形产生的附加内力的变化,为采动区的建筑物保护提供了科学依据。     

基于D-InSAR技术的葛亭煤矿地面沉降监测研究

为了为矿区安全开采和塌陷区环境综合治理提供科学依据,利用精细的D-InSAR技术对7景ENVISAT ASAR影像进行处理,获得了2004～2005年和2008～2009年葛亭煤矿多期地面沉降分布图。然后将D-InSAR结果导入GIS中做后处理,叠加0.25m分辨率的数字正射影像图(DOM)和开采平面图等来分析地面沉降,并以剖面图、3D可视图等进行显示。通过多期结果的相互验证,并与水准资料进行了比较。结果表明,D-InSAR结果可以清楚可靠地给出矿区沉降区域分布和演化,并且获得的矿区沉降范围和位置与实际基本吻合,沉降幅度较小的区域在数量级上和水准资料一致,而最大沉降量出现偏差,这是由于高形变梯度引起了干涉图的完全失相关,超出了D-InSAR技术形变探测的能力范围。     

有限元强度折减法在矿山开采中的应用

利用ANSYS对水平煤层条带开采进行了二维有限元强度折减法数值模拟研究,分析了条带开采中开采宽度对地表的影响,并用安全系数的大小来判断开采后的稳定性,从而为地下工程实践提供依据.     

Mechanical behaviors of coal measures and ground control technologies for China's deep coal mines – A review

This paper reviews the major achievements in terms of mechanical behaviors of coal measures, mining stress distribution characteristics and ground control in China's deep underground coal mining. The three main aspects of this review are coal measure mechanics, mining disturbance mechanics, and rock support mechanics. Previous studies related to these three topics are reviewed, including the geomechanical properties of coal measures, distribution and evolution characteristics of mining-induced stresses, evolution characteristics of mining-induced structures, and principles and technologies of ground control in both deep roadways and longwall faces. A discussion is made to explain the structural and mechanical properties of coal measures in China's deep coal mining practices, the types and distribution characteristics of in situ stresses in underground coal mines, and the distribution of mining-induced stress that forms under different geological and engineering conditions. The theory of pre-tensioned rock bolting has been proved to be suitable for ground control of deep underground coal roadways. The use of combined ground control technology (e.g. ground support, rock mass modification, and destressing) has been demonstrated to be an effective measure for rock control of deep roadways. The developed hydraulic shields for 1000 m deep ultra-long working face can effectively improve the stability of surrounding rocks and mining efficiency in the longwall face. The ground control challenges in deep underground coal mines in China are discussed, and further research is recommended in terms of theory and technology for ground control in deep roadways and longwall faces.     

水平及缓倾斜煤层开采条件下离层值的计算

煤层开采诱发岩层与地表移动和变形所导致的地表沉陷对地表建筑物产生很大的影响和破坏。覆岩离层充填技术作为矿区开采沉陷控制的新方法，在我国一些矿区的应用实践证明，其控制效果和经济效益均很显著，但在减沉机理方面的研究还有待进一步深入，其中离层充填减缓地表沉陷技术在应用中的一个关键任务之一就是确定离层产生的位置及其大小，目前仍处于经验判定阶段，尚没有完善和准确的理论计算方法。根据薄板小挠度力学理论的基本思想，分析了采用薄板小挠度理论计算采动覆岩中离层产生位置及其大小的可行性及边界条件确定的合理性，探讨了水平及缓倾斜煤层开采条件下离层产生位置及离层值大小（薄板挠曲度）的理论确定方法，并给出了相应的计算公式。这些结果对于现场在应用离层充填技术减缓地表沉陷过程中确定离层产生的位置具有理论上的指导意义。     

短壁开采覆岩关键层黏弹性分析与应用

根据短壁开采条件下保护煤柱的布设特点，建立由保护煤柱支承的关键层力学分析模型。针对不同采场设计参数进行关键层受力及变形的弹性和黏弹性分析，得到弹性介质关键层下沉量的理论计算式，及黏弹性介质关键层变形随时间变化的表达式。评价不同采场参数对关键层随时间变形的影响，给出理想的建筑物下短壁开采设计参数范围，为“三下”开采设计和长期地表沉陷预计提供理论依据。     

顺层岩质斜坡开采沉陷预测模型研究

为有效预测地下采矿诱发山区顺层斜坡的沉陷变形,在分析概率积分法水平地表开采沉陷的基础上,以与岩层、矿体的倾角相同或者相近的顺层岩质坡体为研究对象,建立单元体开采和半无限开采情况下顺层岩质倾斜地表的开采下沉变形预测模型,并给出预测模型的解算过程及步骤。通过2个矿山开采沉陷实例,将预测模型的解算结果分别与现场实测数据、相似模拟试验观测数据进行对比分析,结果表明:预测结果与现场实测下沉量吻合良好,与相似模拟试验观测下沉曲线形状相似,最大下沉量基本一致,符合试验原型的实际情况,预测结果能够反映顺层倾斜地表开采沉陷的情况,预测模型具有较好的适用性。     

鲁中矿区地下开采对竖井井塔楼的影响分析

针对鲁中矿区软岩地层地下开采引起岩体移动变形及竖井井塔楼倾斜变形的工程实际情况，将该矿区深埋金属矿体开采引起的岩体移动变形这一客观现象视为一随机事件，建立了开采岩体移动分析数学模型，并利用该模型对开采引起采区岩体移动变形及竖井井塔楼所处地表移动变形进行了具体计算分析。分析结果表明，理论预测值和工程实际观测结果吻合很好；在软岩地层条件下，矿体开采地表移动变形的影响范围有随着采深的增加而逐渐增大的趋势。这些结果可用于矿山竖井及井塔楼的安全评价。     

浅谈地下采煤对地表建筑物的影响

简述了地下采煤引起的地表沉陷研究现状,讨论了地表沉陷的产生原因,指出了煤矿开采沉陷过程中防治地表建筑物遭到大程度破坏的方法和措施,以期推动煤炭工业的进一步发展。     

覆岩主关键层对地表下沉动态的影响研究

在对岩体内部移动与地表沉陷实测资料进行对比分析的基础上,采用物理和数值模拟方法,就覆岩主关键层对地表下沉动态过程的影响进行了研究。研究结果证明,覆岩主关键层对地表移动的动态过程起控制作用,覆岩主关键层的破断将引起地表下沉速度和地表下沉影响边界的明显增大和周期性变化。在此基础上,提出将控制覆岩主关键层不破断失稳作为建筑物下采煤设计原则的观点。     

急倾斜厚大矿体地下与露天联合开采岩体移动分析的模糊数学模型

针对急倾斜厚大矿体地下与露天联合开采岩体移动分析问题，利用模糊数学理论，建立了开采岩体移动分析和边坡稳定性分析的模糊数学模型。对分析过程中的工程参数确定给出了模糊数学方法，利用所建立的数学模型，对我国某地下与露天联合开采矿山急倾斜厚大矿体地下开采导致的岩体移动变形及上部边坡稳定性进行了具体的计算分析，所获结果可作为工程设计参考应用。     

基于GIS的地下开挖沉陷计算的有限层法及数据场表达

地学数字化与可视化构建的主要平台GIS已在许多岩土工程领域得到应用。地下硐室开挖和矿山采掘引起的地表沉陷是一种较为严重的工程灾害,基于“3S”技术对地表沉陷及其沉陷损害进行实时预测预报和评价,其效果和意义都是显著的。给出了一种用于地下开挖地表沉陷计算和岩土体应力分析的方法即有限层法,给出了该方法的位移模式、应变矩阵、弹性矩阵、单元该刚度矩阵和应力矩阵等,并就该方法与GIS集成中的数据模型和数据组织方法进行了探讨,同时还给出了基于GIS的沉陷损害评价系统的多语言集成模式和数据可视化方法,并通过系统应用的工程实例对该方法的可靠性进行了验证。     

地下开采对地表及铁路桥影响的数值模拟研究

根据某矿区铁路桥沉陷实际情况,运用有限元软件ABAQUS,对不同开采方式引起的地表沉陷和水平移动的变化规律进行数值模拟研究,通过数值模拟和理论研究,分析了地表移动的基本特征和相关特性;同时分析了该铁路桥因地表变形产生的附加内力的变化情况.该研究为采动区的桥梁保护提供了参考依据.