共查询到19条相似文献，搜索用时 187 毫秒
1.
从岩石强度理论出发,提出房柱式开采中矿柱安全留设尺寸的宽度折减法思想,通过不断折减矿柱宽度,研究矿柱由稳定状态向临界失稳状态演化过程,从而得到矿柱的临界宽度,引入矿柱安全系数,获得矿柱安全留设尺寸。采用宽度折减法对磨坊矿3#井房柱法开采矿柱安全留设尺寸进行研究,获得不同矿房跨度下矿柱的安全留设宽度。将宽度折减法得到的安全矿柱宽度与Lunder经验公式比较,研究发现,宽度折减法得到的安全矿柱宽度和Lunder经验公式的计算结果较为吻合且偏安全。结合磨坊矿3#井的开采条件和矿柱宽度折减法分析结果,确定矿房基本参数为：矿房跨度为13 m左右,矿柱宽度为5.0～5.5 m。通过对磨坊矿3#井采空区上覆岩层移动规律的监测,发现岩层相对稳定,地表沉降量控制在120～150 mm之间,用宽度折减法分析得到的矿房基本参数是合理的。 相似文献
2.
矿柱宽度和充填体自立高度是阶段嗣后充填顺利实施的重要影响因素。基于弹性力学平面应变基本假设,建立阶段嗣后胶结充填体矿柱力学模型并进行理论求解。以某铁矿为工程分析实例,采用控制变量法（CVM）研究矿柱不同宽度、高度条件下,水平应力和剪应力的变化规律。研究表明：矿房极限宽度和高度分别为19.8 m和103.2 m。胶结充填体矿柱水平应力随矿柱高度的增高而逐渐增大;剪应力在矿柱中心位置达到最大,且高度越大,剪应力值也越大。在胶结充填体矿柱与非胶结充填体接触侧剪应力趋于定值。矿柱宽度分别为15、18、20 m时,其剪应力分别为243.8、292.6、325.1 kPa。而产生剪应力的主要原因是非胶结充填体受水平应力作用在与胶结充填体矿柱接触面产生滑动摩擦力所致。 相似文献
3.
矿柱强度是评估矿柱稳定性的重要因素之一,矿柱的稳定是地下矿床安全开采的基础。以弹性力学理论为基础,分析了缓倾斜层状矿床中矿柱的受力状态,应用图解法绘制出表征矿柱应力状态的广义莫尔圆。根据应力圆与Mohr-Coulomb强度包络线之间的关系,建立了矿柱强度解析式,分析了莫尔圆圆心所在直线斜率tan_β随矿体倾角的变化特性,并结合数值模拟,研究矿体倾角效应对矿柱强度的影响。研究表明:应力圆圆心所在直线斜率tan_β是矿体倾角θ及侧压系数λ的二元函数,当tan_β取得最大值时,矿柱强度最小;当矿柱宽高比w_p/h_p保持一定且矿体倾角在5°～45°区间时,随着矿体倾角增大,矿柱强度逐渐减小。研究可为缓倾斜层状矿床矿柱强度估算提供参考。 相似文献
4.
《岩土力学》2020,(Z1)
倾斜矿体开采中矿柱的应力状态分析是确保矿体安全开采的重要工作之一。以岩体力学理论为基础,建立了压剪荷载作用下倾斜矿柱的力学模型,推导出表征压剪受载矿柱应力状态的广义Mohr圆方程,分析了矿体倾角、荷载对广义Mohr圆圆心位置及半径的影响,揭示了倾斜矿柱应力演化的3种路径,并证明了3种应力路径分别满足直线方程、圆方程和平面方程。针对矿柱的3种应力路径,提出相应的应力路径演化主控模式。基于Mohr强度理论,分析3种主控模式下的应力路径对矿柱稳定性的影响,阐释倾斜矿柱比垂直矿柱更容易失稳的原因。最后,采用数值模拟方法研究得到矿柱的应力状态与采用广义Mohr圆分析得到的结果一致,且压剪受载矿柱的破坏模式为非对称的沙漏状。研究结果可为倾斜矿柱的稳定性分析提供一种思路。 相似文献
5.
春季冻土融化导致黄土地区边坡冻融灾害频繁发生,因对其机理性研究的不足,目前对此尚不能进行量化分析和预测。本文首先对西安Q3原状黄土进行室内冻融试验,研究冻融作用对其剪切强度的影响;其次,基于室内试验数据,运用有限元强度折减法对黄土边坡冻融失稳特征进行数值计算分析。研究发现:黄土试样粘聚力随冻融次数增加呈指数衰减趋势;粘聚力随含水率增加表现出线性衰减特征且冻融后粘聚力与含水率的变化曲线近似重合;内摩擦角无明显规律性变化。黄土边坡安全系数随冻融次数增加亦呈指数衰减趋势,这与粘聚力随冻融次数的变化规律是一致的;安全系数随冻融深度和冻融区初始含水率增加显著减小且降低幅度逐渐增加;安全系数随坡度系数和放坡级数增加近似呈线性增加特征。黄土边坡冻融滑裂面与季节冻融深度线近似重合。 相似文献
6.
《岩土力学》2017,(Z2):273-278
地连墙槽壁加固深度和宽度既要满足槽壁土体整体稳定性要求,又要满足加固体抗滑(剪)、抗倾覆和抗弯能力要求。首先分析了槽壁加固条件下影响槽壁稳定性的各影响因素与槽壁稳定性安全系数的关系,总结出加固体深度和宽度是关键影响因素,也是工程施工前需要求算的重要控制参数。其次提出了搅拌桩加固体抗滑(剪)、抗倾覆和抗弯能力验算原则和安全性判定标准,也提出了搅拌桩加固深度(长度)和宽度计算方法和在搅拌桩桩顶插入钢性筋并嵌固于导墙中和搅拌桩平面外拱布置等方法以提高槽壁稳定性的措施。利用工程实例,对文中提出的搅拌桩加固深度(长度)和宽度计算方法进行了演算,也对提出的搅拌桩桩顶插入钢性筋并嵌固于导墙和搅拌桩平面外拱布置提高的槽壁稳定性安全系数也进行了演算。最后提出了课题研究展望。 相似文献
7.
采空区地表沉降影响因素研究 总被引：4，自引：0，他引：4
采空区地表沉降影响因素众多,以有限元软件ANSYS为基础,利用数值模拟方法的灵活性,分别对各主要影响因素进行分析.选用适合于岩土类材料的德鲁克-普拉格本构模型,利用ANSYS特有的"杀死单元"命令模拟矿体被采出,再通过"激活单元"命令模拟采空区被填充.分别研究了开采深度、开采厚度、地形条件、采空区填充等因素对地表沉降的影响.结果表明:随开采深度的增加,地表变形随之降低;随开采厚度的增加,地表变形增长较快;随着地形坡度的变化,采空区地表移动盆地逐渐向地势较低方向移动;矿体开采后及时充填,对控制地表变形效果显著. 相似文献
8.
露天与地下联合开采引起岩层移动规律的模型试验研究 总被引：2，自引：0，他引：2
非法开采对矿山开采稳定性具有重要影响,以某铁矿为例,进行了二维物理相似模型试验研究,分析得出了在考虑和不考虑非法开采两种情况下的地表变形规律和矿体围岩移动规律。试验结果表明,从-270 m采至-550 m水平期间,地表沉降和围岩变形呈缓慢增加趋势,但当从-550 m水平继续向下开采时,由于矿体倾角变得平缓,地表沉降、深部围岩变形都急剧增加,非法开采会造成矿体上部岩体的应力重分布,虽没有明显增大地表的沉降范围,但增加了开采点附近的地表沉降量,而且大大增大了地表岩层的水平移动。 相似文献
9.
为能精确识别降水和开采对石家庄地下水流场影响强度,应用小波变换和相关分析等研究方法,对区域平均地下水位、地下水降落漏斗面积及中心水位与降水和开采变化之间的互动特征进行了研究。结果表明:① 1961—1973年期间,平均地下水位随降水量增大呈幂函数递减趋势;1974—2010年期间,降水量每减小100 mm,漏斗中心水位下降速率增大7.35 m,平均地下水位下降速率增大2.15 m;② 1961—1973年期间,开采量每增加1亿m3,平均地下水位下降0.28 m,漏斗面积扩大11.74 km2,中心水位下降0.52 m,1974年以来累计超采量每增加1亿m3,漏斗面积增幅1.52 km2,中心水位降幅0.18 m;③ 降水量每减小100 mm,降水贡献度减弱3.0%,人类开采影响强度增大2.76%。 相似文献
10.
采用SoilVision软件,利用测试的矿体和表层黏土的物理力学参数,分析原地浸矿的渗流过程和计算边坡安全系数。现场监测试验矿块的浸润线和裂缝宽度发展,验证了数值计算结果是合理的。根据试验矿块的边坡剖面形状,结合原地浸矿工艺特征,建立了简化模型,分析了导流孔和收液巷道对边坡稳定性的控制作用。数值计算和试验结果表明:当导流孔收液率小于13.35%时,导流孔对边坡安全系数影响很小;当导流孔收液率为13.35%~15.8%时,边坡安全系数随收液率近似成线性增加;对于水平长度为42m的边坡,收液巷道与出渗面距离为12~24m时,收液巷道对控制边坡失稳的作用发挥得最充分。 相似文献
11.
Qing Yu Jinrong Ma Hideki Shimada Takashi Sasaoka 《Geotechnical and Geological Engineering》2014,32(4):821-827
In order to find the relationship between the shaft lining stability and the coal extraction operation, a 3D numerical model of strata layers and shaft lining was established for simulating the influence of coal extraction operation on shaft lining. Certain factors including mining depth, safety pillar width, mining width and mining height were taken as the influence factors in the simulation. The results indicated that the coal extraction could lead to the initiation of the failure in the aquifer and rock layers. As the mining depth increases, the shear strain increment in aquifer becomes small. In this case, the distance between mining panel and aquifer should be larger than 220 m and the safety pillar width should not <70 m. The maximum principal stress in aquifer had a little relation to mining operations. The mining panel width should not exceed 50 m without any support. 相似文献
12.
Prediction of global stability in room and pillar coal mines 总被引：1，自引：0，他引：1
Global stability is a necessary prerequisite for safe retreat mining and one of the crucial and complex problems in room and pillar mining, so its prediction plays an important role in the safety of retreat mining and the reduction of pillar failure risk. In this study, we have tried to develop predictive models for anticipating global stability. For this purpose, two of the most popular techniques, logistic regression analysis and fuzzy logic, were taken into account and a predictive model was constructed based on each. For training and testing of these models, a database including 80 retreat mining case histories from 18 room and pillar coal mines, located in West Virginia State, USA, was used. The models predict global stability based on the major contributing parameters of pillar stability. It was found that both models can be used to predict the global stability, but the comparison of two models, in terms of statistical performance indices, shows that the fuzzy logic model provides better results than the logistic regression. These models can be applied to identify the susceptibility of pillar failure in panels of coal mines, and this may help to reduce the casualties resulting from pillar instability. Finally, the sensitivity analysis was performed on database to determine the most important parameters on global stability. The results revealed that the pillar width is the most important parameter, whereas the depth of cover is the least important one. 相似文献
13.
Some villages and bridges are located on the ground surface of the working district no. 7 in the Wanglou Coal Mine. If longwall mining is adopted, the maximum deformation of the ground surface will exceed the safety value. Strip mining is employed for the working district no. 7 which is widely used to reduce surface subsidence and the consequent damage of buildings on the ground surface. To ensure the safety of coal pillars and improve the recovery coefficient, theoretical analysis and numerical simulation (FLAC 3D) were adopted to determine the coal pillar and mining widths and to discuss the coal pillar stress distribution and surface subsidence for different mining scenarios. The results revealed that the width of coal pillars should be larger than 162 m, and the optimized mining width varies from 150 to 260 m. As the coal seam is exploited, vertical stress is mainly applied on the coal pillar, inducing stress changes on its ribs. The coefficient of mining-induced stress varies from 2.02 to 2.62 for different mining scenarios. The maximum surface subsidence and horizontal movement increase as the mining width increases. However, when the mining width increases to a certain value, increasing the pillar width cannot significantly decrease the maximum subsidence. To ensure the surface subsidence less than 500 mm, the mining width should not be larger than 200 m. Considering the recovery coefficient and safety of the coal pillar, a pillar width of 165 m is suggested. 相似文献
14.
矿井初步设计中边界防隔水煤岩柱留设探讨 总被引：1，自引：0，他引：1
针对一些矿井初步设计中留设边界防隔水煤岩柱不合理而引发矿井老空水矿难的现实,探讨了影响矿井间边界防隔水煤岩柱安全稳定性的因素,提出应充分考虑煤岩柱受覆岩应力破坏变形、覆岩受采动影响产生岩移破坏等,综合分析计算煤柱有效稳定性弹性核区宽度、覆岩导水裂缝带上限岩柱宽度及其抗静水压能力等,择优选取留设矿井边界防隔水煤岩柱。以济宁煤田济宁二矿与三矿边界煤柱的留设为例,计算其边界煤柱留设尺寸为99.56m,较原设计的40m有较大出入,据此对两矿井边界隔离煤柱进行了相应调整,确保了矿井的安全生产。该方法也可用于矿井留设采区、区段隔离煤柱的计算。 相似文献
15.
侧向支承压力分布、资源回收率以及煤柱和巷道的稳定性是大采高综放面区段煤柱宽度留设要兼顾的因素,为了确定大采高综放面区段煤柱宽度,以某矿8103面为工程背景,首先,采用理论计算和现场应力监测等方法确定大采高综放工作面倾向支承压力分布规律,得出应力降低区宽度约为8 m,原岩应力区为巷帮侧28 m外。其次,采用工程类比方法确定大采高综放工作面巷帮外侧煤体严重破裂区宽度约为4 m。最后,采用FLAC3D数值软件分析了下区段工作面回采时窄煤柱（6、8 m）和宽煤柱（28、30 m）的应力场、位移场及塑性区特征,获得不同煤柱宽度时巷道和煤柱力学特征。研究表明：当煤柱宽度6 m和8 m时,在采动支承压力下煤柱几乎无承载能力,且巷道变形量较大;当煤柱宽度28 m和30 m时,在采动支承压力下煤柱中央仍有一定的弹性核,煤柱保持稳定且巷道变形量较小。综合考虑资源回收、巷道稳定性、次生灾害控制等因素,确定大采高综放工作面区段煤柱宽度为28 m。 相似文献
16.
Geological and geotechnical aspects of underground coal mining methods within Australia 总被引：1，自引：1，他引：0
B. Scott P. G. Ranjtih S. K. Choi Manoj Khandelwal 《Environmental Earth Sciences》2010,60(5):1007-1019
About one quarter of the coal produced in Australia is by underground mining methods. The most commonly used underground coal
mining methods in Australia are longwall, and room and pillar. This paper provides a detailed review of the two methods, including
their advantages and disadvantages, the major geotechnical and operational issues, and the factors that need to be considered
regarding their choice, including the varying geological and geotechnical conditions suited to a particular method. Factors
and issues such as capital cost, productivity, recovery, versatility and mine safety associated with the two methods are discussed
and compared. The major advantages of the longwall mining method include its suitability for mining at greater depth, higher
recovery, and higher production rate compared to room and pillar. The main disadvantages of the room and pillar method are
the higher risks of roof and pillar collapse, higher capital costs incurred as well as lower recovery rate. 相似文献
17.
Deyu Qian Nong Zhang Hideki Shimada Cheng Wang Takashi Sasaoka Nianchao Zhang 《Arabian Journal of Geosciences》2016,9(1):82
Goaf-side entry driving in underground coal mines could greatly improve coal recovery rates. However, it becomes more difficult to maintain stability, especially in deep coal mines. Pillar width plays a pivotal role in the stability of goaf-side entry driving. To obtain a reasonable and appropriate narrow pillar width, theoretical calculations of the widths of mining-damaged zone and limit equilibrium zone in the pillar are derived according to limit equilibrium theory. Based on the stability issues of goaf-side entry driving in the first island longwall coal face (LCF) at a depth of 800 m below the surface in Guqiao Coal Mine in China, a numerical model is established by FLAC software to analyze the stability of the surrounding rock of goaf-side entry driving during excavation, using various coal pillar widths and support schemes. The results obtained from theoretical calculations, numerical simulation, and engineering practice indicate that an 8-m-wide coal pillar is relatively reasonable, appropriate, and feasible. Field measurements show that deformations of the surrounding rock could be efficiently controlled 31 days after the support schemes were implemented in goaf-side entry driving with an 8-m-wide narrow pillar along the adjacent goaf side with a compaction duration of 10 months. The mining influence range of the overlying LCF on the stability of goaf-side entry driving is found to be the area from 50 m ahead of the LCF to 70 m behind the LCF as it passes over the measurement point. 相似文献
18.
我国西部神府东胜煤田主要赋存浅埋近距煤层,煤层埋藏浅,覆岩上部厚松散层大范围分布,近距煤层开采导致覆岩与地表裂缝发育严重,加剧了原本脆弱的生态环境进一步恶化。为探究浅埋近距煤层开采覆岩与地表采动裂缝发育规律,掌握其控制方法,以柠条塔煤矿1-2煤层和2-2煤层开采为背景,结合实测统计分析、物理模拟和分形理论,掌握浅埋顶部单一煤层开采和重复采动下覆岩与地表裂缝发育特征,揭示煤柱布置对裂缝发育的控制作用。研究表明,煤层开采导致的地表裂缝可分为平行于工作面的动态裂缝和工作面开采边界地表裂缝(切眼边界侧地表裂缝和区段煤柱侧地表裂缝),动态裂缝在开采后能够实现自修复,工作面开采边界的地表裂缝不能自修复。下煤层开采区段煤柱侧覆岩与地表采动裂缝发育严重,其与区段煤柱错距密切相关。1-2煤层开采后,基岩垮落角为60°,土层垮落角为65°,边界煤柱侧地表裂缝的宽度为0.26 m。下部2-2煤层开采,煤柱叠置、错距20、40 m时,区段煤柱侧覆岩采动裂缝宽度分别为0.81、0.45和0.22 m,地表裂缝宽度分别为0.65、0.30和0.12 m。通过确定合理煤柱布置方式,能够有效控制覆岩和地表采动裂缝的发育程度,据此确定柠条塔煤矿1-2煤层和2-2煤层开采的合理煤柱错距应大于40 m。 相似文献
19.
Hamid Mohammadi Mohammad Ali Ebrahimi Farsangi Hossein Jalalifar Ali Reza Ahmadi 《Rock Mechanics and Rock Engineering》2016,49(1):303-314
In this paper a geometric computational model (GCM) has been developed for calculating the effect of longwall face on the extension of excavation-damaged zone (EDZ) above the gate roadways (main and tail gates), considering the advance longwall mining method. In this model, the stability of gate roadways are investigated based on loading effects due to EDZ and caving zone (CZ) above the longwall face, which can extend the EDZ size. The structure of GCM depends on four important factors: (1) geomechanical properties of hanging wall, (2) dip and thickness of coal seam, (3) CZ characteristics, and (4) pillar width. The investigations demonstrated that the extension of EDZ is a function of pillar width. Considering the effect of pillar width, new mathematical relationships were presented to calculate the face influence coefficient and characteristics of extended EDZ. Furthermore, taking GCM into account, a computational algorithm for stability analysis of gate roadways was suggested. Validation was carried out through instrumentation and monitoring results of a longwall face at Parvade-2 coal mine in Tabas, Iran, demonstrating good agreement between the new model and measured results. Finally, a sensitivity analysis was carried out on the effect of pillar width, bearing capacity of support system and coal seam dip. 相似文献