“三软”特厚煤层开采地表沉陷规律研究

洛阳常村煤矿开采煤层为"三软"特厚煤层,井田范围内村庄较多.为了合理回采村庄下煤柱、提高资源采出率,需要掌握该地质条件下的地表移动变形规律及参数.在该矿"三软"特厚煤层工作面建立了地表移动观测站,对地表沉陷进行现场观测,获得了大量的地表沉陷观测资料.通过对实测资料的分析,得出常村煤矿"三软"特厚煤层开采地表沉陷规律及其参数.研究结果表明:与一般地质采矿条件相比,"三软"特厚煤层放顶煤开采具有地表移动角量参数偏小、影响范围大、下沉系数大等特点,地表沉陷呈现塌陷坑及台阶裂缝形态.     

工业广场密集建筑物下变采(留)宽条带开采技术

为研究煤矿工业广场密集建筑物下压煤开采技术,以平煤七矿开采为例,依据实际采煤条件及条带开采理论,通过理论计算,确定变采(留)宽条带小工作面开采方案,通过概率积分法预计、数值模拟,研究了条带小工作面重复采动的地表下沉盆地的移动变形规律,得出地表移动和变形值及其对地表建(构)筑物的影响情况。结果表明,变采(留)宽条带小工作面开采后,采出率为65.5%,地表最大下沉值为429.3 mm,下沉系数为0.133,地表主要建筑物损害程度在Ι级之内,采空区中心向下山方向偏移距离d为26 m,最大下沉角为85.6°。条带小工作面开采能够在提高回采率的基础上很好地控制覆岩变形与地表沉陷,解决了保护地表建筑物与解放工业广场煤柱的矛盾,为资源枯竭煤矿工业广场煤柱回收在技术和理论上提供了参考。     

采动区建筑物下保护煤柱开采优化设计研究

采用岩层移动角进行留设保护煤柱的传统方法,增大了保护煤柱呆滞量,造成了煤炭资源的巨大浪费.为了探讨综放开采条件下保护煤柱留设的最优尺寸,基于潞安矿区王庄煤矿的地质采矿条件,提出了根据建筑物采动损害允许的临界变形值进行优化设计保护煤柱的新思路.按照概率积分法,预测计算开采工作面位于不同停采线位置时保护煤柱留设的合理尺寸,分析了不同开采方案下建筑物所受采动的影响面积、地表下沉程度及倾斜变形、拉伸变形等地表移动变形对建筑物采动损害的影响程度.通过11个方案的分析比较,结合经济与社会效益,给出了建筑物下保护煤柱留设的最优方案,为综放开采条件下建筑物压煤开采提供了科学依据.     

Knothe模型改进及充填开采岩层移动动态过程分析

Knothe模型是岩层移动动态预测最常用的时间函数模型,但该模型与岩层移动动态演化过程客观规律并不完全相符.通过分析Knothe模型岩层移动预测缺陷,增加表征时间影响函数变化和岩层移动非线性特征的双参数,建立了Knothe时间函数改进模型;基于弹性力学理论,建立充填开采岩层移动的小挠度弯曲变形薄板模型;将Knothe函数改进模型与建立的充填开采岩层移动模型相结合,构建了岩层随时间移动的动态演化过程函数表达式,并将演化过程划分为初始期、活跃期及衰退期.以新汶矿区翟镇煤矿2205工作面矸石充填开采实测数据为样本,开展了充填开采岩层移动动态过程实例验证分析.结果表明:在第22.9个月,地表最大下沉点的下沉速度达10.526mm/月;岩层总移动时间为38.9个月,其中初始期为20.5月、活跃期为5.1月、衰退期为13.3月.基于Knothe改进模型构建的岩层移动动态演化过程的函数表达式能够更客观真实地反映出岩层下沉量、下沉速度、下沉加速度的客观变化规律.     

采空区地表移动监测与规律分析

本文阐述了在矿井采空区首采工作面在采动过程中,通过地表移动变形监测、数据处理,分析出地表变形观测点的下沉与水平变形规律,并求得地表移动的部分参数,可为后续的矿井开采过程提供安全可靠的依据。     

FLAC3D在张集煤矿开采沉陷预测中的应用分析

利用FLAC~(3D)数值分析软件,分析了高潜水的张集煤矿巨厚松散层下12171工作面重复开采对上部17278工作面移动变形区的走向位移、垂直应力分布和塑性破坏区的影响。分析结果表明:数值模拟结果与实测数据基本相符;多煤层重复采动地表下沉具有特殊性,下沉量相比于初次采动是逐渐增大的,随着重复采动次数的增加,下沉量逐渐趋于稳定;同时随着工作面累计推进距离的增加,地面沉陷范围逐渐增加,并形成塌陷盆地;两工作面顶板围岩以剪切破坏为主,局部发生拉伸破坏。     

大采深极不充分开采地表移动和变形规律实测研究

随着我国矿井开采深度的增加,工作面倾斜方向容易出现极不充分开采,深部开采条件下地表移动和变形规律与浅部开采条件下相比发生了较大变化.在对某矿地表移动观测数据处理的基础上,分析了极不充分开采地表移动和动态变形特征,计算了极不充分工作面开采程度和地表下沉盆地的范围,详细描述了极不充分开采地表变形特征以及拐点位置.对于指导相似地质条件下开采,解放建筑物下压滞的大量煤炭具有重要的实用价值和指导意义.     

大采深巨厚砾岩综放开采地表沉陷规律

以常村煤矿工程地质资料和地表移动观测站资料为依据,详细分析了2113工作面地表终态下沉、动态下沉和终态水平移动的特征,从机理上研究了大采深巨厚砾岩开采条件下地表形变异常的原因.通过走向方向最大下沉点下沉速度的变化规律和工程实测资料,得出了地表形变与井下冲击地压的关系,确定了地表移动与变形的角量参数.结果表明,受关键层的控制,在整个观测过程中,地表始终处于缓慢下沉状态,且在沉降过程中不存在下沉突变点;下沉速度的反弹可以作为冲击地压危险的预报信息,巨厚砾岩层的运动是发生矿震的主要力源之一.     

放顶煤开采上覆巨厚砾岩层变形移动规律研究

放顶煤开采时上覆巨厚砾岩层垮落直接影响综放工作面的安全生产,为了研究放顶煤开采上覆巨厚砾岩层变形移动规律,以河南大有能源股份有限公司耿村煤矿综放工作面特厚煤层及其上覆巨厚砾岩层为工程背景,采用相似材料模拟试验,研究了放顶煤开采时上覆巨厚砾岩层变形移动全过程。结果表明:(1)随着煤层开采,依据巨厚砾岩层裂隙场的特征,巨厚砾岩层变形移动和垮落的全过程分为下位和上位垮落过程,其中下位砾岩层初次断裂时垮落体形态为梯形,上位砾岩层断裂控制着地表的变形;(2)当工作面停采后,巨厚砾岩层裂隙演化发展具有较明显的时间效应;(3)下位砾岩层初次垮落步距650. 0 m,周期垮落步距175. 0 m,上位砾岩层初次垮落步距825. 0 m,地表下沉系数0. 267。研究结果可为耿村煤矿巨厚砾岩层下综放开采提供安全技术支撑。     

利用固体充填开采方法保护建筑群安全的研究

我国煤矿建筑物下压煤量占总压煤量的69%,同时每年要向地面排放4.5亿t以上的固体废弃物,因此,研究利用固体废弃物充填开采方法,在保证地表建筑物安全性的基础上,高效开采出下压煤炭资源意义重大.文章应用数值模拟方法,对建筑物下压煤开采所引起的岩层移动过程进行模拟,系统分析了采场围岩塑性区分布及地表沉陷量变化规律,由计算结果分析得知,应用固体充填开采法与无充填直接开采相比,采场围岩破坏单元数较少,围岩稳定性受影响较小,减少地表沉陷量效果明显.以数值模拟结果作为参考,研制了长臂综采矸石充填开采工艺的配套设备,并在某矿建筑物下压煤炭开采的实际应用中取得良好效果,有效控制了地表变形,保证了建筑物的安全性和资源的高效开采.     

Subsidence control method by inversely-inclined slicing and upward mining for ultra-thick steep seams

Ultra-thick steep coal seam mining will inevitably lead to the increase of greater and violent ground subsidence and deformation. A subsidence control method by inversely-inclined slicing and upward mining is proposed in this paper. By this method, the sequence of collapse of overlying strata and the direction of propagation of strata movement are changed, the extent of roof-side deformation thereby is lessened, and boundary angle of roof-side subsidence is reduced by 5°–10°. The mechanism of this mining method for control of strata movement has been evidenced by numerical simulation and experiments with similarity materials. A subsidence prediction model based on the variation of mining influence propagation angle can be used to evaluate the surface movement and deformation of the mining method. The application of the method in No.3 Mine in Yaojie mining area has yielded the expected result.     

Stability of roof structure and its control in steeply inclined coal seams

To improve the effectiveness of control of surrounding rock and the stability of supports on longwall topcoal caving faces in steeply inclined coal seams, the stability of the roof structure and hydraulic supports was studied with physical simulation and theoretical analysis. The results show that roof strata in the vicinity of the tail gate subside extensively with small cutting height, while roof subsidence near the main gate is relatively assuasive. With increase of the mining space, the caving angle of the roof strata above the main gate increases. The characteristics of the vertical and horizontal displacement of the roof strata demonstrate that caved blocks rotate around the lower hinged point of the roof structure, which may lead to sliding instability. Large dip angle of the coal seam makes sliding instability of the roof structure easier.A three-hinged arch can be easily formed above both the tail and main gates in steeply inclined coal seams. With the growth in the dip angle, subsidence of the arch foot formed above the main gate decreases significantly, which reduces the probability of the roof structure becoming unstable as a result of large deformation, while the potential of the roof structure's sliding instability above the tail gate increases dramatically.     

Study of “3-Step Mining” Subsidence Control in Coal Mining Under Buildings

Mining subsidence damage is the main factor of restricting coal mining under buildings. To control or ease effectively the degree of mining subsidence and deformation is essential to resolve this problem. Through analyzing both advantages and disadvantages of some technologies such as mining with stowing, partial extraction and grouting in separated beds of overburden, we used the principle of load replacement and propose a “3-step mining” method, a new pattern of controlling mining subsidence, which consists of： strip mining, i.e. grouting to fill and consolidate the caving zone and retained strip pillar mining. The mechanism of controlling mining subsidence by using the “3-step mining” pattern is analyzed. The effect of the control is numerically simulated. The preliminary analysis shows that the “3-step mining” can effectively control ground subsidence and deformation. By using this method, the ground subsidence factor can be controlled to a value of about 0.25. Coal recovery can reach 80%-90%. Coal mining without removing surface buildins can be realized and the economic loss resultin from round subsidence can be greatly reduced.     

Quantifying relationships between subsidence and longwall face advance using DInSAR

Surface subsidence that results from longwall mining can be large magnitude and can affect significant areas. Conventional methods for subsidence monitoring include leveling, global positioning system(GPS), and photogrammetric surveys. Remote sensing techniques including, aerial LiDAR, terrestrial laser scanning, and satellite-based Differential Interferometric Synthetic Aperture Radar(DInSAR), are also used to measure deformation associated with subsidence. DInSAR data are different than data from conventional subsidence surveys. Images capture data over large areas(hundreds of kilometers), and each pixel(data point) in an image quantifies the average displacement over an area of square meters.DInSAR data can have fairly high time resolution; imaging periods typically range from weeks to months.DInSAR data can be useful to monitor subsidence sequentially over short periods. Regularly monitoring subsidence may help define if caving is progressing normally and can establish relationships between surface deformation and longwall face advance, which has potential to help quantify possible risks to mine stability. In this study, subsidence at a longwall trona mine is monitored over short periods, typically 12 days, as the longwall face is advanced through a panel. C-band interferometric wide swath synthetic aperture radar(SAR) images from the sentinel satellites are used to quantify the subsidence. The onset of subsidence occurs close in time to the beginning of the longwall face advance, and overall,the development of subsidence closely follows the longwall face advance.     

采动区地基、独立基础与框架结构共同作用的力学模型

根据采动区地表变形的规律和独立基础框架结构受力和变形特点，采用合理的地基模型、基础与上部结构共同作用模型和开采沉陷模型，综合应用结构力学、矿山开采沉陷学、土力学、材料力学等相关理论，建立了采动区地基-独立基础-框架结构共同作用的理论计算模型，该计算模型综合考虑了开采盆地形成过程中地表变形对建筑物的动态影响，从理论上揭示了建筑物位于下沉盆地不同位置时，地表变形与建筑物附加变形和附加内力的关系，并推导出计算采动区建筑物附加变形和附加内力的计算公式，通过计算实例进行了验证，为采动区上方框架结构建筑物的保护、加固和设计提供了理论计算依据．     

Top coal caving mining technique in thick coal seam beneath the earth dam

It is important to study the mining technology under structures for raising the coal resources recovery ratio. Based on the geological and mining conditions, the top coal caving harmonic mining technique in thick coal seam beneath the earth dam was put forward and studied. The 5 factors such as the panel mining direction, panel size, panel location, panel mining sequence and panel advance velocity were taken into account in this technique. The dam movement and deformation were predicted after the thick coal seam mining and the effects of mining on the dam were studied. By setting up the surveying stations on the dam, the movement and deformation of the dam were observed during mining. By taking some protective measures on the dam, the top coal caving mining technique in thick coal seam beneath the earth dam was carried out successfully. The study demonstrates that harmonic mining in thick coal seam is feasible under the dam. The safety of the earth dam after mining was ensured and the coal resources recovery ratio was improved.     

Surface Movement Regularity of Super-Wide Mining Face With Top-Coal Caving

No.4326 super-wide panel of Wangzhuang Coal Mine ( in which the fully-mechanized top-coal caving longwall mining method was used) was monitored for dynamic characteristic of surface movement. The dynamic surface movement in and after mining was predicted by using the Mining Subsidence Prediction System. The results indicate that after mining, the surface above the super-wide panel reaches a state of full subsidence, making the No.309 national highway above the panel be located on the flat bottom of the subsidence basin so that the influence of mining activity in both sides of 4326 panel on the national highway is the smallest.     

利用转动不协调确定煤矿覆岩断裂带高度

基于非线性大变形几何场论，建立了覆岩断裂带高度预计的差分余量法，使得地表移动预计和覆岩断裂带的确定统一为一个有机整体；证明了介质变形连续性的协调条件可以用转动协调方程等价表示，微观转动不协调是导致岩石类材料颗粒与夹杂接触边界产生微裂纹的原因。算例的计算结果表明，该方法简单、快速，有望在放顶煤开采和水体下采煤中得到应用。