【作者】 陈绍杰；

【导师】 郭惟嘉； 蒋宇静； 李法柱；

【作者基本信息】 山东科技大学 ， 矿山环境工程， 2009， 博士

【摘要】 随着时间的推移,开始处于稳定状态的条带煤柱在将来可能会失稳坍塌,这些煤柱成为老矿区发展其它工业潜在的灾害源；同时,部分矿井为了延长矿井寿命,不得不考虑开采以前“三下”开采时留设的煤柱。深部煤柱的时效性更为明显,研究深部条带煤柱的长期稳定性对减轻煤柱失稳造成的灾害具有积极的作用,可为煤柱资源的回收提供科学基础。本文采用室内试验、数值模拟、现场实测和理论分析等方法,针对随时间变化的深部条带煤柱长期稳定性进行了较为系统的基础实验研究。论文获得如下主要成果。(1)煤柱稳定性能的长期性表现在煤柱强度的蠕变性和煤柱及采场覆岩结构运动稳定的长期性两个方面。分析了地质条件、采矿条件、条带煤柱自身条件、时间、水等因素对煤柱长期稳定性能的影响,基于矿山压力理论提出了小采宽和大采宽的条带开采采场空间结构模型；煤柱理论长期强度应考虑尺度效应、横向约束效应和时间效应。(2)对多种岩性的岩石进行了Ⅰ类和Ⅱ类曲线单轴压缩试验,分析了岩石Ⅱ类曲线的形成机制、获取方法和产生条件,以此为基础,分析了深井煤柱独特变形特征的产生机制；进行了煤岩单轴压缩强度尺度效应的实验研究,得到了由室内单轴压缩强度与现场煤体强度的关系。(3)对煤岩试件进行了蠕变特性试验研究,分析了其蠕变破坏特征、蠕变力学参数和蠕变本构模型。通过精密蠕变试验明确了煤岩流变过程中微破坏和脆性突变变形的存在。通过自然状态煤岩试件和饱水试件的对比蠕变试验,分析了浸水对煤岩蠕变特性的影响。通过短时和较长时蠕变试验,研究了时间对煤岩长期强度的影响；提出了岩石长期强度的计算公式σT=σ∞+Aexp(-Bt),并据此确定了试验煤岩的理论长期强度为8.2282MPa。(4)结合室内试验成果,采用LS-DYNA和FLAC3D进行了煤柱长期稳定性能的数值试验,分析了岱庄煤矿条带煤柱的长期稳定性能。研究表明,在采矿活动结束的较长时间之后,煤柱状态仍然发生着变化,但稳定煤柱的变化会越来越小,在蠕变15～16个月后煤柱进入长期稳定状态。(5)建立了条带煤柱长期稳定性能的监测方法,对岱庄煤矿和唐口煤矿条带煤柱长期稳定性能进行了监测并分析了其演化规律。通过现场试验研究确定了岱庄煤矿条带煤柱分为弹性核区、塑性破坏区和完全破碎区及其范围；分析了观测煤柱不同部位的强度,并结合现场观测和室内试验成果,确定了岱庄煤矿条带煤柱的长期强度为29.5MPa,研究表明该煤柱是长期稳定的。现场试验研究了唐口煤矿条带煤柱各区域的范围、压力峰值位置、煤柱强度及侧向采动影响范围,并分析了其长期稳定性能。(6)实测研究还表明深井煤柱的深部横向变形是非连续、阶跃式、突变式的；一些在浅部表现为弹性的岩石,虽然在矿井深部因受到大得多的压力而表现为塑性,但它们的弹性、脆性、冲击性在深部矿井会表现的更加突出。更多还原

【Abstract】 As time goes on, some strip pillars will be unstable and collapse in the future then they are steay at formerly, those pillars become potential disasters while development of other industrial in old mining areas.At the same time, in order to extend the mine life, some mines have to consider to exploitate the former pillars.Deep pillar timeliness is more obvious, study the long-term stability of deep coal pilla has a positive role r to reduce disasters caused by coal pillar losing stability and can provide a scientific basis to reexploitate coal resources. A more systematic basic research on the long-term stability of deep strip coal pillar affected with time is carried out by the use of laboratory testing, field measurement, numerical simulation and theoretical analysis methods in this paper. The main study achievements were as follows.(1) The long-term of strip coal pillar stability manifests at the creep of pillar strength and development & stabilination long-term of pillar & overlay stratum. Some factors are analyzed as strip coal pillar of geological conditions, coal pillar own conditions, time and water influencing on long-term stability. The stope spatial structure models of small and large strip mining width are put forward based on mine pressure theory. The theoretical strength of strip pillar should include the scale effect, lateral constraint effect and time effect.(2) Unaxial compressed tests of several typical rocks’classⅠand classⅡcurves are carried out, and the formation mechanism and access method and production conditions of classⅡcurve are analyzed. Dimension-form effect for compressive strength of coal sample is experimental studied and the relation between UCS and coal mass strength in scene.(3) Creep tests are carried out and coal creep failure characteristics and mechanical parameters and constitutive model are analyzed. The existence of the micro-failure and brittle mutation deformation is proved in the creep process of coal through exact creep experiment. The influence on coal creep characteristics of water immersion is studied through contrast creep tests between natural and saturated water coal samples. The concepts of absolute long-term strength and relative long-term strength are cleared and the influence on coal long-term strength is studied through short-term and relative long-term creep tests. The formula of rock long-term strength is put forward asσT=σ∞+A exp(-Bt), then the theoretical long-term strength of coal tested is ascertained as 8.2282MPa.(4) Strip pillar long-term stability of Daizhaung Coal Mine performance is analyzed though numerical experiment using LS-DYNA and FLAC3D combination of laboratory test results and comparing the results of field measurement. The results show that pillar state is still undergoing changes after a long time of the end of mining activities, but these changes will become increasingly smaller. After 15-16months of mining, the coal pillar chang into long-time stable state. (5) The long-term monitoring of coal pillar stability is established, pillar long-term stability performances are monitored in Daizhaung Coal Mine and Tangkou Coal Mine and those evolution laws are analyzed. Based on actual observation, the strip pillar in Daizhaung Coal Mine is divided into elastic core zone, plastic failure zone and completely failure zone and the scope of each zone is determined. The strengths of different parts of the coal pillar are determined through on-site observations. The long-term strength of pillar in Daizhaung Coal Mine is determined as 29.5MPa combination of field observations and laboratory test results and pillar long-term stability performance is analyzed. Based on actual observation, scope of each zone and position of peak pressure and strength from Tangkou Coal Mine strip pillar and lateral incidence of mining are studyed and pillar long-term stability performance is analyzed.(6) Actual observation also shows that the transverse deformation in deep pillar of deep mine is non-continuous, step-type, mutant type. Rocks’flexibility, brittle and impact resistance also will be demonstrated even more prominent though the rocks perform plasticity since bearing more pressure in deep mine that perform elasticity and brittle in shallow mine.更多还原