【作者】 邵小平；

【导师】 石平五；

【作者基本信息】 西安科技大学 ， 安全技术及工程， 2008， 博士

【摘要】 新疆乌鲁木齐矿区蕴藏着丰富的急斜煤层开采资源。水平分段放顶煤作为急斜煤层开采的一种科学方法已成为矿区目前唯一采用的开采方式,而以往的开采实践与理论研究成果均表明增加工作面分段高度是提高矿区煤炭产量的主要手段。“十一五”期间,按照国家煤矿安全监察局对乌鲁木齐矿区急斜放顶煤工作面采放比不超过1:8的要求,矿区各生产矿井的工作面分段高度将逐步提高至30m。如此大段高开采条件下支架能否保持良好的运转特性、围岩是否存在大范围垮落的危险性、工作面采出率如何保证是论文研究的三个主要问题,而其核心是在对工作面围岩运移特征深入了解基础上,研究不同倾角急斜煤层合理段高的取值范围以及进一步增强围岩可控性的方式,即急斜煤层大段高开采条件下的围岩控制理论研究。本论文正是在对比、分析及总结急斜煤层以往相关研究成果基础上,应用现场实测、理论分析、相似材料及数值模拟试验的手段,专门针对大段高工作面开采的以上问题进行了深入研究。基于急斜煤层赋存条件复杂的实际情况,论文首先在现场实测中建立了急斜煤层分段放顶煤工作面的立体监测模式,实现了对工作面矿压显现及围岩运移变化规律的多方位监测。实测表明,支架在走向上分区域承受了不同高度范围内顶煤体完全破坏后的压力,基本顶岩层的垮落区域位于煤壁后方采空区内。工作面沿走向具有明显的周期性矿压显现,但支架的工作阻力并没有随着段高与采深的增加而大幅度增加,说明支架会受到其上方(煤体及采空场)沿走向临时结构的保护作用。其次,在放顶煤试验中顶煤体冒落拱形式的破坏及低位拱失稳后被上位拱所取代的方式说明支架还会受到顶煤体中沿倾向结构的保护作用。因此,保证了大段高开采条件下支架良好的运转特性。进一步的典型倾角急斜煤层相似模拟对比试验表明,顶板岩层中存在“卸载拱”结构。该结构的存在,使工作面开采过程中裸露的顶板岩层仅承受拱内岩层的作用。倾角较大的急斜煤层,开采过程中由于受到“阶梯”形收口处及沿槽形采空区域下移的垮落体对顶板岩层的支承作用,顶板岩层的稳定性大幅提高。理论分析中借助岩层板破断的小挠度理论,推导出了急斜煤层分段放顶煤开采条件下不同倾角的合理段高取值范围,从理论上论证了分段放顶煤工作面在段高所在范围内避免围岩大范围垮落的基本条件是具备的,工作面采出率也可以得到保证。倾角55°以上的急斜煤层,进行30m的大段高开采是可行的。在进一步提高围岩可控性研究方面,填装了总重量达18.6t,且在国内外急斜煤层研究中迄今为止所填装的最大规模的大型组合堆体立体模拟试验。试验揭示了急斜煤层的沉陷特征。即开采后地表为多次反复沉陷,塌陷坑内垮落体由底板侧朝顶板侧呈台阶式下降分布,充填时应由底板侧沿台阶式下降体开始多次充填。而对于充填体作用机理的研究则表明:急斜煤层开采后,如果围岩的自然充填体与人工充填体可以较好地沿煤体开采后形成的槽形采空区域下移,并在此过程中对顶板起到结构支撑作用,则有利于形成工作面上方暂时稳定的结构,控制顶底板的运动,防止工作面大范围悬空后顶板大范围垮落可能形成的灾害。总体上,论文在对急斜煤层大段高工作面开采围岩破坏特征深入研究基础上,提出了选取工作面合理段高取值范围及充填采空区域的围岩控制方式,并在煤矿生产实践中得到了验证。此项研究对于乌鲁木齐矿区急斜煤层大段高工作面安全高效开采有积极的指导意义,对于赋存类似煤层的国内外其它矿区也有一定的借鉴意义。更多还原

【Abstract】 There are abundant of resources of steep seams in Urumqi coal mine in Xinjiang. Horizontal section top-coal caving has become a only mining method used in this mining area as a scientific method, and the past mining practice and theoretical research results indicate that increasing section height is a major mean to improve coal production.In the 11th five-year plan period, section height gradually will try to be increased to 30m in accordance with require of National Coal Mine Safety Supervision Bureau that the ratio of mining to letting is not more than 1:8 in top-coal caving face in Urumqi mining area.There are three main issues in so much of section height, whether or not the support can maintain good operating characteristics, the surrounding rock avoid the existence of large-scale rock with the danger of collapse, and how to ensure recovery rate, the core of which is reasonable range of section height to steep seams with different inclination, as well as further enhances controllability’s way, namely the theoretical research of surrounding rock control on the basis of depth understanding to migration characteristics of surrounding rock. It is on the basis of contrasting, analyzing and summarizing previous researchs of steep seams, above issues are specifically studied by means of site monitoring, theoretical analysis, numerical and similar material simulation in this thesis.Based on the actual situation of complex occurrence conditions in steep seams, firstly, solid monitoring mode was established in top-coal caving face in field. All-round monitoring of strata behavior and migration laws of surrounding rocks are achieved in working face. Site measurement showed that the support bears pressure of different heights of caving completely destroyed along rock strike on different region and collapse range of basic roof is in gob area rear of coal wall. Although the working face has obvious period strata behavior along strike, working resistance of support did not increase along with increasing of mining depth and section height, which indicates that support will be protected by overhead (coal body and gob field) provisional structure along stata strike. Secondly, arch destruction of top-coal and replaced form of instability low arch by upper arch indicate that support will be protected by structure along tendency in top-coal body in top-coal caving trial Therefore, good operation properties of support are related to rock structures under conditions of big section mining.Further comparative similar simulation test of steep seams with typical angle showed that roof strata exists "unloading arch" structure, which makes it only bear strata action within the arch.Stability of roof was largely improved after roof was supported by collapse body which moves along region of the goaf and lies in "ladder" location to steep seams with larger inclinationBy means of small deflection theory of strata’s plate destruction, reasonable high-value range was derived to steep seams with different angle. Therefore, there is basic requisite of avoiding large-scale rock collapse, and recovery ratio also can be guaranteed in working face. Mining 30m section steep seams whose inclation is more than 55°angle is feasible. In research of raising strata controllability, the test of large pile three-dimensional simulation which has total weighing of 18.6t shows characteristics of many times repeated subsidence, and collapse body possesses stepped distribution from bottom to roof. So the pit should be backfilled according this sequence. The action mechanism of filling body shows that it easily forms temporary stable structures above the working face, controls the movement of roof and bottom, and avoids the disaster from large-scale roof collapse.Genarally, this paper pointed out that selection of reasonable range of section height and forms of controlling surrounding rock on the basis of deeply understanding strata’s damage characteristics.The issues have certain guiding significance for horizontal section top-coal caving in Urumqi coal mine, and reference significance to similar coal mine.更多还原