地下矿井深埋巷道岩爆预测及危险性研究

发布时间：2018-12-15 04:26

【摘要】：岩爆是开采矿体时经常遇到的难题,由于它的破坏性很大,常常给施工安全、岩体的稳定带来很多问题,甚至会引发重大安全事故,因此作为防止岩爆灾害的基础,岩爆的预测尤为重要。本文根据地质构造条件、地应力状况、矿井布置条件等影响岩爆的主要因素,利用FLAC3D数值模拟软件,选取侧压系数、高跨比、岩性、节理化程度作为研究参数,分析了不同条件下巷道围岩发生岩爆的可能性,旨在预测这四种因素对岩爆影响程度大小,探索岩爆发生的规律,为今后岩爆的防治工作提供理论依据。主要内容如下:根据山西潞安五阳煤矿地质条件建立矩形巷道,利用巷道最大主应力分析验证了模型的可行性。选取侧压系数作为变量,通过比较选择修改后的谷—陶岩爆判据作为判断岩爆等级的条件,针对不同侧压系数条件下矩形巷道的岩爆规律进行预测研究。结果表明:侧压系数对矩形巷道岩爆等级的影响大小为顶板底板,顶底板岩爆等级均随侧压系数的增加而增加,呈正相关。矩形巷道在侧压系数为0.5时岩爆等级最低。选取高跨比作为变量,探讨高跨比对矩形巷道岩爆等级的影响。结果表明:高跨比对矩形巷道岩爆等级的影响顶板略大于底板,矩形巷道顶底板岩爆等级随着高跨比的增加表现出“增加减小再增加”的趋势,在高跨比为0.5时,岩爆等级最高,高跨比为0.75时,岩爆等级最低。选取岩性作为变量,比较三种岩性条件下矩形巷道的岩爆等级。结果表明:不同岩性发生岩爆可能性的大小为:花岗岩石灰岩泥岩,围岩的硬度大小与顶底板发生岩爆的可能性大小成正相关。建立拱形断面巷道,通过最大主应力分析验证了模型的可行性。选取节理化程度作为变量,比较其可能发生的岩爆等级。结果表明:节理化程度对于拱形巷道围岩发生岩爆可能性的影响大小为:角点拱肩顶点底中,随着岩石质量的减弱,巷道围岩可能发生岩爆的等级逐渐增强。在含有贯穿节理的岩体中开挖,验证了拱形巷道有节理处比无节理处可能发生岩爆的等级大,同时探讨了侧压系数对于节理特征岩体岩爆的影响。结果表明:巷道拱顶与底板岩爆等级均随测压系数的增加而增加,拱顶可能发生的岩爆等级高于底板。综合得出,矩形巷道的围岩在侧压系数为0.5、高跨比为0.75,以及泥岩的条件下为最稳定状态,可能发生的岩爆等级最低。拱形巷道应尽量设置在节理程度较轻的岩体中,且巷道的顶板及角点在开挖过程中岩爆等级较大,较为危险。因此,今后在开采过程中应注重顶板以及角点的支护。
[Abstract]:Rock burst is a difficult problem often encountered in mining orebody. Because it is very destructive, it often brings a lot of problems to construction safety and stability of rock mass, and even leads to major safety accidents, so it is the basis of preventing rock burst disaster. Prediction of rock burst is particularly important. In this paper, according to the main factors affecting rockburst, such as geological structure condition, in-situ stress condition, mine layout condition and so on, the lateral pressure coefficient, height span ratio, lithology and joint degree are selected as the research parameters by using FLAC3D numerical simulation software. This paper analyzes the possibility of rock burst in surrounding rock of roadway under different conditions, in order to predict the influence of these four factors on rock burst, to explore the regularity of rock burst, and to provide theoretical basis for the prevention and control of rock burst in the future. The main contents are as follows: according to the geological conditions of Wuyang Coal Mine in Lu'an, Shanxi Province, the rectangular roadway is established, and the feasibility of the model is verified by the maximum principal stress analysis of the roadway. The lateral pressure coefficient is chosen as the variable, and the modified criterion of valley-pottery rockburst is compared as the condition to judge the grade of rock burst. The prediction of rock burst law of rectangular roadway under different lateral pressure coefficient is studied. The results show that the influence of lateral pressure coefficient on the rock burst grade of rectangular roadway is that of roof and floor, and the grade of roof and floor rockburst increases with the increase of lateral pressure coefficient, which is positively correlated. The rock burst grade of rectangular roadway is the lowest when the lateral pressure coefficient is 0.5. The influence of height to span ratio on rock burst grade of rectangular roadway is discussed by selecting the ratio of height to span as variable. The results show that the influence of height to span ratio on roof is slightly greater than that on bottom, and the roof rock burst grade of rectangular roadway shows the trend of "increase, decrease and increase" with the increase of the ratio of height to span, when the ratio of height to span is 0.5, The rock burst grade is the highest and the rock burst grade is the lowest when the ratio of height to span is 0.75. Taking lithology as variable, the rock burst grade of rectangular roadway under three lithologic conditions was compared. The results show that the probability of rock burst in different lithology is granite limestone and mudstone and the hardness of surrounding rock is positively related to the possibility of rock burst on top and bottom plate. The arch section roadway was established and the feasibility of the model was verified by the maximum principal stress analysis. The degree of jointing is chosen as the variable to compare the grade of rockburst that may occur. The results show that the influence of joint degree on the possibility of rockburst in the surrounding rock of arch roadway is as follows: in the top and bottom of corner arch shoulder, with the weakening of rock quality, the grade of rockburst in surrounding rock of roadway may increase gradually. Excavation in rock mass with penetrating joints verifies that the grade of rockburst with joints in arch roadway is larger than that with no joint. At the same time, the influence of lateral pressure coefficient on rock burst of jointed characteristic rock mass is discussed. The results show that the rock burst grade of the vault and floor increases with the increase of the pressure coefficient, and the rockburst grade of the vault is higher than that of the floor. It is concluded that the surrounding rock of rectangular roadway is the most stable under the condition of side pressure coefficient of 0.5, ratio of height to span of 0.75, and mudstone, and the grade of possible rockburst is the lowest. The arch roadway should be set in the rock mass with light joint degree as far as possible, and the roof and corner of the roadway are more dangerous because of the large grade of rockburst during the excavation process. Therefore, in the future mining process should pay attention to roof and corner support.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD311

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