近距离煤层重复采动对坡体稳定性的影响

(1.西安科技大学 能源学院,陕西 西安 710054; 2.西安科技大学 西部矿井开采与灾害防治教育部重点实验室,陕西 西安 710054)

矿业工程; 采动坡体; 重复采动; 数值模拟; 覆岩破坏

Influence of repeated mining of close distance coal seams on slope stability
YU Xue-yi1,2,MAO Xu-wei1,2

(1.College of Energy Science and Engineering,Xi'an University of Science and Technology,Xi'an 710054,China; 2.Key Laboratory of Western Mine Exploitation and Hazard Prevention,Ministry of Education,Xi'an University of Science and Technology,Xi'an 710054,China)

mining engineering; mining-induced slope; repeated mining; numerical simulation; overburden failure

DOI: 10.13800/j.cnki.xakjdxxb.2019.0106

备注

为研究近距离多煤层重复开采对坡体稳定性的影响,以岔角滩煤矿二采区为研究背景,选取具有明显特征的V号坡体为研究对象,建立力学模型,在天然坡体稳定系数计算公式的基础上,修正给出了采动坡体的稳定系数计算公式。此外,结合数值模拟方法计算分析C19,C20煤层依次开采和一次性开采等厚煤层情况下对地表坡体稳定性的影响。结果 表明,天然状态下处于稳定的地表坡体在受到C19,C20两层煤依次采动后,坡体稳定性系数分别为1.03和0.80.模拟开采等厚煤层结束后,覆岩破坏发育高度约为120 m,地表浅处松散层发生局部破坏; 在C19煤层回采结束后,覆岩塑性破坏区发育高度约为80 m,未波及地表,坡体仍处于稳定状态; 在C20煤层回采结束后,覆岩塑性破坏区发育高度为150 m,地表松散层和基岩风化带整体破坏,坡体稳定性差。当开采单一煤层时,覆岩裂缝发育最大高度为35~40倍采高,对坡体的影响相对较小。近距离两层煤依次开采后,加剧了覆岩破坏,使得坡体失稳。

In order to research the influence ofrepeated mining ofclose distance coal seams on slope stability,the No.2 mining area in Chajiaotan Coal Mine was taken as the research background,and the V slope with obvious characteristics was selected as the research object.The mechanical model was established,and based on the formula for calculating the stability coefficient of natural slope,the formula for calculating the stability coefficient of mining slope was revised.In addition,combined with numerical simulation method,we calculated and analyzed the influence on the stability of the surface slope after C19 and C20 coal seam mining in sequence and one-time mining of equal thick coal seam.The results showed that the slope is stable under natural condition,but after mining of C19 and C20 coal seams,the stability coefficients of steady slope which is in the nature state are 1.03 and 0.80,respectively.The development height of overlying strata plastic failure zone is 120 m after mining of the equal thick coal seam,andlocal damage ofthe loose layer at the shallow of the surface occurs.When the development height of overlying strata plastic failure zone is 80 m after mining of C19 coal seam,it doesn't spread to the earth's surface,and the slope is still in the steady state.When the development height of overlying strata plastic failure zone is 150 m after mining of C20 coal seam,the unconsolidated formation and bed rock weathering zone are generally damaged,and the slope is in poor stability.When a single seam is mined,the maximum height of fracture development is 35~40 times of mining height,and the influence on the slope is relatively small.When the close two layers of coal are mined in turn,the overburden failure is aggravated,resulting in instability of the slope.