地下开采对顺层边坡稳定性的影响

发布时间：2018-03-06 02:36

本文选题：地下开采　切入点：顺层边坡　出处：《重庆大学》2015年硕士论文　论文类型：学位论文

【摘要】：在复杂的地形地质条件下进行地下工程的开挖,尤其是在丘陵山区进行地下工程开挖活动,将会引起上覆岩体的变形和破坏,诱发一系列的地质灾害问题,如引起地表山体滑坡、裂缝、崩塌、塌陷等,尤以采动滑坡最为突出。采动滑坡对人民的生命财产安全危害极大,因此,研究采动滑坡的机理有着重要意义。本文以重庆市某地下开采铁矿井为研究对象,利用其山体实际地形地貌、地质构造、区域地质背景等基本情况,运用UDEC软件对进行地下开挖后坡体滑面形变呈现凸形及反S形的模型进行研究,分析在不同采高情况下进行开挖后坡体的应力应变变化规律,以及覆岩和坡体的变形破坏规律;通过理论分析计算不同采高情况下进行地下开采后的坡体稳定性系数,对坡体的稳定性进行分析与评价;利用可变滑面进行相似模拟试验,研究坡体的变形破坏规律。主要研究成果如下:①试验区山体的数值模拟结果表明,地下开挖后,地表附近岩层出现不同程度的拉应力分布,采空区边界上方均出现拉应力集中分布区,且采高越大,拉应力集中越明显。采空区边界上方至滑面的斜向裂隙发育较为明显,随采高的增大裂隙发育程度明显增大;凸形滑面形态的模型在开挖后对坡体产生的影响主要集中在坡体中部以下,反S滑面形态的模型坡体上部也出现明显的垂直裂隙分布。此外,坡体受采动影响向采空区和下坡方向产生移动,采高越大,滑面最大剪应力值越大,滑面抗剪强度越低,坡体向下滑动的趋势越明显,移动变形量越大,坡体稳定性降低。②由理论分析可得知,计算所得到的开采强度均小于1,采动均属于轻微采动。随着采高的增大,坡体稳定性系数降低。反S滑面模型坡体在开采厚度为2.4m时,坡体由稳定状态变为临近滑动的临界状态。反S滑面形态的坡体由于开挖范围更大,较凸形滑面的坡体受采动影响更大,坡体稳定性降低更为明显。③相似模拟试验中,滑面形态为凸形与反S形的两种模型坡体均未发生整体滑坡,但在模拟采高为2.4m时,模型坡体均在坡脚处发生小范围垮塌。凸形滑面模型坡体,仅在中下部产生明显的垂直大裂隙,而反S滑面形态的模型,由于开采范围较前者大,坡体裂隙发育更明显。此外,坡体的下沉量和水平位移均随采高的增大而增大,凸形滑面测点最大下沉量小于反S形测点最大下沉量数值。以上结论表明反S滑面模型受采动影响大于凸形滑面模型,坡体稳定性更低。
[Abstract]:The excavation of underground engineering under complicated topographic and geological conditions, especially in hilly and mountainous areas, will cause deformation and destruction of overlying rock mass and induce a series of geological disasters. If it causes landslides, cracks, collapses, collapses, etc., mining landslides are the most prominent. Mining landslides do great harm to the safety of people's lives and property. It is of great significance to study the mechanism of mining landslide. This paper takes an underground mining iron mine in Chongqing as the research object, and makes use of the actual terrain and geomorphology, geological structure, regional geological background, etc. UDEC software is used to study the model of slope surface deformation in convex shape and inverse S shape after underground excavation. The variation law of stress and strain and the deformation and failure law of overburden rock and slope body after excavation under different mining height are analyzed. Through theoretical analysis and calculation of slope stability coefficient after underground mining under different mining heights, the stability of slope body is analyzed and evaluated. The main results of the study are as follows: the numerical simulation results of the mountain body in the 1: 1 experimental area show that, after the underground excavation, the distribution of tensile stress in the rock strata near the surface of the earth appears in varying degrees. The higher the mining height, the more obvious the tensile stress concentration. The diagonal fissure from the goaf boundary to the slip surface is obvious, and the fracture development degree increases obviously with the increase of mining height. The influence of convex slip surface shape on slope body is mainly below the middle of slope body after excavation, and the vertical fracture distribution is also obvious in the upper part of slope body of anti-S slip surface model. Under the influence of mining, the slope body moves to the goaf and downhill direction. The higher the mining height, the greater the maximum shear stress of the sliding surface, the lower the shear strength of the sliding surface, the more obvious the downward sliding trend of the slope body is, and the greater the amount of moving deformation is. From the theoretical analysis, it can be concluded that the calculated mining intensity is less than 1 and the mining movement is slight. With the increase of mining height, the slope stability coefficient decreases. Slope body changed from stable state to critical state near sliding. Because of the larger excavation range of slope body with anti-S slip surface, slope body with more convex slip surface is more affected by mining, and the slope body stability decrease is more obvious in the similar simulation test. However, when the simulated mining height is 2.4 m, the model slope body collapses in a small range at the foot of the slope. Only in the middle and lower part are obvious vertical large fissures. However, because the mining range is larger than the former, the slope-body fissures develop more obviously in the model of the anti-S slip surface. In addition, the subsidence and horizontal displacement of the slope body increase with the increase of mining height. The maximum subsidence of the convex slip surface is smaller than that of the inverse S-shaped point. The above results show that the anti-S sliding surface model is more affected by mining than the convex slip surface model, and the slope stability is lower than that of the convex slip surface model.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD803

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