采动条件下陡倾斜平行矿体断层应力演化规律分析

Research on Stress Evolution Laws of Steeply Inclined Fault Parallel to Orebody Under Mining Conditions

陡倾矿体金属矿山中,平行矿体断层的滑移活化成为制约矿山安全生产的主要因素之一。为探明采动条件下断层面应力场响应特征及其对断层滑移活化的影响规律,以湖北省某铁矿为研究背景,采用离散元数值计算方法,对矿体开采过程中断层面正应力、剪应力及活化倾向性指标D的变化规律以及滑动变形演化特征进行了研究,结果表明:陡倾矿体开采影响下,断层面剪应力衰减时间明显滞后于正应力;采矿开始后,断层上部区域D值始终维持在高位(D>0.4),断层中下部区域在活化发生前D值明显增加,达到了0.4以上;陡倾斜平行矿体断层活化通常发生在最深开采水平位于断层下方30~58 m的范围内,与断层滑移变形的现场调查验证结果一致。

In metal mines with steeply inclined ore bodies, slip activation of fault parallel to the ore bodies has become one of the main factor restricting the safe production of metal mines. To explore the stress field response characteristics of fault plane and its influence on fault slip activation under mining conditions, based on the research background of an iron ore in Hubei Province, the discrete element numerical calculation method was used to study the change rules of normal stress, shear stress and activation tendency index D of fault plane, as well as the evolution characteristics of sliding deformation during the mining process of the ore body. The results show that, under the influence of mining steeply inclined ore bodies, the attenuation time of shear stress on fault plane is obviously behind that of normal stress. After mining, the D value in the upper part of the fault remains at a high level(D>0.4), and the D value in the middle and lower part of the fault increases significantly before activation, reaching more than 0.4.The activation of steeply inclined fault parallel to ore bodies usually occurs at the deepest mining level within the range of 30-58 m below the fault, which is consistent with the field investigation and verification results of fault slip deformation.