采矿引起地表塌陷过程中的地应力转移演化规律研究

Study on In-Situ Stress Transfer Evolution Process Caused by Underground Ore Body Mining

为了研究采矿引起地表塌陷过程中的地应力转移演化规律,以某金属矿山地下开采引起山体塌陷为研究背景,采用数值模拟建立含地下矿体、不同岩性的围岩、山体地表等实体模型。模拟了井下矿体的开采过程,模拟了矿体、围岩中的“转移-重分布”演化过程。研究表明:1)地表主应力主要沿着F15断层分布,数值模拟出的结果与矿山实际情况相符合,能够说明数值模拟的结果是可靠的。2)数值模拟得到的矿区中最大拉应力为0.79 MPa,最大压应力为6~8 MPa。3)井下白云岩基本不会发生拉压破坏,而破碎岩、砂岩及含矿白云岩岩体很可能发生拉压破坏,尤其破碎岩很容易发生破坏。4)浅层的围岩体以承受拉应力为主,尤其在断层F15附近的岩体,以受拉应力破坏为主。经过开挖之后在空区附近的应力变大,受岩性条件影响,在岩层交接部位、应力的扰动状态较大。地下开采矿体会导致应力转移到空区附近矿岩体中,整个模型中在空区附近产生应力集中现象,以拉应力为主。研究成果可为矿山设计与安全生产提供参考。

In order to study the law of in-situ stress transfer and evolution in the process of surface subsidence caused by mining,taking the mountain collapse caused by underground mining of a metal mine as the research background,the entity models including underground ore body,surrounding rock with different lithology and mountain surface were established by numerical simulation.The mining process of underground ore body is simulated,and the evolution process of“transfer redistribution”in orebody and surrounding rock is simulated.The results show that:1)The main surface stress is distributed along fault F15,and the results of numerical simulation are consistent with the actual situation of the mine,which shows that the results of numerical simulation are reliable.2)The maximum tensile stress is 0.79 MPa and the maximum compressive stress is 6~8 MPa.3)Generally speaking,there is no tension and compression failure in the underground dolomite,but the fracture rock,sandstone and ore bearing dolomite rock mass are likely to occur tension and pressure failure,especially the broken rock.4)The shallow surrounding rock is mainly subjected to tensile stress,especially in the rock mass near fault F15.After excavation,the stress in the vicinity of the goaf becomes larger,which is affected by the lithologic conditions,and the disturbance state of stress at the junction of rock strata is large.Underground mining of ore body will lead to the stress transfer to the ore body near the goaf.In the whole model,stress concentration occurs near the goaf,mainly tensile stress.The research results can provide reference for mine design and safety production.