倾斜矿体采动与断层活化作用引起竖井变形的物理模型试验

倾斜矿体开采引起的地表变形与断层活化问题给矿山工程带来重大隐患,如竖井破坏。为了研究倾斜矿体采动及断层活化作用下竖井的变形破坏规律,引入一种软材料小模型物理模拟方法,对不同倾斜角度矿体、不同倾角断层下的模型进行开挖试验。结果表明:该方法能够较好地模拟典型的工程地质现象;在试验工况下,矿体倾斜角度不同,则自重应力场中的竖井受到采动影响的程度不同;处于开挖区上方的隐伏断层,倾角极缓时具有一定屏蔽垂直位移的作用,缓倾断层活化对水平位移的影响和陡倾断层活化对于垂直位移的影响具有某些相似性和对称性;倾角越接近45°,断层活化作用越强烈,对地表起伏度的影响越大,且竖井更有可能产生上部沉降、底部拱起的现象。

Physical Simulation Experimental Study on Mining and Fault Activation Induced by Excavation

Underground mining will inevitably change the stress state of the original rock and stress equilibrium state of overlying strata.The overlying strata move and deform during this process until a new stress balance is reached.During this process,the overlying rock layer moves and deforms,and passes upward to cause deformation of the ground surface.Because the ore bodies are mostly inclined,the movement rules of the surface and deep rock bodies caused by underground mining of metal mines are often different from those of sedimentary strata mines such as coal mines.In addition,fault activation often occurs under the action of excavation,leading to discontinuous and uncoordinated deformation of the surface and rock strata.Rock deformation,shaft deformation and fault activation caused by mining of inclined orebody have posed a serious threat to mine engineering.Many researchers have done a lot of research including theory,experiments and numerical simulations.In order to study the deformation and failure rules of vertical shaft under the mining of inclined ore body and fault activation,a physical simulation method for small models of soft materials was introduced.This method overcame many shortcomings of traditional physical simulation methods and had the advantages of simple operation and recycled.It could reflect the influence of self-weight stress on the physical and mechanical properties of materials in the molding process.This method was then used to carry out excavation experiments on models with different inclination angles of ore bodies and faults and good experimental results were finally obtained.The experimental results show that the location and settlement value of the settlement center change with the inclined angle of the ore body under the action of self-weight stress.The shaft is affected in a different way by mining because of varied angle of ore body.The vertical displacement of the shaft may be the result of overlying strata movement in goaf.It may also be due to the superposition of the overburden`s movement and the mining operation below.It depends on relative position of shaft and goaf.The hidden fault above the excavation area has the function of shielding vertical displacement to a certain extent when the dip angle is extremely low.The fault activation become stronger when the fault dip is close to 45°and it has a greater impact on surface deformation.The shaft is also subjected to greater squeezing and shearing action.These results have a valuable reference for mining design and site selection of shaft.