Numerical Simulation And Optimum Technique Of Control For Warter-inrush Of Deep-lying Laneway In Complex Water-rich Baixiangshan Iron Mine

The construction and mining of a complicated water-rich iron mine is often endangered by water-inrush geologic hazards,among which the water-inrush from fault has been much greater.For the increasing requirement of iron ore,the water-inrush is a difficult problem which desiderates to be solved effectively as soon as possible.Relying on the "the development and study on the crucial technology of exploring the complicated water-rich mine"(NO.2006BAB02A01),one of the national "11th Five-Year" science and technology supporting projects,the thesis has researched intensively on the geohydrologic conditions and the water-inrush condition from faults in the typical complicated iron mine of Baixiangshan.In order to make theoretical research serve the practical techniques of prevention and control for water-inrush better,the thesis analyzes various kinds of water-inrush inducements in detail on the whole and seeks after the laws of water-inrushs caused by water-transmissible faults at point.The main works and contents are as fllowed:(1) Many useful informations were fetched and the longitudinal diagrams of the East and West Big Laneways were drawn with the collection and analysis of large numbers of available geological maps and prospecting data.In the longitudinal diagrams,potential threats of water-inrush inducements to excavation are revealed and analyzed easily.The main water-inrush troubles to capital construction and ore extraction of Baixiangshan Iron Mine are water-inrushs caused by big fauts,water burst from small blind faults,water burst from fissures and water transmited by badly sealed drilling holes.According to the needs of prevention and control for water-inrush at the present stage,the primary inducements and critical areas are succeeded in finding.(2) By using fluid-solid coupling mode of 3D-dimensional finite-difference codes method for fluid flow in porous media(FFPM) and abstracting the geological conditions of East Big Laneway passing fault F₅,numerical simulation model of adjacent rock systerm for water-transmissible fault is set up.Under the high geostatic stress and water pressure of fault,the adjacent rock systerm has a law of perturbation-response relation for stress and strain during the closer excavation process to the fault which is uncovered in the end.It reveals that the bottom plate of diorite in metal mine is fine in water-resisting property and surrounding rock stability.Furthermore,the excavation in upper wall has roughly the same law above-mentioned as in lower wall when the dip of the fault is large (the dip is 75°in this simulation model).(3) On the basis of numerical simulation for surrounding rock stability of fault passed by Big Laneway above,the numerical-optimal simulation of pre-grouting programs for fault fracture zone also uses fluid-solid coupling mode of FLAC3D.In this model,the conditions of mine pressure and water pressure are unchangeable.Since the physical and mechanical parameters of fault zone reinforced by pre-grouting,the dimensions of direct arch laneway,and the thickness of grouting shell are all changed,24 pre-grouting programs are designed reasonably and computed in this model.Each of the four kinds of pre-grouting programs has its own minimum thickness of grouted shell through computing,as noted below:"Reforcement for small-section laneway,physical and mechanical parameters of lower strength" is 1.4m;"Reforcement for small-section laneway,physical and mechanical parameters of higher strength" is 1.2m;"Reforcement for large-section laneway,physical and mechanical parameters of lower strength" is 1.8m; "Reforcement for small-section laneway,physical and mechanical parameters of higher strength" is 1.6m.Moreover,for pre-grouting reforcement,the study indicates that it is important to enhance the improving effects and make certain grouted shell as hard as possible instead of expanding the scope indiscriminately.And,in comparison with small-section laneway,the large one is more unstable.So it is necessary to expand the scope and increase the thickness of pre-grouting,especially in the floor of laneway.(4) The conditions of rectangular laneway crossing small water-conducting fault in the bottom plate of diorite is simulated by fluid-solid coupling mode of 3D-dimensional finite-difference codes method for fluid flow in porous media(FFPM) in Baixiangshan Iron Mine.Five factors of fault dip,thickness of grouting,vertical ground pressure, lateral pressure coefficient,and the hydrostatic pressure of fault are synthetically tested in the simulation,which is to analyze and evaluate the influences and actions of each factor to the laneway.The simulation set 60 different tests,which are divided into several groups.And the paper researches the five factors and their influences and actions one by one through the study objects of plastic zone and displacement.The laws and conclusions worked out in the simulation tests can be provided for the problem of laneway crossing small water-conducting fault in similar mines.(5) Finally,for several water-inrush inducements in Baixiangshan Iron Mine there, the warning line for water-transmissible faults is calculated by empirical formula and some methods of geophysical for water-detecting are analyzed contrastively.And direct and indirect blocking ways underground are proposed in view of the depth character, distribution and water inrush mechanism of badly sealed drilling holes.At last,some proposals are put forward to the groundwater regime monitoring to carry out.