Research On Impact Hazard And Main Controlling Factors Of Working Face Under Fault Combination Condition

Compared with other rock bursts,fault-type rock bursts have a larger impact range and stronger destructiveness.At present,there are many theoretical and experimental studies on fault-type rock burst,but the object is limited to the influence of a single fault,and the interaction of complex geological structures is not considered.Practice has proved that the occurrence of rock bursts is often not limited to a single geological condition,but occurs under the mutual coupling of multiple conditions.Based on the current fault-type rock burst research theory,combined with numerical simulation analysis,sudy the stress distribution and energy accumulation of the working face in different combinations.The three-dimensional disturbance coefficient and the maximum slip speed of the fault are used as important indicators to measure fault instability,and the weight of each influencing factor is analyzed by orthogonal experiment method to find out the main controlling factors that affect the mining face.Introduced in detail the basic types,elements,and six combinations of fault structures Including stepped faults,grabens,horsts,imbricate faults,backlashes,and hedges.The mining situation along the middle of the faults on both sides of the working face is studied,combined with the fault-type rock burst instability,the working face shock instability is attributed to fault slipping and instability,coal pillar failure instability and coupled failure.Based on the FLAC^3D simulation software,the working face recovers the stress and energy distribution in different faults.It is concluded that the compound geological special structure hinders the stress transfer,the stress mutation occurs at the fault,and the normal fault is more prominent than the reverse fault.Due to the influence of fault clamping,stress concentration occurs near the working face and in the influence range of the front mining.At the same time,the composite structure of the fault causes the overall rigidity of the rock mass around the working face to become weaker,and it is easier to accumulate a large amount of energy at the coal pillar,which is superimposed with the instantaneous stress generated by the instant slip and instability of the fault,which can easily induce the instability of the coal pillar.Lead to the occurrence of rock brust.Based on the three-dimensional disturbance stress coefficient and the extraction of the maximum slip velocity of the fault as an index for judging the degree of fault instability,to measure the influence of the dip,drop and the width of the coal pillar left between the fault on the mining,and compare the range value through the orthogonal experiment According to the method,the coal pillar width is the most important factor affecting the slip velocity of faults.Under different fault combinations,the main controlling factors affecting the magnitude of the three-dimensional disturbance coefficient are different.In view of the different influencing factors under different fault combinations,the impact prevention of working face should be strengthened to explore,clarify the fault direction,drop and dip angle,strengthen the danger monitoring of the working face,and take targeted risk relief measures when necessary.After on-site practice,the coal pillar The use of large-diameter drilling and deep-hole blasting on the roof can effectively reduce the risk of impact on the working face.This thesis has 92 figures,20 tables and 90 references.