Experimental Study On The Influence Of Normal Faults On The Movement Of Overlying Strata And The Activation Of Faults

The fault is a common geological structure in the mine.The existence of the fault destroys the integrity of the overlying strata,disrupts the continuous overall occurrence of the rock strata and affects the distribution of the original rock stress.During the mining process,the stability state of the fault layer is broken,and it is easy to activation,and then induce different degrees of coal and rock dynamic disasters.In this paper,the fracture characteristics and displacement laws of overlying rock under the influence of fault are studied by means of theoretical analysis and similar material simulation test,and the evolution law of transverse separation fracture,longitudinal fracture and overburden migration form under the influence of fault is studied.Based on the theory of masonry beam,the sequence of fault activation,the amount of fault slip and the degree of fault activation are entered into the sequence of fault activation and the activation of the faultare are studied.The main results are as follows:1)Under the influence of the fault,the direct top is cut down along the fault layer,the basic top produces the cantilever rotary breaking effect,gradually approaching the fault,the basic top period is decreasing and the pressure step distance decreases after the fault,and the periodic pressure step distance increases until the stability.Before the fault,the subsidence of each survey line increases with the increase of fault horizon.After the fault passes,the subsidence of each line decreases with the increase of fault horizon.The measuring line subsidence curve by "V" type to "U" type to "back ?" type to "step" type evolution.2)The separation which is not affected by faults,presents a low,open symmetrical "inverted arch" to the middle closed symmetry"inverted arch" evolution.Under the influence of fault,the separation layer presents the middle closed symmetry,the "inverted arch" to the high open asymmetric "half inverted arch" evolution.The fractures which are not affected by faults extend vertically or tilted from low level to high level,forming fracture zones and compaction zones.Under the influence of faults,the development of fractured fractures is obviously affected by faults,and the height is significantly increased and the width is increased.3)The separated layer fissure and fracture fissure synthesize the symmetrical inner and outer arches,forming stable?unstable?stable form low position to high position.When the arch is connected to the fault,the arches develop into trapezium.4)Fault activation is a dynamic continuous process,where the fault level first activates,and gradually activates to the middle and low level until it is fully activated.5)The working face is approaching the fault gradually,and the effect of fault activation is gradually increasing downward.During the period of the fault and the basic top period,the activation control of the fault is strengthened.The activation of the fault and the high activation control should be strengthened in the period of the initial activation of the fault and the pressure after the basic top period.