Mechanism Of Floor Water Inrush Caused By Rock-mass Breakage And Seepage Flowing Of Confined-water And Its Engineering Practice

The destruction of the coal floor impermeable layer and water inrush caused byconfined water is a major threat to the safe production of the North China coal mine.Hence, it is extremely important to study the mechanism of water inrush in order toeffectively prevent and control the water inrush and ensure the safety of coalproduction.There are two core contents in this study, namely, mechanism of coal floorwater-inrush and its application in controlling water of coal mine. The former is ascience issue, and the latter is a technical problem.The study shows: The water inrush problem focuses on the interaction between theconfined water and impermeable layer. In the process, the confined water breakthroughimpermeable barrier formation water inrush channel and the water inrush. The waterinrush channel is different from the seepage channel in water-resisting layer, alsodifferent from the seepage channel in aquifer instead, a new, and “pipeline” similar innature to the flow channel.Therefore, the mechanism of water inrush from coal floor ismechanism of water inrush channel formed at the impermeable layer. Simple to say istwo problems. One is the formation of water inrush channel, namely method problem, itis the core and focus on the mechanism of water inrush channel. second is the seepagechannel was extended to “how” to achieve the water inrush channel, namely waterinrush channel minimum aperture problem.The mechanism of water inrush was investigated by the analysis of a large numberof water inrush cases and the personal experience about prevention and treatment ofmine water hazards during the work. First proposed that all the water inrush accidentsrelated to the non integrity(i.e. fracture belt) of water-resisting layer. Thus in thepremise of “rock mass structure” and “discontinuous medium model”, put forward themechanism of water inrush is the mechanism of seepage channel in confining bedexpanded into water inrush channel.Second, according to studied on the root of “the original guide lifting height” andthe result of typical field test, it pointed out that the original guide lifting height is theheight of confined water infiltration into impermeable layer, In essence, it isthe permeability of impermeable layer, not the water inrush channel height.Third, based on the analysis of the typical water inrush cases and the pattern offorming water inrush channel, the model of water inrush is attributed to “water burstingby rupture” and “water bursting by seepage”, and put forward three criteria of waterinrush by seepage.Fourth, two simulation tests of water inrush by seepage” is designed and completed.On the one hand, microtubule test (including microtubule water resistance test and microtubule flow test) is designed and completed, which not only shows thegroundwater seepage resistance changes with the diameter of seepage channel inimpermeable layer (conversely, when the seepage channel is expanded, the resistancecharacteristic is the releasing characteristics of confined water potential block), but alsoshows the correlation between the diameter and velocity increment.On the other hand, for the verification of mechanism front, water bursting channeltest of similar materials is designed and completed, which shows the section shape ofwater inrush channel to show the process of water inrush channel formation.Fifth, for the three criteria of water inrush by seepage which includes water inrushcoefficient, and the coefficient of water inrush is the recommended method of theprevention and control groundwater hazards in “water control regulations”, therefore,according to the practical engineering cases, this paper studied the problem of “waterinrush coefficient”, the coefficient of water inrush is a warning parameters that waterinrush “signs”, the final evaluation of mine safety in production is the expected wateryield and the equipped drainage facilities, rather than the coefficient of water inrush.Through the above research, the mechanism of water inrush by seepage accuratelyshowed up.