CSAMT Response Law And Application Of A Coal Mine Goaf In Yangquan Coal Industry Group

At present,most of the researches on coal mine goafs by various electrical exploration methods are focused on single-layer goafs,and there are few studies on the electromagnetic response law of double-layer goafs.CSAMT is a relatively cost-effective method for sounding in the frequency domain and is widely used in coal mine goaf exploration.In this paper,the finite element method is used for numerical simulation of the goaf,combined with actual geological conditions and geophysical characteristics,mainly do some research about the CSAMT response under different scales of goaf collapse and water filling scale.On this basis,the CSAMT response law of double-layer goaf under different electrical combinations and different spacing conditions is studied.Got some coclusions as follows:(1)The single-layer low-resistance goaf is greatly affected by the degree of water filling,and it is difficult to distinguish its boundary when the degree of water filling is low.It is easy to distinguish the boundary when the water filling level is high,and the single-layer low-resistance goaf mainly has a large vertical influence range;The single-layer highresistance goaf is greatly affected by the degree of collapse of the goaf.When the degree of collapse is low,it is easy to distinguish the goaf boundary.When the degree of collapse is high,it is difficult to distinguish the mined-out boundary,and the single-layer high-resistance mined-out area mainly has a larger lateral influence range.(2)For different types of double-layer goafs,double-layer lowresistance goafs can be resolved at intervals of approximately 180 m,with the weakest resolution capability;The double-layer low,high-resistance and double-layer high-resistance goafs can be distinguished when the interval reaches about 120 m,followed by the resolution ability;The double-layer high-and low-resistance goafs can be clearly distinguished into two anomalies when the interval reaches about 60 m,and the resolution is good.(3)When the upper layer is a mined-out area with no collapse and a small amount of collapse(both are not filled with water),the upper and lower abnormal bodies can achieve the resolution effect when the interval is about 60 m;When the upper layer is a 50% collapsed mined-out area,it can be distinguished when the distance between the two layers of anomalous bodies reaches about 90 m;When the upper layer is a fully collapsed mined-out area,the two layers of anomalous bodies can be delaminated when the interval reaches about 120 m.That is,with the degree of collapse is getting lower,the higher the longitudinal resolution of the CSAMT method,and the better the detection effect.Two-dimensional simulation results based on finite element method,it has a certain guiding role in the delineation of the mined-out area,the experimental results prove that the simulation conclusion is reasonable and reliable.It shows that the simulation research provides theoretical basis for guiding the actual work and has guiding significance.