Research On Prediction Model Of Dynamic Subsidence In Changcun Coal Mining Area

In Changcun coal mine,the coal pressure under the railway special line reaches 35 million tons.It is particularly important to ensure the safe operation of the railway while promoting the comprehensive development and utilization of coal resources.In order to accurately predict the dynamic process of mining surface movement and deformation,and provides the foundation for the measures of surface mining resistance and the optimization design of working face.Taking Changcun coal mine as the research object,by combining field measurement,data acquisition and analysis,theoretical calculation and software processing,the dynamic moving deformation of ground form points is firstly studied and Weibull time function model is introduced.Secondly,a surface subsidence basin model is constructed to describe the surface subsidence morphological characteristics.Finally,combined with the time function and the subsidence basin model,a dynamic prediction model which can describe the whole process of dynamic subsidence change and reflect the morphological characteristics of surface subsidence is established.The following research results have been obtained:(1)Combined with field investigation and measured data,the surface movement deformation of the Working face S3-13 in Changcun coal mine is analyzed with the following laws and characteristics:the surface movement deformation is relatively severe,and the deformation distribution is concentrated;The subsidence rate is larger and changes faster,and the final subsidence value is larger.Because of the thick loose layer,the influence range of surface subsidence basin is wider and the convergence of basin edge is slower.(2)The main influencing factors of parameters f and g in Weibull time function model are determined.Combined with the model expression and the measured data,the variation rule of parameters is proposed:with the increasing of the distance between the observation point and the open-cut hole,the variation process of parameter f is 0?fmax?0,and the variation process of parameter g is 1?gmax?g1.Finally,an example is given to further verify the reliability of Weibull time function model and its variation law of parameters.(3)A surface subsidence basin model with a wider range of application and more in line with the actual subsidence form is constructed.Through analysis and discussion of model parameters,it is found that the parameter n in the subsidence basin model reflects the shape of horizontal section,is closely related to the bottom of the subsidence basin,and is mainly related to the degree of mining.The value range should be between 1 and 3.Parameter k reflects the attenuation rate,convergence rate and subsidence influence range of the sinking basin,which is mainly related to coal mining method,roof management method and the thickness of loose layer.The calculation formula of each parameter is given.(4)Combined with the surface subsidence time function and the subsidence basin model,the surface dynamic subsidence prediction model at any time at any point of the gently inclined coal seam strike long-wall working face is constructed.Using S3-13 Changcun coal mine working face multiple time point of the observation point data verification,the results show that dynamic Changcun coal surface subsidence prediction model to predict when the error is small,high precision,not only can reflect the dynamic subsidence process of a single observation points,and can describe the surface subsidence form of whole,it shows that the model can predict the surface dynamic subsidence of Changcun coal mine.