| The strata movement and deformation caused by underground mining activities is a typical "black box" problem.It is difficult to grasp the structural characteristics of complete overburden and the law of mine pressure.The division of vertical zoning of overlying strata,prediction of the development height of water-conducting fractured zone,discrimination of key layer structure of overlying rock and monitoring of advanced abutment pressure are still the main research problems in the field of mining engineering.it is an important guarantee to realize safe and efficient mining.Therefore,to promote the development of monitoring technology of mining induced rock mass deformation has important research value in the mining field.Whether in-situ rock mass deformation monitoring or laboratory model test research,the key to study the deformation law of rock mass structure caused by mining is to obtain various deformation parameters scientifically and accurately.With the rapid development of optical fiber sensing technology,it provides a new method for deformation monitoring of mining rock mass structure.There are many problems to be solved in the application of optical fiber sensing technology to the deformation monitoring of mining rock mass.How to obtain the deformation information and stress evolution law of mining overburden scientifically and effectively through optical fiber sensing technology has become the focus of current research.Based on this,this paper divides the problem of the application of optical fiber sensing technology in deformation monitoring of rock structure into two parts,through theoretical analysis,calibration test of uniform strength beam,ANSYS numerical modeling,compression test of rock specimen,physical similar model test of steep inclined seam mining and shallow buried seam mining,FLAC numerical calculation,research of mine pressure data analysis,etc.The basic theory of optical fiber sensing technology,and the application of optical fiber sensing technology in rock mass deformation monitoring were studied.The main innovations of this paper include:(1)The quantitative index of coupling between mining rock mass and distributed optical fiber is put forward,and the coupling coefficient of different vertical zoning areas is quantitatively analyzed and discussed.Based on this,five different stress media in contact with optical fiber are proposed.(2)The statistical analysis method of strain increasing rate based on FBG and average strain increment based on BOTDA are put forward,and the mathematical expression is given,and used to represent the intensity and position of overburden movement.The essential influencing factors of whether rock mass activity is strain increment mutation are verified and analyzed by statistical T hypothesis test method.(3)The relationship between the shape of strain curve,the development height of water flowing fracture zone and the activity of key layer is established,and the vertical zoning characteristics of overburden rock are characterized by optical fiber sensing.analyze the discrimination method of the main key layer,the mode of instability and breaking of the key layer,the internal mechanism of the key layer identified by optical fiber sensor,the separation caused by the uncoordinated deformation of the key layer and the rock layer below,and the separation tensor has a linear relationship with the axial force of the optical fiber at the corresponding position.Based on this definition,the key layer determination parameter(CSI),of mining overlying strata is sensed by optical fiber,and its effectiveness is verified by the monitoring data of large dip angle and shallow coal seam model test.It is of great academic value and research significance to establish a characterization system of displacement,deformation and structural evolution of overlying strata based on optical fiber sensing technology.Combined with optical fiber sensing temperature\humidity measurement and other related technologies,which provides necessary information of strata deformation field,temperature field,humidity field and so on for the realization of intelligent mining.It is of great significance to promote the development of optical fiber sensing technology in the field of mining industry. |
PDF Full Text Request