Research On Optical Fiber Monitoring System And Early Warning Method Of Shaft Wall Deformation

As the "throat" of coal mine,the stability of shaft is very important for the safety production of coal mine.Combined with the auxiliary shaft structure and engineering geological conditions of Lingdong coal mine,using fiber Bragg grating technology,this thesis studies the evolution characteristics of shaft wall deformation,tests the compressive strength and flexural strength of concrete samples,analyzes the stressstrain distribution curve of concrete structure,determines the early warning threshold of shaft wall deformation,constructs the real-time monitoring and early warning system of shaft wall deformation based on Fiber Bragg grating technology,and establishes the deformation prediction method based on grey theory,It provides a theoretical basis for the safety and stability of the auxiliary shaft in Lingdong coal mine.The research contents of the thesis are as follows:(1)According to the concrete parameters of Lingdong mine wall,the concrete samples are made and tested in laboratory.The strength,compressive elastic modulus and flexural modulus of the concrete samples are analyzed.The crack evolution characteristics of the samples are discussed by using distributed optical fiber sensing technology and photogrammetry method,the determination method of early warning threshold of shaft wall concrete structure is established,and the partition of shaft wall stability state is put forward.(2)According to the engineering geological conditions of the shaft wall,fiber Bragg grating sensors are arranged along the circumferential and axial direction of the shaft wall.Each sensor is introduced into the monitoring room through optical cable,and a real-time monitoring and early warning system for the shaft wall of Lingdong coal mine is constructed,which provides real-time monitoring,data analysis,state identification,prediction and early warning functions,and timely and accurately judges the deformation and failure area and evolution trend.The monitoring results for more than one year show that the auxiliary shaft wall of Lingdong coal mine is in a safe state.(3)According to the grey system theory,the mean GM(1,1)model and residual GM(1,1)model are used to predict the wellbore strain,and the prediction results are verified by Markov model and interval prediction method,so as to provide basis for the prediction and early warning of wellbore deformation.