## 1 Introduction  
The movement of the overlying strata in thick coal seam mining causes the redistribution of stress and forms a stress reduction zone and a stress increase zone in coal along the goaf [1; 2; 3]. This greatly affects the stability of coal along the goaf and makes the working face more prone to coal burst when disturbance occurs. Therefore, carrying out research on the influence of the overlying strata movement on coal along the goaf in thick coal seams, to understand and master the law of overlying strata movement and its action mechanism on coal along the goaf and prevent the occurrence of coal burst, has important theoretical and practical value. It has become important to observe the movement of overlying strata and the deformation rule of coal along the goaf by using similar simulation experiment methods [4; 5; 6; 7; 8; 9]. In recent years, with the improvement of various experimental observation methods, the temporal and spatial non-uniformity characteristics, and the evolution processes of various physical and mechanical quantities in the overburden migration process, as well as the stress distribution and deformation of coal at the edge of the goaf, have aroused extensive research interest of scholars. In the model experiment of fully mechanized caving of thick coal seams, the techniques of optical fiber, resistance strain gauge, and the total station instrument are commonly used experimental observations [10; 11; 12; 13; 14; 15]. Among them, optical fiber and resistance strain gauge were used to monitor the stress in the local area of the model experiment, and the total station instrument was used to quantitatively measure the displacement in the local area of the experimental model. In the study of overlying strata migration, [PERSON], [PERSON] et al. [16] used a borehole television system to study the development height and evolution characteristics of the roof water-flowing fractured zone in fully mechanized caving mining. [PERSON], [PERSON] et al. [17] used digital photography to study the movement, crack distribution, and evolution of the overburden during mining, and found that under the influence of repeated mining, the overburden cracks experienced five dynamic changes. [PERSON], [PERSON] et al. [18] studied the distribution, development, and penetration of vertical and horizontal cracks in the mining overburden using the total station measurement method and proposed an effective method to determine the height of the \"three zones\". [PERSON], [PERSON] et al. [19] used the EH-4 magnet method and the numerical simulation method to determine the failure height of overburden, which was consistent with the theoretical calculation results. [PERSON], [PERSON] et al. [20] studied the overburden structure and its evolution law during mining and proposed the hazard law of the overburden structure during mining. [PERSON], [PERSON] et al. [21] studied the movement law of mining of the overburden structure, the evolution of mining fissures and stress changes in coal seams, and the expansion deformation of coal seams. [PERSON], [PERSON] et al. [22] studied the deformation, failure, and stress distribution evolution characteristics of surrounding rocks in fully mechanized caving mining by using similar simulation and numerical simulation methods, and they proposed the instability modes of the overburden bulk arch structure, such as tensile-compression composite instability and shear instability. Most of the above studies are focused on the overburden movement, but the corresponding relationship between the overburden migration and the evolution of coal and rock deformation along the goal needs further experimental research. In this study, we take Liuxiang Coal Mine as the engineering background, adopt the DIC method and the stress electric measurement as the monitoring methods, and then we carry out a simulation experiment of the overlying strata movement.