## 1 Introduction  
Gradually with the exhaustion of the shallow mineral resources of the Earth, the mining of deep mineral resources has become normal [1; 2; 3; 4]. Uncertainty regarding the failure mechanism and evolution law of the deep rock structure as well as inadequate mining strategy and other factors contribute to the failure of the higher overlaying rock formation. All leads to increasingly serious secondary disasters in mine geology such as rock burst, water inrush of the roof aquifer, damage of surface buildings, deterioration of ecological environment, and so on [5; 6; 7; 8]. The foundation of deep resource development is to study the law of deep science, and the key is to explore the structure and evolution law of deep rock mass. However, under the additional influence of the typical \"high stress, high temperature, high osmotic pressure\" deposit environment and \"strong disturbance\" and \"strong timeliness\" of resource mining, it is difficult to predict and effectively control the movement law of the deep rock mass [9; 10]. The key problem in accurately predicting the movement and deformation rule of the deep rock mass is the accurate acquisition of the mechanical parameters of the deep rock mass [11; 12; 13]. Mechanical parameters of rock mass can effectively participate in the whole dynamic process of the inversion and prediction of the movement and deformation rule of the deep rock mass and energy exchange, and explain the relationship of the surface and surface geological phenomena and deep rock mass deformation, revealing the connection between the mechanism of action of the deep rock mass and kinetic process and the geological disaster formation under the action of coal resources mining in the deep earth [14; 15; 16; 17]. Therefore, it is of great significance to study the optimization of the mechanical parameters of deep rock mass for explaining the scientific mechanism of action of deep earth, and improving the ability of the early warning, prevention, and control of geological disasters [18; 19]. Research on the value technique of rock mass mechanical parameters is currently highly active. The most prevalent approaches include empirical, numerical, the rock mechanics test, inversion analysis, etc. [20; 21; 22; 23]. The empirical method can be applied in the absence of experimental conditions and data, but it requires the necessary empirical guidance and is strongly influenced by the regional location [24]. The numerical method has complete research ideas, and can take values from the statistical point of view, but the computational amount is too large [25]. The rock mechanics test method can carry out different tests according to the actual engineering needs to obtain the basic indicators of the parameters of the rock mass mechanics. However, affected by the field environment and test sampling, the values of the parameters of the rock mass mechanics are largely random and uncertain [26]. By utilizing the displacement of the rock body as measured in the field and other data, the inversion analysis method can obtain the comprehensive value of the macroscopic properties of the rock body mechanics [27]. With the continuous development of science and technology and the continuous improvement in theoretical knowledge, the combination of the inversion analysis method and numerical simulation method is becoming more common [28; 29; 30; 31]. However, for the problem of the formation of rock movement under the influence of a deep, large cutting height coal seam, exploration of the optimization method of deep formation mechanical parameters and the explanation of the linkage law of \"deep formation and earth surface\" still remains lacking. Taking a mining area in Shandong Province as the research background and using the orthogonal test theory [32; 33] and FLAC3D numerical simulation [34], this paper performed the inversion of rock mass mechanical parameters based on the observation of the rock movement and geophysical data of the rock formation of the study area.