## 1 Introduction  
Mechanical characterization methods for rock materials are crucial for continued developments in rock mechanics and stability assessment of rock masses in engineering projects [1]. Many characterization methods have been proposed by researchers to describe rock mechanical behavior conveniently and accurately [2; 3; 4; 5].  
Existing studies on the characterization methods of rock mechanical behavior can be categorized as either macroscopic or mesoscopic. Macroscopic characterization methods involve direct characterization by obtaining a mechanical response through experimental phenomena [6; 7], and do not consider the deformation mechanism in detail. Theoretical models corresponding to the stress-strain curve obtained from experiments are used to characterize rock mechanical behavior [8]. However, these macroscopic characterization methods are extremely simplified in that they mainly focus on the change in the external characteristics of rock mechanical behavior from elastic to plastic [9]. Thus, more detailed rock mechanical characteristics and deformation mechanisms, especially close to failure, cannot be revealed by macroscopic characterization methods.  
Mesoscopic methods involve carrying out several mesoscopic experiments to understand the relationship between mesoscopic deformation and rock mechanical behavior [10; 11; 12; 13]. Mesoscopic models consider micro-crack development and damage evolution when characterizing rock mechanical behavior [14; 15; 16]. In addition, some numerical means, such as rock failure process analysis (RPFA) [17; 18], particle flow code (PFC) [19], and the finite element method (FEM) [20], were also used to establish a numerical model, which was divided into several elements on the mesoscopic scale. For numerical models, simplified damage criteria for elements are first defined, following which the mechanical response of the model under loading is obtained. Although damage evolution was introduced in mesoscopic characterization models to describe the deformation state and strength characteristics of rock [21; 22], the relationship between mesoscopic damage and global mechanical behavior is not clear. In addition, mesoscale models require complex calculations to characterize global mechanical behavior.  
Notably, many experiment-based studies have shown that deformation localization is a necessary process in rock deformation and failure [23; 24; 25; 26]. In fact, deformation localization is a macroscopic phenomenon attributed to the propagation and connectivity of micro-cracks in rock. The deformation localization band (DLB) constitutes the concentrated area of damage, and its material properties are obviously weaker than those of the other parts of the rock. After the formation of DLBs, the deformation of rock transforms into \"structural control\" [27; 28; 29], a very important characteristic of rock deformation. However, existing studies disregarded these structural evolution characteristics in the characterization of mechanical behavior. Structural evolution is a very important feature in the process of rock deformation, especially in the non-linear stage. Therefore, the structural characteristics must be considered when characterizing the mechanical behavior of rock. In this paper, we explore the structural deformation characteristics of rock and characterize the global mechanical behavior of rock from the perspective of structural evolution.  
The remainder of this paper is organized as follows. Section 2 describes the uniaxial compression tests conducted in this study on marble specimens and analyses the deformation evolution characteristics of the specimens. The interrelationship between global mechanical behavior and different deformation stages was obtained. Based on the experimental results, a simplified structural model for the rock specimen is proposed in Section 3. Simulations with the FEM are used to verify the rationality of the structural model. Section 4 presents our conclusions.