# Characteristics of the Deformation and Fracture of Overlaying Slopes in Roof Cutting
## 1 Introduction  
In the continuous development of mining projects, the deformation and failure of overlying slopes caused by mining are increasingly prominent, which seriously threatens safe production, the surrounding ecological environment and the safety of residents and property [1]. The in-depth exploration of the deformation and failure of overlying slopes in roof cutting and the control strategies is of great significance to ensuring sustainable mining. A variety of factors seriously challenge the stability of overlying slopes during mining [2]. Among them, the depth and intensity of mining are the important influencing factors. As the ground stress increases with the mining depth, the pressure on the rock mass also rises to cause damage to the integrity of the rock mass, and, thereby, the slopestability is affected; the increased mining intensity means expansion and intensification of the disturbance to the rock mass, which further weakens the stability of the overlying slope and increases the risk of deformation and failure [3]. Geological structures have a profound impact on slope deformation and destruction. Geological structures such as faults and joints can damage the continuity of rock mass to cause the formation of potential sliding surfaces [4]. During mining, these parts are more prone to stress concentration, which causes displacement and deformation of slope along the tectonic plane and even geological disasters such as landslides [5]. The mechanical properties of rocks cannot be ignored either, as the differences in mechanical parameters such as strength and elastic modulus determine their different deformation responses to mining stress [6]. Slopes composed of soft rocks are more prone to plastic deformation, while hard rock slopes may be unstable due to brittle failure [7]. Groundwater plays a complex role in slope stability. On the one hand, the penetration of groundwater reduces the shear strength and increases the weight of rock mass. On the other hand, changes in pore water pressure change the stress of rock mass. When the pore water pressure increases, the effective stress decreases, resulting in decreased slope stability. In addition, unreasonable mining sequences and methods also exacerbate slope deformation and failure [8; 9; 10]. Improper mining sequence can lead to uneven stress distribution, causing local stress concentration to accelerate slope instability; excessive blasting and other inappropriate mining methods will cause additional damage to rock mass and destroy the original stable structure of the slope [11]. To address the deformation and failure of overlying slopes caused by mining, many control measures have been developed [12]. Support technology is a common method. The provision of bolts, cables and other support structures to introduce prestress on slope rock mass can enhance the integrity and stability of rock mass and resist the influence of mining stress [13; 14; 15]. It is equally critical to optimize the mining scheme. Reasonable mining sequence, mining intensity and mining method can effectively reduce the disturbance to slopes during mining and lower the degree of stress concentration, thereby maintaining the stability of slopes [16; 17; 18; 19; 20; 21; 22; 23; 24]. Furthermore, a monitoring and early warning system is indispensable. Real-time monitoring of the displacement, stress, groundwater level and other parameters of slopes allows timely discovery of potential deformation and failure, which provides a basis for the adoption of corresponding control measures to avoid disasters [25; 26; 27; 28]. At the mining site, a combination of ground and underground measures is used to maintain slope stability. Ground measures include slope cutting and anti-slip piles, etc. Most ground measures are costly and require long construction periods; the underground measures are mostly the increase in slope protection coal pillars, which also causes a lot of waste of coal. Roof cutting for pressure relief is an important innovation in safe and efficient coal mining.