# Mechanics Model of Floor Heave: Case Study on Thin Coal Seam with Soft Roof and Floor
## 1 Introduction
[PERSON] [21] researched the floor heave management at the Glencore Bulga underground operations and investigated the contributing factors to the behavior of the floor. [PERSON] [22] analyzed the stability of tunnels in a deep coal mine using the distinct element method. [PERSON] [23] also studied the stability of entries in a deep coal mine using the finite element method. The mechanisms and methods of roadway floor heave differ due to the various geological circumstances, surrounding rock qualities, and stress states of the roadway. It can generally be broken down into four categories: water swelling floor heave, shear dislocation floor heave, compression folding floor heave, and compressive flow floor heave [24]. Academician [PERSON] noted that one of the main causes of roadway floor heave is the bending and expansion of rock layers [25]. According to [PERSON]'s theory [17], the floor's lithology and horizontal load have a significant influence on floor heave. The fractured floor needs to be strengthened, its peak and residual strength need to be increased, the floor's lithology needs to be improved, and the effect of horizontal load on the floor heave needs to be managed. [PERSON] investigated the fundamental traits of roadway floor heave, examined the causes and mechanisms of four different forms of floor heave, and suggested control methods [2]. [PERSON] created a force model for the floor of the deep well's huge cross-section gob-side entry retaining roadway, and then used the principle of minimum potential energy to compute and analyze the floor's deformation [26]. According to [PERSON], the floor of the roadway ruptures after a single mining operation, and the fractured rock mass of the floor subsequently experiences post peak creep under the action of dynamic stress in both the first and second mining operations [27]. This is the cause of the floor heave of the gob-side entry retaining roadway. [PERSON] et al. [28] pointed out that the occurrence of floor heave phenomenon is related to most temporary roadways, and proposed a method to control the floor heave in mine roadways by consolidating the rock of the mine roadway floor for reinforcement, forming locally strengthened zones. [PERSON] et al. [29] used finite element analysis to analyze the Taldinskaya Zapadnaya-2 mine and studied the causes and mechanisms of the floor heave. It was found that using pressure relief slots in two areas can reduce the amount of the floor heave. [PERSON] [30] proposed a new modeling method of the roadway floor heave under the conditions of dry floor and waterlogged floor, and used two roadways under corresponding conditions to verify the accuracy of the simulation. When estimating the magnitude of support stress during tunnel closure support construction or predicting the maximum acceptable roadway floor uplift based on approved mining techniques, the displacement of the submerged floor calculated by this modeling method is more accurate. [PERSON] et al. [31] used a simple method including Kirsch equation to analyze the stress distribution around the roadway, analyzed the field observation results of the displacement of the roof and floor of the \"deep well\" roadway, established the linear correlation between the roof subsidence and the floor heave, and emphasized that the roof subsidence must be prevented in order to effectively offset the extrusion of the floor strata. [PERSON] [32] studied the mechanism of the floor heave formation by combining the influence of water content on rock properties, and proposed a method for controlling the floor heave through grouting reinforcement. The reliability of this method was verified through numerical simulation. [PERSON] et al. [33] proposed a coal mine floor rating to help evaluate the potential for significant floor heave in underground coal mine roadway development in new mining projects or future work. [PERSON] et al. [34] studied the performance of grouting as a reinforcement material for the floor, controlling the deformation of the tunnel floor heave.