###### Abstract
In order to study the evolution mechanism of water inrush, some scholars have established model test systems for water inrush in high seepage and high in situ stress tunnels [13], a large-scale, three-dimensional model including two stages of tunnel excavation and hydraulic loading [14], a large buried depth and high water pressure tunnel water inrush model test system [15], a tunnel water inrush evaluation model suitable for fluid-structure coupling to test new materials [16], a multi-type water inrush model test system that can be serialized and visualized [17], and research on model tests for filling cracks such as the water inrush process test system [18] to explore the mechanism of water inrush in karst tunnels. At the same time, some scholars have established numerical models to analyze the inrush water caused by the gradual failure of the rock mass [19], the effect of cracks on the water flow [20], the gas-liquid two-phase flow mechanism after the water inrush in the tunnel [21], and the effect of seepage force on the expansion of the water inrush channel [22]. For the stability study of water-resistant rock walls, [PERSON] [23] proposed the upper bound theorem based on limit analysis and a Hoek-Brown failure criterion considering the influence of seepage force; [PERSON] [24] conducted a real triaxial mechanical geological mechanical model test to evaluate rock wall stability; [PERSON] [25] proposed a karst cave water pressure model to study the effect of cave water pressure on tunnel lining; [PERSON], [PERSON] [26] established a simplified mechanical model to study the stability of rock wall caused by water-rich karst caves at the top of the tunnel sexual influence. Regarding the thickness of the water-resistant rock wall, some scholars have used the catastrophe theory and strength theory [27], the orthogonal numerical simulation test [28], combined the numerical simulation results and multiple linear regression [29], and the semi-analytical solution theory of the minimum safe thickness of the karst cave [30], minimum safe thickness calculation theory based on two-band theory and critical water pressure [31], minimum thickness calculation theory combining pseudo-static and dynamic theory [32], minimum safe thickness calculation theory considering energy dissipation [33], the critical safety thickness calculation theory based on the upper theorem of limit analysis [34], among other methods, to study rock wall safety thickness. The above analyses have mainly studied the mechanism of water inrush in karst tunnels under water pressure, while less research has involved the mechanism of water inrush in karst tunnels under the coupling action of blasting load and water pressure. At present, some scholars have established dynamic models to conduct theoretical analysis and numerical analysis on the mechanism of water inrush in karst tunnels under blasting loads [35; 36; 37; 38]. However, there is a lack of scholars to conduct a new numerical analysis on the mechanism of water inrush in karst tunnels under the coupling action of blasting load and karst water pressure. Numerical analysis of the mechanism of water inrush in karst tunnels under blasting load requires the realization of groundwater inrush deformation under blasting disturbance, which cannot be solved by conventional finite element technology. As a new discrete element and finite element coupling calculation method, the Smoothed Particle Hydrodynamic-Finite Element Method (SPH-FEM) technology can solve the large deformation analysis that finite element technology cannot handle [39; 40; 41; 42]. [PERSON] [43] adopted the SPH-FEM coupling calculation method, in which the evolution process of water intrush under the blasting of karst tunnel is simulated by dividing Smoothed Particle Hydrodynamic (SPH) particles into groundwater. However, the above article did not study the minimum outburst prevention thickness of karst tunnels under blasting loads.