## 1 Introduction  
The problem of water inrush with fracture rock mass seriously affects underground engineering. Grouting technology has become an important method for the prevention and governance of water inrush disasters. It is very necessary to enhance the research on the effects of grouting and water plugging with flowing water.  
Abundant achievements have been acquired in grouting technology. Grouting technology is widely used to control water inrush during the construction of tunnels and mines. Grouting plays an important role in mining because fractures are often caused by water inrushes [1], but grouting in rock fractures with dynamic water is still a challenge for engineers [2].  
The geological conditions of grouting in rock mass with fractures are complex, therefore, the factors that influence the grouting sealing effect in fractures are varied, for example, the density of joints, fracture opening, grouting materials, flowing water, etc. Many grouting experiments have been carried out in the field and laboratory, and many factors should be considered during grouting. Grouting materials can be divided into multiple categories, and cement grout and chemical grout are the mainly grouting materials used in grouting engineering.  
The grouting areas often fracture with flowing water. Meanwhile, the pressure of underground water will increase with the difficulty involved in grouting [3]. The flowing water in fractures also affects the grout diffusion, and the flowing water also reduces the strength of adjacent clay [4]. Visualization of grout propagation is achieved through laboratory experiments, using the grout diffusion distance and the shape of grout diffusion as the main research objects. The propagation length of cement grout has positive correlations with the water flow rate and grouting pressure [1], and methods for calculating the diffusion distance of slurry have been proposed [5; 6]. To study the shape of grout diffusion, [PERSON] proposed the U-shaped diffusion theory of cement grouting in a single plate fracture with flowing water [7]. [PERSON] compared the diffusion law of chemical grouting under static water and flowing water and found that the diffusion shape of grout is nearly round under static water conditions [8].  
The goal of grouting is to seal the fracture and block water, and it can be used to improve the shear strength of rock joints [9]. [PERSON] discussed the grouting effects of rock masses by situ experiments and determined that grouting can improve the deformability of rock mass [10]. Chemical grouting was simulated in a model of an indoor coal mine shaft by [PERSON] [11], and grout propagation in soils was determined. [PERSON] investigated the changes in seepage pressure and the grout diffusion law in a plate fracture with flowing water, and determined the relationships among the water flow velocity, gel time, aperture width, and sealing effect of grout [12]. [PERSON] investigated the sealing effect of chemical grouting in an inclined fracture with water and sand, the results showed that grouting plays an important role in controlling the sand and water [13]. In addition, grouting pressure plays an important role in grouting and is a crucial factor for grouting results [14].  
However, the natural fracture surfaces are rough in actual grouting projects. The roughness is one of the basic characteristics of rock masses. The concept of the roughness coefficient of structural surfaces was presented by [PERSON] [15], and the roughness of fractures was divided into 10 grades by [PERSON] [16] according to the degree of fluctuation, where the joint roughness coefficient (\(JRC\)) values were from 0 to 20. Therefore, enhancing research on grouting in rough fractures is necessary. This paper investigated chemical grouting in rough fractures with flowing water, which has a good correlation between theory and actual engineering.