## 3 Results and Discussion
### Bearing and Deformation Characteristics of Gangue Slurry
#### 3.1.2 Change Law of Compressive Bleeding Rate  
(1) Instantaneous loading  
The bleeding rate of the gangue slurry after static and instantaneous loading can be calculated by Equation (3), as shown in Figure 9. Figure 10 shows the compressive bleeding rate stress change curve of the gangue slurry during the instantaneous loading process. Figure 8: Strain–time curve of gangue slurry with different fluidities under the creep compression test: (**a**) \(x=1\), (**b**) \(x=2\), (**c**) \(x=3\), (**d**) \(x=4\). As shown in Figure 9, the static bleeding rate and compressive bleeding rate of the gangue slurry are positively correlated with fluidity. The bleeding rate of the slurry is low in a static state, only 3.37-9.00%. The moisture in the slurry can maintain its good conveying performance. The bleeding rate of the slurry after loading increases significantly, reaching 59.89-72.07%. Specifically, I1-I5 slurries increase by 56.52%, 59.63%, 58.54%, 50.77%, and 72.07%, respectively. When the stress reaches 20 Mpa, the water content in the slurry is less than 45%, and the water remaining in the slurry and gangue particles form a high solid-water ratio compacted body, which plays a bearing role under the loading of overburden. As shown in Figure 10, during the instantaneous loading process, the compressive bleeding rate of the gangue slurry with different fluidities is approximately an exponential function of stress, and there is a bleeding threshold. In addition, the bleeding threshold is negatively correlated with the fluidity. The entire process of compressive bleeding rate of slurries under the loading changes with strain, which can be divided into three stages:  
1. Supersaturated drainage stage (0-4 Mpa): the compressive bleeding rate increases rapidly with the increase of stress, and in the early stage of loading, the compressive bleeding rates of slurries with different fluidities vary slightly, but still increase with the increase of fluidity. Before loading, the slurry is in a supersaturated state, with most of the water being free water. After being compressed in an unsealed space, water is quickly discharged through a drainage pipeline and the slurry does not have a bearing effect. At this stage, the slurry is mainly pressurized by pore water, and its bearing performance is poor. Figure 10: Bleeding curve of slurry under the instantaneous loading. Figure 9: Bleeding rate curve of slurry. 2. Compressive bleeding stage (4-12 Mpa): the compressive bleeding rate increases with the increase of stress decreases. This mainly affects the difference in the final bleeding rate between slurries with different fluidities. The smaller the fluidity, the earlier it enters this stage. After the first stage of loading, all the supersaturated water in the slurry has been discharged, and the remaining water mainly exists in the form of pore water. Under the loading, a water film is formed on the surface of the gangue particles, promoting the sliding and backfilling of the gangue. As the stress continues to increase, the pores in the slurry decrease, and pore water is secreted under loading. The gangue particles of slurry gradually play a dominant bearing role. 3. No bleeding stage (12-20 Mpa): the bleeding rate-stress curve in this stage is almost parallel, and the proportion of the compressive bleeding rate with increasing stress is almost zero. It indicates that there is no more water bleeding. After the first two stages of loading, the content of pores and pore water tends to be constant, and the slurry essentially transforms into a compacted state with a stable ratio of solid to water. Afterward, the gangue particles undergo fragmentation under the continuously increasing stress, and the elastic-plastic structure of the slurry changes, mainly affecting the mechanical properties of the compacted body after the loading. 2. Creep loading Figure 11 shows the compressive bleeding rate of gangue slurry with different fluidities under creep loading conditions. 1.