## 3 Results and Discussion
### UCS of MSWCs after Uniaxial Cyclic Loading and Unloading  
The uniaxial compressive strength is an important indicator to evaluate the stability of the MSWCs. In order to study the UCS of MSWCs under different cyclic load damage effects, a uniaxial compression test with a loading rate of 0.5 mm/min was carried out. The stress-strain curves of different uniaxial cyclic loading and unloading damage and different proportions were measured. Figure 4: Test curves of uniaxial cyclic loading and unloading with different numbers of times. (**a**) \(n=25\). (**b**) \(n=50\). (**c**) \(n=100\). Figure 5: Stress–strain hysteresis loop curves generated at the beginning and end of uniaxial cyclic loading and unloading tests. According to Figure 6, it can be seen that the stress-strain curve of the MSWC shows four typical stages: (I) compaction stage. This stage shows a \"concave\" feature due to the internal pores and cracks of the MSWC specimen gradually closing under the action of uniaxial pressure; (II) elastic deformation stage. This stage is approximately linear. The stress of the MSWC specimen increases rapidly with strain; (III) plastic deformation stage. This stage shows a \"convex\" feature. In this stage, the internal cracks of the specimen develop rapidly, and the strain increases rapidly; (IV) post-peak stage. In this stage, the cracks further develop, and obvious cracks appear on the test surface, but it still has a certain bearing capacity. Figure 6: _Cont_. Figure 6 shows the uniaxial compressive strength of the MSWC after different numbers of uniaxial cyclic loading and unloading. Under different mudstone specific gravity conditions, the stress-strain curves of the MSWC show different characteristics. When \(n=0.2\) and \(n=0.4\), the stress-strain curves of MSWC show obvious brittle failure. Under an alkaline environment, the slag reacts faster than the mudstone, the cementitious products are generated faster, and the strength of the MSWC is higher. When \(n=0.6\) and \(n=0.8\), the plastic stage of the stress-strain curves of the MSWC occupies a higher proportion, and the specimen shows plastic failure. Due to the slow reaction rate of mudstone under alkaline conditions, the cementitious products are less, and the strength is lower. Therefore, with an increase of mudstone proportion, the uniaxial compressive strength of the MSWC decreases continuously, and the failure mode changes from brittle failure to plastic failure gradually. Figure 7 shows the uniaxial compressive strength of the MSWC under the same mudstone proportion and different numbers of uniaxial cyclic loading and unloading. With an increase of loading and unloading times, the strength of the MSWC specimens shows a trend of first increasing and then decreasing. When the number of uniaxial cyclic loading and unloading is small, the internal pores of the MSWC gradually close during the cycle,  
Figure 6: Effect of mudstone proportion (\(r\)) and number of uniaxial cyclic loading and unloading (\(n\)) on the axial stress–strain curve of MSWC. (**a**) \(r=0.2\). (**b**) \(r=0.4\). (**c**) \(r=0.6\). (**d**) \(r=0.8\). and the uniaxial compressive strength of the MSWC gradually increases; when the number of cycles exceeds 50 times, the MSWC generates new cracks inside due to the increase of uniaxial cyclic loading and unloading times, resulting in a gradual decrease in the MSWC's strength, and some obvious cracks are also generated on the surface. To explore the failure modes of MSWC under different mudstone proportions and numbers of uniaxial cyclic loading and unloading, Figure 8 was obtained.