# Experimental Investigation of Mechanical Properties of Clay-Cement Slurry Containing Graphene Oxide
## 3 Results
### Performance Analysis of Grouting Reinforcement
#### 3.1.2 Shear Strength  
The shear strength of the grouted medium is a crucial parameter for evaluating the effectiveness of grouting reinforcement and analyzing the stability of the reinforced strata. This study conducted direct shear tests on specimens with different proportions to determine their shear strength under various ratios. The relationship between GO and OPC addition and the shear strength of the grouting reinforcement body was plotted and is depicted in Figure 5. Based on the shear strength data, an analysis was conducted to investigate the variations in shear strength of the grouted medium and the influence of adding graphene oxide (GO). The findings from Figure 6 indicate that the addition of GO has a substantial impact on the shear strength of the grouted medium. Generally, the shear strength of the specimen increases with an increase in GO addition. For example, considering an OPC addition of 5%, when the GO addition rate remains within 0.03%, there is a more substantial improvement in the shear strength of the grouted medium, reaching 59%. However, when the GO addition rate surpasses 0.03%, the increment in shear strength diminishes to 44.3%. This suggests that the GO addition rate exhibits a turning point in the growth rate of shear strength near 0.03%, which is consistent with the impact of slurry viscosity on compressive strength.  
Figure 5: Effect of GO and OPC content on shear strength of the specimens (water glass of 10 mL/L).  
Figure 6: Effect of GO dosage on time dependence of plastic strength (OPC of 150 g/L, water glass of 10 mL/L) [30].  
In traditional clay-cement slurries, cement hydration generates cement particles with a positive charge. During the process, the cement particles experience a partial charge exchange with clay particles, resulting in the adsorption of clay particles onto the surface of cement particles. This phenomenon leads to agglomeration and the formation of a cohesive gel-like structure under alkaline conditions, which exhibits a certain level of strength. Studies have shown that incorporating graphene oxide into clay-cement slurries has a nucleation effect, promoting cement hydration reactions, and generating more calcium silicate hydrate (C-S-H) within the capillary pores. This facilitates the transfer of additional cement hydration products within the micropores and capillaries. [PERSON] [36] compared X-ray diffraction (XRD) spectra of different amounts of graphene oxide (GO) and observed similar peak shapes without distinct absorption peaks. This implies that the addition of GO does not alter the types of cement hydration products. However, as the amount of graphene oxide (GO) increased, the intensity of the absorption peaks gradually increased. This observation indicates that GO promotes the formation of cement hydration products and enhances the strength of the specimens.  
During the grouting process, an increase in the addition of graphene oxide (GO) results in a larger volume of clay-cement particle aggregates. This leads to an increase in the thickness of the slurry vein and enhances its compaction effect on the surrounding soil mass. As a result, the compactness of the soil mass improves, which enhances the friction, embedding, and interlocking effects between the soil particles. Ultimately, this improvement in the interparticle interactions leads to an enhancement in the shear strength of the grouted medium. Additionally, GO can transfer more cement hydration products into microcapillary pores and act as a crack bridge within the material's microcracks, thereby improving its shear resistance [37].