# Strength Prediction Model for Cohesive Soil-Rock Mixture with Rock Content
## 5 Conclusions  
In this study, cohesive SRM samples were prepared using high-strength matrix as the soil matrix and high-calcium limestone as the block material. Given the excellent water absorption properties of bentonite, it is essential to allow adequate time for bentonite to fully absorb water and expand, thereby forming a suspended and gelled state that optimally utilizes its properties. The curing time for the matrix varied depending on the W/B ratio.  
(1) The shear strength and modulus of elasticity of the cohesive SRM samples increased with increasing P\({}_{\rm BV}\). P\({}_{\rm BV}\) significantly influenced the shear damage characteristics of the cohesive SRM, and the shear behaviors of the cohesive SRM with low P\({}_{\rm BV}\) were similar to those of its matrix soil. When P\({}_{\rm BV}\) reached a high level, the shear damage of the cohesive SRM exhibited pronounced softening characteristics, accompanied by a significant shear expansion phenomenon.  
(2) A numerical model of the cohesive SRM was established using PFC\({}^{\rm 3D}\) to further analyze the effects of P\({}_{\rm BV}\) and \(\alpha\) on its macroscopic mechanical properties. The results showed that the strength of the samples first decreased and then increased as \(\alpha\) increased from 0\({}^{\circ}\) to 90\({}^{\circ}\) at a fixed P\({}_{\rm BV}\). When P\({}_{\rm BV}\) was low, the blocks uniformly distributed within the cohesive SRM could bear the external loads, thereby enhancing the rock's resistance to damage. When P\({}_{\rm BV}\) was too high, it led to an increase in the contact between the blocks, resulting in a relatively weakened bonding effect of the cohesive SRM. In this case, the rock  
Figure 14: Relationship curve between P\({}_{\rm BV}\) and shear strength.  
was prone to stress concentrations which occurred in the block contact area, which reduced the overall strength.  
(3) The relationship between the \(P_{\text{BV}}\) and shear strength of the cohesive SRM can be described by the equation \(\tau=A+\frac{\tau_{0}-A}{1+\left(\frac{P_{\text{BV}}}{2\pi}\right)^{2}}\). This formula facilitates the strength prediction for the cohesive SRM with different \(P_{\text{BV}}\) values.  
The limitation of this work only concerns the relationship between the shear strength of the cohesive SRM and the amount of stone content, and it is difficult to study the relationship between the shear strength of the SRM and the block inclination due to the difficulty of controlling the block inclination of the cohesive SRM in the experiments. Future efforts will be devoted to the further study of block inclination.  
Conceptualization, Y.S. and J.X.; Methodology, Y.S. and H.D.; Validation, Y.S. and J.X.; Investigation, H.D.; Visualization, Y.S., J.X. and J.H., J.Y. and Y.H.; Supervision, J.H. and H.D. All authors have read and agreed to the published version of the manuscript.  
This research was supported by the Science and Technology Project Fund of Jiangxi Provincial Department of Transportation (2022Z0001 and 2022Z0002).  
Not applicable.  
Data Availability Statement: Data is not available due to privacy and ethical restrictions.  
Authors [PERSON] and [PERSON] were employed by the company Jiangxi Transportation Research Institute Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The authors declare no conflicts of interest.