## 7 Conclusions  
This study focused on argillaceous siltstone, conducting uniaxial failure tests and microscopic chemical experiments under varying water temperatures. The research investigated the damage to argillaceous siltstone and changes in cation concentration in the solution at different water temperatures. Based on these findings, a damage constitutive model for argillaceous siltstone under varying water temperatures was established, and the evolution of its damage variable was analyzed. The results obtained are as follows:  
(1) With increasing water temperature, the peak strength and elastic modulus of argillaceous siltstone exhibit a \"concave\" trend, initially decreasing and then increasing, while the cation concentration in the solution shows a \"convex\" trend, first rising and then falling. The flocculent structures within the mesoscopic interior of the argillaceous siltstone initially increase and then decrease. Integrating both microscopic and mesoscopic studies, it is evident that the chemical interactions between water and rock are highly significant under water temperatures ranging from 5 \({}^{\circ}\)C to 25 \({}^{\circ}\)C, while these interactions gradually weaken at temperatures between 25 \({}^{\circ}\)C and 35 \({}^{\circ}\)C.  
(2) Based on the constructed temperature-stress coupling damage variable, and taking into account factors such as the initial compaction stage and damage threshold, a uniaxial compression damage constitutive model for argillaceous siltstone under different water temperatures was established. The Weibull parameters within this model partially reflect the strength and plasticity characteristics of argillaceous siltstone, and the theoretical results are largely consistent with laboratory findings. (3) With the increase in water temperature, the variation trends of damage variables \(D_{1}\) and \(D_{12}\) are generally consistent. Overall, damage variable \(D_{1}\) first increases and then decreases with the rise in water temperature. In the initial soaking period (1-3 days), the impact of water temperature on damage variable \(D_{1}\) is not significant. However, as the soaking duration increases, this effect becomes more pronounced. Conversely, the variation of damage variable \(D_{12}\) is opposite to that of \(D_{1}\). Damage variable \(D_{3}\) indicates the degree of degradation of argillaceous siltstone after soaking. As the soaking duration increases, damage variable \(D_{3}\) gradually decreases, indicating that the extent of degradation in argillaceous siltstone increases with longer soaking times. These findings have important implications for practical engineering applications, such as tunnel excavation and underground storage construction. By understanding the effect of temperature on the mechanical properties of argillaceous siltstone, engineering design and risk assessment can be better conducted. This research has achieved excellent results, but there are still the following shortcomings:  
In the stress-strain curves, when the argillaceous siltstone undergoes the failure stage, the change in its curve is not very ideal, resulting in poor fitting in the failure stage. In the future, the constitutive model can be improved by adding new parameters to achieve better fitting. This paper only analyzes the effects of different water temperatures on argillaceous siltstone. In the future, the effects of different water temperatures on clay-rich rocks can be analyzed. Conceptualization, N.L. and D.L. ; data curation, T.J.; formal analysis, N.L. and D.L. ; funding acquisition, N.L. ; investigation, T.J. and J.Z. ; methodology, T.J. and J.Z. ; resources, N.L. and D.L. ; validation, T.J.; writing--original draft, N.L. and T.J.; writing--review and editing, N.L., T.J., and J.Z. All authors have read and agreed to the published version of the manuscript.