## 1 Introduction
[10] studied the post-peak mechanical behavior of sandstone under water-pressure coupling, observing that peak strength and residual strength decreased as water pressure increased, and established a predictive model for the post-peak strength of sandstone under different water pressures. [PERSON] et al. [11] investigated the effects of water content on the mechanical properties and fracture behavior of three different types of shale, finding that higher water content led to lower strength and greater susceptibility to fracture. These studies demonstrate that higher water content and larger grain sizes both contribute to a reduction in rock strength and an exacerbation of its damage, while an increase in water pressure further decreases both peak strength and residual strength. Regarding the combined effects of temperature and water on rocks, [PERSON] et al. [12] conducted temperature-water coupling experiments on sandstone with varying internal ring diameters, discussing the influence of temperature and water on sandstone damage and degradation. However, they did not consider the effects of different temperatures, and the experimental conditions differed from real construction environments. [PERSON] et al. [13] subjected granite to thermal-liquid coupling treatments and used uniaxial compression tests to examine the physical and mechanical damage caused by thermal-liquid-mechanical coupling. [PERSON] et al. [14] conducted water-rock interaction tests on heat-treated granite under high temperatures and pressures, observing that thermal expansion initially increased permeability, which later decreased. [PERSON] et al. [15], focusing on deep geothermal energy exploitation, used Hopkinson bar tests to conduct dynamic tests under thermal-water-mechanical conditions, establishing a damage model based on deformation characteristics and revealing the dynamic damage failure patterns of rocks. [PERSON] et al. [16] analyzed the effects of temperature-water coupling on coal samples, finding that as the temperature increased, the coal's energy storage capacity initially decreased and then increased. These studies demonstrate that the combined effect of temperature and water intensifies rock damage, affects its energy storage capacity, and causes changes in permeability due to thermal expansion. It is evident that a wide range of scholars have conducted relevant research concerning the evolution of rock damage, destruction patterns, and theoretical analyses under the combined effects of temperature and water, achieving fruitful results. However, in current international and domestic transportation tunnel construction, the high ground temperatures encountered are generally below 100 \({}^{\circ}\)C. The Seikan Tunnel, which crosses the seabed, faces a construction environment with high temperatures (up to 55 \({}^{\circ}\)C), high pressure, and high water content. Similarly, the Gotthard Base Tunnel also encounters high temperatures (up to 46 \({}^{\circ}\)C) and humid conditions during its construction. In the construction of the Sang Zhuling Tunnel, temperatures can reach 89 \({}^{\circ}\)C, while the temperatures in the tunnels of the Andes Mountains approach 100 \({}^{\circ}\)C. However, there are few reports on the damage evolution and destruction patterns of sandstone with different water contents below 100 \({}^{\circ}\)C. This study conducts uniaxial compression tests on sandstones with different soaking times (varying water contents) and temperatures (below 100 \({}^{\circ}\)C) to investigate the alterations in sandstone mechanical properties influenced by temperature and water, analyze the damage and destruction characteristics of the sandstones, and establish a damage equation based on dissipated energy, thereby facilitating the examination of damage and destruction patterns of sandstone under the interactions of temperature and water.