## 1 Introduction  
In the field of geological and geotechnical engineering, the stability of soft rock has consistently been a focus of research due to its complex mineral composition, including kaolinite and montmorillonite; the minerals undergo dissolution, hydrolysis, ion exchange, and redox reactions upon water exposure, altering the rock's microstructure [1]. Shallow groundwater, a vital component of subsurface spaces, experiences temperature variations from external environmental changes, typically ranging from 0 \({}^{\circ}\)C to 40 \({}^{\circ}\)C [2]. Water temperature changes not only impact the rock's thermodynamic state but also potentially modify the internal moisture distribution, mineral composition, and chemical reaction rates, subsequently affecting both the microstructure and macroscopic mechanical properties of the rock. With global climate change contributing to more frequent extreme weather events, temperature fluctuations in shallow groundwater increasingly threaten the operational safety of underground constructions like tunnels, subways, and underground storage. Especially in clay mineral-rich soft rock formations, these temperature variationsmay intensify hydrolysis and ion exchange reactions, weakening rock strength and altering deformation characteristics, potentially leading to mining collapses and landslides (Figure 1). Understanding the impact of water temperature on the mechanical properties of argillaceous siltstone is crucial for predicting and controlling the stability of argillaceous siltstone in practical engineering applications. In industrial fields such as oil and gas extraction and geothermal energy development, knowing the effects of water temperature on rock properties can optimize extraction techniques, reduce resource waste, and improve energy efficiency. This study aims to systematically analyze the effects of shallow groundwater temperature changes on the mechanical properties and microchemical interactions of argillaceous siltstone through experimental testing and theoretical analysis. It is essential not only for revealing the mechanical behavior of argillaceous siltstone under complex environmental conditions but also for ensuring the long-term stability and safety of underground engineering. This research can provide new data and theoretical support for geology, materials science, and environmental science, allowing for a deeper understanding of the reaction mechanisms and evolution processes of argillaceous siltstone under different temperature conditions. There have been extensive scientific investigations into the effects of temperature on rock mechanics. [PERSON] et al. conducted mechanical tests on gypsum rock in a high-temperature saline solution, revealing that the rock strength decreases and damage intensifies with an increase in temperature [3]. [PERSON] et al. discovered that the peak strength and elastic modulus of fully saturated argillaceous siltstone increase with water temperature [4]. [PERSON] et al., using uniaxial compression tests and scanning electron microscopy (SEM), found that rock strength increases with temperature between 30 \({}^{\circ}\)C and 50 \({}^{\circ}\)C but slightly declines at higher temperatures, though with minimal variation [5]. [PERSON] et al., Using a custom-designed thermostatic water tank within the electrohydraulic servo-controlled testing system (MTS816), a series of uniaxial compression tests were conducted on sandstone samples immersed at varying temperatures (25 to 95 \({}^{\circ}\)C). The study systematically analyzed the water absorption characteristics and the effects of water and temperature on the uniaxial compressive strength (UCS) of the samples. The results revealed that the hydration effect of sandstone is highly sensitive to water temperature. When the water temperature increased from 25 \({}^{\circ}\)C to 95 \({}^{\circ}\)C, the UCS and elastic modulus of the saturated sandstone increased linearly by 21.3 MPa and 20.2%, respectively [6].