## 1 Introduction  
There are many regions in the world with abundant precipitation. For example, Yunnan Province has a daily precipitation exceeding 25 mm for about 20 days in a year, and 10 days is the maximum number of days of continuous precipitation per year. It has been found that a large amount of continuous precipitation and frequent flooding disasters generally lead to the rapid increasing in the water content in the concrete used in the construction of the foundations of common buildings found in local villages, approaching saturation at about 4 days or less. Moreover, the mechanical properties, such as the compressive strength of concrete under static loading, deteriorate with the increase in the water content [1; 2]. Therefore, it is necessary to consider the effect of the water content on the mechanical property evolution of concrete foundations [3]. Moreover, the low strength of concrete in village buildings and the large-scale manual mixing are subject to high dispersion in terms of mechanical properties, and further research is needed on the damage mechanisms and overall reliability of village building foundations in rain-fed areas. Furthermore, this will be beneficial for the structural design and maintenance of village buildings in areas with abundant precipitation. A large number of researchers have carried out experimental studies on the mechanical properties of immersed concrete. [PERSON] et al. [4] investigated the evolution of the water content in concrete specimens in terms of the immersion times and the concrete strength experimentally and analyzed the effect of the water content on the compressive strength of concrete. [PERSON] et al. [5] analyzed the effect of different immersion times on the strength of concrete foundation pile core samples by studying the mechanical properties of concrete foundation piles in a humid environment. [PERSON] et al. [6] observed the effect of moisture on the mechanical properties of bricks, mortar, and masonry. [PERSON] et al. [7] found that, with the increase in the pore water saturation in fly ash concrete, the compressive strength decreased, but the ultrasonic velocity and elastic modulus increased. Furthermore, some scholars have conducted research on the modeling theory and method for the mechanical properties of immersed concrete. The representative contributions are as follows: [PERSON] et al. [8] quantifiably observed the effect of the porosity on the effective volume and shear modulus of saturated concrete by utilizing a three-phase spherical model and a hollow cylindrical rod model. [PERSON] et al. [9] investigated the dynamic response of concrete structures affected by the strain rate dependence of concrete material, which is related to the water content and microporous structure. [PERSON] et al. [10] developed a strength-porosity-saturation model based on the strength-porosity model of Ryshkewithh, by considering the effect of the water content and porosity on the compressive strength. [PERSON] et al. [11] adapted the Hsieh-Ting-Chen four-parameter damage criterion to develop a damage model for concrete based on a simplified uniaxial damage evolution equation. [PERSON] et al. [12] proposed a uniaxial tensile statistical damage model for saturated concrete considering the dynamic strain rate effect and the \"effective stress principle\" of [PERSON]. [PERSON] et al. [13] established an elastoplastic damage model for saturated concrete under uniaxial compression based on damage mechanics. However, there are few studies in the literature that have reported on experimental investigations of the random mechanical properties of wet concrete under compression considering different immersion times (i.e., water contents or saturation degrees) [4; 5; 6; 7] or stochastic constitutive models of wet concrete [8; 9; 10; 11; 12; 13] considering both immersion and damage effects.