# The Effect of the Water Table on the Bearing Capacity of a Shallow Foundation
## 1 Introduction
[27] performed a series of model footing load and cone penetration tests using a hydraulic control room system, considering different groundwater levels and soil conditions. The bearing capacity of the footings decreased as the water table increased and was most pronounced at a water table depth equal to the footing width (1.0 B). The bearing capacity of loose soil with lower relative density decreases more with the groundwater level. In most of the above studies, few scholars have studied the critical burial depth of building foundations from the perspective of safety impact depth and capillary water level rise to reduce the impact of water table rise in immersion areas on the bearing capacity of shallow foundations. In the process of reservoir survey and design, it is very important to evaluate and analyze the immersion problem. Currently, most engineering circles use the capillary rise height and the foundation depth as the standard for the critical depth of building immersion [28; 29; 30]. Since the influence of the rising groundwater level on the physical and mechanical properties of the foundation soil layer has not been fully considered, the evaluation of building flooding problems according to this standard is not perfect, and sometimes there are certain risks. In this paper, natural and saturated soil samples with an area of S = 30 cm\({}^{2}\) and a height of H = 2 cm were prepared in the laboratory by taking the low liquid limit clay in the immersion zone with a ring knife and the mechanical properties of compression and consolidation were tested [31; 32; 33]. The influence of saturation on the strength and deformation index of low liquid limit clay was analyzed. Based on the experimental research, the influence mechanism of immersion on the bearing capacity of the shallow buried foundation is analyzed, and the method for determining the critical burial depth of immersion groundwater in the reservoir is obtained. Taking the typical building foundation of Luohuang Town in the immersion area of Xiaonanhai Reservoir as an example, the influence of foundation width and burial depth on the safety limit depth was studied, and the final critical burial depth of the shallow foundation was determined. The research technology roadmap is as Figure 1:  
1. research background and purpose
2. research status
3. research contents and methods  
Study on basic physical and mechanical properties of soil in immersion area  
Study on influence of immersion on bearing capacity of shallow foundation  
1. Summarize test results
2. Analyze existing problems
3. Propose further research directions  
**2. Physical and Mechanical Properties Tests**  
2.1. Physical Properties of Soil  
According to the geotechnical structure characteristics of Luohuang Town, the soil mass in Luohuang Town is mainly composed of low liquid limit clay and sand gravel. Two shallow pits were designed in Luohuang Town, and two blocks were sampled along with the depth of each pit. The soil sample numbers in Luohuang Town were LTC1\(-\)1, LTC1\(-\)2, LTC2\(-\)3, and LTC2\(-\)4. The sampling depth of LTC1\(-\)1 and LTC1\(-\)2 is 2 m, and the sampling depth of LTC1\(-\)3 and LTC1\(-\)4 is 2.5 m. According to field sampling and analysis, the soil layer affected by immersion is mainly a clay layer with a low liquid limit, and the physical properties are shown in Table 1.  
Low liquid limit clay, the particles are mainly powder, the powder content was generally more than 60%, and clay content was less than 20%. The natural density was 1.69 g/cm\({}^{3}\)-2.01 g/cm\({}^{3}\), the average was 1.83 g/cm\({}^{3}\), the void ratio was 0.682\(-\)0.847, moisture content was 15.8\(-\)27.9%, and the converted saturated density is 1.91 g/cm\({}^{3}\)-2.01 g/cm\({}^{3}\), the average value was 1.94 g/cm\({}^{3}\), the liquid limit was 27.6\(-\)31.1%, the liquid index