# Study on the Influence of Moisture Content and Void Ratio on the Disintegration of Red Clay
## 2 Red Clay Disintegration Test  
### Sample Preparation and Experimental Setup  
Red clay from the foundation pit of Guilin University of Technology's new teaching building (Yanshan Campus) was collected, air-dried, purified, dried, and crushed. It was sieved through a 0.2 mm standard sieve and stored for later use. According to the collected geotechnical investigation reports, the natural moisture content of red clay in the Guilin area ranges from 24% to 31%. Therefore, four different initial moisture contents were set at 24%, 26%, 28%, and 30%, respectively. To conduct the experiment, an appropriate amount of purified water was added to the dry red clay to achieve the desired moisture content. These soils were prepared with three different void ratios of 1.0, 1.1, and 1.15, and four different moisture contents. A total of 12 groups of red clay samples were prepared for the disintegration test. The soil samples were cylindrical in shape, with a diameter of 60 mm, a height of 106 mm, and a volume of 300.0 cm\({}^{3}\). The disintegration test apparatus was self-made and is shown in Figure 1. The sieve plate used to hold the soil sample was an 80 mm \(\times\) 80 mm corrosion-resistant metal grid with a mesh size of 10 mm \(\times\) 10 mm. A tensile tester was connected to a computer to record the residual mass of the soil sample after disintegration every second. To maintain a constant experimental temperature, a temperature controller was connected. The purified water used in the experiments was prepared by the YAZD-5 type electrothermal purified water sterilizer in the on-campus laboratory. The quality of purified water meets the third-level water standard specified by the People's Republic of China. The conductivity of purified water is \(\leq\)0.50 mS/m, the content of oxidizable substances is \(\leq\)0.4 mg/L, and the residue after evaporation is \(\leq\)2.0 mg/L.  
Once the preparation work was ready, the temperature controller probe was inserted into the middle of the water tank to test the temperature of the disintegration solution first. If the temperature of the disintegration solution was below 20 \({}^{\circ}\)C, the temperature compensation device would be automatically started. If the temperature of the disintegration solution was too high, the dissolution solution would be naturally cooled to the set value, and the temperature deviation controlled within \(\pm\)0.5 \({}^{\circ}\)C. The tensile tester was zeroed after being started, and the soil sample was placed on the sieve plate. The change in soil sample mass was recorded every second with an accuracy of 1 g, while the phenomenon of disintegration was observed.  
The disintegration rate and disintegration resistance index were calculated according to Formulas (1) and (2) respectively.  
\[v=\frac{A_{t}^{i}-A_{t}^{i+1}}{t_{i+1}-t_{i}} \tag{1}\]  
\[S_{I}=\frac{A_{t}^{max}}{A_{0}}\times 100\% \tag{2}\]  
\(v\) represents the disintegration rate (g/s) of the soil sample between \(t_{i}\) and \(t_{i+1}\);  
\(A_{t}^{i}\), \(A_{i+1_{i}}\) represent the mass (g) of the soil sample at time \(t_{i}\) and \(t_{i+1}\), respectively;  
\(t_{i}\), \(t_{i+1}\) represent the time (s) during the experiment;  
\(S_{I}\) represents the disintegration resistance index (%);  
\(A_{0}\), \(A_{t}^{max}\) represent the mass of the soil sample at the beginning and end of the disintegration process, respectively (g).