# Study on the Influence of Moisture Content and Void Ratio on the Disintegration of Red Clay
## 4 The Influence of Moisture Content and Void Ratio on Disintegration
### Combined Water Saturation under Natural Conditions  
According to the literature [47], there is a cutoff point on the transverse relaxation time T\({}_{2}\) distribution curve. When the transverse relaxation time of the pore fluid is greater than the cutoff point, the fluid can flow freely; otherwise, it is combined fluid. Therefore, the content of combined water or free water in the soil can be determined by the cutoff point on the transverse relaxation time T\({}_{2}\) distribution curve. The method of empirical judgment to define the T\({}_{2}\) value at the midpoint between the highest and lowest points on the T\({}_{2}\) distribution curve as the cutoff point is known as the 'half point' method. When  
Figure 5: Free induction decay curves of natural-state red clay.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{3}{*}{
\begin{tabular}{c} **Moisture** \\ **Content** \\ **(\%)** \\ \end{tabular} } & \multirow{3}{*}{**Void**} & \multicolumn{3}{c}{**The Main Peak**} & \multicolumn{3}{c}{**The Secondary Peak**} \\ \cline{3-10}  & & & **Starting** & **End T\({}_{2}\)** & **Peak T\({}_{2}\)** & **Peak T\({}_{2}\)** & **Peak T\({}_{2}\)** & **Peak T\({}_{2}\)** \\  & & **T\({}_{2}\) Value** & **Value** & **Value** & **Area** & **T\({}_{2}\) Value** & **Value** & **Value** & **Area** \\  & & **(ms)** & **(ms)** & **(ms)** & **(ms)** & **(ms)** & **(ms)** & **(ms)** & **Area** \\ \hline
24 & 1.00 & 0.00594 & 1.8679 & 610.9146 & 697.08 & & & & \\
24 & 1.10 & 0.00594 & 1.8679 & 581.0081 & 657.19 & 136.6716 & 10,000 & 0.0098 & 57.13 \\
24 & 1.15 & 0.00594 & 1.8679 & 581.8194 & 649.91 & & & & \\
26 & 1.00 & 0.00594 & 1.8679 & 672.6039 & 791.97 & 5231.0993 & 10,000 & 0.1289 & 401.70 \\
26 & 1.10 & 0.00594 & 1.8679 & 644.4348 & 759.32 & 3489.1012 & 10,000 & 0.2814 & 1169.2 \\
26 & 1.15 & 0.00594 & 1.8679 & 626.7187 & 735.24 & 3783.4626 & 10,000 & 0.2718 & 1090.8 \\
28 & 1.00 & 0.00594 & 2.0255 & 726.4200 & 893.58 & 3783.4626 & 10,000 & 0.0330 & 133.48 \\
28 & 1.10 & 0.00594 & 2.0255 & 708.3817 & 866.21 & & & & \\
28 & 1.15 & 0.00594 & 2.0255 & 688.3959 & 841.59 & 2146.1412 & 10,000 & 0.1508 & 732.52 \\
30 & 1.00 & 0.00594 & 2.1964 & 799.4056 & 1041.81 & 91.1589 & 690.5514 & 0.3447 & 110.94 \\
30 & 1.10 & 0.00594 & 2.1964 & 755.6883 & 988.44 & 51.7092 & 283.3096 & 0.8112 & 110.32 \\
30 & 1.15 & 0.00594 & 2.1964 & 742.1578 & 956.70 & 43.9760 & 261.2675 & 0.7209 & 87.63 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Summary of peak information of T\({}_{2}\) spectrum curves for natural samples.  
the transverse relaxation time of the main peak is less than 10 ms, the T\({}_{2}\) cutoff point can be taken near the 'right half point' of the main peak; when the main peak is greater than 10 ms, the T\({}_{2}\) cutoff point can be taken near the 'left half point' of the main peak. Since the transverse relaxation time of Guilin red clay is all less than 10 ms, the 'right half point' method was taken to find the cutoff point.  
According to Table 4 and the calculation results of combined water saturation, it is found that when the void ratio is constant, the combined water saturation increases with the increase of moisture content. When the moisture content is constant, the combined water saturation decreases with the increase of void ratio. Through the fitting display of origin8.0, it is found that the combined water saturation, initial moisture content, and void ratio has a high correlation. The adjusted R\({}^{2}\) is 0.9929, indicating a good fitting effect. The fitting equation is:  
\[S_{r}^{\prime}=0.04963\cdot\omega-0.253\cdot e-0.313 \tag{6}\]  
\(S_{r}^{\prime}\) represents the combined water saturation degree (%);  
\(\omega\) is the initial moisture content of the soil (%);  
\(e\) is the void ratio of the soil.