# Study on Microstructure of Cemented Organic Soil in Dianchi Lake, China
## 2 Materials and Methods
### Methods  
The overall plan of this study is as follows. (1) Preparing cemented organic soil samples indoors. (2) Curing the samples. (3) Conducting UCS, SEM, EDS, and XRD tests on the samples after curing. (4) Analyzing test results and summarizing research conclusions.  
The test set the water content by mass (\(\omega\) = 24%), void ratio (e = 0.8), and water-cement ratio (c = 0.5) of the sample. According to the previous research results, the total content of HG in the peat soil of Dianchi Lake is between 7.15% and 50.06%. Among them, the HA content is between 2.36% and 28.13% [28]. The results provide the basis for incorporating HA reagents in the samples.. The HA content of the sample (\(\lambda\)) and the cement ratio (\(\beta\)) (check Formula (1)) are shown in Table 2. Considering the stability and reliability of  
Figure 4: HA molecular structure.  
Figure 5: X-ray diffraction pattern of original test soil.  
the testing effect, each test group planned to make four parallel samples, and a total of 560 samples were made for the research.  
The test was carried out according to the \"Standards for Geotechnical Test Methods\" (GB/T50123-2019) [23]. The sample preparation process can be described as follows. The original test soil is dried in the oven at 105 \({}^{\circ}\)C \(\pm\) 5 \({}^{\circ}\)C, then crushed into powder and passed through 2 mm sieves. The mass of soil particles, HA reagent, cement, and distilled water is calculated according to Formulas (1)-(3). In order to ensure the uniformity of the sample, the above materials are thoroughly mixed and divided into three parts and placed in a mold. The three-part mold with an inner diameter of d = 39.1 mm and a height of h = 80.0 mm was selected for this test. After the sample is made, it is sealed with a film for conservation. The temperature of the curing box is controlled at 20 \(\pm\) 3 \({}^{\circ}\)C for seven days, and it is soaked in distilled water after curing. In this test, six parallel samples were made for each ratio to ensure the accuracy of the test. The sample preparation process is shown in Figure 6.  
\[\beta=\frac{\mathrm{m_{s(ce)}}}{\mathrm{m_{s(HA)}+m_{s(soil)}}}\times 100\% \tag{1}\]  
\[\lambda=\frac{\mathrm{m_{s(HA)}}}{\mathrm{m_{s(HA)}+m_{s(soil)}}}\times 100\% \tag{2}\]  
\[\mathrm{m_{(w)}}=\left(\mathrm{m_{s(HA)}+m_{s(soil)}}\right)\times\omega+ \mathrm{m_{s(ce)}}\times c \tag{3}\]  
where \(\mathrm{m_{s(ce)}}\) is the mass of cement particles, \(\mathrm{m_{s(HA)}}\) is the mass of HA particles, \(\mathrm{m_{s(soil)}}\) is the mass of the original test soil, and \(\mathrm{m_{(W)}}\) is the mass of distilled water.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Tests**} & **Cement Ratio** & **HA Reagent** & **Imersion Age (d)** \\  & & \(\beta\) (\%) & **Content \(\lambda\) (\%)** & **Imersion Age (d)** \\ \hline \multirow{2}{*}{1} & \multirow{2}{*}{UCS} & 5, 10, 15, 17.5, 20, & \multirow{2}{*}{0, 10, 12.5, 15, 20} & \multirow{2}{*}{28} \\  & & 25, 30 & & \\ \hline
2 & SEM, EDS, XRD & 17.5 & 0, 15, 20 & \\ \hline \hline \end{tabular}
\end{table}
Table 2: Design of sample preparation.  
Figure 6: Sample preparation process.  
After the sample preparation is completed, it is subjected to UCS, SEM, EDS, and XRD tests. The UCS test apparatus is the YSH-2 lime-soil electromotive UCS instrument. The scanning electron microscope test uses a Czech TESCAN-VEGA3 automatic tungsten filament scanning electron microscope. The X-ray diffraction test uses Holland PANalytical X'Pert3 (Figure 6). Samples were taken from the interior of cemented soil to measure their microscopic morphology and conduct elemental analysis. After the cemented soil samples are ground, they are sieved with a geotextile. The measured samples' particle size is less than or equal to 45 \(\upmu\)m [29].