## 3 Results
### Shear Strength Parameters  
Cohesion and internal friction angle are two essential shear strength parameters. Figure 6 plots the effects of the content of CLI and curing time on cohesion and internal friction angle. Both parameters were obtained by using the least squares fitting method to fit the major and minor principal stresses. As shown in Figure 6a, for the samples after the same curing time, the cohesion generally increased with the increase in the content of CLI from 0 to 8%, while the cohesion showed a strong decreasing trend for the content of CLI increasing from 8% to 12%. This indicates that soil particles were cemented with CLI, and the pores in the soil were clogged, forming a more stable structure. When the content of CLI increased beyond the optimum value, the excessive aggregates formed with CLI and soil particles induced some large pores forming in the soil. The curing time contributed marginally to the cohesion of non-modified samples: the cohesion increased by 1.11 kPa as  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Confining Pressure (kPa)**} & \multirow{2}{*}{**Curing Period (Day)**} & \multicolumn{4}{c}{**Peak Deviatoric Stress (kPa)**} \\ \cline{3-6}  & & **0\%** & **4\%** & **8\%** & **12\%** \\ \hline \multirow{4}{*}{100} & 1 & 436.25 & 511.89 & 969.43 & 568.37 \\  & 3 & 462.22 & 588.37 & 1159.71 & 905.82 \\  & 7 & 532.38 & 658.66 & 1294.08 & 1111.63 \\  & 14 & 551.66 & 708.78 & 1321.26 & 1128.24 \\ \hline \multirow{4}{*}{200} & 1 & 625.73 & 704.65 & 1292.26 & 1126.90 \\  & 3 & 621.36 & 759.06 & 1402.02 & 1172.51 \\  & 7 & 678.27 & 836.29 & 1578.68 & 1378.64 \\  & 14 & 703.57 & 1048.52 & 1770.43 & 1460.54 \\ \hline \multirow{4}{*}{300} & 1 & 682.43 & 821.99 & 1463.42 & 887.69 \\  & 3 & 781.92 & 912.32 & 1622.21 & 1021.21 \\ \cline{1-1}  & 7 & 812.43 & 1018.81 & 1824.41 & 1251.76 \\ \cline{1-1}  & 14 & 824.73 & 1165.35 & 1956.54 & 1324.65 \\ \hline \hline \end{tabular}
\end{table}
Table 1: The peak deviatoric stress of specimens for various curing periods and confining pressures.  
the curing time increased from 1 day to 14 days. The CLI-treated soils increased by 6.48 kPa, 5.55 kPa, and 5.88 kPa with contents of 4%, 8%, and 12% with an increase in the curing time from 1 day to 14 days. The results show that the improvement in cohesion was more significant before 7 days, and the enhancement of cohesion was marginal after 7 days.  
Figure 6b reveals that the trend of the internal friction angle with the content of CLI and curing time was similar to that of cohesion. As shown in Figure 6b, the internal friction angle increased first and decreased with the content of CLI. When the content of CLI was 8%, the internal friction angle reached the peak value, which was about 2 times that of the non-modified samples after different curing times (1, 3, 7, 14 days). For the non-modified samples, the effect of curing time on the internal friction angle was marginal. It increased by 0.36-1.11\({}^{\circ}\) as the curing time increased from 1 day to 14 days. Moreover, with the increase in the curing time, the effect of different contents of CLI on the internal friction angle was more significant. It can be seen that the internal friction angle of the samples after curing for 14 days was enhanced compared to that of the samples cured for 1 day by about 49.16% (content of CLI = 4%), 24.74% (content of CLI = 8%), and 31.24% (content of CLI = 12%), respectively.