## 4 Results and Discussion
### Effect of Different Initial Brine Temperatures on Freezing Effect  
This section examines the effect of initial brine temperature on the freezing effect by simulation. Four sets of controlled simulation experiments with experimental conditions are shown in Table 4.  
The simulated results are presented in Figure 6.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Time (Days)** & **0** & **1** & **5** & **10** & **15** & **20** & **30** & **40** \\ \hline Case \(1\) & \(10\) & \(2\) & \(-16\) & \(-23\) & \(-25\) & \(-27\) & \(-29\) & \(-30\) \\ temperature (\({}^{\circ}\)C) & \(0\) & \(-6\) & \(-20\) & \(-25\) & \(-26\) & \(-28\) & \(-30\) & \(-30\) \\ \hline Case \(3\) & \(-10\) & \(-14\) & \(-24\) & \(-27\) & \(-28\) & \(-30\) & \(-30\) & \(-30\) \\ temperature (\({}^{\circ}\)C) & \(-20\) & \(-22\) & \(-26\) & \(-28\) & \(-29\) & \(-30\) & \(-30\) & \(-30\) \\ \hline \hline \end{tabular}
\end{table}
Table 4: Cooling schedule for different initial temperatures.  
Figure 5: Comparison of test results and simulated temperature at the observation points. (**a**) Comparison on C5; (**b**) comparison on C7.  
It can be seen from Figure 6 that the different starting brine temperatures led to variability in temperature development at the beginning of freezing. However, the effect of the different initial temperatures on the final freezing effect of the soil layer was not significant. The reasons for the different initial temperatures of the soils are described below. In order to meet different engineering needs, it is often necessary to mix different levels of cement slurry into the soil to strengthen and improve the local soil, and the initial temperature of the soil may be too high due to the effect of the heat of hydration. Alternatively, the initial ground temperature is affected by the ambient temperature differently due to seasonal variations during the construction. The initial freezing temperature will only affect the freezing effect at the early stage of freezing, but the freezing temperature field development change pattern will not change and will exhibit a minor effect on the final freezing effect in the frozen area [11; 12; 13].  
The temperature development at the observed cross-section for different cases is shown in Figure 7.  
Figure 6: Temperature development at the observation point during freezing at different initial temperatures.  
Figure 7: \(Cont.\)  
In Figure 7, it can be seen that due to the different starting brine temperatures, the variability of temperature development at the beginning of freezing at the observation points was large, but the effect of different initial temperatures on the final freezing effect of the soil layer was not significant. The difference in freezing effect caused by the difference in the starting brine temperature of the soil mainly occurred before the soil froze to \(0\,^{\circ}\)C. In an actual project, during the construction of the building, the local soil needs to be reinforced and improved by mixing different degrees of cement slurry into the soil to meet the different engineering needs. The initial temperature of the soil during freezing is influenced by the heat of the hydration of the cement, and its initial ground temperature varies from the ambient temperature due to seasonal variations during the construction. Different initial temperatures affect the development of the freezing process at the beginning of active  
Figure 7: Temperature distribution clouds on each cross-section under different working conditions.  
freezing, but the freezing temperature field development change pattern does not change and exhibits a negligible effect on the final freezing effect of the frozen zone.