## 4 Results and Discussion
### Simulation of the Effects of Rainfall Intensity on Slope Stability
#### 4.5.3 Simulation Case of a Clay Loam Soil  
The last simulations were undertaken to verify the performance of the typical clay loam soil. The results of the simulation have also followed a similar procedure to the previous section. A detailed description and discussion of the results are documented below. Simulations of the FoS Using SLIDE Model under Sunny Conditions in Clay Loam Soil Slope  
Last, the simulation was performed to verify the stability of the slope in sunny conditions within clay loam soil. Indeed, the results of the simulation (see Table 4) correlated very well with silt soil slope by denoting that the slope is considered stable. For the sake of argument, the results of the simulation appear to correlate very well with the observation in sunny conditions, however, further supporting simulation in rainy conditions are documented below. Simulations of the FoS Using SLIDE Model under Rainy Conditions in Clay Loam Soil Slope  
The last simulations were undertaken to verify the performance of the typical clay loam soil. The results of the simulation, in this case, also suggest an unstable slope under heavy raining conditions. Low FoS values were estimated throughout using different methods as illustrated in Figures 27-30. This means that clay loam slopes in the Thulamela area are prone to failure when exposed to typical local heavy rainfalls. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Factor of Safety (FoS)**} & \multirow{2}{*}{**Volume of Rainfall (m\({}^{3}\))**} & \multicolumn{2}{c}{**Slope Max Shear Strain**} \\  & & **(Displacement in Shear)** \\ \cline{3-4}  & & **Minimum Shear Strain** & **Maximum Shear Strain** \\ \hline
1.94 & 1000 & \(2.500\times 10^{-8}\) & \(4.432\times 10^{-7}\) \\
1.76 & 1500 & \(2.500\times 10^{-8}\) & \(6.718\times 10^{-7}\) \\
1.54 & 2000 & \(5.000\times 10^{-9}\) & \(1.491\times 10^{-7}\) \\
1.26 & 2500 & \(1.0\times 10^{-7}\)Simulations of the FoS Using FLACSlope (FDM) Model under Sunny to Rainy Conditions in Clay Loam Soil Slope  
Results show that slope was stable in sunny conditions (see Figures 31-34 and Table 7), meanwhile the stability of the slope gradually reduced with the increase in the water table. The simulation in Figure 33 suggests that the selected slope is prone to failure provided it is exposed to extreme rainfalls. It is arguable that the gradual drop on FoS is relative to the increase in pore water pressure, and as already indicated, the failure observed in the study area has been noted to occur when soil phases changes due to extreme rainfalls. Therefore, one can draw an overall conclusion that the extreme rainfall is indeed one of the common triggering factors of slope instability. Figure 30: Safety factor simulated for drained to undrained conditions in clay loam soil slope using (**a**) the Lower Karafiath method and (**b**) the Gle/Morgenstern Price method. Figure 28: Safety factor simulated for drained to undrained conditions in clay loam soil slope using (**a**) [PERSON]’s method and (**b**) Corp of Engineers’ Number One method. Figure 29: Safety factor simulated for drained to undrained conditions in clay loam soil slope using (**a**) Corp of Engineers’ Number Two method and (**b**) the Lower Karafiath method. Figure 31: Simulated FoS of the clay loam soil slope using FLACSlope in sunny with a water table with 1000 m\({}^{3}\) volume of water. Note that maximum shear strain simulated ranges between \(2.500\times 10^{-8}\) to \(4.989\times 10^{-7}\). Figure 32: Simulated FoS of the clay loam soil slope using FLACSlope in rainy conditions with a water table with 1500 m\({}^{3}\) volume of water. Note that maximum shear strain simulated ranges between \(1.0\times 10^{-8}\) to \(2.833\times 10^{-7}\). Figure 33: Simulated FoS of the clay loam soil slope using FLACSlope in rainy conditions with a water table with 2000 m\({}^{3}\) volume of water. Note that maximum shear strain simulated ranges between \(2.500\times 10^{-8}\) to \(7.418\times 10^{-7}\).