## 4 Results and Discussion
### Simulation of the Effects of Rainfall Intensity on Slope Stability
#### 4.5.1 Simulation Case of a Clay Soil  
From Section 4.4, it was conjectured that extreme rainfall has been influencing the recurrence of slope instability within the study area. To test this, numerical simulations were used to estimate the safety factors of various soil slopes of the area under sunny and rainy conditions. Simulation models included the following: finite element method \"SLIDEs\" ([PERSON]'s simplified, [PERSON]'s Simplified, [PERSON]'s corrected, [PERSON]'s, Corp of Engineers' Number One and Number Two, Lower Karafiath and Gle/Morgenstern Price) and finite difference method \"FLAC Slope\". The summary of the results is shown in Table 4 for both FoS simulated using FEM and FDM. However, a detailed description of each simulation is denoted in the subsections below. In Table 4, the FoS of the slope is denoted using different methods subjected to change in volume of the water table. In this regard, rainfall departure ranging from 1000 m\({}^{3}\) to a maximum of 2500 m\({}^{3}\) were implemented or used the input parameters for the water table. However, these values were used as accumulated volume. Furthermore, the simulation using an initial volume of rainfall which is considered to be in normal condition has documented in the table meanwhile the actual simulation are not listed to avoid a large number of images, readers are referred to [PERSON] and [PERSON] (2014), for the simulation in normal conditions. It is, therefore, crucial to indicate that the initial and the final volume of rainfall water was used in the SLIDEs model meanwhile the variety of rainfall volume was used in FLACSlope. Furthermore, the simulation using FDM was intended to outline the behavior of the slope with an increase in the volume of water, however, the model (FLACSlope) has the ability to provide a simulation of Safety Factor and slope displacement. This model was there used to critically analyze the influence of rainfall intensity on the stability of the slope. The alternative method was to implement eight limit equilibrium method using the SLIDEs model in simulating the Safety factor of the slope when the slope was exposed to rainfall with a maximum of 2500 m\({}^{3}\) of water or rainfall. As already indicated above, a summary of the results is denoted in Table 4, and a more detailed discussion is outlined in the respective subsections. Simulations of the FoS Using SLIDE Model under Sunny Conditions in Clay Soil Slope  
With reference to Table 4, FoSs values of the slope with clay soil were simulated using nine methods as indicated in Table 4. The simulations have revealed that the slope is unstable or prone to fail, such failure is believed to be influenced by the properties of the material, as well as the properties of the slope. In supporting the simulation, field observations (see Figure 3) whereby the extent of slope failure was very wide in clay soils than in other soils, indeed the properties of soil material could have been played a major role. In summary, the simulation results have some correlation with empirical analysis and observations. This provides a certain degree of reliability in the simulation model produced in this study. Furthermore, simulation in rainy conditions with the increase in rainfall volume or accumulated water table was based on rainfall departure.