# Field and Numerical Investigation of Taihu Resort Cut Slope Failure in Suzhou, China
## 5 Simulation of Sequential Slopes under Excavation and Rainfall Scenarios
### Establishment of Slope Finite Element Model
#### 5.2.2 Stress Analysis  
The height of the excavation on the slope greatly impacts the stress distribution and stability of the slope. In the previous section, numerical simulations of the slope ensured that the excavations resulted in an increase in the distribution of shear strain within the slope body. In order to analyze the stress changes within the slope during the process of excavation, a detailed comparison is carried out to evaluate the effect of excavation on the distribution of horizontal stress. Additionally, a detailed analysis is conducted of the horizontal stress development at two selected points at the mid-toe and mid-top along the shear strain of the slope. The Midas GTS software defines negative stress as compressive stress and positive as tensile stress. Before excavations proceeded, it can be observed from the horizontal stress distribution of the original slope in Figure 11a that the stress distribution zone within the original slope indicated compressive stress and diffused over the entire slope. When the fourth slope excavation stage occurred at 10 m of elevation, as can be seen in (Figure 11b), the horizontal stress distribution within the  
Figure 10: Changes in the maximum shear strain distributions under excavation conditions. (**a**) Original slope, (**b**) Excavation stage 1, (**c**) Excavation stage 2, (**d**) Excavation stage 3, (**e**) Excavation stage 4.  
initial slope was redistributed and increased at the final excavation stage, where the slope excavation significantly affected the stress distribution and also led to demolishment in the stresses within the slope body, which the horizontal stress redistributed after the newly excavated slope surface. In detail, the height of the tensile stress distribution range is about 4 to 6 m along the argillaceous siltstone layer, and it extends partially over the slope toe. Therefore, the tensile stress of the excavated slope was substantially higher in the soil slope layer compared to the original slope. Therefore, the fourth excavation stage resulted in an opposite reaction to the stability of the slope, which affected the stability of the slope negatively.  
The change in the horizontal stress of the slope during the excavation process has a great influence on the slope's stability. To determine the horizontal stress variation within the slope from the original slope to the fourth excavation stage, two points at the middle-top and middle-lower of the slope were set to observe the changes. Figure 12a,b show the horizontal stress development at each excavation stage of the middle and top of the slope, respectively. It can be seen from Figure 12 that the horizontal compressive stress for all excavation stages decreases gradually with the progress of the excavation rate for both the top and middle selected points, except for the original slope horizontal stress, which indicates that the horizontal compressive stress increases gradually with time. Moreover, the horizontal compressive stress at the middle-lower values is greater than the horizontal compressive stress of the mid-top values.  
Figure 11: Stress distribution: (**a**) original slope; (**b**) fourth slope excavation stage.