## 3 Experiment Results and Analysis
### Analysis of the Soil Pressure  
In order to uniformly express the soil settlement for the different subsidence widths, [PERSON] et al. [27] proposed the relative settlement \(d\), as shown in Equation (1).  
\[d=(S/B)100, \tag{1}\]  
\(d\) represents the relative settlement, \(S\) represents the soil settlement, and \(B\) represents the subsidence width and the units are %, m and m, respectively.  
Figure 5 shows the variation of the soil pressure of the half-symmetric model H2-H4 groups within the subsidence area. Each curve is roughly divided into two stages. The steep-dropping stage occurs at \(d=0\)-\(0.33\%\), and the soil pressure of each curve of the subsidence area decreases rapidly. The soil pressure of the subsidence area is small when \(d=0.33\)-\(10\%\), which is classified as a gentle-change stage. The tensile failure of the geotextile of the geotextile is \(0.45\%\), which is \(0.45\%\), which is \(0.45\%\), which is \(0.45\%\), which is \(0.45\%\), which is \(0.45\%\), which is \(0.45\%\), which is \(0.45\%\).  
Figure 4: Comparison between the model test and the numerical model results of the half-symmetric model and the full-section (\(L=2.0B\)) at the final state of a subgrade collapse: (**a**) comparison of the soil pressure curves below the geotextile; (**b**) comparison of the tensile force curves of the geotextile; (**c**) Settlement amount of the subsidence area.  
half-symmetric model H3 and H4 groups occur at the relative settlement \(d=6.7\%\) and \(d=5.1\%\), respectively.  
Figure 5a shows that the soil pressure variation curve of the location of T1 within the subsidence area. The soil pressure of the H2 group under the gentle-change stage decreases to 0 kPa when \(d=7\%\), which indicates the geotextile seperated from the movable bottom plate, at this moment. The membrane pulling effect is fully achieved and the geotextile is controlling the subgrade collapse. The soil pressure of the H3 and H4 groups are about 7.8 kPa and 15.9 kPa, respectively, so the movable bottom plate still bears a certain amount of soil pressure, and the membrane pulling effect of the geotextile has not been fully developed.  
The soil pressure variation curve of the location of T2 within the subsidence area is shown in Figure 5b. With the relative settlement increases, the soil pressure of each curve under the gentle-change stage gradually decreases. The relative settlement corresponding  
Figure 5: Change of soil pressure of the subsidence area: (**a**) soil pressure variation curve of the location of T1 with the relative settlement; (**b**) soil pressure variation curve of the location of T2 with the relative settlement.  
to the location of T2 is closer to 0 than the location of T1 in the same group due to the different locations of the two soil pressure sensors. It shows that the relative settlement required for the soil pressure of the location of T2 to approach zero is greater.  
Figure 6a shows that the soil pressure variation curve of the location of T3 within the stable area. Each curve has a peak value when \(d=1.0\%\), and then gradually decreases and tends to be stable. Figure 6b shows that the soil pressure variation curve of the location of T4 within the stable area. The soil pressure of the location of T4 has different peak values. Comparing with the location of T3, the soil pressure of the location of T4 increases before the soil pressure tends to be stable. When \(d=0\)-\(1\%\),with the larger subsidence width, the growth rate becomes greater.  
Figure 6: Change of soil pressure of the stable area: (**a**) soil pressure variation curve of the location of T3 with the relative settlement; (**b**) soil pressure variation curve of the location of T4 with the relative settlement.  
The soil pressure of the location of T3 shows a decreasing trend and the soil pressure of the location of T4 shows an increasing trend when \(d\) = 1-5%, which indicates the load is transferred from the location of T3 to the location of T4 within the stable area and the pulling effect of the geotextile is further developed.