Figure 9
The line graph shows the relationship between tunnel free cross-section (A0) in square meters and two variables: exterior peak-to-peak load (Δpp) in kilopascals and required sealing time constant (τmin) in seconds. The x-axis ranges from 65 to 105 m2, and the y-axis on the left measures exterior Δpp from 3.0 to 6.0 kPa, while the y-axis on the right measures required sealing τmin from 10 to 24 seconds. Three data points are plotted at 70 m2, 85 m2, and 100 m2, each with error bars. At 70 m2, exterior Δpp is about 5.5 kPa and required sealing is about 22 seconds. At 85 m2, exterior Δpp is about 4.5 kPa and required sealing is about 18 seconds. At 100 m2, exterior Δpp is about 3.5 kPa and required sealing is about 12 seconds. The graph indicates that as the tunnel free cross-section increases, both the exterior peak-to-peak load and the required sealing time decrease.Cross-section trade-off (L = 2 km, 350 km/h, single train): exterior peak-to-peak load with GCI error bars (left axis) and the sealing time constant required to meet the UIC comfort criteria (right axis). Source: Author's own work