landfilldesign.com
™
Drainage:Access Ramp - Design Calculator
This calculator evaluates if the access ramp can adequately drain the water from a storm rain fall event. Water that is gathered on the above watershed and flows into the ramp needs to be drained away to.
The Factor of safety is given as follows:
with advised minimum Factor of Safety of 2-3. If the flow capacity within the roadway is insufficient, then a drainage geocomposite with higher transmissivity can be chosen or a surface flow channel might give the extra drain capacity.
Estimation of the flow rate into the ramp structure:
| C | = 1 |
| I | Rainfall (cm / hour) |
| Awatershed | Area of the watershed (m2) |
| θ | Transmissivity (m3 / sec.m) |
| i | gradient of the slope (= tan(β)) |
| W | Width of the ramp (m) |
Estimation of the maximum (in plane) flow capacity of the road:
Flow capacity of the Road base material
| k | Coefficient of permeability (m / sec) |
| i | Gradient of the slope (= tan(β)) |
| W | Width of the ramp (m) |
| T | Thickness of the ramp (m) |
"Designing with Geosynthetics." R.M. Koerner , Prentice Hall Publishing Co., Englewood Cliffs, NJ, 1998.
G. N. Richardson and R. M. Koerner, "Geosynthetic Design Guidance for Hazardous Waste Landfill Cells and Surface Impoundments", 1987.
Copyright 2001 Advanced Geotech Systems. All rights reserved.