What is the formula for getting the Thickness of a Pavement using Expansion Pressure

The thickness of a pavement can be calculated using the expansion pressure experienced during the expansion of subgrade soil due to moisture changes, as well as other factors. The general formula to determine the thickness $H$ of pavement involves factors such as the expansion pressure $P$, the modulus of elasticity $E$ of the base material, and the allowable stress $\sigma$.

Here’s a simplified version of the equation often used in pavement design:

$H = \frac{P \cdot L^2}{8 \cdot \sigma}$

where:

• $H$ = Thickness of the pavement (in units of length, typically mm or inches)
• $P$ = Expansion pressure (in units of force per unit area, typically psi or kPa)
• $L$ = Length over which the stress is distributed (in units of length)
• $\sigma$ = Allowable stress on the subgrade (in units of force per unit area)

Keep in mind that this is a simplified formula and actual pavement design takes into account numerous factors including traffic load, soil characteristics, drainage, and environmental conditions. Always consult highway engineering designs or guidelines for specific conditions.