What is the detail behind the factors in Australia Envirocalc?
Sliding capacity parameters/specific formulas used in Envirocalc.
|
Symbol |
Parameter Name |
Description/Formulas |
|
Pfr |
Factored Base Friction Resistance |
The frictional resistance from the base soil, calculated as: (Total Vertical Force) × tan(Reduced Friction Angle) × (Structure Factor). The formula is φn * (Pav + W_total) * tan(φ' * φd). |
|
Pp |
Reduced Total Passive Resistance |
The ultimate passive earth pressure resistance, calculated using the standard formula (0.5*Kp*γ*H²em) but then multiplied by the Load Factor on Static Resisting Dead Loads (Gdr). The formula is 0.5 * Kp * Gdr * γ * H²em. |
|
PpH |
Factored Horizontal Passive Resistance |
The horizontal component of passive resistance. It is calculated by taking the reduced passive resistance (Pp) and multiplying it by the Structure Classification Design Factor (φn). The formula is φn * Pp. |
|
PSR |
Total Factored Sliding Resistance |
This represents the Total Design Sliding Resistance. It is the sum of the factored resisting components: PSR = Pfr + PpH. This is the final "capacity" (ΦR*) side of the ULS check. |
|
Pah |
Factored Horizontal Thrust |
The driving action (S*). It is the sum of the horizontal components of the active earth pressure from the backfill (Pah,bf) and the surcharge (Pah,su). |
|
S.F. |
Safety Factor |
The final result, calculated as the ratio of the total factored resistance to the factored driving action: S.F = PSR / Pah. |