This standard provides guidelines for the design of road embankments using geosynthetic materials. It covers design principles for reinforced soil embankments on both firm and soft foundations, as well as the use of geosynthetic-encased stone columns and piled embankments. The code specifies factors of safety, material properties, and design methodologies for ensuring stability.
Provides guidelines for the design and use of geosynthetics in road embankments.
Quick Reference Values
Min. FoS for overall stability (static)1.30
Min. FoS for overall stability (seismic)1.10
Min. FoS for internal rupture (static)1.50
Partial factor for geogrid strength (γm g)1.40
Partial factor for soil friction angle (γm φ')1.25
Max. allowable strain in reinforcement5%
Key Formulas
T_d = T_ult / (RF_CR * RF_ID * RF_D) — Long-term design strength of geosynthetic
FoS_sliding = [ (W_R + P_v) * tan(φ'_b) * C_i_b ] / P_a_h — Factor of safety against sliding
T_req = Ka * (γz + q) * S_v — Required reinforcement tensile force at depth z
Practical Notes
Always account for reduction factors (creep, installation damage, durability) to determine the long-term design strength of the geosynthetic; do not use ultimate strength directly in stability calculations.
The interaction coefficient between soil and reinforcement is a critical parameter. Use values from laboratory pullout tests for accuracy, or conservative estimates from Table 4 if test data is unavailable.
Proper site drainage and quality of backfill material are as crucial as the reinforcement design for the long-term performance and stability of the embankment.