Performance of Geosynthetic-Reinforced and Cement-Fly Ash-Gravel Pile-Supported Embankments over Completely Decomposed Granite Soil: A Case Study

Table 3

Summary of approaches of different design methods for the aching effect.

Design method	Main parameter	Arching geometry	Subsoil support	Equation of critical height	Critical height (m)
BS8006	s, d, Cc, γ	3D-SSA	No	1.4 (s − d)	1.82
Modified BS8006	s, d, Cc, γ	3D-SSA	No	1.4 (s − d)	1.82
Nordic method	s, d, α0, γ	3D-SSA	No	1.2 (s − d)	1.56
CA model	s, d, Kp, γ, k, φk′	2D-SSA	Ground reaction module		1.27
EBGEO [23]	s, d, , Kp, k, γ, φk′	2D-SSA	Ground reaction module	s/2	0.9

Note. s is the pile spacing (1.8 m); s_d is the diagnose pile spacing (2.55 m); d is the pile diameter (0.5 m); C_c is the arching coefficient; γ is the unit weight of the fill material (19 kN/m³); α₀ is the angle of load diffusion in geosynthetic reinforcement and fill for the Nordic method; is the tensile stiffness of the geogrid (1600 kN/m); k is the ground reaction modulus; φ_k′ is the fill material internal friction angle (35 degrees); SSA is the semispherical arch; K_p is the passive earth pressure coefficient.