A conventional drilled and grouted soil nail wall will be designed to
retain a long, vertical excavation in a silty sand. The soil properties and
the design excavation depth are shown in Figure 7.60. The following initial
parameters are also given:
Pullout factor of safety, FSp = 2.0
Global factor of safety, FSG = 1.35
Nail horizontal spacing, SH = 1.5 m
Nail vertical spacing, SV = 1.5 m
Nail inclination = 15 degrees
Drillhole diameter, DDH = 10 cm
Ultimate pullout resistance, qu = 120 kN∕m²
Determine:
(1) The preliminary nail length and maximum design nail tensile force
to satisfy the global stability.
(2) The factor of safety against sliding.
(3) The factor of safety against heaving of the foundation soil.
