### DESIGN CHARTS FOR ANCHORED BULKHEADS IN SAND.

**1.**The depth of embedment

**2.**The tensile force in the anchor rod and

**3.**The maximum moment in the sheet piling

The charts are applicable to sheet piling in sand and the analysis is based on the free-earth support method. The assumptions made for the preparation of the design charts are:

**1.**For active earth pressure, Coulomb's theory is valid

**2.**Logarithmic failure surface below the dredge line for the analysis of passive earth pressure.

**3.**The angle of friction remains the same above and below the dredge line

**4.**The angle of wall friction between the pile and the soil is 0/2

The various symbols used in the charts are the same as given in

**Fig. 20.15**where,

ha = the depth of the anchor rod below the backfill surface

hl =the depth of the water table from the backfill surface

h2 - depth of the water above dredge line

H = height of the sheet pile wall above the dredge line

D = the minimum depth of embedment required by the free-earth support method

Ta = tensile force in the anchor rod per unit length of wall

Hagerty and Nofal developed the curves given in

**Fig. 20.18**on the assumption that the water table is at the ground level, that is h1 = 0. Then they applied correction factors for h1, > 0. These correction factors are given in

**Fig. 20.19**. The equations for determining D, Ta and M(max) are

The theoretical depth D as calculated by the use of design charts has to be increased by 20 to 40% to give a factor of safety of 1.5 to 2.0 respectively.

**Figure 20.15**Depth of embedment of an anchored bulkhead by the free-earth

support method (method 1)

**Figure 20.18**Generalized (a) depth of embedment, Gd, (b) anchor force Gt,and (c)

maximum moment Gm (after Hagerty and Nofal, 1992)

**Figure 20.19**Correction factors for variation of depth of water h1 (a) depth

correction Cd, (b) anchor force correction Ct and (c) moment correction Cm (after

Hagerty and Nofal, 1992)

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