FROM CONE PENETRATION DATA ( CPT TEST )

BEARING CAPACITY OF SOIL

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WARNING!!!!

Meyerhof (1956) suggest for foundation on the sand soil :

Rectangular or square footing for width B ≤ 1,2 m :

Rectangular or square footing for width B ≥ 1,2 m :

where : Allowable bearing capacity for settlement of 2,54 cm (1”)

Conus penetration(qc ) taking on average of qc from 0 level to B depth of foundation.

230 cmkgqq c

a

2

230,050 cm

kgB

Bqq ca

aq

Result of investigation data from SPT test have shows a relation with :

for B ≤ 1,2 m :

for B ≥ 1,2 m :

where : Kd = 1+0,33Df/B ,maks. Kd = 1,33

Nqc 4

220 cmkgKqq d

ca

2

230,033 cm

kgB

Bqq ca

Sanglerat (1972) suggest the relationship between undrained shear strength (cu ) with conus penetration

on cohesive (=0)

For normal consolidated :

For over consolidated :

220cm

kgqc 1518cc

uqtoqc

225cm

kgqc 2226cc

uqtoqc

Example problem :

Average of conus penetration under the foundation is :

235cm

kgqc

Take of width B = 1,5 m ,so using a formula for B > 1,2 m :

230,050

B

Bqq ca

2

2

01,15,130,05,1

50 cmkgqq c

a