The CPT Method of Determining Ultimate Bearing Capacity

Cohesionless Soils
Relationship Between qc, Dr and 0
Relationships between the static cone penetration resistance qc and 0 have been developed by Robertson and Campanella (1983b), Fig. 9.15. The value of $ can therefore be determined with the known value of q . With the known value of 0, bearing capacity factors can be determined and  hence the ultimate bearing capacity. Experience indicates that the use of qc for obtaining 0 is more reliable than the use of N.

Bearing Capacity of Soil
As per Schmertmann (1978), the bearing capacity factors N and N for use in the Terzaghi bearing capacity equation can be determined by the use of the equation

eq 12.41

 

where qc = cone point resistance in kg/cm2 (or tsf) averaged over a depth equal to the width below the foundation.

Undrained Shear Strength
The undrained shear strength cu under 0 = 0 condition may be related to the static cone point resistance qc as [Eq. (9.16)]

eq 12.42

 

When once cu is known, the values of qm and qna can be evaluated as per the methods explained in earlier sections.

Revisions

There are no revisions for this post.

Tags:

No comments yet.

Leave a Reply