A Numerical Study of Chamber Size and Boundary E ects on CPT Tip Resistance in NC Sand


1 Department of Civil Engineering,Sharif University of Technology

2 Department of Civil and Environmental Engineering,University of Alberta


A numerical modeling procedure was used to quantify calibration chamber size and boundary
e ects for cone penetration testing in sand. In the numerical analyses, chamber diameter
and boundary conditions were varied to investigate the e ects of chamber size and boundary
conditions on cone tip resistance. These analyses show that, for loose sand, a chamber-tocone
diameter ratio of 33 is sucient for the boundaries to have no in
uence on the cone tip
measurements. However, for very dense sand, the numerical analyses show that the chamberto-
cone diameter ratio should be more than 100 to ensure that boundaries have no in
on cone tip measurements. Numerical analysis indicates that, not only the sand relative density
but its stress state is also a signi cant factor in in
uencing the chamber size e ects. The
results of the numerical analyses were compared to existing empirically based relationships.
Suggestions are provided to reduce the e ects of chamber size and boundaries on cone tip
resistance measurements in sand.