Date of Award

January 2014

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Civil Engineering

First Advisor

Rodrigo Salgado

Committee Member 1

Monica Prezzi

Committee Member 2

Terry R. West

Committee Member 3

Steve Wereley

Abstract

As more advanced theoretical methods become available for solution of the complex cone penetration (CPT) boundary-value problem, it is essential to develop methods to validate those solutions experimentally. A large scale model penetrometer testing facility, consisting of a half-circular calibration chamber with digital image correlation (DIC) capability, was developed for experimental simulation of cone penetration. The flat side of the chamber is transparent, made of Plexiglass. In individual tests, sand samples are prepared inside the half-circular chamber by pluviation; the half-circular cone is then pushed into the sand model flush against the Plexiglas, with the penetration process digitally imaged for DIC analysis. The displacement data obtained from DIC analysis provided valuable insights into the cone penetration boundary-value problem. Experiments with three different types of silica sands show that sand crushability influences the slip pattern around the advancing cone and also the cone penetration resistance. The derived strain paths show that very complex modes of deformation are experienced by the soil elements in close proximity of the penetrometer tip. The close-up imagery of the interface zone provided useful information for understanding the model penetrometer-sand interface behavior. The series of cone penetration tests conducted in layered sand profiles show that the sensing and development depths are dependent upon the position of weak and strong layers with respect to the direction of the advancing cone. The observed influence zone as interpreted from DIC analysis is smaller than stated in the literature.

Download

Share

COinS