Date of Award

3-2010

Degree Name

MS in Civil and Environmental Engineering

Department

Civil and Environmental Engineering

Advisor

Gregg Fiegel, Ph.D., P.E., G.E.

Abstract

Water jetting as a means for removing anomalous materials from cast-in-drilled-hole (CIDH) piles was examined. The primary objective of this research was to establish empirical relationships between different jetting parameters and the removal of commonly occurring anomalous zone materials, including low-strength concrete, slurry mixed concrete, grout, and clay soil. Also investigated was the current standard-of-practice used by water jetting contractors within California. The testing specimens consisted of typical anomalous material with unconfined compressive strengths between 5 and 6,000 psi. The experimental work consisted of water blasting submerged specimens using rotary jets, nozzles, and pumping equipment typically used in construction practice. Two testing protocols were developed. The first testing protocol called for the nozzle to be held stationary and the second allowed the nozzle to be cycled up and down across the anomaly. During testing, material removal rates were measured as a function of jet pressure and standoff distance. Water blasted specimens were cut apart after testing to confirm erosion measurements and to permit inspection of the water blasted surfaces. Based on the results, erosion rates and the effectiveness of water jetting are primarily influenced by unconfined compressive strength, when using standard test equipment and jetting pressures. Further, aggregate size and material type in the anomalous material does not appear to influence both total erosion and erosion rate.

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