Date of Award

Fall 1996

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering - (M.S.)

Department

Civil and Environmental Engineering

First Advisor

John R. Schuring

Second Advisor

Edward G. Dauenheimer

Third Advisor

Dorairaja Raghu

Abstract

This thesis develops a mathematical design model for predicting ground deformations resulting from pneumatic fracturing. Pneumatic fracturing is a patented process developed for the purpose of enhancing the in situ treatment and removal of hazardous contaminants from geologic formations. During pneumatic injections, measurable ground deformations are experienced both during and after the process. Safe application of pneumatic fracturing to contaminated plumes occurring beneath existing structures and utilities requires that the elastic deformation behavior of the geologic formation and overlying structures be quantified.

Data from five pneumatic fracturing sites were regressed to establish the characteristic polynomial describing the curvature of ground deformation. A model was then developed using theories of elastic plate bending and ground deformations by igneous laccolith intrusions. The deformed geologic formation is modeled as a circular plate subjected to a linear tapering pressure distribution. Comparison of the model results with actual field data displayed reasonable agreement.

An instrumented field test was performed beneath an actual contaminated industrial facility to obtain data on the dynamic response of the structure. Based on the field test results, as well as experience from over 40 additional pneumatic fracturing sites, a systematic design guideline was developed. The guideline classifies structures as either flexible or rigid, and then categorizes them into one of three characteristic design cases.

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