Date of Award

Summer 2016

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Materials and Infrastructure Systems

First Advisor

Tom Isley

Abstract

The information presented in this dissertation is based on research work conducted at Trenchless Technology Center (TTC) at Louisiana Tech University. This work was performed through a contract with China University of Geoscience (CUG) for a gas company. China's gas pipelines need replacement or rehabilitation after 15 to 30 years of service. China's gas industry is looking for suitable techniques to transfer into their market.

When compared to conventional excavation pipeline renewal or replacement methods, there are obvious advantages of TRT for gas pipelines that can impact the triple bottom-line of economic, social and environmental benefits. An introduction of TRT for gas pipelines has been provided. Also, an overview of international and China's TRT for gas pipelines is provided. The focus is on specific questions existing for urban gas pipeline networks. Based on the international survey and literature review of TRT, TTC evaluated the candidate technologies and developed a selection criterion. A new composite hose was selected as the specific candidate technology for China gas pipelines.

TTC performed mechanical and material property tests on the composite hose for pressure gas pipeline rehabilitation. These tests included long-term and short-term tension and bending tests, as well as tests for hardness and thickness. The performance of the hose has been completed including flexibility, strength and burst testing with connections. Taking advantage of the material parameters and the burst testing results, the Finite Element Analysis (FEA) and Approximate Analytical Calculation (AAC) of the pressure carrying capacity of the hose has been completed.

The purpose of the theoretical analysis was to find a simple and practical design principle and equation for the composite pipe with the Pipe-in Liner (PIL) method.

The hoop stress equation was validated and set up as the design principle for the multi-layer hose. The PIL construction scope and technical advantages were determined. Installation details and technical parameters for the lowest Life Cycle Cost (LCC) were optimized. Industry Standards and Testing Requirements for Fiber Reinforced Polyethylene Hose for Trenchless Rehabilitation were completed in English and Chinese versions.

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