Doctor of Philosophy
Civil and Environmental Engineering
Dr. Hesham El Naggar
The Queenston shale among other shales from southern Ontario exhibits time-dependent deformation behaviour. This behaviour is manifested in the form of volume increase which can cause damages to the hosted underground structures. The time-dependent deformation of rocks can cause cracks in the springline of tunnels, wall inward movement, roof spalling and floor heave, which requires costly remedial measures. The expansion of the existing infrastructures in southern Ontario requires construction techniques, such as micro-tunneling to build new tunnels and pipelines under the existing structures with minimal impact to these structures and to the environment. However, adopting this technique in swelling rocks, such as the Queenston shale requires an evaluation of its feasibility and functionality prior to its application. Accordingly, a comprehensive study that included experimental and numerical investigations was conducted to evaluate the impact of lubricant fluids used in micro-tunneling applications on their time dependent behaviour. The experimental program evaluated the impact of water, bentonite and polymer solutions on the Queenston shale through: i) investigating the influence of lubricant fluids on the time-dependent deformation behaviour of the Queenston shale through performing free swell, semi-confined, and null swell tests on Queenston shale in these fluids, ii) investigating the impact of lubricant fluids on the strength of the Queenston shale utilizing the Brazilian, direct tension, unconfined compression, and triaxial compression tests, before and after soaking in lubricant fluids, and iii) investigating the depth of penetration of lubricant fluids and water into the Queenston shale. It was revealed that the impact of polymer solution was significant in reducing the time-dependent deformation of the Queenston shale compared to bentonite solution and water. The strength of the Queenston shale was remarkably decreased after their continuous exposure to water and lubricant fluids with minimal impact caused by polymer solution. The penetration of lubricant fluids was found smaller compared to water, and a relation was derived to compute the penetration depth of each fluid in Queenston shale with time. The numerical investigation comprised finite element parametric analyses using the derived tests results along with time-dependent deformation model employing computer program PLAXIS 2D. Different pipe diameter, pipe depth, in-situ stress ratio, and waiting time before final grouting were used in the analyses. Accordingly, micro-tunneling was found to be workable and feasible technique to construct tunnels and pipelines in the Queenston shale of southern Ontario. Recommendations to use the appropriate strength of the make concrete; waiting time and the most suitable depth for micro-tunneling applications are given. The results are envisioned to aid in determining whether or not micro-tunneling technique is a feasible construction technique for pipelines / tunnels in Queenston shale of southern Ontario.
Al-Maamori, Hayder Mohammed Salim, "Time-dependent behaviour of micro-tunneling construction in Queenston shale" (2016). Electronic Thesis and Dissertation Repository. 4064.
Available for download on Monday, December 31, 2018