Mian Huang

Topic

Experimental Investigation into the Behavior of Geocell-Reinforced Bases under Freeze-Thaw Cycles

Department of Civil Engineering

Date & location

• Friday, May 3, 2024

• 9:00 A.M.

• Virtual Defence

Reviewers

Supervisory Committee

• Dr. Cheng Lin, Department of Civil Engineering, University of Victoria (Supervisor)

• Dr. Min Dun, Department of Civil Engineering, UVic (Member)

• Dr. Sanat Pokharel, Department of Civil Engineering, UVic (Outside Member – Stratum Logistics) 

External Examiner

• Dr. Xiaoming Yang, Department of Engineering, Georgia Southern University 

Chair of Oral Examination

• Dr. Gourab Ray, Department of Mathematics and Statistics, UVic

   

Abstract

Freeze-thaw (F-T) cycles significantly contribute to the deterioration of roadways in seasonal frost regions. Among various countermeasures to mitigate F-T damages, the application of geocells for base stabilization has demonstrated its effectiveness in enhancing the F-T performance of road bases due to their three-dimensional stiffening and reinforcing effects. Despite the practical success of the use of geocells in base stabilization, a scarcity of research has focused on qualitative or quantitative evaluation on the benefits of geocells in improving the F-T performance of bases. To address this research gap and assess the F-T performance of geocell-stabilized bases, this study conducted a series of laboratory element and model tests as well as full-scale field tests. This study first introduced the development of a customized model test apparatus capable of performing unidirectional F-T tests and plate loading tests on the geosynthetics-stabilized bases in Chapter 1. Utilizing this apparatus, influencing factors of fines content (Chapter 2), water supply and compaction degree (Chapter 3) were investigated directly. Furthermore, the F-T effect on the mechanical behavior of geocell-stabilized soils was explored through elements tests, serving as a complement to the comprehensive assessment (Chapter 4).

A significant portion of this study involved comprehensive full-scale field tests that comparatively investigated the efficacy of applying geocells and geogrid composites in a flexible pavement in Alberta, Canada. This comparison was made across three test sections stabilized with two types of Novel Polymeric Alloy (NPA) geocells and a geocomposite. A full instrumentation program with the design and installation of different sensors such as earth pressure cells, thermocouples, and moisture sensors was introduced in Chapter 5. Short-term testing and long term monitoring were implemented. Short-term tests included plate loading tests and trafficking tests before and after the first seasonal F-T cycles, while the long-term monitoring focused a 12- month monitoring of soil temperatures, moisture contents and loads transferred to the subbases after open to general traffic (Chapter 6).

The results of the experimental tests including element and model tests was field investigations significantly contributed to the understanding of the effectiveness of geocell stabilization in mitigating F-T induced damages, providing insights into the underlying stabilization mechanisms.