Wride, Natalie (2022) Analysis of cohesive subgrade subject to long term cyclic loading. PhD thesis, University of Warwick.

Preview

PDF WRAP_Theses_Wride_2022.pdf - Submitted Version - Requires a PDF viewer. Download (32Mb) | Preview

Request Changes to record.

Abstract

Rail transportation is a key consideration for the future of sustainable cities. As cities develop and grow, greater demands are placed on existing infrastructure, and as rail networks expand, the construction of new routes will be governed by land availability. In this case, it is likely these routes will transit soft clay subgrade material. Quantifying the response of cohesive subgrades under repeated loading is therefore important for both the design and construction of future rail links and the maintenance of existing routes.

A body of triaxial test data is presented examining the performance of reconstituted kaolinite samples to cyclic loading. Reconstituted Gault clay samples, obtained from bulk samples, where also tested. In total, 20 monotonic tests, 59 cyclic triaxial tests and 12 post-cyclic triaxial tests were performed in this study. These tests examined the influence of load frequency and load magnitude, defined in terms of a cyclic stress ratio, to characterise the cyclic behaviour. Further studies demonstrated the performance of cohesive subgrade material considering preloading and examined the response of a sample under partial drainage. The laboratory tests were complimented by an undrained cyclic numerical model, extended to consider vertical drainage. Finally, the influence of various factors on cohesive subgrade beneath slab track were analysed and design charts presented to determine the cyclic stress for input to the numerical model.

Findings of this study highlighted some of the key considerations for cohesive subgrade soils when subjected to cyclic loading and the influence on the strain accumulation and excess pore pressure response. For the Gault clay, the difference in response with respect to the compressibility of the samples was investigated considering the plasticity of the clay. The results from this study provided further validation data for the existing undrained cyclic model, and predictions of partially drained soil response are in good agreement with the case studies analysed.

Item Type:	Thesis (PhD)
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TF Railroad engineering and operation
Library of Congress Subject Headings (LCSH):	Loads (Mechanics), Soil mechanics, Soil compaction, Clay soils -- Testing, Geotechnical engineering, Strains and stresses, Railroads -- Earthwork, Railroads -- Buildings and structures -- Foundations
Official Date:	April 2022
Dates:	Date Event April 2022 UNSPECIFIED
Institution:	University of Warwick
Theses Department:	School of Engineering
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Geng, Xueyu ; Utili, Stefano ; Mottram, Toby
Sponsors:	Marie Skłodowska-Curie Actions ; Engineering and Physical Sciences Research Council
Format of File:	pdf
Extent:	xx, 312 leaves : illustrations
Language:	eng

Request changes or add full text files to a record

Repository staff actions (login required)

View Item

Downloads