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Remoulding of the Mercia Mudstone Group around CFA pile shafts

Seward, L. J., Stallebrass, S. E. & Skipper, J. (2013). Remoulding of the Mercia Mudstone Group around CFA pile shafts. Quarterly Journal of Engineering Geology and Hydrogeology, 46(1), pp. 41-51. doi: 10.1144/qjegh2011-053


A field test has been undertaken to investigate changes to in situ Mercia Mudstone at the pile soil interface after installation of four 5.5 m long 350 mm diameter CFA piles. The test investigated whether a remoulded zone exists, the extent of the zone, changes caused by remoulding and the effect of the installation method. The piles and surrounding soil were excavated after installation to a depth of just under 2 m. The sections of pile and surrounding soil were returned to the laboratory where a variety of detailed observations at both micro and macroscopic scales were undertaken, together with chemical and mineralogical analysis. It was found that a remoulded zone existed in all piles but that this varied in thickness both laterally and vertically around a pile. Across all piles the maximum thickness observed was 55 mm. The average thickness, fabric and texture were all affected by installation method. A distinctive vertically orientated fabric was observed in which up to four vertically orientated layers could be distinguished. There was evidence of changes in texture/fabric, structure, colour, mineralogy and chemistry.

Publication Type: Article
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
Departments: School of Science & Technology > Engineering
SWORD Depositor:
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