Professor Bentley is an Engineering Geologist.

He graduated from Nottingham University with top honours having won the Williamson Prize and a University Exhibition for being the top student in his year. At Leeds University he undertook a NERC sponsored MSc in Engineering Geology and Geotechnics and then moved to the Civil Engineering Department for doctoral research with Professor I J Smalley. His PhD thesis concerned the relationship between geochemistry and geotechnical behaviour of clays and was funded by the then Science Research Council; the thesis was completed in less than 2 years and resulted in 5 journal papers. The external examiner was Professor J R L Allen.

During his career at Cardiff Prof Bentley has acted as sole supervisor to 12 PhD and MPhil research students, five of which were sponsored by EPSRC, together with over 60 MSc research projects. Many of the PhD research topics involved industrial sponsorship; companies have included Hyder, Welsh Water, Halcrow, Railtrack (now Network Rail) and the Wales Environment Trust.

He has reviewed grant applications for NERC and EPSRC and examined PhD theses at the universities of Birmingham, Durham, Nottingham and Loughborough. For three years Prof Bentley was the External Examiner for the MSc Degree in Engineering Geology at Durham University.

Highlights of his research work include the textbook `Correlation of Soil Properties` which has been adopted by many consultancy firms as a standard reference book. He has recently completed a new book on a similar theme which will be published by John Wiley in 2016. Also the visualisation software, `STRATA`, which was used in the design of the foundations for the 5.1 km bridge over the Severn Estuary in SW England. The STRATA software was successfully commercialised and was sold into over 100 companies in 12 countries worldwide.

Prof Bentley has acted as a consultant to the Department of the Environment (UK) on the comprehensive earth science mapping of the land adjacent to waters impounded by a Severn Barrage. He has also been retained as a consultant to the Departments of Public Works in Brunei and Saudi Arabia.

Prof Bentley has 110 publications, over 45 of which are journal papers.

Prof Bentley has been involved in the establishment of the engineering training company, Engineering Practice Ltd, the engineering consultancy, Earth Science Partnership, the software and utility support company, MBA Group Ltd and the not for profit recycling company and fore-runner to WRAP Wales the Wales Environment Trust.

He is currently the International Dean for the College of Physical Sciences and Engineering.