As editor of Ground Improvement from time to time I am asked what is the value or, indeed, purpose of a journal dedicated to this field. This question arises because the research and practice of ground-improvement technologies can, perhaps, be considered to fall within the broader and more general field of geotechnical engineering. If you are reading this editorial as a subscriber to the journal then I do not need to explain the value or purpose of Ground Improvement to you! However, if you are glancing through this journal in a library, have picked up a copy from a colleague's desk or stumbled upon this editorial on-line, then possibly the question about the need for this journal has occurred to you already.
While it is true that the field of ground improvement falls under the wider banner of geotechnical engineering, it is a very distinct subset of the broader discipline with its own specialist researchers and practitioners. What marks it out is the wide range of techniques that can be used to modify the properties of soil or the engineering performance of a soil system in order to permit engineering works to proceed. Furthermore, not only is there an extremely wide range of ground-improvement techniques – from enhancing soil properties with additives, such as cement or lime, to reinforcing soil using inclusions such as geogrids or soil nails – but within each of these techniques there can be many different methodologies. This is demonstrated by the scope of the papers in this issue of Ground Improvement, which deal with a wide range of techniques for altering the properties of soil in situ. Ground improvement is a field that is developing very rapidly internationally and for each of the broad range of ground-improvement technologies and the variations within these there is a requirement for the applicability of techniques to given situations to be demonstrated though laboratory-based proof-of-concept research, well-documented monitoring programmes, suitably developed quality-control methodologies, and validated design methods. It is the purpose of this journal to provide the vehicle for this new knowledge to be disseminated throughout the world to relevant engineers, specialist contractors and academics working in the field of ground improvement.
As I indicated above, this issue of Ground Improvement contains a group of five papers that deal with changing the properties of soils; these papers demonstrate the wide range of different techniques that can be used to do this. Perhaps the most novel technique reported is a biological approach to soil stabilisation described by Ahmed and Hussain (2010). The paper describes a study in which soil was stabilised using natural polymers that are produced by bacterial polysaccharides. The study investigated how variables such as nutrient concentration and temperature affected the engineering properties of the ‘biologically stabilised' soil. Another unusual approach to the modification of soil properties is the use of ultrasound treatment in dredged material described in the paper written by Meriggi and Del Fabbro (2010). Ultrasound may be used as a means to remove pollutants from the soil and the purpose of the authors' work was to investigate if a technique applied for environmental benefit would enhance or degrade the geotechnical properties of the dredged material as it settles from slurry to form soil.
In a series of two papers Wilkinson et al. (2010a, b) present the results of a study to investigate how three different industrial by-products readily available in Australia might be used to stabilise a range of problematic soils encountered in that country. The two papers present a detailed study of the microstructure of the stabilised soil and the geotechnical properties resulting from changes in the micromechanical behaviour, respectively. The final paper in this issue of Ground Improvement also considers the efficacy of a waste material in the stabilisation of soil. In this case, however, Hossain (2010) investigated the use of rice-husk ash and naturally occurring lime as a means to improve the strength and stiffness of lateritic soils for use in road construction in Papua New Guinea.
While describing studies to investigate a variety of techniques to improve the geotechnical properties of soil, the papers in this issue also provide an insight into the richness of research in this aspect of ground improvement. Not only do the papers describe the application of a range of stabilising additives – from blastfurnace slag to rice-husk ash and polysaccharides – but also the depth of research, which includes detailed studies of microstructure as well as the assessment of more conventional geotechnical properties. If you are the occasional reader and you have made it to the end of this editorial, I hope that you will join the regular readers of this journal in enjoying the papers that follow. I am sure that these will demonstrate clearly the value of an international journal dedicated to the field of ground improvement.
