Your spotlight on site investigation (Ground Engineering November 1998) and the new AGS code of conduct provided little evidence of any real prospect of an improvement in the perception of the site investigation industry. The latest initiative by the AGS follows a long tradition of missing one central point, namely that the structure of much of the site investigation 'industry' in Britain is fundamentally flawed.
Site investigation is the process by which a geotechnical specialist seeks to characterise and model a site as a precursor to, for instance, designing foundations for a new development. Genuine SI is a 'professional' pursuit that, in all but the most trivial instances, can only be the responsibility of an appropriately qualified and experienced engineering geologist or geotechnical specialist, with a supporting professional team of colleagues as appropriate to the scale of the project. This specialist relies upon various means to achieve his or her end, including, of course, ground investigation activities.
The trouble with site investigation is that much of the commercial industry providing the service and the majority of the contractual arrangements for procuring site investigation are not structured in a way that maximises the likelihood of a professional site investigation being delivered to the client. There is also rarely a single point of professional liability.
In broad terms the typical SI may be broken down into a series of essentially professional and technician activities. These are summarised in Table 1, based on the terminology used by the Site Investigation Steering Group in 1993.
In my opinion the ideal linkages required to deliver a professional site investigation are that (i) the same geotechnical specialist supervises the project through from the preliminary investigations right to the interpretative report and (ii) at the ground investigation stage the same geotechnical person logs the exploratory holes, makes the field geological interpretations, schedules the testing and produces the final exploratory hole records, all under the direct supervision of the geotechnical specialist responsible for the project.
In the early days of the SI industry in the 1950s and early 1960s these linkages were generally in place, with a small number of one-stop, genuinely specialist, consultant geo-technical organisations. This phase of the industry's history came to an end when most of the leading firms of consulting civil engineers started employing geotechnical staff. This in turn led to the 'contractorisation' of ground investigation and the associated 'them and us' mindset. Crucially, under most forms of contract the GI contractor was given the task of producing the exploratory hole records. This was, and continues to be, a fundamental mistake. Incidence are all too common of 'consultants' writing interpretative reports without ever having seen the site and materials present, and of GI 'contractors' only interested in bashing out drilling meterage.
The contractual arrangements for SI should mirror the ideal sub-division of tasks and permit the businesses involved in SI to focus on delivering quality (and profit) in their chosen area or areas of business. The very different nature of the three businesses participating in SI is illustrated, somewhat tongue in cheek, in Table 2. I contend that there is no compelling commercial logic to combining these businesses. Indeed, from the viewpoint of achieving good practice in SI, there appears to be good reason for keeping them separate.
If an organisation does wish to operate in more than one of the three businesses, this requires each area to remain relatively autonomous. There are few things more damaging to the reputation of the industry than an organisation responsible for designing a GI specifying for instance costly boreholes or effective stress testing primarily because the parts of the same organisation providing those services are short of work! This point primarily relates to existing organisations that operate towards the 'contractor' end of the spectrum.
At the 'consultant' end of the spectrum, the key question relates to setting the extent of their involvement in an SI project. In this context consultants comprise a variety of technical professionals including architects, building surveyors, structural and civil design engineers. This group is frequently the commissioning agent for GI on behalf of an employer and hence frequently feels under a strong obligation to be seen to be trying to obtain value for money for the employer. This often translates into a situation were the non - specialist undertakes part of the SI process, eg elements of a desk study, then procures a low-cost GI for a scope of work which has not been adequately thought through. Immediately the professional liability is split and the project has all the potential for not achieving its aims. Organisations at the 'consultant' end of the spectrum should decide on a job by job basis either to take on the whole role of the professional geotechnical team, as outlined in Package 1 in Table 1, or essentially none of it.
Parts of the SI industry act as if they have an overriding vested interest in maintaining the structural and contractual status quo, despite much evidence of the longer term damage being done to the image of the industry by this stance. Sadly, this does appear to be influencing the debate and stifling change.
A H Marsh, managing director