The role of interpretation and communication in geotechnical investigations for waterworks

A fundamental problem in investigating and designing earthworks for economical and safe performance is the multi-disciplinary nature of the investigation and design teams. Each segment of the design team has a different technical objective, be it production of plans, survey data, geotechnical information or design layouts. Because of the increasingly specialised nature of those disciplines, it is not likely that the average practitioner of one discipline will be able to anticipate problems in another discipline.

This paper attempts to provide formal guidelines for geologists to achieve more effective communications, and informal practices in establishing inter-disciplinary dialogues. In the case of geotechnical investigations, the development of clearly stated engineering objectives at each stage of an investigation, in conjunction with progressive developments of geological models, will allow more efficient interpretation of sampling results. In the absence of adequate funds to exhaustively explore a site, interpretation using well established geological models is the most effecti ve way to develop worthwhile information for designers.

This paper argues that detailed logging of all exposed geological features should take place as early as possible in geotechnical in vestigations. Development of geological hypotheses or models for the site(s) should take all available information for the site into account (including mineralogical and textural interpretation) and should agree with currently accepted geological concepts. Reliance on previously proposed regional models for the region should be abandoned if necessitated by fresh data.

An automatic control on the amount of expenditure on exploration will be provided by clear and specific statements of engineering objectives prior to commencement.

The basic aim of geological investigation is to provide adequate data to designers to achieve secure foundations. As a corollary to this, adequate information must be available to tendering contractors so the successful bidder can carry out the required work without disputes arising. Geological investigation needs to be carried on throughout the construction phase, so that late design changes can be anticipated and that an adequate geological model is formulated after completion. Monitoring of the performance of structures after completion will be facilitated, as natural features which may later cause problems have already been interpreted to the fullest possible extent.

The role of training less experienced personnel (including engineers) in more effective communication is also noted. Teaching of thinking processes and communication skills should be actively encouraged, so that set programs of activity can be modified in novel situations.