A COMPARISON OF DATA FROM AGRICULTURAL SOIL SURVEYS WITH ENGINEERING INVESTIGATIONS FOR ROADWORKS IN AYRSHIRE

Abstract

SummaryRecently a number of outline soil survey maps, on a scale I: 25 000, each covering some IOO km square, have been made available by the Soil Survey of Scotland to County Advisory Officers) Planning Officers, and others who have specialist requirements. In North Central Ayrshire a number of major roadworks have been completed in recent years and the Kilmarnock and Hurlford Bypasses are at present under construction. Site investigations have been undertaken in connection with these works and construction records kept. These make possible the assessment of the usefulness of the soil survey maps for initial route and realignment planning of roads.The delineation of the various soil associations on the soil survey maps related very closely to the limits of the various engineering soils encountered. The groupings adopted by the soil surveyors for boulder clays have, however, been found to be narrower than presently required by engineers) while the groupings adopted with respect to the raised beach and alluvial deposits too wide.It is suggested that the engineering behaviour of boulder clays needs closer examination and any correlations between engineering and soil association groupings should be sought. Also if the grading, water content, and bulk density of the raised beach sands and gravels could be given by the soil survey, this information would permit engineers to make a much better judgement of the road‐bearing capacity of these materials. Alluvial deposits should be similarly tested and distinguished as either riverine or lacustrine deposits.To avoid duplication of effort in the future when geotechnical maps are produced and to gain the maximum benefit of the information so far collected, a closer liaison between engineers and the Soil Survey of Scotland is suggested.