Urban planning: storage and processing of geotechnical data

Abstract

Planning the development of an urban area is a complex operation. In practice, and often intuitively, the required style of the ultimate development is reduced to a series of discrete but converging aims and the plan that is usually adopted attempts to achieve these aims at minimum cost. If only the geological factors which impinge on planning decisions are considered, a particular structure will cost the least to build in locations offering the most favourable ground conditions. A generally more economic venture will also result when the expected cost of building the structures in less geologically-favourable locations is allowed to influence the style of development during the planning process. Unfortunately, suitably precise geological and geotechnical information for conditioning the planning decision is seldom available at this early stage of urban development. Balanced against the cost of geological data collection are the concomitant savings which arise from a reduced risk of foundation failure. When the two, costs and savings, are equal, further testing and analysis become financially redundant. However, the benefit to the overall urban development costs brought about by performing site investigation can be prone to much uncertainty. In this thesis, a probabilistic method for the evaluation of the economic advantage likely to accrue from site investigation activity has been developed. As a demonstration of the application of this theoretical analysis, the actual site investigation for a settlement tank at Howdon sewage treatment works (near Newcastle-upon-Tyne) has been examined. During urban development, most geological and geotechnical data are collected immediately prior to the foundation design stage. In order that geotechnical data can be made available at the early stages of planning or for higher level probabilistic evaluation, a digital computation facility for the storage and processing of considerable quantities of data is necessary. In discussing the use of such a facility the thesis describes a suite of computer programmes called Geosys which have been written for the storage, retention, retrieval and presentation of geotechnical data obtained during site investigation studies.