Improving the quality and reducing the costs of engineering-geologic investigative surveys for hydrotechnical construction

Abstract

From The Editors. A. G. Lykoshin's article raises serious questions vith regard to reducing the costs and curtailing the lengths of time required for engineering-geologic surveys, which comprise the principal and most labor-consuming part of such surveys. Therefore, these questions are extremely urgent now and require wide discussion. The editors request builders, designers and planners, surveyors, as well as workers in scientific-research institutes and institutions of higher learning to comment on the essential points of the questions raised in this article.Improving the quality and reducing the costs of engineering-geologic investigative surveys depend, for the most part, upon perfecting methods of carrying out these operations. All the other elements of technical progress (utilizing new equipment, raising the level of mechanization of labor-consuming production processes, and so forth) play a secondary role. In our opinion, we must adhere to two basic principles in perfecting the methods of engineering-geologic investigative surveys. The first of these is a differentiated approach to determining the composition and scope of operations, depending on the degree of importance of the facilities under construction, with a subdivision into the following two categories: principal structures of hydro-complexes and auxiliary facilities (settlements, roadways, transmission lines' etc.). The second is a distinction to be made at the facilities of the primary degree of importance between the main and the secondary engineering-geologic factors. The main ones, moreover, should be thoroughly studied in the maximum possible detail, whereas the secondary ones could be studied in a less detailed manner, allowing for a calculated engineering risk. The degree of the latter should be determined by the characteristics of the natural situation and the technical potential for eliminating unexpected complications during construction with sufficient speed and without undesirable consequences.Complications appear most frequently as a result of the disclosure after construction pits have been opened up of sources of local water flow, karst hollows (sink holes), zones of tectonic fracturing, etc. Such unexpected factors may require an intensified pumping, sealing with concrete or cementing rocks, on-site utilization of anchor bolts, and so forth.In carrying out investigative surveys at major facilities, principal attention should be concentrated on the most exact possible exposition of the principal engineering-geologic factors, determining the most important planning decisions. It is important, moreover, to establish the principle that in opening up a construction pit the complications mentioned above might manifest themselves and, accordingly, direct the planners to work out design or construction measures the implementation of which might be required during the course of construction. We should not economize on detailed surveys in those instances where an insufficiently precise knowledge of the facility's foundation might bring about ...