Role of engineering investigations in the scientific substantiation of earthen dams

Abstract

Experience is cited for work involving investigation of gravelly-pebbly soils.Investigations of the procedure used to construct earthen dams, which are directed toward substantiation of design solutions and implementation on actual projects, are one of the basic trends in the business of the JSC NIIÉS.Complex studies involving the indicated trend are conducted as applies to various types and designs of dams: plane-earth and hydraulic-fill, rock-and-earth-fill, and riprap, which includes reclamation systems, water-supply systems, flood protection of land, etc., are component parts of structures intended for water power and water transport.Studies were conducted for dams subjected to various geologic-engineering conditions in a moderate climate, and in the northern climatic-construction zone, as well as in zones with a tropical climate. Results of the engineering investigations are being implemented in water-development works under construction, and in regulatory documents, brought to light in monographs and papers of leading scientific institutes, and discussed at conferences and congresses convened in our country and abroad.Great scientific and technical achievements are being made in engineering studies of earthen dams for such projects as:-the Zhigulevsk HPP (Russia), where a new production procedure has been worked out for the construction of hydraulic-fill structures by releasing a slurry onto a beach with a large jet from the ends of overhead pipelines at negative ambient air temperatures. This has made it possible to shorten substantially the construction time of channel dams, and ensure timely placement of the project in service;-the Aswan hydroproject (Egypt) and Kapchagai HPP (Kazkhstan), where rip-rap is flushed with sand, as a result of which the designs of the barrages have been optimized, and underwater work for the installation of multilayer filters has been precluded;-the Nurek HPP (Tadjikistan) and Teri HPP (India), which were constructed in seismically active regions. A procedure for construction of the central core of high rip-rap dams formed from artificially prepared mixtures of largelump and clayey soils by increasing the filtration-suffosion strength of the core and improving the stress-strain state of body of the dams has been worked out at these hydroelectric plants. A procedure has been developed for the design of compaction parameters, and in-service methods of monitoring the quality of compaction of these soil mixtures. Technical solutions were substantiated for the filling and compaction of the lateral prisms of dams formed from gravelly-pebbly soils. Th above-indicated investigations have been accompanied by the attainment of high operational qualities of these structures;-the Al Khadissi (Iraq) and Tishrin (Syria) hydroprojects, where the possibility of using weathered and leached weak carbonate rocks from suitable pits and near-by deposits in lieu of a rock mass of tough stone, the quarries of which were located far from the damsites, was first confirmed. A structural classification...

Protection Parameters against the Cracks by the Method of Volume Compensation Dam

“…Where ߗ -the surface area of the ridge, for one pile (or a jack or an injection well), defined step piles or their rows, ‫ܭ‬ ௨ -coefficient unevenness of sealing between the pile space (approximately equal to 1.5 -for distributed piles and 1.2 -for a pile rows), ‫ܭ[‬ ௦.р ] -admissible generalized coefficient stock for the dam under the deformations of its elongation (approximately equal to 1.5 ... 2.0) [10][11][12][13][14].…”

Calculation the options of cracks in the earth dam

“…1 for C ୵ =0 is recommended by many authors to determine the depth of cracks as well as the height of the maximum sustainable vertical ground slope [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17].…”

“…Where: ܴ -strength of the soil compression by the limit equilibrium theory [11][12][13][14][15][16][17][18][19].…”

Stress - strain state dams on a loess subsidence base

“…The calculation of the stress-strain state, given by us, is based on the analysis of world experience in dam building and taking into account the main features of the behavior of earth dams during their construction [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18].…”