The use of the energy of a blast for constructing profile earth structures began for the first time in the Soviet Union in the 1930s. Originally small embankments for industrial installations were constructed by the directional blasting method. Later this method began to be used for constructing dams and embankments. During the past 15-20 years such large structures were constructed by massive directional blasting as the 72-m-highmudflow protection dam at Medeo; the 65-m-high dam of the Baipaza hydro development on the Vakhsh River; the 91-m-high embankment across the gorge of the Akh-Su River; the 50-m-high experimental dam on the Burlykiya River.Comprehensive investigations were carried out on these structures, which expanded the amount of knowledge about the construction and seepage properties of the rock of the body of dams constructed by directional blasts~ The results of the investigations showed that earth dams constructed by this method have a high reliability. Thus the mudflow-protective dam at Medeo withstood a catastrophic mudflow in 1973.
The Tyrnyauz tungsten-molybdenum deposit in the mountains of the central Caucasus has hitherto been worked by underground mining. However, progress in open-cut mining with up-to-date machinery has enabled us to convert to the more economic combined (open-underground) method of working.The first open-cut operations were begun in 1969, directly above the working underground blocks in the Mukulansk are field of the deposit. Experience accumulated by the group showed the possibility of further extension of the open-cut workings. Combined open-underground working enables us to extract a large amount of ore which would be lost in underground mining because it would be economically disadvantageous to extract it. Furthermore, the use of the combined method enables us to advance the opening up of new veins and to increase the output per man-shift.However, combined mining in conjunction with the complex relief of the region requires the solution of some very complicated technical problems -the disposition and retention of a large volume of caved rock in a steeply dipping gorge, the elimination of a large landslide in the western part of the quarry boundary, the cutting of motor roads in rocky mountain territory, etc. The most complex of these problems is the elimination of the landslide. The moving mass of rock with f = 12-14, and area of about 1 km 2, and a bulk of 10-12 million m a, slides about 100 cm per year and presents a real threat to the further development of dumping operations in the quarry. There are technical difficulties in eliminating it by the usual method (explosion of loosening charges in boreholes and excavation from above downward), owing to the danger of running an excavator on the fissured slope in the zone of active movement of the rocks and because of the lack of reliable approaches to the moving mass.Under these conditions, the only possible method is to knock down the moving mass by large-scale blasting using charges which are approached from underground workings cut in stable zones of the rock not affected by the movement.In 1972 the Tyrnyauz Combine, in conjunction with the Soyuzvzryvprom Trust, decided to use large-scale blasting to eliminate the landslide.The whole of the sliding mass lies within the take of theproposed Mukulanskii quarry, and therefore all the costs of blasting must be assigned to the estimates of the open-cut operations in the Mukulansk ore body, and thus they do not influence the initial estimated costs of the open-cut workings.A plan for the first large-scale blast to knock down the slide, 4-5 million m 3 in volume, was devised by the Central Production-Experimental Special Construction Laboratory of the Soyuzvzryvprom Trust in conjunction with the Tyrnyauz Combine. The main outlines of the plan are as follows.The slide region is at an elevation of 2690-3087 m above sea level and includes three beds of rock extending in the north-south direction along the strike of the Kurgashilli-Tau ridge and sloping steeply down to the thalweg of the Bol'shaya Mukulanskaya gorge. The mo...
The Soyuzvzryvpmm group has devised and perfected a method of creating earth-rock fill structures by means of a system of expIosive charges. A number of small hydraulic structures have been raised in this manner, and thus enough experience was accumulated for the construction of large high-rise dams by this method. The method was used to construct the high-rise dam of the Baipaz hydroengineering complex* on the Vakhsh River in Tadzhikistan. The reliability of this new method of constructing hydrotechnical structures was shown by the exactitude of placing the blasted rock in the required space delineated by the dam contours, by the absence of much flying rock which is usually found during blasting, by the smalIness of the seismic vibrations within a radius of 150-200 re, where the important units of the hydraulic engineering complex were situated, and finally by the high packing density of the blasted material in the body of the dam due to the high degree of rock fragmentation.At the end of 1972 the Dagestan Administration of the Soyuzvzryvprom group, folIowinga project by the Central Laboratory of the group, carried out work on blasting out a dam on the Akh-Su River to create a transportation link between the right and left banks of the river in the region of the Chirkey hydroelectric station. The volume of the dam is 254,000 m a, its width 280 m, its length along the crest about 180 m, and its planned height 95 m. According to the project, as a result of the blast the height of the dam should not reach more than 75 m; it is l~lanned to increase this by mechanical means. The new blasting method has permitted a more effective utilization of the blasted-down mass and can create a dam 91 m high, i.e., it can reduce the amount of extra filling required for the body by a factor of 6-7, and purely on this basis can cut down the time of construction by 3-4 months.The construction time is also reduced by use of large-scale blasting to create a filled structure instead of mechanized filling or construction of a bridge across the gorge, and also by adoption of innovations such as replacement of a reinforced-concrete channel by a tunnel, etc. The total reduction in construction time was 18 months.The fractional composition of the rock fill is as follows: the yield of fractions with maximum edge length of not over 30 cm is 60%; that with length of over 1 m is 1%. According to observations of the VODGEO Institute. the flow below the dam was reduced in 3 h from 0.18 to 0.07 mS/see after the blast.We must mention three basic features of the work. The first is that the height of the dam is 91 m; such aheight is unique for this method of construction. It exceeds the highest dams at Baipaz? [2] and Medeo,:~ raised by blasting to a height of 29-30 m. Thus, in appropriate technicaI and topographical conditions, it is possible to create rock fill structures over 100 m high.A second feature is the difficulty of access to the site due to mountains and ravines. If the body of the structure had been filled by machines, it would have bee...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.