Use of linear crater charges in canal construction

Abstract

The area of possible use of blast energy for moving earth masses is expanding with the development of canal construction. This is being promoted also by the development and investigation of the progressive blasting method using linear crater charges, which consist of a continuous mass of explosives placed in charge trenches.In comparison with the previously used rows of chamber charges the linear form offers the following important advantages: a) the possibility of complete mechanization of work with a considerable decrease in labor intensity; the charge trenches are dug by excavators, the explosives are fed into the trench by a truck-mounted crane or along chutes, tamping is done by a bulldozer covering the explosives with the soil excavated earlier; b) acceleration of work, their concentration in space and time during operation of mechanized columns (excavator, equipment for charging explosives, bulldozer) successively performing all technological operations in a confined and rapidly advancing section of the route; c) possibility of obtaining an even bottom in the cuts (without projections between charges), and also uniformity of compression of the bases of the cuts upon blasting, which lessens the seepage of water during operation of the canal.In comparison with the use of excavating equipment, the use of linear charges provides a high rate of earth-moving with considerably smaller capital investments and labor expenses.Under favorable conditions the cost of moving earth by explosives approaches the cost of removal by excavators.Linear crater charges were used in the construction of the Irtysh-Karaganda, Volga-Ural, Nura-Sarysu, and other canals.They are promising for the planned diversion of part of the runoff of Siberian rivers to Central Asia and Kazakhstan.The Institute of Specialized Operations of the All-I~ion Planning, Surveying, and Scientific-Research Institute (Gidrospetsproekt) has carried out a program of experimental investigations of the characteristics of the action of linear charges in soft soils. It included modeling, blasting at testing-grounds on a scale approximating to that necessary for the construction of canals, and an analysis of the data from industrial explosions. The testing-ground explosions were carried out by the Kazakh branch of the State All-Union Trust for the Stabilization of Foundations and Structures (Gidrospetsstroi) in different varieties of foams and loamy sands with a density from 1.5 to 2 g/cm 3 and water content from 4 to 18%.The main results of these tests are given below, which permit a substantiated design of the detonation of linear charges.The mass of 1 m of linear crater charge can be calculated by the equationwhere Ql is the weight of 1 m of linear charge, kg; K is the calculated specific consumption of explosives, kg/m3; this coefficient depends on the s0il in which blasting is carried out; it is taken from the recommendations in technical guides (e.g., [i]) and refined by test shots; e is the conversion coefficient of the consumption of explosives relative to...

Applicability and design criteria of a blasting method for constructing deep-cut sections of a canal for transferring part of the flow of Siberian rivers

“…In calculating the blasting parameters, use was made of the method developed by the State Trust for Design of Special Structures (Gidrospetsproekt) [3].…”