A parametric description of a blasting process is proposed on the basis of analysis and codification of data on experimental detonations simulating planned blasts.Construction of the Kambarata HPP-2 was renewed in 2008. Based on a plan, which had been tabled in the late 1980s, and which is now completed, the dam for the powerhouse is to be constructed by blasting, as a result of which a rock mass will be crushed and thrown-off into the channel of the Naryn River.Use of large-scale blasting is fraught with risks of earthquake-induced effects for entities within the construction site of the HPP, which is situated 3.5 km from the village of Shopokovo. In addition to the potential danger, and the seismic energy released by the blasting, it is possible, in principle, to speak of the problem involving its activation of natural seismicity in the area surrounding the HPP. In contrast to the hypothesis relative to the dangerous level of seismicity that is brought about, including by blasting, the reality of which (hypothesis) raises doubts and should, in any case, be regulated as a function of the intensity of the blast effect, the natural seismicity of the region is an imperatively significant condition for reliability assurance of entities at the HPP.The set of problems indicated renders their analysis and a prognostic assessment of factors having an effect during the blasting and in the period of construction requisite.Blast-induced seismic effect. To form the body of the dam at its site on the right bank of the Naryn River, it is planned to detonate two explosive charges weighing 700 and 2160 tons with a 2-sec delay between the detonations. The charges are to be placed in drifts subparallel to the strike of the inclined daylight surface such that the line of least resistance (normal to this surface -LLR) for detonation of the basic charge (2160 tons) exceeds 100 m. The required volume of rock mass that falls into the channel is ensured by the design values for the specific consumption of explosive, and the functions of the blast factor for the basic charge are approximately q, f(n) = 1.High-liability structures of the HPP (situated at epicentral distances of 350 -1000 m), and the residential and agricultural buildings in the village of Shopokovo are preservable entities with respect to which possible losses due to the seismic effect of the blast must be eliminated or evaluated.The JSC "SPII "Gidrospetsproekt," which is developing the plan for blasting, has carried out seismic investigations during test detonations under field conditions simulating the full-scale planned blasting to substantiate the reliability of its safety in 2008. Specialists of the Institute of Seismology at the National Academy of Sciences of the Kyrgyz Republic were invited to take seismic measurements on their own recording equipment.The methodical and technical solutions adopted fulfilled two basic requirements for proper utilization of results derived from the test detonations to predict the seismic effect of the planned blasts:-similarity bet...

It is known that in hydrotechnical construction boring and blasting works near the designed lower contour of the foundation pits of important structures have specific characteristics.They are related to the need to protect the rock foundations of structures from impermissible cracking under the effect of the blast loads.Construction Norms and Regulations (SNIP) III-45-76 and other standards specify that so-called protective layers, which are worked out by means of hole charges, be left at the lower contour of pits.Such a scheme of works has substantial shortcomings:considerable labor intensity of short-hole compared to long-hole drilling, long period of works on preparing foundations, unhealthy conditions of the work and its low degree of mechanization when boring the short blast holes, and considerable volume (30-50%) of manual excavation of the protective layers.The State Special Design Institute (Gidrospetsproekt) [i] carried out theoretical and analytical-experimental investigations and developed rational schemes of boring and blasting works near the lower contour of the foundation pits of important structures for various conditions, which improve the technicoeconomic indices of the works without lowering the requirements imposed on the quality of the foundations.One such scheme was used for preparing the foundation of the Dnestr hydroelectric station (Fig. i).The rock mass excavated at the contour of the pit is composed of sandstones in the upper part and the granites in the lower part (2-3 m above the designed level of the foundation). The characteristics of the rocks are given in Table i. The plan of boring and blasting works, developed in conformity with the requirements of the standards, called for loosening and excavating the last rock layer with a thickness of 5-6 m in the following way.The upper 4-5 m should have been loosened (Fig. i) by firing the long-hole charges with a diameter of 0.11marranged, as specified by SNIP, without overdrilling in a close pattern (the distances between charges amount to 70% of those usually used).After the blasted mass is removed by excavators the l.O-m-thick layer should be loosened by short-hole charges to a depth of 0.6 m (the holes are bored to a depth of 1.0 m and arranged in the usual [2] pattern) and to the remaining 0.4 m manually by picks and wedges.The scheme adopted on the basis of the results of investigations and used for excavating the near-contour layer of rock consisted in that the upper 3-4 m were loosened by firing long-hole charges with a diameter of 0.15 m arranged in the usual (not close) pattern and with overdrilling; the lower 2 m of the layer were loosened by close long-hole charges of a calculated diameter located in O.ll-m-diameter boreholes.The thickness of the layer loosened by the long-hole charges of the calculated diameter and the value of this diameter were calculated by the method in [i] on the basis of the parameters (Table i) of the rock being excavated and conditions of protecting the foundation from impermissible disturbances by the ...

Translated from Gidrotekhnicheskoe Stroitel 'stvo, No. 12, December 2005, pp. 25 -30. A model for computing the impact of blast energy irradiated into the three-dimensional space of the enclosing medium is suggested, which makes it possible to predict the parameters of the action of an arbitrary blast source on an arbitrarily located watched object. As a consequence, it becomes possible to optimize safe conditions of the building process under virtually any conditions of blasting.Evaluation of the mechanical effect propagating into the deformed surrounding medium from the source of a blast has always been an important problem and is acquiring special urgency in connection with the task of ensuring quality results and reliable safety of the ambient (in the broad sense of the term including engineering objects, buildings, and structures). Until quite recently such problems have not been solved in a universal and adequate manner, but modern advances in the field of generalization of accumulated experience of analytical and instrumental studies have created basic prerequisites for the development of a computational model, at least in an engineering approximation, for the process of loading of the ambient by the energy irradiated into space from a blast.In our earlier works [1 -5] we considered various aspects of applied representation of the wave mechanical effect of blasts concentrated and divided in volume and time. The method for computing the intensity of seismic load suggested in [3] and realized in patent [6] for a firing technique is based on numerous experimental data and theoretical studies and has been confirmed by long-term experience of safe firing, including firing under strained conditions.However, the suggested and tested solutions of [5, 6] can be generalized formally only to the cases when the region of the blast and the object affected (watched object WO) lie at the same altitudinal level (differing in the bordering length) in three fixed directions of the planned dislocation of linearly divided charges (a row of charges) and WO located in the end of the row, opposite to the end of the row, and opposite to the middle of the row. At the same time, the mutual location of the charges and of the WO can be arbitrary in a half-space (in a special case in a space or in a volume) of the medium in which the blast energy propagates. It is obvious that the action of a blast of linearly divided charges in rows should be considered in a continuous three-dimensional model, as can be seen, for example, from the figure. No theoretical constraints exist in such statement of the problem.Efficiency of action of a blast of divided charges. In [2 -4] we substantiated the conditions for determining what is known as the effective part of divided charges for characteristic fragments of the blast-affected volume, which is in fact responsible for the resulting impact of the blast at the given point (or WO).In the general form for an arbitrary point (but for r ¹ 0) of the medium loaded with the blast this parameter can be ...

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