The regularities and methods of forming the parameters of the explosive momentum of charges of low-density foamed explosive compositions in the technologies of compaction of structurally unstable soils are chosen as the subject of research. In the dissertation on the basis of the offered and improved compoundings of the low-density foamed explosive compositions processed by ultrasonic radiation for the purpose of formation of necessary explosive parameters that for the first time allowed in a complex with the offered way of preparation and the developed device for formation of to carry out blasting works to ensure the stability of structurally unstable soils.
Particular attention is paid to the effect of ultrasonic radiation on the structure and physical and mechanical characteristics of ammonium nitrate and on the detonation characteristics of foamed explosive compositions.
During the microscopic examination of the external and internal structures cleavage granules (particles) of ammonium nitrate was found that existing on the surface of the pores are in the range of 3% to 8% and that of the surface pores existing pellet is not implemented because it is sealed.
It is known that one of the methods of explosion control in the soil massif is the optimization of the amplitude-time parameters of the explosion pulse. Therefore, the article theoretically considers the impulse of the explosion at the boundary of the explosive – soil mass distribution for advanced foamed explosives compared to conventional ones, namely ammonite and igdanite, and found that the maximum pressure of the foamed explosive treated with ultrasonic explosives 49 % amonit and 40 % for ignadite. The maximum duration of the explosive pulse at the "detonation products - medium" boundary for foamed explosives treated with ultrasonic radiation is slightly more than 3 times. In charges based on foamed explosives, the main part of the explosive pulse has a minimum value of peak pressure and maximum duration, as for explosives with the lowest detonation rate and the largest width of the chemical reaction zone. The pressure of the foamed explosive after treatment with ultrasonic radiation is slightly lower than that of a conventional foamed explosive, but the duration of the explosive pulse is shorter.
The nature of the propagation of explosive waves in the soil environment for structurally unstable soils is as follows - at the boundary with the cavity in the explosion of the charge of igdanite are achieved much higher values of hydrostatic pressure and maximum volumetric deformation than in the explosion of foamed explosives. This is due to the higher detonation characteristics of igdanite. In addition, at distances greater than 40 r0, the highest pressures and volumetric deformations are achieved during explosions of foamed explosives. Moreover, for the foamed explosive treated with ultrasonic radiation, the residual deformation is greater than in the explosion of conventional foamed explosives by 9–10%.
Research degree of compaction structurally unstable soils using blasting using overhead and counter-prone wells showed that the optimal angle wells is in the range of 20 to 30 °. Surface charges of providing sealing mass of soil to a depth of 2.0 m for igdanite and a depth of 3.0 m for explosives with low charge density at a power of 100 mm.
It has been experimentally established that foamed explosive compositions provide compaction of subsidence loess soils to a greater depth of the massif, which is 27–30 charge capacities in comparison with igdanite, which provides compaction to a depth of up to 20–25 charge capacities.
Due to the results obtained compression studies found that when adjusting the degree of compaction can provide the required performance characteristics of deformation for sustainability structurally unstable soils.
Devices for preparation of explosive compositions have been developed and proposed, in which mechanical mixing of surfactant solution and ammonium nitrate is carried out in low-speed mode without foaming the mixture, supplying this suspension under pressure to the blasting object and dosed aeration due to ejection of air issuing a foamed explosive composition to the site of application. This increases the safety of work, because the unfoamed mixture of surfactant solution and ammonium nitrate is not sensitive to impact and friction, and the explosive properties of this suspension are manifested only after saturation of the mixture with air bubbles at the exit of the foam suspension from the ejector.
Keywords: ultrasonic radiation, holding capacity, foamed explosive composition, structurally unstable soil, degree of compaction, explosive pulse, pulse duration, pulse rise time, device for preparation of explosive compositions, detonation characteristics, peak pressure, detonation of near-surface, shallow-buried explosives, deformation pressure.
