RU2329463C1 - Shortened monolithic stemming plug - Google Patents

Abstract

FIELD: blasting.

SUBSTANCE: invention relates to the field of drilling and blasting in hard rock quarries and may be applied in various industries where blasting in rock masses is used. A shortened monolithic stemming plug is made of a concrete mixture. The bottom portion of the stemming plug receives a hollow conical pressboard or plastic element that is mounted with its tip pointing upwards and occupies up to a half of the stemming plug height. The conical element is mounted onto a foam polystyrene or foam plastic pack being placed between an explosive charge and the monolithic stemming plug.

EFFECT: reducing the volume of concrete mixture required for making a monolithic concrete stemming plug.

2 dwg

Description

The invention relates to the field of drilling and blasting in strong rocks in quarries and can be used in various industries using blasting in rock massifs of rocks.

Known stemming in the form of self-jamming corks from hardened concrete, consisting of a conical element placed on a clay cork above the explosive charge and directed with its tip pointing upwards and side wedges mounted on a cone [1]. Such a plug has sufficient strength, good resistance to buoyancy forces, since with their increase the lateral spacer increases, which increases the friction force between the walls of the hole and the side wedges.

The disadvantage of this design is the poor adhesion of the side concrete wedges to the walls of the well of a disturbed structure (with wall outfalls), as well as the need to install a protective plug made of clay between the cone and the explosive charge, which complicates the work on the formation of clogging.

The closest to the essentially solvable problem is concrete jamming, made of concrete mix, hardening in a hole or well [2]. The use of such clogging increases the beneficial effect of an explosion several times.

The disadvantage of this clogging is the need to deliver large volumes of concrete mixture to the charging unit.

The technical problem, the solution of which the invention is directed, is to reduce the volume of concrete mix for the manufacture of monolithic concrete clogging.

The problem is achieved in that in a shortened monolithic stemming made of concrete mixture according to the invention, a hollow conical element made of thick cardboard or plastic is installed in the lower part of the stemming, pointed upward and occupying up to half the stemming height, while the conical element is mounted on a cork of polystyrene foam or polystyrene foam, which is placed between the explosive charge and monolithic stemming.

The invention is illustrated by drawings.

Figure 1 schematically shows the process of pouring concrete mixture on a conical element; figure 2 - shortened monolithic stemming in the well.

The shortened monolithic stemming includes a conical element 1 made of dense cardboard or plastic with a diameter of 4-8% less than the diameter of the hole or well. The conical element 1 is placed on a plug 2 of polystyrene foam, located above the explosive charge 3, placed in the hole or well 4, and poured with concrete mixture 5.

Shortened monolithic stemming is formed as follows. In a hole or well 4, an explosive charge 3 of a given height is formed and the initiating pulse conductor 6 (detonating cord, waveguide, wires from an electric detonator, etc.) is brought out along the wall of the hole or well 4 to the surface. Over the explosive charge 3 place a plug 2 of polystyrene foam backfill granular foamed polystyrene to the calculated height. Due to the fact that the walls of the wells in the upper part are often broken, periodically measure the height of the obtained plug 2. To facilitate the formation of plug 2, a foam can be used in the form of a parallelepiped of a given height with the largest cross-sectional area of 0.52 well diameters, and the gap between it and the walls of the well fall polystyrene foam. The conical element 1 is lowered onto the cork 2 with its tip upward. Then pour the concrete mixture 5. Foamed polystyrene prevents the leakage of the liquid part of the concrete mixture. This completes the process of forming a shortened monolithic stemming, and it remains until the concrete mix 5 has the necessary strength. When using quick-hardening concrete, this process is completed within several hours, and the charging of blocks usually lasts several times longer. After the concrete mixture 5 has hardened, the stemming becomes a monolith and obtains strong adhesion to the walls of the well.

Measurements showed that both granular foamed polystyrene and foam can withstand a fairly high load with an acceptable amount of precipitation.

When the detonation of the charge, the conical element 1 burns out, due to the forces of adhesion to the walls of the hole or well 4, the hardened concrete mixture 5 resists the repulsive effect of the explosion products until the destruction of the walls of the well. An additional positive effect is also exerted by the expansion by gases of the explosion of the conical part of the monolithic stemming into the walls of the well. Reducing the stemming height due to the foam polystyrene plug allows you to increase the zone of controlled crushing in the well, and locking detonation products until the rock mass is completely destroyed increases the duration of the explosion on the mass, which increases the use of explosion energy on the rock mass. The use of a hollow conical element allows you to speed up the process of formation of stemming and reduce the volume of concrete delivered to the block.

Thus, the claimed shortened monolithic stemming allows you to lock the products of the explosion in the charging cavity of holes or wells until the destruction of the array and thereby increase the efficiency of the use of explosion energy for crushing rocks and solve the technical problem of reducing the consumption of concrete mix.

Information sources

1. Berishvili G.A. The effect of drilling holes on the efficiency of an explosion in the conditions of the Chiatura manganese deposit // Blasting No. 57/14. M: Subsoil. 1965. S.330-338.

2. Legastaev EG Investigation of the effect of expanding drilled holes on the results of the explosion // Sat. Blasting business No. 59/16. M .: Nedra, 1966. - S.262-266 (prototype).

Claims (1)

Shortened monolithic stemming made of concrete mixture, characterized in that in the lower part of the stemming there is a hollow conical element made of thick cardboard or plastic, pointed upward and occupying up to half the height of the stemming, while the conical element is mounted on a foam polystyrene or foam plug, which is placed between the explosive charge and monolithic stemming.

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