RU2101673C1 - Method of explosive breaking of broken-up rock mass at breaking onto basset - Google Patents

Abstract

FIELD: breaking of broken-up rocks of any types. SUBSTANCE: the method consists in drilling-up of rows of well blastholes in area of the rock mass to be broken in a strictly definite order: the distance between the rows of blast-holes (wells) should be equal to W (not more); the distance between the blast-holes (wells) in rows should be equal to r_r (not more), and their breaking in turn, producing the design contour of the broken-up mass. The values of W and r_r are determined depending on the strength characteristics of the broken-up mass and powder of the explosive used. EFFECT: enhanced efficiency. 1 dwg

Description

 The invention relates to the mining industry and can be used for explosive destruction of a fractured mountain massif during blasting to a bare plane.

A known method of explosive destruction of a fractured rock mass [1]
The disadvantages of the method are: the lack of consideration of the influence of the confusion zone formed during the explosion, the strength characteristics of the array (depending on the fracturing and power of the explosion); the strength criterion for the destructible massif, on which the parameters of the explosion funnel depend, is not defined (the tensile strength of the destructible rock for explosion is taken as an example); non-optimality and instability of the proposed method.

The closest in technical essence and the achieved result is a method of destruction of rocks according to [2]
The disadvantages of the method are: do not take into account changes in the strength characteristics of the fractured fractured massif depending on the intensity of fracturing and the power of the explosion; non-optimality of the proposed method for fracturing a fractured massif.

 The aim of the invention is to increase the efficiency of explosive fracture of a fractured mountain massif under various mining and geological conditions, the possibility of taking into account the changes in the strength characteristics of the massif depending on the degree of disturbance and power of the explosive used in this process.

To this end, in the known method, including drilling a series of holes (wells) in the contour of a fractured fractured array, placing explosive charges in them and blasting them alternately, drilling holes (wells) is carried out in such a way that the distance between the rows of holes (wells) should be equal r _p (not more than this value), and the distance between the rows of holes (wells) should be equal to W (not more than this value).

 The drawing shows the location of the holes (wells) over the area of the beaten out fractured rock mass (I rows of breaking; 1, 2, 3 - sequence of breaking).

The method is as follows. In the design contour of the knocked-out fractured massif, rows of holes (wells) are drilled in such a way that the distance between the rows of holes (wells) is W (no more than this value), and the distance between the holes in the rows is r _p ; make charging drilled holes (wells) and their alternate blasting (figure 1, 1,2,3 sequence of blasting).

Величина W определяется из соотношения:
W r_pcos30^o, (5)
где
d_см диаметр образующейся при взрыве зоны смятения, м;
d диаметр отбойных шпуров (скважин), м;
g -плотность ВВ в заряженном шпуре (скважине), кг/м³;
v скорость детонации применяемого ВВ, м/с;
τ_ср предел прочности пород на срез, Па;
K_c коэффициент структурного ослабления, д. ед;
σ_сж предел прочности пород на сжатие, Па;
r_p1 радиус взрывной воронки, определяемый для условий отбойки монолитного массива, м;
l_m среднее расстояние между трещинами длиной более одного метра, м;
a коэффициент, зависящий от направления трещиноватости по отношению к направлению отбойки (линии наименьшего сопротивления; для разнонаправленной трещиноватости блочный массив a 0,072), д.ед;
Сущность и пример конкретного выполнения способа заключается в следующем. Определяются горно-геологические и горнотехнические условия отбойки трещиноватого массива; например, необходимо произвести отбойку трещиноватого массива в породах с пределом прочности на сжатие 100 МПа; предел прочности пород на срез 30 МПа; трещины разнонаправленные, среднее расстояние между трещинами (блочность массива) 0,2 м; диаметр шпуров 0,04 м; плотность заряжания 900 кг/м³; ВВ детонит 10 А (скорость детонации 4,9 км/с).The value of r _p is determined as follows:

The value of W is determined from the ratio:
W r _p cos30 ^o , (5)
Where
d _cm diameter of the confusion zone formed during the explosion, m;
d diameter of boreholes (wells), m;
g is the density of explosives in a charged hole (well), kg / m ³ ;
v detonation velocity of the used explosives, m / s;
τ _{av the} ultimate tensile strength of the rocks, Pa;
K _{c the} coefficient of structural attenuation, D. units;
σ _cr ultimate rock compressive strength, Pa;
r _p1 radius of the explosive funnel, determined for the conditions of breaking the monolithic massif, m;
l _m average distance between cracks more than one meter long, m;
a coefficient depending on the direction of fracture with respect to the direction of breaking (line of least resistance; for multidirectional fracturing, block array a 0.072), unit
The essence and example of a specific implementation of the method is as follows. The geological and mining conditions are determined for breaking the fractured massif; for example, it is necessary to break off a fractured mass in rocks with a compressive strength of 100 MPa; tensile strength of rocks at a slice of 30 MPa; cracks are multidirectional, the average distance between cracks (blockiness of the array) is 0.2 m; hole diameter 0.04 m; loading density 900 kg / m ³ ; BB detonite 10 A (detonation velocity 4.9 km / s).

 1. Determine the radius of the zone of crushing formed during the explosion (according to formula 2).

2. Определяем радиус образующейся при взрыве воронки для монолитного массива (согласно формуле 4):

3. Определяем коэффициент структурного ослабления (учитывающий прочностные характеристики массива в зависимости от расстояния между трещинами и мощности применяемого ВВ; согласно формуле 3):

4. Определяем расстояние между шпурами в рядах отбойки (радиус образующейся взрывной воронки для трещиноватого массива; согласно формуле 1):

5. Определяем линию наименьшего сопротивления (расстояние между рядами отбойных шпуров; согласно формуле 5):
W 98•cos30^o 0,848 0,85 м.

2. Determine the radius of the funnel formed during the explosion for a monolithic massif (according to formula 4):

3. We determine the coefficient of structural attenuation (taking into account the strength characteristics of the array depending on the distance between the cracks and the power of the explosive used; according to formula 3):

4. Determine the distance between the holes in the rows of blasting (the radius of the resulting explosive funnels for a fractured array; according to formula 1):

5. Determine the line of least resistance (the distance between the rows of boreholes; according to formula 5):
W 98 • cos30 ^o 0.848 0.85 m.

 Having all the necessary data, we proceed to drilling, loading and breaking off the fissured rock mass (with the condition that the distance between the rows of holes is 0.85 m; between the holes in the row is 0.98 m).

 Thus, the proposed method has the following advantages compared to the prototype: it allows to ensure the stability of blasting for various mining and geological and mining conditions; get the optimal number of holes (wells) for specific mining and geological and mining conditions; take into account the power of the used explosive, the diameter of the holes (wells) in which the charge is formed, the strength characteristics of the fractured massif (depending on the intensity of fracturing and the power of the applied charge).

Claims (1)

The method of explosive destruction of the rock mass during blasting to a bare plane, according to which the distance between the holes (holes) in the rows of the holes is determined, the distance between the rows of holes (wells) is determined, parallel holes (holes) are drilled, explosive charges are placed in them and their sequential order blasting, starting from the exposed plane, characterized in that when the fractured rock mass is destroyed to determine the distance between the boreholes (wells), the structural factor is taken into account in the same row of weakening

where a is a coefficient depending on the direction of fracture with respect to the direction of breaking (for multidirectional cracks, block array a is 0.072);
r _{p l} radius of the explosive funnel, determined for the conditions of breaking the monolithic massif, m;
l _m average distance between cracks more than one meter long, m,
the distance between the holes (wells) in the rows of blasting is determined from the expression

where d _{with m is the} diameter formed by the explosion of the collapse zone, m;
d diameter of boreholes (wells), m;
g density of explosives in a charged hole (well), kg / m ³ ;
V detonation velocity of the explosive used, m / s;
τ _cp is the ultimate tensile strength of the rocks, Pa;
K _{with the} coefficient of structural attenuation d.ed,
and the distance between the rows of holes (wells) is determined from the expression W = r _p • cos30 ^° .1