SU1602997A1 - Method of driving mine workings - Google Patents

Abstract

The invention relates to making drilling and blasting workings. The goal is to expand the scope of application of the method to conditions with the prevailing effect of horizontal stresses. The stress state of the array is estimated by the magnitude and direction of the action of the main horizontal stresses. They form advanced production / MF / smaller sections by drilling and blowing up cords with a length not less than twice the value of the unloading zone length. In this case, the PV passes a trapezoidal shape with the angle of inclination of the side walls to the base, calculated as a function of vertical and horizontal stresses. At the same time, a high voltage is passed in the direction of voltage with the highest value. Expansion of the generation is carried out to the extent that the ratio of the cross-sectional area of the extended output to the cross-sectional area of the PS does not exceed the ratio of the width of the discharge zone of the generation of the designed section to the width of the discharge zone of the PV. The blasting of bore-holes is first carried out along the contour of the PV, then at an interval equal to the relaxation time of stresses in the beam. After that blow up the rest of the hole PV. The last step is to expand the output to the design section. 5 il.

Description

The invention relates to mining and can be used in mining operations by drilling and blasting.

The purpose of the invention is to expand the scope of application of the method on conditions with the prevailing effect of horizontal stresses.

Figure 1 depicts the relative position of the bottom holes of small and large sections, traversed in the direction of maximum principal tensile stresses.

MF in Fig. 2 shows the optimal ratio between the dimensions of the advanced and design workings in the absence of horizontal stresses; fig. 3 - the same, under conditions of action of tensile stresses, in Fig. 4 the order of blasting of holes in advanced development; Fig. 5 illustrates the implementation of the method in the presence of horizontal compressive stresses.

In the drawing, numbers and letters indicate the massif 1 of rocks, the contouring holes 2 of the first set, advanced generation 3, compensation holes 4 of the first set, cut holes 5, holes of the second set 6, generation 7 of the design section, section Sa, Si advanced. ; the values of ai stg +1 of the effective vertical and horizontal stresses, the width Lp, IP of the discharge zone; angle of inclination of the walls of the advanced generation.

Os Oh

you you h

The method uses an artificial change in the direction of application of the resultant forces by imparting certain inclinations to the walls.

To compensate for the effect of horizontal stresses, a change in the direction of application of the main vertical stresses sp and one of the horizontal stresses is used, for example

af + 1 a &.

With a trapezoidal form of production

on its walls, the stresses ai and are balanced, which follows from the equation

- 2

(71 cosa: -n- stna.

where is arctg

2CT1

(figure 2 is taken into account

0-3 on both sides of the production of compensation).

In this connection, the blasting of bore holes along the contour of a trapezoidal excavation with the specified angle of inclination ahead of the relaxation time of the stresses, the blasting of the first and third cutting boreholes at the time of occurrence of elastic stresses immediately after their explosion creates a uniaxial (or close to it) ) compression for the first set of boreholes, which significantly increases the efficiency of the explosion.

Breaking rock (ore) in the cross section of the projected development, provided that the ratio of its section to the advanced section

/ Ln 2 output will not exceed j j

will also occur in the absence of horizontal stresses, which will ensure high stability of the development.

The method is carried out as follows.

Before starting the tunneling works in array 1, one of the known methods, for example, the unloading method, determines the magnitude and direction of the main stresses of the SP: ai; a + i, as well as the dimensions of the discharge zone, and the stress concentration factor Lp, p, and Kk.n. The development is carried out in the direction of the voltage with the highest value,

Further perpendicular to the direction

 the contour area Si 1,4 / 10-Lpx xKk.n.-1 / m advanced production 3 smaller than the designed production, sections, in the form of a trapezoid with an angle of inclination of the walls

making arctg

And in

2g | . SP +1

The contour holes 2 are blown up first. Depending on the diameter and the level of the acting stresses, the distance between the contour holes 2 can be reduced to the penetration hole, but half of the holes (in one) are used as compensating holes 4. After a while

Tr of relaxation of stresses produces blasting of bore holes 5, and then in the received sequence - the remaining boreholes of the first set. After advance development 3 will be passed on

a length of more than 2 Lp, drills and blows up the bore-holes of the second set 6, thus forming the design cross-section of the excavation 7, provided that the ratio of the area of the extended excavation to

advanced production area not exceeding (G

em

Claims (1)

Claim Method of excavation of mine workings, including assessment of the stress state of the massif, formation of advanced production of a smaller section by drilling and blasting holes of a length of more than twice the length of the discharge zone and subsequent expansion of development to the design section, characterized by the fact that applying the method to conditions with the prevailing effect of horizontal stresses, the estimation of the stress state of the array is carried out according to the magnitude and direction of action of the main horizon lnyh voltages tunneling generation is produced in the direction T with the highest voltage value at this advanced generation extend trapezoidal shape with an inclination angle of the side walls relative to the base / 2ai and arctg ( a + t) where (71 is the vertical stress; (jf + i is the horizontal stress orthogonal to the direction of penetration, and the extension of the excavation is made to the size at which the ratio of the shadow area of the expandable excavation to the cross-sectional area of the advanced generation is not less than (Lp / lp) 2, where Lp and IP are the width of the discharge zone from the workings of the projected section and the section of the advanced development, respectively, and blasting holes are first carried out the contour of the advanced development, then at an interval equal to the relaxation time of the stresses, in the cutting edge, after which the rest of the advanced development boreholes are blown up. Figg (f & 2 LP FIG. five FI.4 l four FI.5