RU1776322C - Method for protecting mine working - Google Patents

Abstract

Usage: the invention prevents the swelling of the soil of mine openings. SUMMARY OF THE INVENTION: a system of discharge slots is formed in the excavation soil, which is oriented across the longitudinal axis of the excavation at an angle of 90 °; - p to the horizontal, where p is the angle of internal friction of soil rocks. In this case, the depth of the slots is 0.5-0.75 of the working width, the distance between them is twice the depth, and the width is determined from the expression d (100t- - 20) btgЈ, mm, where cg is the voltage at the working depth at untouched massif, MPa; Rc is the uniaxial compression strength of soil rocks, MPa; b - the width of the development, m. 3 ill.

Description

The invention relates to mining and is intended to protect the mine workings from large deformations of soil heaving.

A known method for preventing heaving of soil rocks in the workings of thin coal seams is to undermine the coal seam to a depth of 3.5 m and a height of 0.1-0.15 m in the side wall of the drift of the opposite lava.

Closest to the proposed one is a method of combating soil rock heaving, which means that the development takes place with the formation of a layer of stable rocks between its soil and heaving rocks, and discharge slots cut from both sides of the mine to the upper border of the heaving rocks,

produce a height greater than the design by the value of Ah determined from the expression

L h Kb / cos (arcsln 51) (1 - ф2),

where K is the coefficient of compaction of pliable material;

d is the width of the discharge gap;

m is the power of a stable rock beam;

I is the depth of the discharge gap.

However, this method provides the operational ability and stability of the mine in a very limited number of cases, especially at great depths and under difficult geological conditions. This is due to the fact that for the overwhelming number of mine workings, the heaving rocks are directly in the soil (especially for

XI XI

about s y u

W

preparatory workings) and the formation of a stability layer in them is almost impossible. An example of this is the frequent destruction of roof supports with a reverse arch, especially under the influence of treatment works. In addition, the absence of correlation of the parameters of discharge slots with mining and technical and mining and geological conditions, for example, the value of Ah does not depend on the heaving value. The same applies to other parameters, although it is clear that after closing the slots, the discharge effect will disappear. At the same time, the method requires significant labor and material costs, because includes excavation of increased height, strengthening of the underlying layer, etc. (The magnitude of heaving reaches 1-2 m).

The aim of the invention is to prevent heaving of the excavation soil and increase the period of maintenance-free maintenance by redistributing stress concentrations around its contour by choosing the orientation and location of the discharge cavities and a differentiated approach to determining their parameters.

The goal is achieved in that a system of discharge slots with a depth f equal to (0.5-0.75) b, where b is the width of the excavation, is formed in the soil of the protected excavation in the direction transverse to its longitudinal axis at an angle of 90 ° - p to the horizontal, where p is the angle of internal friction of the soil, the distance between adjacent slots is 21, and the gap width is determined from the expression:

5 (100-pЈ-20) btgp, mm

(1)

where o is the voltage at a depth of the working location in the untouched massif, MPa;

RC is the uniaxial compression strength of soil rocks, MPa;

b is the width of the output, m

Figures 1, 2, 3 show a guarded mine with discharge slots in two vertical sections,

The invention is carried out as follows.

Production 1 is carried out at a depth of 1000 m, a width of 5 m, a 3-meter layer of shale Rc 20 MPa lies in the soil, the angle of internal friction is 25 °, the stress concentration coefficient due to the influence of

treatment works KG 1.45, bulk density of rocks, 5t / m3.

Since the sheathing layer has a thickness of 3 m, it makes sense to cut only it. According to the method, the discharge slots 2 are cut in the soil of the excavation transversely to the longitudinal axis at an angle of 90 ° / 90 - 25 - 65 ° to the horizontal. In this case, the length of the slit must satisfy the condition: s1n (90 ° - / o) 3 m or

3 / sln65 ° 3.31 m, which is 0.662.

The distance between the discharge slots is 21.6.62 m.

The width of the gap is determined by the formula (2)

twenty

(5 () btgp () btgp

l- "YW 1.45 1000-0.025 olch s. „„, ,, in about 100 (--tt 20) 5 tg 2cr 376 mm

We emphasize that the depth of the gap is determined from the condition that it completely cuts through the zone of inelastic deformations, which determines the main deformations of the soil heave (zone of intense fracturing), the value of which is 0.5-0.755 (see above). In this

example, this value does not exceed 3.31 m,

Claims (1)

SUMMARY OF THE INVENTION A method for protecting a mine working area, including conducting unloading slots in the soil, characterized in that, in order to prevent heaving of the working soil, to increase the period of maintenance-free maintenance, unloading slots in the working soil are carried out with a depth I equal to 0.5-0.75 of the working width, in the direction transverse to its longitudinal axis at an angle of 90 ° - p to the horizontal, where p is the angle of internal friction of the soil, the distance between adjacent discharge slots is chosen equal to 21. and the width of the slots is determined from the expression b (1QOflr -20) b -tg / e.mm, where 7 is the voltage at a depth of the development in an untouched massif, MPa; RC is the uniaxial compression strength of soil rocks, MPa; b is the width of the output, m Mr. L 21 90 ° -jD 3 (f + J Figure 1 6-5