SU1213194A1 - Method of monitoring state of rock - Google Patents

Description

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The invention relates to the mining industry and can be used to control the stability of the pillars and the roof of mine workings, especially devices with wireless transmission of readings from control points.

The purpose of the invention is to increase the accuracy of control of the state of mountain pores due to the combination of control zones by movement parameters and acoustic emission.

Fig, 1 shows a diagram of the installation in the borehole cross-overs and acoustic emission sensors; in fig. 2 - timing diagrams that explain the operation of the channel for the registration of acoustic emission pulses.

In the hole G drilled in the array

2 mountain rocks, set the rapper

3 and 4 and sensors 5 and 6 of acoustic emission. Zone 7 of the control of acoustic emission parameters is limited to the surface 8 of the hyperboloid of rotation. The control zone 7 according to the parameters of acoustic emission from below is bounded by the surface 9 of the roof or pillar, where the hole 1 is located. The movement control zone (not shown) is located in the area of reverts 3 and 4. One reference point 3 is set close to the mouth, the other reference point 4 is deep in the ptu. The distance between frames 3 and 4, which is the depth of the control zone, is equal to ft, the distance between the frame 4, located between the acoustic emission sensors 5 and 6, and the acoustic emission sensor 5, located between reference frames 3 and 4, is c), the distance between the acoustic emission sensors 5 and 6 is equal to B.

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In the rock massif 2, there are cracks 10 located in zones 7 of the control according to the parameters of acoustic emission, and cracks 11 located outside zone 7 of the controls according to the parameters of acoustic emission. Timing diagram 12 shows the pulse 13 detected by the acoustic emission sensor 5 located between reference points 3 and 4. The timing diagram 14 shows the pulse 15 detected by another acoustic emission sensor 6 when crack II is outside the control zone 7 by parameters acoustic emission. Timing 16 shows

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pulse 17, registered by the same acoustic emission sensor 6, when the crack 10 is in zone 7 of the control according to the parameters of acoustic emission. Diagram 18 shows an impulse 19 time zone.

The method of monitoring the condition of mine workings is carried out as follows.

In the hole 1, drilled from the mine workings in the array of 2 rocks, install the sensor 6 acoustic emission. The initial data for determining the depth of installation of the acoustic emission sensor 6 are the parameters of the required control zone 7, such as depth h and maximum size L of the boundary of the control zone on a plane normal to the hole axis and passing through the frame. These parameters are determined from technological requirements, so L is determined by the roof’s 5th, and b is the power of possible collapse. In addition, the velocity V of the elastic waves in the rock is determined in advance of the samples, and the duration t of the prohibition zone should be known The speed of the devices (not shown) that process the acoustic emission pulses. With their large speed, the value of i is less. At the same time, the acoustic emission sensor b is installed in the hole to a depth equal to w -fh-d, from the wellhead, where the parameter b is determined from the required depth control zone, and the parameters E and 1 of the suggested ratios based on the values of the parameters h, L, t, V.

Then, the frame 4 is set at a depth h, and the acoustic emission sensor 5 is set at a depth LL. The frame 3 is installed near the mouth of the hole I. The acoustic emission sensor 5 is connected to the starting circuit of the former (not shown) of the time zone of the prohibition, so that the beginning of the pulse 19 of the time zone of the ban coincides with the beginning of the pulse 13 detected by the acoustic emission sensor 5 located between the frames 3 and 4. When an artifact rock appears in zone 7 of the control 2 of the rock 2, the acoustic signal is recorded by sensors 5 and 6 of acoustic emission, and the change in the deformed state of the rocks is recorded by monitoring the mutual about moving the benchmarks 3 and 4 one relative to another. If the crack 11 appears outside the control zone 7, the acoustic signals fall into the temporary zone of prohibition and they are not recorded, and the changes in the deformed state of the rocks are insignificant and they are also not recorded.

The intensive process of cracking in the roof, preceding its collapse, characterizes the dangerous state of the rocks and is recorded both by sensors 5 and 6 of acoustic emission, and as a result of mixing reference points 3 and 4. After measuring the values of acoustic parameters

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213194.4

emissions (following frequency, pulse energy or other) and values of parameters of longitudinal displacements of frames one relative to another (magnitude of displacements, their speed, acceleration, etc.), in a multidimensional parameter space divided into areas of a rock mass state ( areas of stable 0 out, critical and dangerous states), determine the point corresponding to the obtained values of the parameters, as a result of which the region and state of the mountain massif are determined.

15 rocks corresponding to the values of the parameters. Such identification is possible, since the control zones for acoustic emission parameters and displacement parameters coincide.

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Editor Mi Bpanar

Compiled by G. Alekseeva-,

Tehred M. Gergel Corrector G, Reshetnik

Order 762/44 Circulation 470 Subscription VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Branch PPP Patent, Uzhgorod, st. Project, 4

0U9.Z

Claims (1)

METHOD FOR MONITORING THE STATE OF ROCKS, including measuring the parameters of the movement of the benchmarks relative to each other, installed in the borehole, measuring the parameters of the acoustic emission pulses by the sensors installed in the borehole, the formation of a temporary ban eon, and the beginning of the formation of a temporary ban zone is combined with the beginning of the acoustic emission pulse of one of these sensors, combine with the beginning of the formation of the temporary prohibition zone, compare the values of the longitudinal displacements of • benchmarks and parameters of the impulse of ac emission emission with predetermined ones, characterized in that, in order to improve the accuracy of monitoring the condition of the rocks by combining control zones according to the parameters of movement and acoustic emission, the frames and acoustic emission sensors are installed alternately along the borehole axis, and the distance t between the acoustic emission sensors is selected from ratios ^{? = V, t} V ^{+ _} 4 ^_ * V ~ t ~ h + h ** and the distance d between the acoustic emission sensor located between the benchmarks and the benchmark located between the acoustic emission sensors is selected from the ratio. d- _r <T | where V is the speed of elastic waves in the rock; t is the duration of the time zone of the ban; L - maximum zone size 1 ₊ V___1____ 4 * Vftih + h * Oh, control on a plane normal to the axis of the hole and passing through the benchmark; h is the distance between the benchmarks. J 1213194 I 12