SU543905A1 - The method of determining the boundaries of the strained massif around the mine workings - Google Patents

Description

(54)

METHOD FOR DETERMINING THE BORDER OF A STRESSED MASSIF AROUND MINING PRODUCTIONS

The invention relates to geophysical exploration methods and can be used, in particular, to determine the boundary of the arctic array around gene patterns.

The ultrasonic method, carried out by drilling wells in the rock mass of the surrounding rocks, is known for drilling with subsequent logging along the well length. To implement this method, it is required to perform work on drilling wells in the array under study and to send a source of oscillations and receiving sensors to the well. In addition, the ultrasonic method is not suitable for the simultaneous study of large volumes of rock mass due to the need to drill a well network and small bases between the measuring points.

In the gofnaic exploration, it is known for a collection of hodographs to determine the depth of the aerial layers, which consists in the fact that, based on seismograms obtained by shooting through the seam patterns, the phases or the first arrivals build up a year and produce them nfc. .

However, to construct the hodographs, seismograms of elastic oscillations of the layers of mountainous pfdods, possessing various physicomechanical you, which would serve as the boundaries of the section, are necessary. This thickness of the layers should be several tens of hundreds of meters.

There is also a known method of acoustics on determining the non-uniformity of an array in output, which consists in the fact that elastic oscillations are excited in the acoustic duct and the amplitudes of elastic waves reflected from the nonuniformities of the elastic waves are recorded,;. aspolozhennyh in the definition-i lennom porvdke on the surface of the book, in the excavation PV / vfitelno determined polozhenve sound {fovoda about azovan th region of elevated natf zheny, lszhalnzovannoy VBL um s rabotki "excite elastic loav Banwa opoedelennoy frequency acoustic line n on the level m signals of gfynty receivers,

The magnitudes of the size and shape of single-U-JCTH on the pedewavestheplaces determine the size and shape.

This method requires a preliminary determination of the position of the sound duct, which is associated with the performance of labor-intensive work on drilling holes or wells in the wall of the mine to establish an area of high stresses. In addition, it requires the placement of the radiators of the elastic gables; in this area Drilling holes in the array to accommodate the emitters of elastic oscillations redistributes the value of stresses in the array and reduces the accuracy of the measurements according to the estimate of the array or array around the exercises.

The aim of the invention is to increase the efficiency of the method.

This is achieved by exciting elastic oscillations in the range of 1–5 kHz on the surface of an unstressed array, directing them perpendicularly to the boundary of the stressed array, and judging from the kinematic and dynamic characteristics of the ecstatic oscillations, determine the location of this boundary.

The method is illustrated in the drawings (Fig. 1 and 2).

In the mountain mass, O1fuzhaksh (I eat up 1, under the influence of the mass of overlying rocks, stress concentrations arise that can be divided into three zones: an unstressed massif 2, an increased stress zone 3, and a natural stress zone 4. Each of the zones under consideration , due to the different loading of the array, it will have different speeds of elastic oscillations.In zone 2 there will be speed V. in zone 3, in zone 4 - ultrasonic, accordingly cooTHoiab-ine speeds will be V. V, V-.

The proposed method is based on the detection of forward longitudinal waves passing through layer 2, reflected longitudinal waves from zone 3, as well as refracted longitudinal waves in zone 3.

For the production of measurements, the source of elastic oscillations 5 and the receivers of elastic oscillations 6, 7, 8, 9, 1О, 11, 12, 13, 14 are placed on the surface of generation 1, along the profile m (Fig. 2),

The collectors on the wall are placed in separate groups in the zone of action of the forward longitudinal wave / Pi / 6, 7, 8, reflected / Pc / 9, 1O, 11; refracted / Pi2i / 12, 13, 14.

The waves from the oscillator 5 propagate in all directions and to the tinder of receivers 6, 7, 8 will come straight longitudinally B.. When reaching the forward wave j; t: -r - female array 3 here obr. ; :, tf reflected P and 11reloml% n 1-l

All listed 1.; e b. register. Repeated measurements are made by placing the source of oscillations at point 15; Goh Eraphs of waves P are plotted by the first recorded oscillations; P, 121, direct longitudinal wave p ,, gives an estimate of the velocity of propagation of elastic oscillations in the zone of an unstressed mass, which can be determined using the following formula:

v |

(one)

where is the speed of a direct longitudinal wave in an unstressed array; C is the distance from the oscillation source to the receivers 6, 7, 8: is the propagation time of the forward longitudinal wave in the non-stressed array.

By the value of the velocity, the state of the unstressed mass around the mine is estimated.

Hodograph of the reflected wave P - allows you to establish the time of arrival of the reflected wave and determine the thickness of the layered stress array during the design by the formula:

H ..v.8r (a)

where hf is the thickness of the layer unstressed

array, around the development; i.- time of propagation of the reflected wave;

and, is the distance from the oscillation source to the receivers of the reflected wave 9, 1O, 11.

From the hodograph derivative of the 1-felled PIOI wave, the effective value of the velocity of the longitudinal wave in the prestressed array is determined.

where uEj is the increment of the distance between the supply of elastic waves of a given frequency 12, 13, 14; d - time increment

refracted wave along the profile of the receivers 12, 13, 14; refracted wave velocity

zone of unstressed array. The quantitative value of the velocity Vj makes it possible to estimate the state of the stressed array around the workpiece. Since the pre-emlon waves in the tensioned array go along its surface, the entrance to it at the angle of total internal reflection i, the depth of the location of the tensioned array is determined by the formula:

h (Va-Ug

 avjcos

where h is the depth of the tension of the tension array;

t is the propagation time of the refracted wave;

6 is the distance from the source of oscillations to the receivers of the refracted wave 12;

4 is the angle of total internal reflection (3ini Vj / Vj).

Using the proposed method provides in comparison with existing methods the following advantages.

No drilling or drilling in the test mass is required;

the supply of elastic waves of a given frequency of 1–5 kHz allows filtering the oscillations and extracting useful longitudinal waves carrying information about the array array;

2 /

 U

-.-1 -b- | 7- | - VI I

1l-srca

the use of the boundaries of the zones of the stressed array as a reflecting layer and the recording of the reflected and refracted waves from this layer makes it possible to make a rapid assessment of the state of the array around the windings;

It is possible to determine the depth of the distraction zone of the unstressed zone and the location of the stressed array by two types of waves, reflecting and refracted, which ensures the density and reliability of the results.

Claims (1)

Invention Formula The method of determining the boundary of the inflatable mass around the mine workings by exciting and recording elastic oscillations on the production wall with subsequent analysis of recorded oscillations, characterized in that, in order to improve the efficiency of the method, elastic oscillations in the unstressed mass in the 1-5 kHz range are excited They are perpendicular to the boundary of the stressed array and, judging by the Juchematic and dynamic characteristics of the recorded oscillations, judge the location of this boundary. - / ki t-j jiAiiu (() (// l FIG. 2 cm s il