CN103104294B - Rock burst prediction method - Google Patents

Abstract

The invention discloses a prediction method of rock burst. In the present invention, the three-dimensional vibration pickup connecting sleeve (2) is fixed between the coal electric drill (1) and the drill pipe (3), and the three-dimensional vibration signal of the drill pipe during drilling is collected synchronously by the three-dimensional vibration pickup connecting sleeve (2). The vibration signal is wirelessly transmitted to the signal transceiver (6) by the wireless radio frequency transceiver chip (5) on the three-dimensional vibration pickup connection sleeve (2) for storage, and a spectrum curve is output every interval T, and the first 8 of each spectrum curve is recorded output the main vibration frequency of each order with the drilling depth or time variation curve, and then predict the rockburst tendency of the coal seam according to the number of distortion points of the main vibration frequency with the drilling depth or time variation curve, and then combine the drilling The rockburst can be predicted comprehensively with the chip amount and the vibration curve obtained during drilling. The invention digitizes the phenomena of drill suction, drill sticking and drilling impact, and greatly improves the accuracy of rock burst prediction.

Description

A Prediction Method of Rock Burst

technical field

The invention relates to a method for predicting rockburst or rockburst in mines.

Background technique

Rockburst, also known as rockburst, refers to the dynamic phenomenon of sudden violent destruction due to the instantaneous release of elastic deformation energy of the rock mass around the shaft or working face, often accompanied by throwing of coal and rock mass, loud noise and air waves, etc. Phenomenon. It is very destructive and is one of the major disasters in coal mines. There are omens before the occurrence of rock burst, the main manifestations are: severe periodic pressure, coal wall side cuts, top and bottom ends falling, roof sinking speed increases; drill stuck when drilling pressure relief guns and pressure relief holes and suction phenomenon.

Generally, rock burst occurs in the stress concentration area of the mining face. The larger its peak value and the closer the peak position is to the coal wall, the greater the risk of rock burst. Before the rock burst occurs, the deformation of coal and rock stagnates, the moving speed of the roof and floor slows down, and the pressure of coal from the working face also slows down. The compressed coal seam and the deformed roof and floor are elastically deformed to withstand high pressure and accumulate a large amount of deformation energy. By monitoring acoustic emissions and microseismic activity caused by changes in deformation energy, it is possible to infer the impact hazard. The more accumulated energy, the greater the impact risk. If it is multiple releases, the scale of the releases is small. If it is a concentrated release, the impact is strong.

The prediction methods of rock burst can be roughly divided into two categories besides the previous empirical analogy method. One is the local detection method based on the drilling cuttings method, including the deformation observation method of coal and rock mass, the stress measurement method of coal and rock mass, the mobile ground sound detection method, and the rock cake method. This type of method is mainly used to detect the degree of impact risk in local mining sections, and it is simple, intuitive and reliable, and has been widely used. But the disadvantage of this kind of method is that the prediction work is discontinuous in time and space, and it is labor-intensive and time-consuming.

The second category is system monitoring methods, including geosound system monitoring method and microseismic system monitoring method, as well as other geophysical methods, such as: electromagnetic radiation, earth temperature, geomagnetism, etc. This type of method predicts the dangerous state of rock burst based on the continuous recording of dynamic phenomena in coal and rock bodies. The basic condition on which it is based is the dangerous failure process of the rock mass structure, and a series of physical phenomena appearing in advance are used as information. Such methods can realize continuous monitoring in space and time. However, it is difficult to maintain and manage using this method, and it is difficult to analyze data and determine the mechanical state of coal and rock mass. It requires long-term experiments and a large amount of empirical data to accurately predict.

Therefore, a method for predicting the dynamic parameters of rockburst drill pipes is developed, and these vibration phenomena are recorded by using a vibration pickup device during drilling, and whether there is a risk of impact can be judged according to the characteristic values of these vibration phenomena. Or the signal collected by the vibration picking device can be used as the main indicator of rock burst monitoring by the cuttings method to improve the prediction accuracy of the cuttings method, which has obvious significance for improving the early warning degree of coal mine safety.

Contents of the invention

In order to solve the above technical problems, the present invention provides a method for predicting rock burst with high accuracy.

The technical scheme that the present invention solves the problems of the technologies described above comprises the following steps:

1) Connection detection device: connect one end of the three-dimensional vibration pickup sleeve to the drill pipe, and after confirming that the signal transmission between the three-dimensional vibration pickup sleeve and the signal transceiver is normal, connect the other end of the three-dimensional vibration pickup sleeve to the drill pipe. The coal electric drill is socketed, and the coal electric drill is started for trial operation;

The three-dimensional vibration pickup connecting sleeve is composed of a three-dimensional acceleration sensor and a connection device I and a connection device II at both ends of the three-dimensional acceleration sensor. A wireless radio frequency transceiver chip is fixedly connected, the connecting device I is socketed with the coal electric drill, and the connecting device II is fixedly connected with the drill pipe.

2) Pre-drilling: Pre-drill 1m in the non-high stress concentration area and collect the amount of coal powder, record the time required for drilling 1m, divide this time by 15 and round to get the output interval time T of the spectrum curve; when drilling The three-dimensional acceleration sensor synchronously collects the three-dimensional vibration of the drill pipe during drilling, and the wireless radio frequency transceiver chip Ⅰ fixed on the shell of the three-dimensional acceleration sensor transmits the three-dimensional acceleration signal collected by the three-dimensional acceleration sensor to the signal transceiver with the wireless radio frequency transceiver chip II On-board storage, the digital signal stored on the signal transceiver is transformed by the frequency spectrum module on the signal transceiver to obtain the main vibration frequency of the digital signal and form a vibration spectrum curve.

3) Drilling and signal acquisition: Start the drilling rig to drill, and the three-dimensional acceleration sensor will synchronously collect the three-dimensional vibration of the drill pipe during drilling, and transmit the three-dimensional acceleration signal to the signal transceiver through the wireless radio frequency transceiver chip I for storage. Output a spectrum curve at time T , record the first 8 main vibration frequencies of each spectrum curve, and output the variation curve of each main vibration frequency with time or drilling depth; stop drilling after drilling 1m, and collect the amount of pulverized coal.

4) Prediction of rockburst: For normal drilling without rockburst, the longitudinal and lateral vibrations of the drill pipe are equivalent to the vibration dynamics model of a simply supported beam at both ends, and when the drill is stuck, it is equivalent to a certain vibration in the beam. If an intermediate support is added to limit the radial displacement of the point, the lateral vibration frequency will increase significantly when the drill is stuck, that is, the curve of "lateral vibration frequency-drilling depth" will show distortion; and when drilling impact occurs, If the end conditions of the longitudinal vibration of the drill pipe change, the longitudinal vibration frequency will increase significantly during drilling impact, that is, the curve of "longitudinal vibration frequency-drilling depth" also shows distortion;

Therefore, according to the number of distortion points of the main vibration frequency versus time or drilling depth variation curve in step 3), the rock burst tendency of the coal seam can be predicted, combined with the amount of drilling cuttings and the vibration obtained during pre-drilling in step 2) Spectrum curve comprehensive prediction of rock burst.

Further, the acceleration sensor described in step 1) adopts a piezoelectric acceleration sensor with a built-in charge amplifier, the drill pipe adopts a twist drill pipe, and the coal electric drill adopts the one required for drilling a φ42~50mm hole in a high-stress coal mass. coal drill.

The beneficial effect of the present invention is: according to three parameters such as drill cuttings amount, drill pipe transverse main vibration frequency and drill pipe longitudinal main vibration frequency to predict the impact tendency of the coal body, the auxiliary parameters in the cuttings method (suction drill, The digitization of drill sticking and drilling impact) avoids the phenomenon of missing ground pressure impact caused by the operator's omission in the drilling cuttings method construction; at the same time, the main vibration frequency of the drill pipe vibration during drilling is used as the main prediction parameter. The accuracy of rock burst prediction is greatly improved.

Description of drawings

Fig. 1 is a structural diagram of the device used in the method of the present invention.

In the figure: 1. Coal electric drill, 2. Three-dimensional vibration pickup connecting sleeve, 3. Twist drill pipe, 4. Drill bit, 5. Radio frequency transceiver chip Ⅰ, 6. Signal transceiver, 7. Radio frequency transceiver chip Ⅱ, 21 . Connection device I, 22. Three-dimensional acceleration sensor, 21. Connection device II.

Detailed ways

The present invention will be described in further detail below in conjunction with accompanying drawing 1 and specific embodiments.

A method for predicting rock burst, the steps are as follows:

1) Connection detection device: connect one end of the three-dimensional vibration-picking connecting sleeve 2 to the drill pipe 3, and after confirming that the signal between the three-dimensional vibration-picking connecting sleeve 2 and the signal transceiver The other end of 2 is socketed with the coal electric drill 1, and the coal electric drill 1 is turned on for trial operation;

The three-dimensional vibration pickup connecting sleeve 2 is composed of three-dimensional acceleration sensor 22 and connecting device I 21 and connecting device II 23 at both ends of the three-dimensional acceleration sensor. The three-dimensional acceleration sensor 22 is provided with a wireless radio frequency transceiver chip I5; 6 is provided with a wireless radio frequency transceiver chip II7, the connecting device I 21 is socketed with the coal electric drill 1, and the connecting device II 23 is fixedly connected with the drill pipe 3;

The acceleration sensor 22 adopts a piezoelectric acceleration sensor with a built-in charge amplifier, the drill rod 3 adopts a twist drill rod, and the coal electric drill adopts a coal electric drill required for drilling a φ42-50mm hole in a high-stress coal mass.

2) Pre-drilling: Pre-drill 1m in the non-high stress concentration area and collect the amount of coal powder, record the time required for drilling 1m, divide this time by 15 and round to get the output interval time T of the spectrum curve; when drilling The three-dimensional acceleration sensor 22 synchronously collects the three-dimensional vibration situation of the drill pipe 3 when drilling, and the fixed wireless radio frequency transceiver chip I5 on the three-dimensional acceleration sensor 22 shell transmits the three-dimensional acceleration signal collected by the three-dimensional acceleration sensor 22 to the wireless radio frequency transceiver chip. II7 is stored on the signal transceiver 6, and the digital signal stored on the signal transceiver 6 is transformed by the frequency spectrum module on the signal transceiver to obtain the main vibration frequency of the digital signal and form a vibration spectrum curve.

3) Drilling and signal collection: First, determine the drilling depth according to 3.5 times the mining height and prepare the drill pipe and threaded connecting sleeve. After everything is ready, start the drilling rig to drill. When drilling, the three-dimensional acceleration sensor 22 synchronously collects the During the three-dimensional vibration of the drill pipe, the three-dimensional acceleration signal is transmitted to the signal transceiver 6 through the radio frequency transceiver chip I 5 for storage, and a spectrum curve is output every interval T , and the first 8 main vibration frequencies of each spectrum curve are recorded , output the change curve of the main vibration frequency of each order with time or drilling depth; stop drilling after drilling 1m, and collect the amount of coal powder;

4) Prediction of rockburst: For normal drilling without rockburst, the longitudinal and lateral vibrations of the drill pipe are equivalent to the vibration dynamics model of a simply supported beam at both ends, and when the drill is stuck, it is equivalent to a certain vibration in the beam. If an intermediate support is added to limit the radial displacement of the point, the lateral vibration frequency will increase significantly when the drill is stuck, that is, the curve of "lateral vibration frequency-drilling depth" will show distortion; and when drilling impact occurs, If the end conditions of the longitudinal vibration of the drill pipe change, the longitudinal vibration frequency will increase significantly during drilling impact, that is, the curve of "longitudinal vibration frequency-drilling depth" also shows distortion;

Therefore, according to the number of distortion points of the main vibration frequency versus time or drilling depth variation curve in step 3), the rock burst tendency of the coal seam can be predicted, combined with the amount of drilling cuttings and the vibration obtained during pre-drilling in step 2) Spectrum curve comprehensive prediction of rock burst.

Claims (4)

1. a Forecasting Methodology for bump, the steps include:

1) connect checkout gear: be fixed on drilling rod (3) by one end of three-dimensional pick-up adapter sleeve (2), the other end and electric coal drill (1) are socketed, open electric coal drill (1) test running;

Described three-dimensional pick-up adapter sleeve (2) is composed of a fixed connection by the linkage I (21) at three dimension acceleration sensor (22) and three dimension acceleration sensor two ends and linkage II (23), the shell of described three dimension acceleration sensor (22) is connected with radio transceiver chip I (5); The shell of signal transmitting and receiving machine (6) is connected with radio transceiver chip II (7);

2) prebored hole: collect coal dust amount at non-high stress concentration zone prebored hole 1m, the time of record boring needed for 1m, rounds this time divided by 15 and obtains the rumble spectrum curve output gap time t; The three-dimensional vibrating situation of drilling rod (3) when three dimension acceleration sensor (22) synchronous acquisition creeps into during boring, the three-dimensional acceleration signal that three dimension acceleration sensor (22) collects is transferred to the upper storage of signal transmitting and receiving machine (6) with radio transceiver chip II (7) by radio transceiver chip I (5), and the data signal be stored on signal transmitting and receiving machine (6) obtains the master oscillator frequenc of data signal and forms rumble spectrum curve after the spectrum block Spectrum Conversion on signal transmitting and receiving machine;

3) boring and signals collecting: start drill hole of drilling machine, the three-dimensional vibrating of drilling rod (3) when three dimension acceleration sensor (22) synchronous acquisition creeps into during boring, three-dimensional acceleration signal is transferred to the upper storage of signal transmitting and receiving machine (6), at interval of the time by radio transceiver chip I (5) texport a spectrum curve, record the front 8 rank master oscillator frequencs of each spectrum curve, export every rank master oscillator frequenc in time or drilling depth change curve; Often stop creeping into after boring 1m, and collect coal dust amount;

4) prediction of bump: according to master oscillator frequenc in step 3) in time or the bump-prone property in the measurable coal seam of distortion point number of drilling depth change curve, then in conjunction with coal powder quantity of bore and step 2) prebored hole time the rumble spectrum curve generalization predicting rock burst that obtains.

2. the Forecasting Methodology of a kind of bump as claimed in claim 1, the acceleration transducer (22) described in step 1) adopts the piezoelectric acceleration transducer of built-in charge amplifier.

3. the Forecasting Methodology of a kind of bump as claimed in claim 1, the drilling rod (3) described in step 1) adopts twist drill rods.

4. the Forecasting Methodology of a kind of bump as claimed in claim 1, the electric coal drill (1) described in step 1) adopts in high-stress coal, bores electric coal drill required when φ 42 ~ 50mm holes.