阅读说明：本技术 一种煤与瓦斯突出危险性随钻预测装置及其预测方法 (Coal and gas outburst danger prediction while drilling device and prediction method thereof ) 是由 胡杰 韩恩光 吕贵春 赵旭生 张宪尚 康建宁 于海云 张睿 刘志伟 李建功 陈德 于 2020-12-03 设计创作，主要内容包括：本发明涉及一种煤与瓦斯突出危险性随钻预测装置及其预测方法,依次包括中空钻头、孔底封堵机构、双臂钻杆和气流导向机构,钻头顶端开设有出风口；孔底封堵机构包括外管和固定安装在外管前端内壁上的内管,内管后侧的外管上膨胀孔处的外管外壁上固定安装有膨胀胶囊,内管前侧第二通气孔前侧的外管内固定安装有螺纹连接有旋转螺丝的挡板,旋转螺丝上套设有压缩弹簧,旋转螺丝末端固定安装有用于自由封堵第一通气孔的堵孔片；气流导向机构远离钻头的一侧固定安装有气流导向阀门和送风尾辫接口；参数测定机构与双臂钻杆内腔中心管连通,双臂钻杆环形腔上连接有压力表,解决现阶段工作面突出危险性无法实现随钻实时预测的难题。(The invention relates to a coal and gas outburst danger prediction while drilling device and a prediction method thereof, which sequentially comprise a hollow drill bit, a hole bottom plugging mechanism, a double-arm drill rod and an airflow guiding mechanism, wherein the top end of the drill bit is provided with an air outlet; the hole bottom plugging mechanism comprises an outer pipe and an inner pipe fixedly installed on the inner wall of the front end of the outer pipe, an expansion capsule is fixedly installed on the outer wall of the outer pipe at the expansion hole on the outer pipe on the rear side of the inner pipe, a baffle plate in threaded connection with a rotating screw is fixedly installed in the outer pipe on the front side of a second vent hole on the front side of the inner pipe, a compression spring is sleeved on the rotating screw, and a hole plugging piece used for freely plugging a first vent hole is fixedly installed at the tail end of the rotating; an airflow guide valve and an air supply tail braid interface are fixedly arranged on one side of the airflow guide mechanism, which is far away from the drill bit; the parameter measuring mechanism is communicated with a central pipe of an inner cavity of the double-arm drill rod, and a pressure gauge is connected to an annular cavity of the double-arm drill rod, so that the problem that the emergent danger of the working surface at the present stage cannot be predicted in real time while drilling is solved.)

1. The coal and gas outburst danger prediction while drilling device is characterized by sequentially comprising a hollow drill bit, a hole bottom plugging mechanism, a double-arm drill rod and an airflow guiding mechanism which are detachably and fixedly connected, wherein a pipeline on the airflow guiding mechanism is connected with a parameter measuring mechanism; the top end of the drill bit is provided with an air outlet;

the hole bottom plugging mechanism comprises an outer pipe and an inner pipe fixedly installed on the inner wall of the front end of the outer pipe, a cavity of the inner pipe is a first air vent, the length of the inner pipe is smaller than that of the outer pipe, an expansion hole is formed in the outer pipe on the rear side of the inner pipe, an expansion capsule is fixedly installed on the outer wall of the outer pipe at the expansion hole, a second air vent is formed in the outer pipe on the front side of the inner pipe, a baffle plate in threaded connection with a rotating screw is fixedly installed in the outer pipe on the front side of the second air vent, a compression spring is sleeved on the rotating screw, and a plugging piece used;

an airflow guide valve and an air supply tail braid interface are fixedly arranged on one side of the airflow guide mechanism, which is far away from the drill bit;

the air flow guide mechanism communicated with the inner cavity of the double-arm drill rod is a central pipe, the air flow guide mechanism communicated with the annular cavity of the double-arm drill rod is an annular space, the parameter measuring mechanism is communicated with the central pipe, and the annular space is connected with a pressure gauge.

2. The coal and gas outburst danger while drilling prediction device according to claim 1, wherein the airflow guiding mechanism further comprises a drill pipe connecting rod member in threaded connection with the two-arm drill pipe, a central pipe airflow interface with a central pipe airflow interface switch is arranged on the drill pipe connecting rod member connected with the inner two-arm drill pipe, and an annular space airflow interface with an annular space airflow interface switch is arranged on the drill pipe connecting rod member connected with the outer two-arm drill pipe.

3. The device for predicting the coal and gas outburst risk while drilling as claimed in claim 1, wherein the parameter measuring mechanism is communicated with the central pipe through a rubber pipe, and further comprises a shell, an air inlet and an air outlet which are arranged on the shell, and a gas concentration sensor, a timer, a data processor, a display screen and a power supply battery pack which are arranged inside the shell.

4. The coal and gas outburst risk while drilling prediction device according to claim 1, wherein the airflow guiding valve comprises a guiding disc B and a guiding disc C which rotate relatively, the guiding disc B and the guiding disc C are evenly and alternately divided into a plurality of sectors along a central angle, a stop block of each sector opposite to the central pipe is a sector, a stop block opposite to the annular space is an arc-shaped block, the sectors and the arc-shaped blocks on the guiding disc B are arranged in a staggered mode, and the sectors and the arc-shaped blocks on the guiding disc C are arranged oppositely.

5. The device for predicting coal and gas outburst danger while drilling as recited in claim 1, wherein a groove is formed on the outer wall of the outer pipe at the expansion hole, and the expansion capsule is clamped in the groove in an inwards concave manner.

6. The device for predicting the coal and gas outburst risk while drilling as claimed in claim 1, wherein the tail end of the drill bit is provided with 2 layers of threads which are in threaded connection with a hole bottom plugging mechanism.

7. The prediction method of the coal and gas outburst risk while drilling prediction device is characterized by comprising the following steps of:

s1, adjusting the rotary screw according to the underground wind pressure to ensure that the first vent hole can be opened after the expansion capsule is fully expanded, namely the pressure of the expansion capsule when fully expanded is P1, and the pressure of the first vent hole when opened by the wind pressure is P2, which satisfies that P2 is more than P1;

s2, sequentially connecting a drill bit, a hole bottom plugging mechanism, a double-arm drill rod and an airflow guide mechanism in a threaded connection mode, connecting an air supply tail braid at an air supply tail braid interface at the tail end of the airflow guide mechanism, closing an interface switch of the airflow guide mechanism, and simultaneously adjusting an airflow guide valve to ensure that compressed air is conveyed to the hole bottom only through a double-arm drill rod central tube and an inner tube of the hole bottom plugging mechanism to start normal drilling, and conveying coal scraps at the hole bottom to the outside of the hole through a gap between the outer wall of the device and the wall of the hole;

s3, after the coal is drilled to the specified position, stopping drilling and continuing air supply for 3min to blow off coal dust impurities in the inlet hole; continuing to drill forward for 1m, stopping drilling, immediately opening an interface switch of the airflow guide mechanism, connecting the airflow guide mechanism with an upper parameter measuring mechanism, simultaneously adjusting an airflow guide valve to control the air pressure to reach the bottom of the hole only through the annular space of the dual-arm drill rod and the hole bottom plugging mechanism, giving constant pressure to supply air continuously, wherein the air supply pressure is not less than P1, after the expansion capsule completes the expansion action, the compression spring is influenced by the pressure to open the air vent under the action of the continuous air pressure to form a loop, and the gas desorbed from the freshly exposed coal dust at the bottom of the hole flows through the parameter measuring mechanism along with the air flow through;

s4, collecting data in the wind flow by a gas concentration sensor and a timer in the parameter measuring mechanism, accessing the data into a data processor, calculating by using a prediction algorithm, and outputting and displaying a calculation result on a display screen;

s5: after the measurement process is finished, air supply is stopped, the connection between the parameter measurement mechanism and the airflow guide mechanism is disconnected, pressure relief and the restoration of the expansion capsule and the compression spring are finished in the prediction while drilling device, an interface switch of the airflow guide mechanism is closed, forward drilling is continued, and prediction while drilling is achieved.

8. The prediction method of the coal and gas outburst risk while drilling prediction device as claimed in claim 7, wherein the prediction algorithm adopted in step S4 is:

establishing a prediction index system: y → [ T1, T2, (1-X)/T2]

Wherein Y is a prediction index system; t1 is the duration/s of the gas concentration in the determination process being 100%; t2 is the duration/s for the gas concentration to decrease from 100% to be stable; the concentration of the gas in the wind flow is X when the concentration is stable;

taking the gas content value and the critical value of a measurement-while-drilling site as standards, investigating and establishing the critical values of prediction indexes T1, T2 and (1-X)/T2 on site, and judging that the outburst risk exists when 3 indexes exceed the critical values.

Technical Field

The invention belongs to the field of coal mine safety, and relates to a coal and gas outburst danger prediction while drilling device and a prediction method thereof.

Background

Coal and gas outburst accidents are one of the main disasters faced by production mines, the loss and the influence brought to coal mine enterprises are huge, and effective prevention and control of the coal and gas outburst accidents are always the key and technical difficulties of the tasks of outburst mines. Because of numerous outburst inducers and complicated outburst mechanism, the method mainly adopts a mode of 'parameter measurement drilling construction-coal sample collection-parameter measurement' to calculate the prediction index value and realize the prediction of coal and gas outburst risks at present. However, along with the increase of the mining depth of a mine year by year, the complexity of geological conditions is aggravated, the regular change of gas content and gas pressure is not obvious, the loss of gas cannot be collected when coal dust is initially broken in the coal sample acquisition process, the accuracy of a gas desorption rule model, the applicability of a prediction index critical value and the sensitivity of the index when a coal body is exposed to the completion of coal sample acquisition are all problems required to be solved by the current prediction method, meanwhile, the traditional coal and gas outburst prediction method needs the procedures of drilling in advance, coal sample acquisition and the like, the measurement process is complicated, professional technicians need to follow up with the duty to measure, a certain production time is occupied, the automatic and intelligent development direction of a new era in the coal mine industry is not met, and therefore, in order to realize the efficient production of the mine, the outburst risk prediction device and method while drilling need urgently, and the outburs, the prediction link is simplified, the personnel investment and the labor cost are reduced, and a foundation is laid for highlighting the automation and the intellectualization of the prediction.

Disclosure of Invention

In view of the above, the invention provides a coal and gas outburst risk prediction while drilling device and a prediction method thereof, in order to solve the problem that the outburst risk of the working face cannot be predicted in real time while drilling at the present stage.

In order to achieve the purpose, the invention provides the following technical scheme: a coal and gas outburst danger prediction while drilling device sequentially comprises a hollow drill bit, a hole bottom plugging mechanism, a double-arm drill rod and an airflow guide mechanism which are detachably and fixedly connected, wherein a pipeline on the airflow guide mechanism is connected with a parameter measuring mechanism; the top end of the drill bit is provided with an air outlet;

the hole bottom plugging mechanism comprises an outer pipe and an inner pipe fixedly installed on the inner wall of the front end of the outer pipe, a cavity of the inner pipe is a first air vent, the length of the inner pipe is smaller than that of the outer pipe, an expansion hole is formed in the outer pipe on the rear side of the inner pipe, an expansion capsule is fixedly installed on the outer wall of the outer pipe at the expansion hole, a second air vent is formed in the outer pipe on the front side of the inner pipe, a baffle plate in threaded connection with a rotating screw is fixedly installed in the outer pipe on the front side of the second air vent, a compression spring is sleeved on the rotating screw, and a plugging piece used;

an airflow guide valve and an air supply tail braid interface are fixedly arranged on one side of the airflow guide mechanism, which is far away from the drill bit;

the air flow guide mechanism communicated with the inner cavity of the double-arm drill rod is a central pipe, the air flow guide mechanism communicated with the annular cavity of the double-arm drill rod is an annular space, the parameter measuring mechanism is communicated with the central pipe, and the annular space is connected with a pressure gauge.

The beneficial effect of this basic scheme lies in: the hole plugging piece in the hole bottom plugging mechanism is fixed at one end of a compression spring, the other end of the compression spring is connected with a rotating screw, and the rotating screw is fixed between an inner pipe and an outer pipe through threads to form an elastic structure. The compression spring can be driven to compress and expand by rotating the rotary screw, so that the elasticity of the compression spring is changed; the rotary screw screwing degree is adjusted according to the air pressure of the underground working face of the coal mine, so that the compression action of the compression spring is completed after certain pressure is met, and the first vent hole is communicated.

Furthermore, the airflow guide mechanism also comprises a drill rod connecting rod piece in threaded connection with the double-arm drill rods, a central pipe airflow interface with a central pipe airflow interface switch is arranged on the drill rod connecting rod piece connected with the inner double-arm drill rod, and an annular space airflow interface with an annular space airflow interface switch is arranged on the drill rod connecting rod piece connected with the outer double-arm drill rod.

Further, parameter measurement mechanism and center tube pass through the rubber tube intercommunication, and parameter measurement mechanism still includes the casing, installs air inlet and gas outlet on the casing and sets up in inside gas concentration sensor, time-recorder, data processor, display screen, the power supply group battery of casing.

Furthermore, the airflow guide valve comprises a guide disc B and a guide disc C which rotate relatively, the guide disc B and the guide disc C are uniformly and alternately separated into a plurality of sector areas along a central angle, a stop block of each sector area, which is opposite to the central pipe, is a sector block, a stop block, which is opposite to the annular space, is an arc block, the sector blocks and the arc blocks are arranged in a staggered mode on the guide disc B, and the sector blocks and the arc blocks are arranged oppositely on the guide disc C. Has the advantages that: by rotating the guide disc B and the guide disc C on the airflow guide valve, the air flow can be controlled to independently enter the drill rod from the annular space or independently enter the drill rod from the central pipe.

Furthermore, the outer wall of the outer pipe at the expansion hole is provided with a groove, and the expansion capsule is clamped in the groove in an inwards concave mode. Has the advantages that: the expansion capsule is clamped in the groove in an inwards concave mode, so that the effect of protecting the expansion capsule can be achieved, and the expansion capsule is prevented from being damaged when coal dust at the bottom of the hole is conveyed along the gap between the outer wall of the device and the hole wall.

Furthermore, the tail end of the drill bit is provided with 2 layers of threads which are in threaded connection with the hole bottom plugging mechanism. Has the advantages that: the connection stability of the drill bit and the hole bottom plugging mechanism is enhanced.

A prediction method of a coal and gas outburst risk while drilling prediction device is carried out on the basis of the coal and gas outburst risk while drilling prediction device, and specifically comprises the following steps:

s1, adjusting the rotary screw according to the underground wind pressure to ensure that the first vent hole can be opened after the expansion capsule is fully expanded, namely the pressure of the expansion capsule when fully expanded is P1, and the pressure of the first vent hole when opened by the wind pressure is P2, which satisfies that P2 is more than P1;

s2, sequentially connecting a drill bit, a hole bottom plugging mechanism, a double-arm drill rod and an airflow guide mechanism in a threaded connection mode, connecting an air supply tail braid at an air supply tail braid interface at the tail end of the airflow guide mechanism, closing an interface switch of the airflow guide mechanism, and simultaneously adjusting an airflow guide valve to ensure that compressed air is conveyed to the hole bottom only through a double-arm drill rod central tube and an inner tube of the hole bottom plugging mechanism to start normal drilling, and conveying coal scraps at the hole bottom to the outside of the hole through a gap between the outer wall of the device and the wall of the hole;

s3, after the coal is drilled to the specified position, stopping drilling and continuing air supply for 3min to blow off coal dust impurities in the inlet hole; continuing to drill forward for 1m, stopping drilling, immediately opening an interface switch of the airflow guide mechanism, connecting the airflow guide mechanism with an upper parameter measuring mechanism, simultaneously adjusting an airflow guide valve to control the air pressure to reach the bottom of the hole only through the annular space of the dual-arm drill rod and the hole bottom plugging mechanism, giving constant pressure to supply air continuously, wherein the air supply pressure is not less than P1, after the expansion capsule completes the expansion action, the compression spring is influenced by the pressure to open the air vent under the action of the continuous air pressure to form a loop, and the gas desorbed from the freshly exposed coal dust at the bottom of the hole flows through the parameter measuring mechanism along with the air flow through;

s4, collecting data in the wind flow by a gas concentration sensor and a timer in the parameter measuring mechanism, accessing the data into a data processor, calculating by using a prediction algorithm, and outputting and displaying a calculation result on a display screen;

s5: after the measurement process is finished, air supply is stopped, the connection between the parameter measurement mechanism and the airflow guide mechanism is disconnected, pressure relief and the restoration of the expansion capsule and the compression spring are finished in the prediction while drilling device, an interface switch of the airflow guide mechanism is closed, forward drilling is continued, and prediction while drilling is achieved.

Further, the prediction algorithm adopted in step S4 is:

establishing a prediction index system: y → [ T1, T2, (1-X)/T2]

Wherein Y is a prediction index system; t1 is the duration/s of the gas concentration in the determination process being 100%; t2 is the duration/s for the gas concentration to decrease from 100% to be stable; the concentration of the gas in the wind flow is X when the concentration is stable;

taking the gas content value and the critical value of a measurement-while-drilling site as standards, investigating and establishing the critical values of prediction indexes T1, T2 and (1-X)/T2 on site, and judging that the outburst risk exists when 3 indexes exceed the critical values.

The invention has the beneficial effects that:

1. the invention discloses a coal and gas outburst danger while drilling prediction device which mainly comprises a drill bit, a hole bottom plugging mechanism, two-arm drill rods, an airflow guide mechanism and a parameter measurement mechanism. In the normal drilling process of the drill bit, the air flow guide valve is controlled to enable compressed air to be conveyed to the bottom of a hole through the central pipe of the double-arm drill pipe and the inner pipe of the hole bottom plugging mechanism, then coal scraps at the bottom of the hole are conveyed out of the hole through a gap between the outer wall of the device and the hole wall, drilling is stopped after the drill bit is drilled to a specified position, air supply is continued to blow off impurities of the coal scraps in the hole, the drill bit drills forwards for 1m, then the parameter measuring mechanism is connected, the air flow guide valve is operated to control air pressure to reach the bottom of the hole only through the annular space of the double-arm drill pipe and the hole bottom plugging mechanism, constant air pressure is given to supply air continuously, the expansion capsule is expanded to complete sealing between the hole bottom plugging mechanism and the hole wall, the compression spring is influenced by the continuous air pressure, then the air vent is opened to form a loop, gas flow in the hole, And establishing a coal and gas outburst while drilling prediction system according to the relation between the concentration and the time of the gas. The whole prediction device has the advantages of compact and reasonable structure, convenient operation, good dynamic performance, high accuracy and stable and reliable measurement result, the measurement result can reflect the gas flow distribution along the way in the continuous drilling process, and the prediction device has wide practicability.

2. The coal and gas outburst danger prediction while drilling device disclosed by the invention can realize the outburst danger prediction while drilling in the drilling process, simplify the outburst prediction process at the present stage, reduce the personnel investment, improve the production efficiency, reduce the production cost of a mine, and accord with the development direction of automation and intellectualization of the outburst prediction.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.

Drawings

For the purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic structural diagram of a coal and gas outburst risk prediction while drilling device according to the present invention;

FIG. 2 is a schematic structural diagram of a hole bottom plugging mechanism in the coal and gas outburst risk prediction while drilling device according to the invention;

FIG. 3 is a cross-sectional view taken along line A-A of FIG. 1 in accordance with the present invention;

FIG. 4 is a cross-sectional view taken along line B-B of FIG. 1 in accordance with the present invention;

fig. 5 is a cross-sectional view taken along line C-C of fig. 1 in accordance with the present invention.

Reference numerals: the device comprises a drill bit 1, an air outlet 1-1, a hole bottom plugging mechanism 2, an expansion capsule 2-1, an expansion hole 2-2, a first vent hole 2-3, a second vent hole 2-4, a hole plugging sheet 2-5, a compression spring 2-6, a rotary screw 2-7, a double-arm drill rod 3, an air flow guide mechanism 4, a drill rod connecting rod piece 4-1, an air flow guide valve 4-2, an air supply tail braid interface 4-3, a central tube air flow interface 4-4, an annular space air flow interface 4-5, a central tube air flow interface switch 4-6, an annular space air flow interface switch 4-7, a parameter measuring mechanism 5, a shell 5-1, a rubber tube 5-2, a pressure gauge 5-3, an air inlet 5-4 and an air outlet 5-5.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

The coal and gas outburst danger while-drilling prediction device sequentially comprises a hollow drill bit 1, a hole bottom plugging mechanism 2, a double-arm drill rod 3 and an airflow guide mechanism 4 which are in threaded connection, wherein 2 layers of threads are arranged at the tail end of the drill bit 1 and are in threaded connection with the hole bottom plugging mechanism 2. The airflow guide mechanism 4 is connected with a parameter measuring mechanism 5 through a rubber pipe 5-2. The top end of the drill bit 1 is provided with an air outlet 1-1.

The hole bottom plugging mechanism 2 comprises an outer pipe and an inner pipe fixedly arranged on the inner wall of the front end of the outer pipe, the cavity of the inner pipe is a first air vent 2-3, the length of the inner pipe is smaller than that of the outer pipe, an expansion hole 2-2 is formed in the outer pipe on the rear side of the inner pipe, an expansion capsule 2-1 is fixedly arranged on the outer wall of the outer pipe at the position of the expansion hole 2-2, a second air vent 2-4 is formed in the outer pipe on the front side of the inner pipe, a baffle plate in threaded connection with a rotating screw 2-7 is fixedly arranged in the outer pipe on the front side of the second air vent 2-4, a compression spring 2-6 is sleeved on the rotating screw 2-7, and a hole plugging piece 2-5 for freely plugging the; the hole plugging piece 2-5 in the hole bottom plugging mechanism 2 is fixed at one end of a compression spring 2-6, the other end of the compression spring 2-6 is connected with a rotary screw 2-7, and the rotary screw 2-7 is fixed between an inner pipe and an outer pipe through threads to form an elastic structure. The compression springs 2-6 can be driven to compress and expand by rotating the rotary screws 2-7, so that the elasticity of the compression springs 2-6 is changed; the screwing degree of the rotary screws 2-7 is adjusted according to the air pressure of the underground working face of the coal mine, so that the compression springs 2-6 complete compression after certain pressure and are communicated with the first vent holes 2-3.

An airflow guide valve 4-2 and an air supply tail connector 4-3 are fixedly arranged on one side of the airflow guide mechanism 4, which is far away from the drill bit 1; the airflow guide mechanism 4 further comprises a drill rod connecting rod piece 4-1 in threaded connection with the double-arm drill rod 3, a central pipe airflow interface 4-4 with a central pipe airflow interface 4-4 switch is arranged on the drill rod connecting rod piece 4-1 connected with the inner double-arm drill rod 3, and an annular space airflow interface 4-5 with an annular space airflow interface 4-5 switch is arranged on the drill rod connecting rod piece 4-1 connected with the outer double-arm drill rod 3.

The airflow guide valve 4-2 comprises a guide disc B and a guide disc C which rotate relatively, the guide disc B and the guide disc C are uniformly and alternately separated into a plurality of sector areas along a central angle, a stop block of each sector area, which is opposite to the central pipe, is a sector block, a stop block, which is opposite to the annular space, is an arc block, the sector blocks and the arc blocks on the guide disc B are arranged in a staggered mode, and the sector blocks on the guide disc C are arranged opposite to the arc blocks. By rotating the guide disk B and the guide disk C on the airflow guide valve 4-2, the air flow can be controlled to independently enter the drill rod from the annular space or independently enter the drill rod from the central pipe.

The air flow guide mechanism 4 communicated with the inner cavity of the double-arm drill rod 3 is a central pipe, the air flow guide mechanism 4 communicated with the annular cavity of the double-arm drill rod 3 is an annular space, and the annular space is connected with a pressure gauge 5-3. The parameter measuring mechanism 5 is communicated with the central pipe through a rubber pipe 5-2, and the parameter measuring mechanism 5 further comprises a shell 5-1, an air inlet 5-4 and an air outlet 5-5 which are arranged on the shell 5-1, and a gas concentration sensor, a timer, a data processor, a display screen and a power supply battery pack which are arranged inside the shell 5-1.

A prediction method of a coal and gas outburst risk while drilling prediction device is carried out on the basis of the coal and gas outburst risk while drilling prediction device, and specifically comprises the following steps:

s1, adjusting the rotary screw 2-7 according to the underground wind pressure, ensuring that the first vent hole 2-3 can be opened after the expansion capsule 2-1 is fully expanded, namely the pressure of the expansion capsule 2-1 which is fully expanded is P1, and ensuring that the pressure of the first vent hole 2-3 which is opened by the wind pressure is P2, wherein the pressure is required to be P2 > P1;

s2, sequentially connecting a drill bit 1, a hole bottom plugging mechanism 2, a double-arm drill rod 3 and an airflow guide mechanism 4 in a threaded connection mode, connecting an air supply tail braid at an air supply tail braid interface 4-3 at the tail end of the airflow guide mechanism 4, closing an interface switch of the airflow guide mechanism 4, and simultaneously adjusting an airflow guide valve 4-2 to ensure that compressed air is conveyed to the hole bottom only through a central pipe of the double-arm drill rod 3 and an inner pipe of the hole bottom plugging mechanism 2 to start normal drilling, and conveying coal scraps at the hole bottom to the outside of the hole through a gap between the outer wall of the device and the hole wall;

s3, after the coal is drilled to the specified position, stopping drilling and continuing air supply for 3min to blow off coal dust impurities in the inlet hole; continuing to drill forward for 1m and stopping drilling, immediately opening an interface switch of an airflow guide mechanism 4 and connecting a parameter measuring mechanism 5, simultaneously adjusting an airflow guide valve 4-2 to control air pressure to reach the bottom of the hole only through an annular space of a double-arm drill rod 3 and a hole bottom plugging mechanism 2, giving constant pressure and continuously supplying air, wherein the air supply pressure is not less than P1, after the expansion capsule 2-1 completes the expansion action, a compression spring 2-6 is influenced by pressure to open a vent hole under the action of the continuous air pressure to form a loop in the drill rod, and the gas which is exposed freshly at the bottom of the hole and desorbed by coal scraps flows through the parameter measuring mechanism 5 along with the air flow through a central;

s4, collecting data in the wind flow by a gas concentration sensor and a timer in the parameter measuring mechanism 5, accessing the data into a data processor, calculating by using a prediction algorithm, and outputting and displaying a calculation result on a display screen;

the prediction algorithm is as follows:

establishing a prediction index system: y → [ T1, T2, (1-X)/T2]

Wherein Y is a prediction index system; t1 is the duration/s of the gas concentration in the determination process being 100%; t2 is the duration/s for the gas concentration to decrease from 100% to be stable; the concentration of the gas in the wind flow is X when the concentration is stable;

taking the gas content value and the critical value of a measurement-while-drilling site as standards, investigating and establishing the critical values of prediction indexes T1, T2 and (1-X)/T2 on site, and judging that the outburst risk exists when 3 indexes exceed the critical values.

S5: after the measurement process is finished, air supply is stopped, the connection between the parameter measurement mechanism 5 and the airflow guide mechanism 4 is disconnected, pressure relief and the resetting of the expansion capsule 2-1 and the compression spring 2-6 are finished in the while-drilling prediction device, an interface switch of the airflow guide mechanism 4 is closed, forward drilling is continued, and while-drilling prediction is achieved.

Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.