阅读说明：本技术 一种井下直流赤道向偶极动源异常自显式超前探测方法 (Underground direct-current equatorial dipole dynamic source abnormity self-display type advanced detection method ) 是由 石显新 于 2021-08-05 设计创作，主要内容包括：本发明公开一种井下直流赤道向偶极动源异常自显式超前探测方法,该方法将接收电极M或将接收电极M和N固定布置在掘进面上,发射电极A和B布置在巷道底板且发射电极AB连线的垂直平分线为巷道底板中线,发射电极A和B从A-(1)B-(1)处向掘进面方向移动,形成依次位于A-(1)B-(1),A-(2)B-(2),...,A-(i)B-(i)...,A-(n)B-(n)位置点的偶极移动源；发射电极A和B在每个位置点发射电流一次,接收电极M或MN对应测量电压一次,进行偶极动源超前探测。本发明提高了井下直流超前探测的准确性,是一种利用稳定电流场对称性自显异常的快速探测方法。(The invention discloses a self-display type advanced detection method for underground direct current equatorial dipole dynamic source abnormity, which is characterized in that a receiving electrode M or receiving electrodes M and N are fixedly arranged on a tunneling surface, transmitting electrodes A and B are arranged on a roadway bottom plate, a vertical bisector of a connecting line of the transmitting electrodes AB is a central line of the roadway bottom plate, and the transmitting electrodes A and B are arranged from A to B 1 B 1 Move towards the direction of the heading face to form a position A 1 B 1 ，A 2 B 2 ，...，A i B i ...，A n B n A dipole moving source of location points; and the transmitting electrodes A and B transmit current once at each position point, and the receiving electrode M or MN measures voltage once correspondingly to perform dipole dynamic source advanced detection. The invention improves the accuracy of underground direct current advanced detection, and is a rapid detection method for self-display abnormality by utilizing the symmetry of a stable current field.)

1. A self-display type advanced detection method for underground direct current equatorial dipole dynamic source abnormity is characterized in that a receiving electrode M or receiving electrodes M and N are fixedly arranged on a tunneling surface and are positioned on a vertical bisector of the bottom edge of the tunneling surface, transmitting electrodes A and B are arranged on a roadway bottom plate, the vertical bisector of a connecting line of the transmitting electrodes A and B is a central line of the roadway bottom plate, and the transmitting electrodes A and B are arranged from A to B₁And B₁The position moves towards the direction of the heading face to form a position A₁And B₁Position point, A₂And B₂Location points, a_iAnd B_iPoints of position, a_nAnd B_nA dipole moving source of location points; transmitting current once by the transmitting electrodes A and B at each position point, and measuring voltage once by the receiving electrode M or the receiving electrodes M and N correspondingly, and performing dipole dynamic source advanced detection;

when the monopole receiving electrode M is fixedly arranged on the heading face, the estimation formula of the maximum advanced detection distance is as follows:

in the above formula, O 'O is the distance from the emitting electrode to the midpoint O' of AB to the midpoint O of the bottom edge of the driving face, I_ABmaxIn order to achieve the maximum emission current,the rho is the resistivity of the rock stratum in front of the driving face and is the noise level observed by the receiving electrode M;

when the dipole fixedly arranges the receiving electrodes M and N on the heading face, the estimation formula of the maximum detection distance of the advanced detection is as follows:

in the above formula, O'₁O is the midpoint of emitter electrode distance AB'₁The distance from the midpoint O of the bottom edge of the heading face to the point O, O 'O is the distance from the receiving electrode to the point O from the midpoint O' of the MN, I_ABmaxIn order to achieve the maximum emission current,ρ is the resistivity of the formation in front of the face to receive the noise level observed by the electrode spacing MN.

2. The method of claim 1, wherein A is a direct current equatorial dipole source anomaly self-explicit advanced detection method₁And B₁Position point, A₂And B₂Location points, a_iAnd B_iPoints of position, a_nAnd B_nThe smaller the interval between the position points is, the higher the detection resolution is; emitter electrodes A and B from A₁And B₁Starting at the position point, the distance between the transmitting electrode and the midpoint O' of the AB moves to the direction of the tunneling surface at intervals required by resolution along the central line of the roadway bottom plate, and the depth of the current field penetrating into the front of the tunneling working surface is from shallow to deep.

3. The method of claim 1, wherein the monopole receiving electrode M is fixedly arranged on the heading face and located at A with the transmitting electrodes A and B_iAnd B_iSounding point D corresponding to position point_iHe-ShiResistivity ofThe formula of (1) is:

D_i≈O′₁O-O′_iO，(i＝1,2,...,n) (2a)

o 'of the above formula'₁O is determined by formula (1a), O'_iO is the midpoint of emitter electrode distance AB'_iDistance to O;

in the above formulaIs A_iThe distance to M,Is B_iA distance to M, wherein MO is the distance from M to O,the emitting electrodes A and B are located at A_iAnd B_iThe emission current corresponding to the location point,is anda corresponding observed voltage;

when the dipole receiving electrodes M and N are fixedly arranged on the tunneling surface, the dipole receiving electrodes M and N are positioned at A with the transmitting electrodes A and B_iAnd B_iSounding point D corresponding to position point_iAnd apparent resistivityThe formula of (1) is:

D_i≈O′₁O-O′_iO，(i＝1,2,...,n) (2c)

of which O'₁O is determined by formula (1b), O'_iO is the midpoint of emitter electrode distance AB'_iDistance to O;

in the formulaIs A_iThe distance to M,Is B_iThe distance to M,Is A_iThe distance to N,Is B_iDistance to N, where MO is the distance from M to O, NO is the distance from N to O,the emitting electrodes A and B are located at A_iAnd B_iThe emission current corresponding to the location point,is andthe corresponding observed voltage.

4. The method according to claim 3, wherein after the detection is finished, error records in the measured data are used as a criterion for the interpretation of the abnormality;

when the monopole receiving electrode M is fixedly arranged on the heading face, the measured data is interpreted as abnormal if the following formula (3a) is satisfied:

when the receiving electrodes M and N are fixedly arranged on the heading face, the measured data is interpreted as abnormal if the following equation (3b) is satisfied:

wherein Mean. + -. S.D. is Mean. + -. standard deviation, A_iM、B_iM、A_iN and B_iN is defined in formula (2).

5. The method according to claim 4, wherein when there is no abnormal body in the maximum detection distance range in front of the heading face, the noise level is observed by the receiving electrode M or the receiving electrodes M and N due to the symmetry of the electrode arrangement and the symmetry of the electric flow field; when the abnormal body exists in the maximum detection distance range in front of the tunneling surface, the current field loses symmetry, and when a voltage signal of 3-5 times of noise level is observed by the receiving electrode, the abnormal body existing in front of the tunneling surface can be judged.

6. The method according to claim 4, wherein when there is an anomalous body in the maximum detection distance range in front of the heading face but the current field has not yet contacted the anomalous body, the noise level is observed by the receiving electrode M or the receiving electrodes M and N; and (3) as the transmitting electrodes A and B move towards the direction of the tunneling surface, the current field is contacted with the abnormal body and disturbed, and when the disturbance is transmitted to the tunneling surface and the receiving electrodes observe a voltage signal with 3-5 times of noise level, the existence of the abnormal body can be judged.

Technical Field

The invention belongs to the field of electrical and electromagnetic prospecting, relates to an underground direct current advanced detection technology, and particularly relates to an underground direct current equatorial direction dipole dynamic source abnormity self-display advanced detection method.

Background

The underground direct current advanced detection is one of the main methods for detecting abnormal bodies in front of the driving face of the underground coal mine in China. In the current dc advanced detection method, a monopole transmitting-dipole receiving device called a tripolar method is generally adopted, a transmitting electrode is fixedly arranged on or near a heading face, and a receiving electrode moves away from the heading face. Thereafter, there has been established a multi-monopole-dipole combination method improved on the basis of the three-pole method. Due to the nature of the close-acting DC electric field, the response of the anomaly upon excitation by the emission source is always transmitted outward from the periphery of the anomaly by the field, with the intensity decreasing with increasing distance from the anomaly. By fixing the transmitting electrode near the tunneling surface and moving the receiving electrode to the opposite direction of the tunneling working surface, the obtained abnormity is weak, and the abnormity body behind the tunneling surface can interfere with the advanced detection to cause misjudgment.

Disclosure of Invention

Aiming at the defects and shortcomings in the prior art, the invention provides a self-display type advanced detection method for the abnormality of an underground direct current equatorial dipole moving source, which is used for fixedly arranging a receiving electrode on a tunneling working surface to be close to a front abnormal body as far as possible and realizing advanced detection by moving a transmitting electrode to the tunneling working surface. The method forms a symmetrical current field by the geometric symmetry relationship between the electrodes and the roadway. During the detection process, when the receiving electrode measures a signal exceeding the noise level, the abnormal body in front of the heading face can be automatically displayed.

In order to achieve the purpose, the invention adopts the following technical scheme:

a self-display type advanced detection method for abnormality of underground direct current equatorial dipole moving source is characterized in that a receiving electrode M or receiving electrodes M and N are fixedly arranged on a tunneling surface and positioned on a vertical bisector of the bottom edge of the tunneling surface, transmitting electrodes A and B are arranged on a roadway bottom plate, the vertical bisector of a connecting line of the transmitting electrodes A and B is a central line of the roadway bottom plate, and the transmitting electrodes A and B are arranged from A to B₁And B₁The position moves towards the direction of the heading face to form a position A₁And B₁Position point, A₂And B₂Location points, a_iAnd B_iPoints of position, a_nAnd B_nA dipole moving source of location points; transmitting current once by the transmitting electrodes A and B at each position point, measuring voltage once by the receiving electrode M or the receiving electrodes M and N correspondingly, and performing dipole moving source advanced detection;

when the monopole receiving electrode M is fixedly arranged on the heading face, the estimation formula of the maximum advanced detection distance is as follows:

in the above formula, O 'O is the distance from the emitting electrode to the midpoint O' of AB to the midpoint O of the bottom edge of the driving face, I_ABmaxIn order to achieve the maximum emission current,the rho is the resistivity of the rock stratum in front of the driving face and is the noise level observed by the receiving electrode M;

when the dipole fixedly arranges the receiving electrodes M and N on the heading face, the estimation formula of the maximum detection distance of the advanced detection is as follows:

in the above formula, O'₁O is the midpoint of emitter electrode distance AB'₁Distance to the midpoint O of the bottom edge of the heading face, O 'O is the distance from the receiving electrode to the midpoint O' of MN, I_ABmaxIn order to achieve the maximum emission current,ρ is the resistivity of the formation in front of the face to receive the noise level observed by the electrode spacing MN.

The invention also comprises the following technical characteristics:

optionally, A is₁And B₁Position point, A₂And B₂Location points, a_iAnd B_iPoints of position, a_nAnd B_nThe smaller the interval between the position points is, the higher the detection resolution is; emitter electrodes A and B from A₁And B₁Starting at the position point, the distance between the transmitting electrode and the midpoint O' of the AB moves to the direction of the tunneling surface at intervals required by resolution along the center line of the roadway bottom plate, and the depth of the current field penetrating into the front of the tunneling working surface is from shallow to deep.

Alternatively, when the monopole receiving electrode M is fixedly arranged in the excavationAt surface level, at A with the emitting electrodes A and B_iAnd B_iSounding point D corresponding to position point_iAnd apparent resistivityThe formula of (1) is:

D_i≈O′₁O-O′_iO，(i＝1,2,...,n) (2a)

o 'of the above formula'₁O is determined by formula (1a), O'_iO is the midpoint of emitter electrode distance AB'_iDistance to O;

in the above formulaIs A_iThe distance to M,

Is B_iA distance to M, wherein MO is the distance from M to O,the emitting electrodes A and B are located at A_iAnd B_iThe emission current corresponding to the location point,is anda corresponding observed voltage;

when the dipole receiving electrodes M and N are fixedly arranged on the tunneling surface, the dipole receiving electrodes M and N are positioned at A with the transmitting electrodes A and B_iAnd B_iSounding point D corresponding to position point_iAnd apparent resistivityThe formula of (1) is:

D_i≈O′₁O-O′_iO，(i＝1,2,...,n) (2c)

of which O'₁O is determined by formula (1b), O'_iO is the midpoint of emitter electrode distance AB'_iDistance to O;

in the formulaIs A_iThe distance to M,

Is B_iThe distance to M,Is A_iThe distance to N,Is B_iDistance to N, where MO is the distance from M to O, NO is the distance from N to O,the emitting electrodes A and B are located at A_iAnd B_iThe emission current corresponding to the location point,is andthe corresponding observed voltage.

Optionally, after the detection is finished, taking an error record in the actually measured data as a criterion for the abnormal interpretation;

when the monopole receiving electrode M is fixedly arranged on the heading face, the measured data is interpreted as abnormal if the following formula (3a) is satisfied:

when the receiving electrodes M and N are fixedly arranged on the heading face, the measured data is interpreted as abnormal if the following equation (3b) is satisfied:

wherein Mean. + -. S.D. is Mean. + -. standard deviation, A_iM、B_iM、A_iN and B_iN is defined in formula (2).

Optionally, when no abnormal body exists in the maximum detection distance range in front of the tunneling surface, the symmetry of the current field is caused by the symmetry of the electrode arrangement, and a noise level is observed by the receiving electrode M or the receiving electrodes M and N; when the abnormal body exists in the maximum detection distance range in front of the tunneling surface, the current field loses symmetry, and when a voltage signal of 3-5 times of noise level is observed by the receiving electrode, the abnormal body existing in front of the tunneling surface can be judged.

Optionally, when an abnormal body exists in the maximum detection distance range in front of the tunneling surface but the current field does not contact the abnormal body yet, a noise level is observed by the receiving electrode M or the receiving electrodes M and N; and (3) along with the movement of the emitting electrodes A and B towards the direction of the excavation face, the current field is contacted with the abnormal body and disturbed, and when the disturbance is transmitted to the excavation face and the receiving electrodes observe a voltage signal with 3-5 times of noise level, the existence of the abnormal body can be judged.

Compared with the prior art, the invention has the beneficial technical effects that:

(1) according to the principle of direct current electric field close-range action, the receiving electrode is fixedly arranged on the tunneling working face, and response signals of abnormal bodies in front of the tunneling face under the excitation of the emission source are approached to the maximum extent; the emission electrode moves towards the direction of the heading face, the depth of the current field penetrating into the front of the heading face is observed from shallow to deep, and the signal-to-noise ratio is increased along with the increase of the detection distance.

(2) The geometric symmetry of the electrode arrangement is such that the receiving electrode will observe a signal that exceeds the noise only if there is an anomaly in front of the face. According to the standard that the signal is more than 3-5 times of the noise level, the front abnormity can be quickly judged on the construction site, and the real-time performance of advanced detection is improved.

(3) The given maximum detection distance estimation formula establishes the relationship among various elements such as the geometric space of electrode arrangement, emission current, rock stratum resistivity, environmental noise level and the like, and provides quantitative basis for determining the construction parameters of the automatic explicit advanced detection of the underground direct current equatorial to dipole dynamic source abnormity.

(4) The given depth measurement point and apparent resistivity calculation formula corresponding to the movement of the transmitting electrode once is an algorithm designed by the invention and has specificity; and the error record of the actually measured data is used as a discrimination standard of abnormal response, so that more guarantee is provided for the reliability of data interpretation.

(5) The equator of the invention transmits to the dipole device, can be constructed in a very short roadway, the required transmitting equipment is light, and the self detection distance loss of axial dipole transmission is avoided; in the aspect of a receiving device, two receiving modes of a single pole and a dipole are respectively and fixedly arranged on a vertical bisector of a tunneling working face, so that whether a geological abnormal body exists in front of the tunneling face can be quickly judged on a construction site according to the symmetry change of a current field, and reliable data can be provided for underground tunneling construction in time; and can adapt to different noise level, can choose for use according to different operating modes.

Drawings

Fig. 1 is a schematic view of the construction layout of the present invention, wherein 1a is monopole reception and 1b is dipole reception.

Fig. 2 is a schematic diagram of the advanced sounding point of the present invention, in which 2a is monopole reception and 2b is dipole reception.

FIG. 3 is a graph showing the results of the experiment.

In the figure: 1-tunneling surface; 2-a roadway; 3-an anomaly; 4-earth.

The invention is described in detail below with reference to the drawings and the detailed description.

Detailed Description

In order to further improve the accuracy of underground direct current advanced detection, the equatorial dipole moving source abnormity self-display advanced detection method comprises the steps that a receiving electrode M or receiving electrodes M and N are fixedly arranged on a vertical bisector of a heading surface, transmitting electrodes A and B are arranged on the vertical bisector of a roadway bottom plate midline and are away from the heading surface A₁B₁The position of the driving source A is moved to the direction of the driving face along the center line of the roadway floor at intervals required by resolution ratio to form a series of dynamic sources A_iB_i. When no abnormal body exists in the advancing detection distance in front of the tunneling surface, the electrode M or MN receives the noise levelOrWhen an abnormal body exists in front of the tunneling surface, the current field loses the original symmetry, and an abnormal body response signal is loaded to the receiving electrode M or the receiving electrodes M and N, so that the abnormal body in front of the tunneling surface can be quickly judged on a construction site. The invention provides a maximum detection distance estimation formula of two receiving modes of an equatorial dipole dynamic source, and A_iB_iCorresponding depth measuring points and apparent resistivity calculation formulas, a method for acquiring noise level in a maximum detection distance estimation formula, a method for measuring signal-to-noise ratio in a detection process, a formula for judging abnormality by using error records in measured data and the like.

Following the above technical solutions, specific embodiments of the present invention are provided below, and it should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes based on the technical solutions of the present application fall within the protection scope of the present invention. The present invention will be described in further detail with reference to examples.

Example 1:

the present embodiment provides a method for self-explicit advanced detection of downhole DC equatorial dipole source anomalies, as shown in FIGS. 1a and 1b, respectivelyFixedly arranging a receiving electrode M or receiving electrodes M and N on a tunneling surface, wherein the receiving electrode is positioned on a vertical bisector of the bottom edge of the tunneling surface, and is close to a geological abnormal body in front of the tunneling working surface as much as possible, so that the influence of the abnormal body near a roadway top bottom plate and a side wall is avoided; the emitting electrodes A and B are arranged on the tunnel bottom plate, the perpendicular bisector of the connecting line of the emitting electrodes A and B is the central line of the tunnel bottom plate, and the emitting electrodes A and B are arranged from A₁B₁The position of the probe moves to the direction of the heading face at intervals required by resolution along the center line of the roadway floor, the signal-to-noise ratio increases along with the increase of the detection distance, and the probe is sequentially positioned at A₁And B₁Position point, A₂And B₂Location points, a_iAnd B_iPoints of position, a_nAnd B_nA dipole moving source of location points; the emitting electrodes A and B emit current once at each position point, and the receiving electrode M or the receiving electrodes M and N correspondingly measure voltage once to perform dipole dynamic source advanced detection; when the influence of a roadway is neglected, the initial position of the transmitting electrode and the position of the maximum advanced detection distance are symmetrical relative to the tunneling surface, so that the distance between the initial position of the transmitting electrode and the midpoint O of the bottom edge of the tunneling surface is the maximum detection distance;

when the monopole receiving electrode M is fixedly arranged on the heading face, the estimation formula of the maximum advanced detection distance is as follows:

in the above formula, O 'O is the distance from the emitting electrode to the midpoint O' of AB to the midpoint O of the bottom edge of the driving face, I_ABmaxIn order to achieve the maximum emission current,the rho is the resistivity of the rock stratum in front of the driving face and is the noise level observed by the receiving electrode M;

when the dipole receiving electrode MN is fixedly arranged on the heading face, the estimation formula of the maximum detection distance of the advanced detection is as follows:

in the above formula, O'₁O is the midpoint of emitter electrode distance AB'₁The distance from the midpoint O of the bottom edge of the heading face, O 'O is the distance from the midpoint O' of the receiving electrode MN to the point O, I_ABmaxIn order to achieve the maximum emission current,ρ is the resistivity of the formation ahead of the face for the noise level observed by the receiver electrodes M and N.

A₁And B₁Position point, A₂And B₂Location points, a_iAnd B_iPoints of position, a_nAnd B_nThe smaller the interval between the position points is, the higher the detection resolution is; emitter electrodes A and B from A₁And B₁Starting at the position point, the distance between the transmitting electrode and the midpoint O' of the AB moves to the direction of the tunneling surface at intervals required by resolution along the central line of the roadway bottom plate, and the depth of the current field penetrating into the front of the tunneling working surface is from shallow to deep.

In particular, noise levels are determined by the receiver null acquisition when the transmitter is not transmitting current before sounding is initiatedOrThe maximum detection distance is estimated by substituting into equations (1a) and (1 b).

In the above-described probing process, a is located for each emitter electrode_iB_iPosition, by empty and actual acquisition of the receiver when the transmitter is not transmitting and transmitting current, determining the noise levelOrAnd receiving a voltageOrAnd determining whether repeated observation is carried out or not according to the signal-to-noise ratio, and primarily judging whether an abnormal body exists in front of the tunneling surface or not on the site. This step is not omitted when downhole operation time permits.

Calculating the position of the transmitting electrode at A by formula (2)_iAnd judging whether the abnormal body in front of the tunneling surface is a low-resistance body or a high-resistance body according to the corresponding depth measuring point and the apparent resistivity.

When the monopole receiving electrode M is fixedly arranged on the heading face, the monopole receiving electrode M is connected with the A_iB_iCorresponding depth measuring point D_iAnd apparent resistivityThe formula of (1) is:

D_i≈O′₁O-O′_iO，(i＝1,2,...,n) (2a)

o 'of the above formula'₁O is determined by formula (1a), O'_iO is the midpoint of emitter electrode distance AB'_iDistance to O;

in the above formulaIs A_iThe distance to M,

Is B_iA distance to M, wherein MO is the distance from M to O,is A_iB_iThe emission current of (a) is measured,is anda corresponding observed voltage;

when the dipole reception electrodes M and N are fixedly arranged on the heading face, the dipole reception electrodes A and M are connected with the dipole reception electrodes A_iB_iCorresponding depth measuring point D_iAnd apparent resistivityThe formula of (1) is:

D_i≈O′₁O-O′_iO，(i＝1,2,...,n) (2c)

of which O'₁O is determined by formula (1b), O'_iO is the midpoint of emitter electrode distance AB'_iDistance to O;

in the formulaIs A_iThe distance to M,

Is B_iThe distance to M,Is A_iThe distance to N,Is B_iDistance to N, where MO is the distance from M to O, NO is the distance from N to O,is A_iB_iThe emission current of (a) is measured,is andthe corresponding observed voltage.

After the detection is finished, taking error records in the actually measured data as a discrimination standard of the abnormal interpretation;

when the monopole receiving electrode M is fixedly arranged on the heading face, the measured data is interpreted as abnormal if the following formula (3a) is satisfied:

when the dipole reception electrodes M and N are fixedly arranged on the heading face, the measured data is interpreted as abnormal if the following equation (3b) is satisfied:

wherein Mean. + -. S.D. is Mean. + -. standard deviation, A_iM、B_iM、A_iN and B_iN is defined in formula (2).

When no abnormal body exists in the maximum detection distance range in front of the tunneling surface, the receiving electrode M or the receiving electrodes M and N observe a noise level due to the symmetry of the electrode arrangement, which causes the symmetry of the electric flow field; when an abnormal body exists in the range of the maximum detection distance in front of the tunneling surface, the current field loses symmetry, and when a voltage signal of 3-5 times of noise level is observed by the receiving electrode, the abnormal body existing in front of the tunneling surface can be judged.

When an abnormal body exists in the maximum detection distance range in front of the tunneling surface but the current field does not contact the abnormal body, the noise level is observed by the receiving electrode M or the receiving electrodes M and N; with the emitter electrode A_iB_iMoving towards the direction of the heading face, enabling the current field to be in contact with the abnormal body and be disturbed, and judging when the disturbance is transmitted to the heading face and the voltage signal of 3-5 times of noise level is observed by the receiving electrodeThe presence of an abnormality is determined.

And (3) experimental verification:

in order to verify the correctness and the validity of the formula, numerical simulation calculation is carried out by using the formula. Assuming that there are 1 high-resistance bodies with radius of 5m under the tunnel floor 20m, the resistivity of the high-resistance bodies is 1000 Ω · m, and the resistivity of the surrounding rock is 100 Ω · m, an equatorial dipole transmitting and dipole MN receiving device is adopted to calculate by using the formula (2 d). Fig. 3 shows the corresponding calculation results, with distance in m on the abscissa and apparent resistivity in Ω · m on the ordinate of fig. 3. As can be seen from the figure, the position of the maximum anomaly calculated by the formula corresponds to the actual model position, indicating that the formula is valid and usable.