CN104181611A - Mine working face top board and bottom board mining breaking fracture development dynamic monitoring method - Google Patents

Abstract

The invention belongs to the technical field of detection of mining cracks on the roof and floor of mine working faces, and relates to a dynamic monitoring method for the development of mining damage cracks on the roof and floor of mine working faces. The distribution of the plastic area of the roof and floor of the working face, the construction of the drilling hole in the roadway of the working face and the arrangement of three groups of cracks to develop dynamic detection holes; then use the surrounding rock cracks in the construction to dynamically monitor the detection holes, and check the electrodes in the detection holes, roadway electrodes and measuring lines Make layout, collect data on the working face through the data acquisition transmission line; then establish a geophysical model and perform data forward and inversion; finally analyze the mining damage cracks of the roof and floor of the mine working face; the monitoring process is simple, the operation is convenient, and the construction Safety, rigorous design, reasonable structure, convenient underground construction, high data collection efficiency.

Description

A dynamic monitoring method for the development of mining damage cracks in the roof and floor of mine working face

Technical field:

The invention belongs to the technical field of detection of mining cracks on the roof and floor of a mine working face, and relates to a method for dynamically monitoring the development of mining damage cracks on the roof and floor of a mine working face based on resistivity detection.

Background technique:

With the mining of coal resources, the depth of China's coal mining has shifted from shallow to deep; coal production areas have gradually shifted from central and eastern to western and northwestern. For the mining of deep coal seam resources, the geological structure and hydrogeology have become increasingly complex. Mine pressure, mining The damage depth of dynamic stress to the floor is increasing, and the problem of water inrush is becoming more and more serious; for the coal seams in Ningxia, western Ordos, Shaanxi and Xinjiang, the coal seam roof rocks are mostly mudstone with soft rock mechanical properties, and relatively hard rock mechanical properties. Due to the composition of glutenite and sandstone in the upper four zones of the coal seam and the glutenite water in the theory of the upper three zones of the coal seam will become the key factors of roof water inrush, and the key factor in the problem of roof and floor water inrush—mining fractures The height and depth of development have become important contents in the study of water inrush mechanism.

At present, the main methods for detecting the development of coal seam mining fractures include drilling double-end plugging leak detection method, ultrasonic detection method, borehole imaging method and geophysical prospecting method. Among them, the ultrasonic detection method is only applicable to the situation where there is water in the coal seam floor borehole. The water in it is used as the ultrasonic coupling medium, but this method cannot be used for observation holes in the bottom plate holes or roof water-conducting cracks where there is no water; the detection principle of the borehole imaging method is the imaging of the borehole camera, which can only be observed The development of fissures in the surrounding rock wall can be used to infer the development degree of fissures in the entire rock formation; in the case of turbid water and high-temperature steam in the borehole, the borehole imaging cannot be observed; the borehole resistivity method is often used in geophysical prospecting methods. By measuring the electrical characteristics of the surrounding rock of the borehole, and using the corresponding relationship between fractures and resistivity, the fracture development characteristics of the entire rock formation can be inverted. The shape and dynamic evolution of mining fractures cannot be realized; the double-end plugging leak detection method is currently the most practical and comprehensive method for detecting water-conducting fractures. relationship, to detect the degree of development of mining fissures, but this method requires corresponding water and air pipelines for on-site construction, and cannot dynamically present the development of mining fissures, especially for boreholes with high roof fissures, due to static water Due to the existence of pressure, the water injection pipeline depends on the drill pipe, and the sealing of the water injection pipeline hinders the detection of water-conducting fracture zones in thick coal seams; for observation holes with deep mining fractures in the floor, also due to the existence of hydrostatic pressure, lead to The water injection pressure is high, and the sealing of the airbag becomes the main problem affecting the observation accuracy. To sum up, the existing detection methods of coal seam mining fracture development have their corresponding limitations.

Invention content:

The purpose of the present invention is to overcome the shortcomings of the prior art, and to provide a dynamic monitoring method for the development of mining damage cracks on the roof and floor of the working face based on resistivity detection. The method can effectively observe the development pattern and law of cracks in the roof and floor of the working face in real time, and at the same time provide effective early warning for water inrush on the roof and floor.

In order to achieve the above object, the present invention includes numerical simulation of mining surrounding rock in mine working face, design and construction of drilling holes for dynamic monitoring of mining cracks in roof and floor of mine working face, dynamic collection of monitoring drilling electrical data, establishment of geophysical model and data normalization. There are five steps in the inversion and analysis of mining damage cracks on the roof and floor of the mine working face, and the specific monitoring process is as follows:

(1) Numerical simulation of the mining surrounding rock of the mine working face: According to the existing drilling data of the mine, the rock samples of the top and bottom slabs of the adjacent working face are collected, and the triaxial rock mechanics test is carried out on the rock samples to obtain the rock mechanics parameters. The obtained rock mechanics parameters are used in the numerical simulation calculation of the failure of the roof and floor surrounding rocks of the working face; the numerical simulation is carried out according to the actual geological and hydrogeological conditions of the mine working face, and the elastic deformation of the roof and floor rock layers of the working face affected by mining is carried out. plastic region for analysis;

(2) Drilling design and construction for dynamic monitoring of mining cracks in the roof and floor of the mine working face: According to the numerical simulation calculation results obtained in step (1), and then according to the distribution of the plastic area of the roof and floor of the working face, construction drilling in the roadway of the working face Three groups of dynamic detection holes for fracture development are arranged in the nest, and each group of dynamic monitoring holes for fracture development is composed of four detection holes, of which there are two detection holes on the top plate, and the inclination angle of one detection hole on the top plate is greater than that of the other detection hole on the top plate; There are also two bottom plate detection holes, the inclination angle of one bottom plate detection hole is greater than that of the other bottom plate detection hole; the slant length and angle of the drilling hole are based on numerical simulation;

(3) Dynamic collection of electrical data of detection holes: use the surrounding rock cracks under construction to dynamically monitor the detection holes, arrange the electrodes in the detection holes, roadway electrodes and measuring lines, arrange a measuring line in each detection hole, monitor the holes There are data acquisition transmission lines and electrodes inside; three measuring lines are arranged continuously in the roadway; after the arrangement of the measuring lines is completed, the data acquisition of the working face is carried out through the data acquisition transmission line, and the electrical data of the measuring line is collected every time the working face advances 10m;

(4) Establishment of geophysical model and forward and inversion of data: According to the detection porosity data collected in step (3), combined with the geological, hydrogeological and geophysical properties of the roof and floor strata of the working face, an inclined layered earth is established The physical model is used to increase the response sensitivity to mining fractures on the roof and floor of the working face and improve the ability to distinguish fractures; and use the established inclined layered geophysical model to construct a forward modeling simulation program based on the existing ansys software and a Gaussian-quasi-Newton based Method inversion procedure;

(5) Analysis of mining damage cracks on the roof and floor of the mine working face: Combined with the factors affecting the development of mining cracks on the roof and floor of the working face, according to the dynamic monitoring results, the development law, shape, development height of the roof crack zone, The development depth of mining fractures in the floor was analyzed. At the same time, the relationship between the water-richness of the roof and floor aquifer, the thickness of the relative aquifer, and the development of mining fractures were analyzed by using the theory of the upper three zones and the theory of the lower four zones. The occurrence type, threat degree and water inflow of floor water damage are evaluated to ensure safe recovery of the working face.

The rock mechanics parameters described in the present invention include the size of the working face (mainly the span L of the working face), mining speed, rock lithology of the roof and floor of the working face, coal mining thickness and rock mechanics parameters of the roof and floor strata.

The roof detection hole and the bottom detection hole of the present invention are respectively arranged in the boreholes of the track lane and the belt lane of the working face. The length is 150m, and the maximum hole depth is not more than 200m; the projection length of the floor detection hole on the belt lane is 150m, and the maximum vertical depth is 30m.

The measuring line of the present invention adopts a high-density resistivity measuring line, the electrodes in the detection holes of the top plate and the bottom plate adopt ring electrodes, and the electrode layout adopts a blocking device, the blocking medium is gas or water, and the blocking pressure is 1MP. The airbag of the device is fixed on the pipeline, and the pipeline is a sealed pipeline of PVC material. The airbag injects the blocking medium through the airbag hole, and the expansion of the inflated space makes the ring electrode contact the hole wall of the detection hole, and the ring electrode and the spiral multi-core cable pass through The electrode connecting wire and the connecting wire are connected for data transmission; the inflatable space is inflated by an inflatable device composed of an inflatable needle and a rubber tube. The multiple air bags of the inflatable device are independent of each other, so as to avoid the overall leakage of the air bag when the detection hole collapses and cause the ring electrode to be inflated. It cannot be in contact with the hole wall of the detection hole. The spiral multi-core cable is the connection line between the ring electrode and the external acquisition instrument. Its helical structure prevents it from being torn off when the hole collapses; The petal-shaped sealing plug is buckled in the socket of the pipeline, and the sealing sleeve fixes and seals the spiral multi-core cable and the petal-shaped sealing plug; the electrode spacing in the detection hole on the top plate and the detection hole on the bottom plate is 5m, and the electrodes are arranged according to the oblique length of the detection hole Quantity, the length of the measuring line arranged in the roadway of the working face is 450m, and the electrode spacing is also 5m; when collecting data, the existing two-pole data acquisition device, three-pole data acquisition device, and equatorial dipole data acquisition device are used. A variety of data acquisition devices comprehensively eliminate false anomalies and improve detection accuracy.

Compared with the prior art, the present invention can perform real-time dynamic monitoring on the shape and development law of the crack development of the roof and floor of the mining coal seam, solve the limitations of the previous detection technology for the mining crack of the coal seam, and expand the application environment of the crack development detection; its monitoring The technology is simple, the operation is convenient, the construction is safe, the design is rigorous, the structure is reasonable, the underground construction is convenient, and the data collection efficiency is high.

Description of drawings:

Fig. 1 is a schematic diagram of the principle of dynamic monitoring of mining crack development on the roof and floor of the mine working face according to the present invention, wherein 101 is a detection hole on the roof, 102 is a detection hole on the floor, and 103 is a measurement line on the floor of the roadway.

Fig. 2 is a schematic diagram of the layout structure principle of the survey line according to the present invention, wherein 101 is the detection hole on the top plate, 102 is the detection hole on the bottom plate, 103 is the survey line on the bottom plate of the roadway, and 104 is the electrode position.

Fig. 3 is a schematic diagram of the principle of detection hole layout according to the present invention, wherein 105 is roof detection hole 1#, 106 is roof detection hole 2#, 107 is a goaf, 108 is a roadway, and 109 is a borehole.

FIG. 4 is a schematic diagram of the principle of the electrode structure of the present invention, which includes an air bag hole 114 , a ring electrode 115 , an air bag 116 and a spiral multi-core cable 117 .

5 is a schematic diagram of the principle of the cross-sectional structure of the electrode of the present invention, which includes a ring electrode 115, an air bag 116, a spiral multi-core cable 117, an electrode connecting wire 121, an inflatable space 122, an inflating needle 123, a rubber tube 124 and a connecting wire 125.

FIG. 6 is a schematic diagram of the structural principle of the sealing hole of the spiral multi-core cable according to the present invention, which includes a spiral multi-core cable 117 , a petal-shaped sealing plug 118 , a sealing sleeve 119 and a pipeline 120 .

FIG. 7 is a schematic diagram of a tilted layered geophysical forward modeling model established by the present invention, which includes model grid nodes 110 , model boundaries 111 , model unit boundaries 112 and model units 113 .

Detailed ways:

The present invention will be further described below by way of embodiments and in conjunction with the accompanying drawings.

Example:

This embodiment mainly includes the numerical simulation of mining surrounding rock in the mine working face, the design and construction of drilling holes for dynamic monitoring of mining cracks in the roof and floor of the mine working face, the dynamic collection of monitoring drilling electrical data, the establishment of geophysical models, and the forward and inversion of data. Five steps for analysis of mining damage cracks on roof and floor of mine working face:

(1) Numerical simulation of mining surrounding rock in mine working face

Since the current working faces are all mining technologies such as large mining thickness, large span, and fully mechanized caving technology, the development mechanism of mining fractures in the past cannot estimate the development range of mining fractures and the elastic-plastic area of mining surrounding rock. In the past, triaxial rock mechanics tests were carried out on cores of exploration holes, and numerical simulation calculations were carried out based on the obtained rock mechanics parameters; when numerical simulations were carried out on the development of mining cracks on the roof and floor of the working face, the current mining technologies such as fully mechanized mining and fully mechanized caving were added. The main factors affecting the development of fractures include the size of the working face (mainly the span L of the working face), the recovery speed, the rock lithology of the roof and floor of the working face, the thickness of coal mining, and the rock mechanical parameters of the roof and floor strata. parameters, the numerical simulation accuracy of crack development in roof and floor strata has been greatly improved, and the construction of dynamic monitoring holes can be more effectively guided;

(2) Construction of dynamic monitoring holes for mining fractures in the roof and floor of the drilling face

According to the numerical simulation calculation results, three groups of dynamic monitoring holes for crack development are used in the corresponding boreholes 109 of the mine working face track lane and belt lane, and each group of crack development dynamic monitoring holes is composed of four monitoring holes, of which the roof detection hole 101 is Two, one low angle (top plate detection hole 2#106), one high angle (top plate detection hole 1#105); the bottom plate detection hole 102 is also two, one low angle, one high angle, and arrange high-density electrical method After the surveying line is laid out, data is collected every 10m of the working face; the diameter of the dynamic monitoring hole for cracks in the roof and floor is 85mm, and the projected length of the roof detection hole 101 in the roadway is 150m, and the maximum hole depth does not exceed 200m. The depth of the hole is determined to be guided by numerical simulation; the projected length of the floor detection hole 102 in the roadway is 150m, the maximum vertical depth is 30m, and the slant length and angle of the borehole are guided by numerical simulation;

(3) Dynamic monitoring of mining fractures on the roof and floor of the drilling face

After the construction of the mining crack observation hole on the roof and floor, a dynamic monitoring high-density resistivity measuring line is arranged, and the electrode arrangement in the detection hole adopts a gas/water sealing contact device, and the sealing device is closed separately, which not only ensures the tight contact between the electrode and the hole wall, It also ensures that all the airbags leak due to the collapse of the hole; the transmission line in the pipeline adopts a spiral device to prevent the transmission line from breaking when the dynamic monitoring hole collapses;

The electrodes in the detection hole 101 of the top plate and the detection hole 102 of the bottom plate adopt the ring electrode 115, and the electrode arrangement adopts a blocking device, the blocking medium is gas or water, the blocking pressure is 1 MP, and the air bag 116 of the blocking device is fixed on the pipeline 120, The pipeline 120 is a sealed pipeline made of PVC material. The airbag 116 injects the plugging medium through the airbag hole 114. The expansion of the air-filled space 122 makes the ring electrode 115 contact with the hole wall of the detection hole. The ring electrode 115 and the spiral multi-core cable 117 respectively pass through The electrode connection line 121 is connected to the connection line 125 for data transmission; the inflatable space 122 is inflated by an inflatable device composed of an inflatable needle 123 and a rubber tube 124, and a plurality of air bags 116 of the inflatable device are independent of each other to avoid the air bag caused by the collapse of the detection hole. The overall leakage of 116 makes the ring electrode 115 unable to contact the hole wall of the detection hole. The spiral multi-core cable 117 is the connection line between the ring electrode 115 and the external acquisition instrument, and its helical structure prevents the hole from being torn off when the hole collapses; The petal-shaped sealing design is adopted when the pipeline 120 is connected, and the petal-shaped sealing plug 118 is buckled in the socket of the pipeline 120, and the sealing sleeve 119 fixes and seals the spiral multi-core cable 117 and the petal-shaped sealing plug 118; the detection hole 101 on the top plate The electrode spacing in the detection hole 102 of the bottom plate is 5m, and the number of electrodes is arranged according to the oblique length of the detection hole. Advanced two-pole data acquisition device, three-pole data acquisition device, equatorial dipole data acquisition device, and various data acquisition devices comprehensively eliminate false anomalies and improve detection accuracy;

(4) Geophysical forward and inverse simulation based on dynamic monitoring of mining surrounding rock drilling

According to the azimuth of the rock layer revealed by the dynamic detection hole, the inclined layered geophysical model is established; using the inclined layered geophysical model, the forward modeling simulation program based on ansys software is developed, and the inversion program based on the Gaussian-quasi-Newton method is developed; the inclined layer is established The shape geophysical forward modeling model is composed of model grid nodes 110, 1 model boundary 111, model unit boundary 112 and model unit 113. The forward modeling software uses the ANSYS finite element method calculation software as the basis to develop the forward modeling program. The program is as follows:

/prep7

k,1,-800

k,2,800

k,3,-800,5

k,4,800,5

k,5,-300,-10

k,6,300,-10

k,7,-300

k,8,300

k,9,-800,-10

k,10,800,-10

k,11,-800,-500

k,12,800,-500

k,13,-800,400

k,14,800,400

k,15,100,40

k,16,120,40

k,17,100,80

k,18,120,80

a,1,2,4,3

a,5,6,8,7

a,1,9,5,7

a,6,10,2,8

a,9,11,12,10

a,3,4,14,13

a,15,17,18,16

aovlap, all

aglue, all

numcmp,area

save

This program forwardly simulates the distribution characteristics of the mining fracture damage geophysical field, which is convenient for the subsequent inversion calculation. The data processing adopts the inversion theory based on the Gaussian-quasi-Newton method. By reducing the error between the forward modeling model and the collected data, the final Determine the inversion model;

(5) Interpretation of mining damage fracture data on the roof and floor of the mine working face

Through dynamic monitoring, analyze the development law and development layers of cracks in the surrounding rock of the roof and floor of the working face, and use the theory of the upper three zones and the theory of the lower four zones to analyze the water-richness of the roof and floor aquifer, the thickness of the relative water-resisting layer, and the development of mining fractures etc., evaluate the risk assessment of roof and floor water inrush, and ensure the safe mining of the working face.

Claims (4)

1. a mine working face roof and floor is adopted and is destroyed cranny development dynamic monitoring method, it is characterized in that comprising that mine working face adopts that country rock numerical simulation, mine working face roof and floor mining-induced fissure dynamic monitoring drilling design and construction, monitoring hole that electrical dynamic measuring, geophysical model are set up and data FORWARD AND INVERSE PROBLEMS and mine working face roof and floor are adopted and destroyed crack analysis five steps, its concrete observation process is:

(1), mine working face is adopted country rock numerical simulation: according to the existing borehole data of mine, gather Adjacent Working Face adjoining rock rock sample, and rock sample is carried out to three axle rock mechanics experiments, obtain rock mechanics parameters, by the rock mechanics parameters obtaining for workplace roof and floor surrounding rock failure numerical simulation calculation; Carry out numerical simulation according to the actual geology of mine working face and hydrogeological situation, and workplace adjoining rock is subject to mining influence and the elastoplasticity region of growing is analyzed;

(2), mine working face roof and floor mining-induced fissure dynamic monitoring drilling design and construction: the numerical simulation calculation result obtaining according to step (1), again according to workplace roof and floor plastic region distribution situation, in roadway workface, construction is bored nest and is arranged three groups of cranny development dynamic instrumentation holes, every group of cranny development dynamic monitoring hole is made up of four exploration holes, wherein top board exploration hole is two, and the angle of inclination of a top board exploration hole is greater than the angle of inclination of another top board exploration hole; Base plate exploration hole is similarly two, and the angle of inclination of a base plate exploration hole is greater than the angle of inclination of another base plate exploration hole; , boring plagioclase and angle are taking numerical simulation as foundation;

(3), the electrical dynamic measuring of exploration hole: the wall-rock crack dynamic monitoring exploration hole that utilizes construction, electrode, tunnel electrode and survey line in exploration hole are arranged, in each exploration hole, all arrange a survey line, monitoring is provided with data acquisition transmission line and electrode in hole; In tunnel, arrange continuously three surveys line; After arrangement of measuring-line completes, by data acquisition transmission line, workplace is carried out to data acquisition, the every propelling of workplace 10m all carries out electrical data acquisition to survey line;

(4), geophysical model is set up and data FORWARD AND INVERSE PROBLEMS: the electrical data of exploration hole that collect according to step (3), and in conjunction with geology, hydrogeology and the Geophysical Properties of workplace adjoining rock, set up dipping bed spheroidal earth physical model, in order to increase workplace roof and floor mining-induced fissure response sensitivity, improve crack resolution characteristic; And utilize the dipping bed spheroidal earth physical model of setting up to build the forward simulation program based on existing ansys software and the inversion program based on Gauss-plan Newton method;

(5), mine working face roof and floor is adopted and is destroyed crack analysis: in conjunction with affecting workplace roof and floor mining-induced fissure developmental factors, according to the dynamic monitor result, to workplace roof and floor cranny development rule, form, top board emits and splits band development height, base plate mining-induced fissure Growth Depth is analyzed, simultaneously, utilize upper three band theory and lower four-tape theories, analyze the watery in roof and floor water-bearing zone, relative water resisting layer thickness, mutual relationship between mining-induced fissure growth etc., to roof and floor water damage occurrence type, threaten degree and water yield are evaluated, ensure the safe back production of workplace.

2. mine working face roof and floor according to claim 1 is adopted and is destroyed cranny development dynamic monitoring method, it is characterized in that described rock mechanics parameters comprises size, drawing speed, workplace roof and floor rock lithology, coal mining thickness and the adjoining rock rock mechanics parameters of workplace.

3. mine working face roof and floor according to claim 1 is adopted and is destroyed cranny development dynamic monitoring method, it is characterized in that described top board exploration hole and base plate exploration hole are separately positioned in the brill nest in workplace track lane and belt lane, the aperture of top board exploration hole and base plate exploration hole is 85mm, wherein top board exploration hole is 150m in the projected length in workplace track lane, and maximum hole depth is no more than 200m; Base plate exploration hole is 150m in the projected length in belt lane, and maximum vertical depth is 30m.

4. mine working face roof and floor according to claim 1 is adopted and is destroyed cranny development dynamic monitoring method, it is characterized in that described survey line adopts high-density resistivity survey line, electrode in top board exploration hole and base plate exploration hole adopts ring electrode, pole layout adopts plugging device, shutoff medium is gas or water, shutoff pressure 1MP, the air bag of plugging device is fixed on pipeline, pipeline is the sealing pipeline of PVC material, air bag is injected shutoff medium by pneumatopyle, the expansion of plenum space makes ring electrode contact with the hole wall of exploration hole, ring electrode is connected the transmission of carrying out data by electrode connecting line and connecting line with helical multi-core cable, plenum space adopts the aerating device being made up of Aerating needle and proofed sleeve to inflate, the multiple air bags of aerating device are separate, while avoiding exploration hole collapse hole, cause air bag entirety reveal and ring electrode cannot be contacted with the hole wall of exploration hole, helical multi-core cable is the connecting line of ring electrode and external acquisition instrument, when its helical structure is avoided collapse hole, pulls apart, helical multi-core cable adopts lobe type Seal Design while picking out pipeline, lobe type sealing-plug is buckled in the jack of pipeline, and sealing shroud is by helical multi-core cable and lobe type sealing-plug fixing seal, electrode separation in top board exploration hole and base plate exploration hole is 5m, arranges number of electrodes according to the plagioclase of exploration hole, and the survey line length being laid in lane, workplace road is 450m, and electrode separation is similarly 5m, while carrying out data acquisition, adopt existing two utmost point data collectors, three utmost point data collectors, dipole equatorial data collector, several data harvester is comprehensively rejected spurious anomaly, improves detection accuracy.