CN111581703A - Method for determining water-retaining coal mining support equipment for non-pillar gob-side entry retaining - Google Patents
Method for determining water-retaining coal mining support equipment for non-pillar gob-side entry retaining Download PDFInfo
- Publication number
- CN111581703A CN111581703A CN202010392131.4A CN202010392131A CN111581703A CN 111581703 A CN111581703 A CN 111581703A CN 202010392131 A CN202010392131 A CN 202010392131A CN 111581703 A CN111581703 A CN 111581703A
- Authority
- CN
- China
- Prior art keywords
- coal
- block
- retaining
- rock
- basic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000003245 coal Substances 0.000 title claims abstract description 116
- 238000005065 mining Methods 0.000 title claims abstract description 70
- 238000000034 method Methods 0.000 title claims abstract description 62
- 239000011435 rock Substances 0.000 claims abstract description 71
- 230000006835 compression Effects 0.000 claims abstract description 12
- 238000007906 compression Methods 0.000 claims abstract description 12
- 238000001125 extrusion Methods 0.000 claims abstract description 5
- 230000008093 supporting effect Effects 0.000 claims description 72
- 238000004364 calculation method Methods 0.000 claims description 33
- 230000008569 process Effects 0.000 claims description 29
- 230000009172 bursting Effects 0.000 claims description 17
- 230000009471 action Effects 0.000 abstract description 4
- 238000011161 development Methods 0.000 description 25
- 230000001174 ascending effect Effects 0.000 description 21
- 238000010586 diagram Methods 0.000 description 21
- 206010017076 Fracture Diseases 0.000 description 17
- 238000002955 isolation Methods 0.000 description 15
- 230000001965 increasing effect Effects 0.000 description 11
- 208000010392 Bone Fractures Diseases 0.000 description 7
- 238000009795 derivation Methods 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 4
- 238000011160 research Methods 0.000 description 4
- 239000010878 waste rock Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 238000005422 blasting Methods 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 230000000717 retained effect Effects 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 238000005315 distribution function Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000006260 foam Substances 0.000 description 2
- 238000012856 packing Methods 0.000 description 2
- 235000008708 Morus alba Nutrition 0.000 description 1
- 240000000249 Morus alba Species 0.000 description 1
- 238000004873 anchoring Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000009533 lab test Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/10—Geometric CAD
- G06F30/13—Architectural design, e.g. computer-aided architectural design [CAAD] related to design of buildings, bridges, landscapes, production plants or roads
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21C—MINING OR QUARRYING
- E21C41/00—Methods of underground or surface mining; Layouts therefor
- E21C41/16—Methods of underground mining; Layouts therefor
- E21C41/18—Methods of underground mining; Layouts therefor for brown or hard coal
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Geometry (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Evolutionary Computation (AREA)
- Mining & Mineral Resources (AREA)
- General Engineering & Computer Science (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Remote Sensing (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Computational Mathematics (AREA)
- Mathematical Analysis (AREA)
- Mathematical Optimization (AREA)
- Pure & Applied Mathematics (AREA)
- Devices Affording Protection Of Roads Or Walls For Sound Insulation (AREA)
Abstract
The invention discloses a method for determining a water-retaining coal mining support device for a non-coal-pillar gob-side entry retaining coal mining, which can calculate equivalent stress of a basic top breaking block according to the compression strength of a rock block, the ratio of the extrusion strength of the rock block at a corner end to the compression strength of the rock block, the thickness of the basic top breaking block, a rotation angle and length which are measured on site, obtain the volume weight of a direct top rock stratum and the volume weight of a basic top rock stratum, the thickness and the length of the direct top breaking block, calculate the weight of the direct top breaking block and the weight of the basic top breaking block, obtain a coal wall bearing coefficient, calculate the length of a coal wall bearing force action area, calculate a first bearing force, obtain a gangue bearing coefficient, calculate a second bearing force, finally calculate the in-lane internal bearing resistance, select the water-retaining coal mining support device for the non-coal-pillar gob-side entry retaining coal mining according to the in-lane gob-side bearing force, realize accurate selection of the water-retaining coal mining support device for, the safety of using the selected support equipment to carry out related operation is improved.
Description
Technical Field
The invention relates to the technical field of coal-pillar-free gob-side entry retaining, in particular to a method for determining water-retaining coal mining support equipment for a coal-pillar-free gob-side entry retaining.
Background
China has rich coal resources, and the consumption proportion of coal in primary energy is very large. Although the new energy is developed greatly, the traditional coal resources cannot be replaced within a short time due to the limitation of technical and economic conditions. In the coal mining process, the isolating coal pillars are reserved between two adjacent working faces to support the top plate and isolate the goaf, so that a large amount of high-quality coal resources are wasted, and dynamic disasters such as rock burst, coal and gas outburst and the like are easily caused. In addition, the support condition of the isolation coal pillar to the overlying strata is different from the support condition of the gangue in the goaf to the overlying strata, so that the development height of the ascending fracture of the boundary of the goaf is about 10-15% higher than that of the water-flowing fracture zone in the goaf. Meanwhile, the setting of the isolation coal pillars is not beneficial to overall settlement after surface mining, so that the development height of the ascending cracks and the development depth of the descending cracks are large, the ascending cracks and the descending cracks are easy to communicate, and a water-resisting layer loses a water-resisting effect, thereby causing a water inrush accident of a mine.
By adopting the non-coal-pillar gob-side entry retaining water-retaining coal mining method, the development height of the upward cracks of the mining overburden rock on the working face can be reduced, the upward cracks and the downward cracks are quickly closed, the whole subsidence after surface mining is realized, the upward cracks and the downward cracks are prevented from being communicated, the water-resisting stability of the mining overburden rock water-resisting layer is ensured, and the water-retaining coal mining is realized. The non-pillar gob-side entry retaining water-retaining coal mining method mainly has 2 modes: one is roof cutting pressure relief, namely, in a certain range of an advanced working face, in the edge of a retained roadway, roof cutting is carried out by adopting a presplitting blasting technology or a high-pressure water fracturing technology, an advanced presplitting joint is formed between a top plate above a goaf and a top plate above the roadway, stress relation between basic roofs is cut off, and a lateral support pressure peak value is reduced and is transferred to the deep part of a coal seam. And the other is roadside filling, namely, the roadside filling is carried out along a stoping roadway along with the advancing of a working face. The roadside filling entry retaining speed is low, the cost is high and the process is complex. Compared with the prior art, the roof-cutting pressure-relief gob-side entry retaining technology requires less equipment, is low in cost and simple in system, and avoids the problem of auxiliary transportation of a large amount of filling materials required by roadside filling. At present, most of researches on gob-side entry retaining without coal pillars are concentrated on gob-side entry retaining processes, top cutting parameters, pre-splitting blasting parameters, roadside filling body sizes, strength and the like. No research literature on the aspects of reducing the development height of the ascending cracks and the development depth of the descending cracks of the gob-side entry retaining without the coal pillar, realizing the overall subsidence after surface mining and the like on water retention is found. The related research of the calculation of the supporting resistance in the gob-side entry retaining without the coal pillar is less, and the accurate selection of the required supporting equipment is difficult to realize.
Disclosure of Invention
Aiming at the problems, the invention provides a method for determining water-retaining coal mining support equipment for a non-pillar gob-side entry retaining.
In order to realize the aim of the invention, the method for determining the water-retaining coal mining support equipment for the non-pillar gob-side entry retaining comprises the following steps:
s10, according to the compression strength sigma of the rock mass measured on sitecAnd the ratio of the compression strength of the rock at the corner end to the compressive strength of the rock η, substantially bursting the block thickness h2Angle of revolution theta1And length L, calculating the equivalent stress P of the basic top breaking blockd；
S20, obtaining the volume weight gamma of the direct roof rock stratum1And the bulk density gamma of the basic top rock layer2Thickness h of direct roof broken block1And length l, calculating weight G of direct roof breaking block1And a basic crest broken block weight G2；
S30, obtaining the coal upper bearing coefficient k1Bearing capacity of coal sideLength of action zone l1Calculating the first bearing capacity F of the roadside coal body1；
S40, obtaining a goaf gangue bearing coefficient k2And calculating the second bearing capacity F of the caving gangue in the goaf2；
S50, according to the equivalent stress P of the broken blockdDirect roof breaking block weight G1Basic top broken block weight G2First bearing capacity F1And a second bearing force F2And calculating the in-tunnel supporting resistance P, and selecting supporting equipment for non-pillar gob-side entry retaining water-retaining coal mining according to the in-tunnel supporting resistance P.
In particular, the basic bursting block is subjected to an equivalent force PdThe calculation process of (2) includes:
wherein, PdRepresenting the equivalent force of the broken block, η representing the ratio of the compression strength of the broken rock at the corner end to the compression strength of the rock, h2Representing the thickness, θ, of the basic bursting block1Representing the angle of revolution of the basic bursting block, L representing the length of the basic bursting block, sigmacIndicating the compressive strength of the rock mass.
Specifically, immediate roof breaking block weight G1The calculation process of (2) includes: g1＝γ1h1l；
Weight of basic top broken block G2The calculation process of (2) includes: g2＝γ2h2L。
In particular, the first bearing force F1The calculation process of (2) includes:
in particular, the second bearing force F2The calculation process of (2) includes:
specifically, the calculation process of the in-lane supporting resistance P comprises the following steps:
P＝G1+G2-Pd-F2-F1。
the method for determining the water-retaining coal mining support equipment for the non-pillar gob-side entry retaining can be based on the actually measured compressive strength sigma of the rock mass on sitecη ratio of the crush strength of the rock at the corner end to the compressive strength of the rock, breaking essentially the thickness h of the block2Angle of revolution theta1And length L, calculating equivalent stress P of the broken blockdObtaining the volume weight gamma of the direct roof rock stratum1And the bulk density gamma of the basic top rock layer2Thickness h of direct roof broken block1And calculating the weight G of the direct top broken block body according to the length l of the direct top broken block body1And a basic crest broken block weight G2Obtaining the coal slope bearing coefficient k1Length l of load-bearing area of coal side1Calculating the first bearing capacity F of the roadside coal body1Obtaining the bearing coefficient k of the gangue in the goaf2And calculating the second bearing capacity F of the caving gangue in the goaf2And calculating the in-tunnel supporting resistance P, and determining the supporting parameters and supporting equipment of the non-pillar gob-side entry retaining water-retaining coal mining according to the in-tunnel supporting resistance P, so that the accurate selection of the non-pillar gob-side entry retaining water-retaining coal mining supporting equipment is realized, and the safety of performing related operations by using the selected supporting equipment is improved. The development height of the ascending cracks of the mining overburden rock on the working face is reduced by adopting a coal-pillar-free gob-side entry retaining method, the ascending cracks and the descending cracks are quickly closed, the overall subsidence of the ground surface after mining is realized, the ascending cracks are prevented from being communicated with the descending cracks, the water-resisting stability of the mining overburden rock water-resisting layer is ensured, and the water-retaining coal mining is realized.
Drawings
Fig. 1 is a flowchart of a method of determining a water-retaining coal mining support device for a pillar-free gob-side entry retaining according to an embodiment;
FIG. 2 is a schematic diagram illustrating the development of mining water-flowing fractures of adjacent working faces when an isolation coal pillar is left in place according to an embodiment;
FIG. 3 is a schematic diagram illustrating the development of an A-A section of an ascending fracture and a descending fracture when an isolation coal pillar is left in accordance with an embodiment;
FIG. 4 is a schematic diagram illustrating development of mining water-flowing fractures of adjacent working faces when a coal pillar-free gob-side entry retaining is performed according to an embodiment;
FIG. 5 is a schematic diagram illustrating the development of an ascending fracture and a descending fracture of a B-B section during gob-side entry retaining without a coal pillar according to an embodiment;
FIG. 6 is a direct roof rupture block force diagram of in-lane support resistance calculation of one embodiment;
FIG. 7 is a basic burst block diagram of in-lane support resistance calculation of one embodiment;
FIG. 8 is a basic top break block equivalent force diagram of in-lane support resistance calculation of one embodiment;
FIG. 9 is a schematic cross-sectional view of a pillar-free gob-side entry retaining roadway of an embodiment;
FIG. 10 shows the supporting resistance P and the rotation angle θ of the key block B according to one embodiment1A relationship diagram of (1);
FIG. 11 shows the supporting resistance P and the roadway slope bearing coefficient k according to an embodiment1A relationship diagram of (1);
FIG. 12 shows the support resistance P and the goaf gangue bearing coefficient k according to an embodiment2A graph of the relationship (c).
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.
By means of automatic roadway forming through roof cutting and pressure relief, isolation coal pillars and roadside filling bodies between sections are completely eliminated, coal pillar-free mining is achieved, support of traditional isolation coal pillars and roadside filling bodies for overlying rocks is converted into support of supporting bodies in the roadway to the overlying rocks, and roadway supporting difficulty is increased. In order to solve the problems of repeated support and the like caused by improper selection of roadway retaining support parameters and support equipment in the method, referring to fig. 1, fig. 1 is a flow chart of a determination method for the non-pillar gob-side roadway retaining water coal mining support equipment provided by an embodiment, and the determination method comprises the following steps:
s10, according to the compression strength sigma of the rock mass measured on sitecη ratio of the crush strength of the rock at the corner end to the compressive strength of the rock, breaking essentially the thickness h of the block2Angle of revolution theta1And length L, calculating the equivalent stress P of the basic top breaking blockd。
In the practical application process, the compressive strength sigma of the rock mass can be obtained according to the modes of field actual measurement and the likecη ratio of the crush strength of the rock at the corner end to the compressive strength of the rock, breaking essentially the thickness h of the block2Basically breaking the block body by a rotation angle theta1And a substantially burst block length L.
In particular, the basic bursting block is subjected to an equivalent force PdThe calculation process of (2) includes:
wherein, PdRepresenting the equivalent stress of the basic bursting block body, η representing the ratio of the extrusion strength of the rock block at the corner end to the compression strength of the rock block, which is a dimensionless number, h2The thickness of the basic top breaking block can be expressed in m, theta1The unit of the rotation angle of the basic top breaking block can be shown, L represents the length of the basic top breaking block, and the unit can be m, sigmacThe compressive strength of the rock mass can be expressed in MPa.
S20, obtaining the volume weight gamma of the direct roof rock stratum1And the bulk density gamma of the basic top rock layer2Thickness h of direct roof broken block1And the length l of the direct top breaking block body, and calculating the weight of the direct top breaking block bodyQuantity G1And a basic crest broken block weight G2。
In the above steps, the volume weight gamma of the direct roof rock stratum can be obtained by means of laboratory tests1And the bulk density gamma of the basic top rock layer2Direct roof rock layer volume weight gamma1And the bulk density gamma of the basic top rock layer2All units of (a) are kN/m3. Determining the thickness h of the direct roof broken block according to the geological exploration result of the mine1And a basic burst block thickness h2The units are m. According to field tests, the length L of the basic top breaking block body and the length L of the direct top breaking block body are determined, and the unit is m.
Specifically, immediate roof breaking block weight G1The calculation process of (2) includes: g1＝γ1h1l；
Weight of basic top broken block G2The calculation process of (2) includes: g2＝γ2h2L。
S30, obtaining the coal upper bearing coefficient k1Length l of load-bearing area of coal side1Calculating the first bearing capacity F of the roadside coal body1。
In the above steps, the coal upper bearing coefficient k can be determined according to the inversion of the field measured data1In units of MPa/m; determining the length l of the bearing force action area of the coal upper1In the unit m.
In particular, the first bearing force F1The calculation process of (2) includes:
s40, obtaining a goaf gangue bearing coefficient k2And calculating the second bearing capacity F of the caving gangue in the goaf2。
The steps can determine the gangue bearing coefficient k of the goaf according to the field measured data2In units of MPa/m; determining the length L of the direct top breaking block and the length L of the basic top breaking block, wherein the unit is m.
In particular, the second bearing force F2The calculation process of (2) includes:
s50, breaking the equivalent stress P of the block body according to the basic burstingdDirect roof breaking block weight G1Basic top broken block weight G2First bearing capacity F1And a second bearing force F2And calculating the in-tunnel supporting resistance P, and determining supporting parameters and supporting equipment for the non-pillar gob-side entry retaining water-retaining coal mining according to the in-tunnel supporting resistance P.
Specifically, the calculation process of the in-lane supporting resistance P comprises the following steps:
P＝G1+G2-Pd-F2-F1。
wherein G is1The weight of the direct roof breaking block is kN; g2The weight of the basic top breaking block is kN; pdThe equivalent stress of the block is basically broken, and the unit is kN; f1The bearing capacity of the roadside coal side is expressed in kN; f2The bearing capacity of the waste rock in the goaf is kN.
Further, the calculation formula of the in-lane supporting resistance P can be written as follows:
wherein gamma is the direct roof stratum volume weight gamma1Bulk density gamma to the base top rock layer2Average value of (a).
Further, the supporting resistance P in the lane is calculated, and the purpose is to determine supporting parameters and supporting equipment in the lane. According to the calculation result of the in-tunnel supporting resistance (in-tunnel supporting resistance P), selecting supporting equipment with proper supporting resistance such as anchor rods (cables), single pillars or steel pipe concrete pillars, optimizing the selected supporting parameters such as the row spacing, the pretightening force, the anchoring force between the anchor rods (cables) or the supporting density and the working resistance of the single pillars and the steel pipe concrete pillars, and finally ensuring that the supporting resistance of the supporting equipment on the unit area of the roadway roof is larger than the calculated in-tunnel supporting resistance P, so that the gob-side entry retaining roadway roof is well controlled, and the problem of repeated supporting caused by improper selection of the supporting equipment or unreasonable design of the supporting parameters is solved.
The method for determining the water-retaining coal mining support equipment for the non-pillar gob-side entry retaining can be based on the actually measured compressive strength sigma of the rock mass on sitecη ratio of the crush strength of the rock at the corner end to the compressive strength of the rock, breaking essentially the thickness h of the block2Basically breaking the block body by a rotation angle theta1Calculating the length L of the basic top breaking block body and calculating the equivalent stress P of the basic top breaking block bodydObtaining the volume weight gamma of the direct roof rock stratum1And the bulk density gamma of the basic top rock layer2Thickness h of direct roof broken block1And calculating the weight G of the direct top broken block body according to the length l of the direct top broken block body1And a basic crest broken block weight G2Obtaining the coal slope bearing coefficient k1Length l of load-bearing area of coal side1Calculating the first bearing capacity F of the roadside coal body1Obtaining the bearing coefficient k of the gangue in the goaf2And calculating the second bearing capacity F of the caving gangue in the goaf2And calculating the in-tunnel supporting resistance P, and selecting the supporting parameters and supporting equipment of the coal-pillar-free gob-side entry retaining according to the in-tunnel supporting resistance P, so that the supporting equipment of the coal-pillar-free gob-side entry retaining can be accurately selected, and the safety of related operations performed by using the selected supporting equipment is improved. The development height of an ascending crack of the mining overburden rock on the working face is reduced by adopting a coal-pillar-free gob-side entry retaining water-retaining coal mining method, the ascending crack and the descending crack are quickly closed, the whole subsidence of the ground surface after mining is realized, the ascending crack is prevented from being communicated with the descending crack, the water-resisting stability of the mining overburden rock water-resisting layer is ensured, and the water-retaining coal mining is realized.
In an embodiment, the determination method of the above-mentioned water retention coal mining support parameters and support equipment for the coal pillar-free gob-side entry retaining is described with reference to fig. 2 to 12, fig. 2 is a schematic diagram of development of mining water-flowing fractures of adjacent working faces when an isolation coal pillar is left in this embodiment, fig. 3 is a schematic diagram of development of upward fractures and downward fractures of an a-a section when an isolation coal pillar is left in this embodiment, fig. 4 is a schematic diagram of development of mining water-flowing fractures of adjacent working faces when a coal pillar is left in the gob-side entry retaining in this embodiment, and fig. 5 is a schematic diagram of development of upward fractures of a B-B section when a coal pillar is left in the gob-sideFig. 6 is a diagram of a direct top-breaking block force diagram of calculation of in-lane support resistance in the derivation process in this embodiment, fig. 7 is a diagram of a basic top-breaking block force diagram of calculation of in-lane support resistance in the derivation process in this embodiment, fig. 8 is a diagram of an equivalent of the basic top-breaking block force diagram of calculation of in-lane support resistance in the derivation process in this embodiment, fig. 9 is a diagram of a section of a gob-side entry retaining roadway without coal pillars in this embodiment, and fig. 10 is a diagram of a rotation angle θ between support resistance P and a key block B in this embodiment1Fig. 11 is the supporting resistance P and the roadway coal side bearing coefficient k in this embodiment1FIG. 12 is a graph showing the supporting resistance P and the goaf gangue bearing coefficient k in this example2A graph of the relationship (c). In each figure: 1 represents an upper working face initial mining line; 2 represents an upper working face gob; 3 represents the stoping line of the upper working face; 4, an upper working face section air inlet roadway; 5 denotes an isolation coal pillar; 6 represents the goaf of the working face; 7, a return airway of the working face section; 8 denotes a stope face; 9, an air inlet gallery of the section of the working face; 10 represents the development height of the ascending fissure of the working surface; 11 represents the upgoing fissure development height of the upper working surface; 12 represents the downward crack of the working surface; 13 represents the upper face down fissure; 14, upper face gob-side entry retaining; 15 denotes an upper face foam isolator; 16 denotes the present working face foam spacer; 17, the roadway of the working face is reserved; 18 represents a reserved roadway of the working face; 19, representing the ascending fracture development height of the working face and the upper working face of the gob-side entry retaining without the coal pillar; 20 denotes a height-adjustable steel pipe concrete pillar; 21 denotes a coal seam; 22 denotes a direct roof; 23 denotes a basic ceiling; 24 denotes a substantially top rock layer (medium sandstone); 25 denotes pre-splitting blasting slitting; key block B is denoted by 26.
As can be seen from fig. 2 to 5, because the support conditions of the gangue in the upper working face gob 2 and the present working face gob 6 for the overlying strata are different from the support conditions of the isolation coal pillar 5 for the overlying strata, the development heights of the upper working face ascending fractures 11 and the present working face ascending fractures 10 on the isolation coal pillar 5 are 10% to 15% higher than those of the ascending fractures in other areas. The gob-side entry retaining water-retaining coal mining method without coal pillars does not need to retain safe coal pillars, and the supporting condition of a support body in the entry retaining lane to overlying strata is the same as the supporting condition of gangue in a goaf to the overlying strata, so that the development heights H' of the mining overlying strata upward fissure of the upper working face and the mining overlying strata upward fissure 19 of the working face are smaller than the development heights H of the mining overlying strata upward fissure 11 of the upper working face and the mining overlying strata upward fissure 10 of the working face when the isolation coal pillars are retained. After the working face of the gob-side entry retaining without the coal pillar is mined, because the ground surface is wholly sunk, the development depth D' of the downward crack of the upper working face and the downward crack of the working face is smaller than the development depth D of the downward crack of the upper working face and the downward crack of the working face when the isolation coal pillar is reserved. In addition, the non-coal-pillar gob-side entry retaining water-retaining coal mining method can realize the rapid closure of the upper working face ascending crack 11, the lower working face descending crack 13, the working face ascending crack 10 and the working face descending crack 12, prevent the communication of the upper working face ascending crack 11, the upper working face descending crack 13, the working face ascending crack 10 and the working face descending crack 12, ensure the water-resisting stability of a mining overburden rock water-resisting layer, and further realize water-retaining coal mining.
The method completely cancels the isolation coal pillars and the roadside packing bodies between sections in a roof cutting pressure relief automatic lane forming mode, realizes coal pillar-free mining, converts the support of the traditional isolation coal pillars and the roadside packing bodies to the overlying rock into the support of the supporting bodies in the retained lane to the overlying rock, and provides a calculation method of the supporting resistance of the supporting bodies in the lane based on the theory of short-arm beams, wherein the derivation process of the calculation formula of the supporting resistance in the lane is as follows: when the gangue does not effectively support the right end of the roadway roof structure, the roof can be regarded as a short cantilever beam structure. The top plate is most easy to be unstable when in a short cantilever beam structure state, and a stress model of the direct roof is shown in figure 6. The condition of stress balance in the vertical direction of the direct roof is as follows:
wherein, F1Giving a load to the base roof; g1The weight of the block is directly propped and broken; q (x) is a solid coal bearing capacity distribution function; p is the supporting force of the supporting body in the lane; l1The length of the pressure action area is supported by the coal side.
Further, FIG. 7 is a basicBreaking the block by force characteristics, F1Supporting force of direct roof to basic roof block, F2The support force of the caving gangue in the goaf on the basic roof breaking block is provided. The basic bursting block stress model shown in fig. 7 is converted into a common calculation model in the mine pressure theory, as shown in fig. 8.
Further, the expression of the stress at the two ends of the basic bursting block is obtained as follows:
wherein, TAHorizontal extrusion force borne by two ends of the broken block body; pdThe block is basically broken through equivalent stress; h is2Is the thickness of the basic bursting block body; l is the length of the basic bursting block; theta1Is the rotation angle of the block body which is basically broken.
Further, the maximum horizontal extrusion force for preventing the basic top breaking block from generating rotary deformation instability is as follows:
wherein η is the ratio of the compression strength of the rock at the corner end to the compression strength of the rock, σcThe compressive strength of the rock mass.
Further, the equivalent bearing capacity of the obtained basic bursting block meets the following requirements:
further, the support load borne by the basic bursting block from the direct roof is obtained as follows:
F1＝G2-F2-Pd
further, the stress of the obtained gob-side roadway support body meets the conditional expression:
specifically, the stress expression of the gob-side roadway support body is obtained as follows:
further, assuming that the coal side in the roadway satisfies the linear bearing relationship, that is:
q(x)＝k1(l1-x)
in the formula: k is a radical of1The bearing coefficient of the coal side.
Further, the bearing capacity of the roadside coal upper is obtained as follows:
further, the weights of the obtained direct top breaking block and the basic top breaking block are respectively as follows:
G1＝γ1h1l，G2＝γ2h2L
in the formula: gamma ray1Is the volume weight of a direct roof rock stratum and has the unit of kN/m3；γ2Is the basic top rock layer volume weight and has the unit of kN/m3；h1The thickness of the direct roof breaking block is m; h is2Is the thickness of the basic bursting block body, and the unit is m; l is the length of the direct roof breaking block body, and the unit is m; l is the length of the basic bursting block in m.
Further, the effective support range of the basic top breaking block subjected to the caving gangue in the goaf is obtained as follows:
lc＝L-l
furthermore, a local coordinate system is adopted to describe the supporting effect of the goaf waste rock, and the supporting load of the goaf waste rock is known to satisfy the linear relation:
q2(X)＝k2X
in the formula: q. q.s2(X) is a distribution function of the bearing capacity of the caving gangue in the goaf; k is a radical of2The bearing coefficient of the waste rock in the goaf is obtained; and X is a local coordinate system coordinate.
Further, the bearing capacity of the caving gangue in the goaf meets the following requirements:
further, directly taking the volume weight gamma of the top rock stratum1Bulk density gamma to the base top rock layer2The average value gamma of the support body stress is analyzed, and the calculation formula of the support body stress of the gob-side roadway is obtained as follows:
example 1: this example takes the second well 3302 of the mulberry terrace in the Hancheng mining area as an example of a working face belt conveyor lane. The roadway section is as shown in fig. 9, and it is worth explaining that the derivation of the calculation formula of the supporting resistance in the roadway by the non-pillar gob-side entry retaining water coal mining method is based on that the roof cutting height does not penetrate through the basic roof, the roof cutting height of the 3302 working face just penetrates through the basic roof, and the key rock stratum broken block B is a broken rock block at the basic roof position, which is included in the context of the derivation of the formula. The actual geological parameters and mining parameters of the working face are taken, and the basic calculation parameters are as follows: l is 24.6m, h28.4m (overlying 6.6m weak formation), l1＝3m，l＝7.6m，h1＝7.8m，γ＝(γ1+γ2)/2＝25kN/m3，θ1＝6°，η＝0.3，σc＝20.4MPa，k1＝0.1MPa/m，k20.3 MPa/m. Research on key block B rotation angle theta by using control variable method1Solid coal upper bearing coefficient k1Bearing coefficient k of gangue in goaf2Influence on the supporting resistance.
(1) Key block B rotation angle theta1
The key block B is not effectively supported at the initial stage of goaf gangue collapse, namely the gangue bearing coefficient k2At this stage, the supporting body plays a major role. Coal side bearing coefficient k10.1MPa/m, angle of rotation theta1Increasing from 0 to 8,support resistance with theta1The variation of (2) is shown in fig. 10.
As can be seen from FIG. 10, the support resistance follows the rotation angle θ1The increase is approximately linear, theta1The supporting resistance is averagely increased by 712kN and theta every time the supporting resistance is increased by 1 DEG1When the angle is increased to 8 degrees, the supporting resistance is increased to 7476 kN. The above rules show that the rotation deformation of the key block B brings great resistance increasing effect to the support body in the roadway, and the rotation deformation is limited, so that the resistance reduction of the support body is facilitated.
(2) Roadway solid coal side bearing coefficient k1
Key block B rotation angle theta1At 6 degrees, the gangue bearing coefficient is 0.3MPa, and the coal slope bearing coefficient k1When the pressure is increased from 0MPa to 0.3MPa, the supporting resistance is changed along with k1The variation of (2) is shown in fig. 11.
As can be seen from FIG. 11, the support resistance follows the coal upper bearing coefficient k1The increase of the supporting resistance is linearly reduced, the supporting resistance is reduced by 225kN when the bearing coefficient of the coal side is increased by 50kPa, and the supporting resistance is reduced to 613kN when the coefficient is increased to 300 kPa. The law shows that the coal slope keeps good bearing performance, which is beneficial to the resistance reduction of a supporting body, and the adoption of a reasonable surrounding rock reinforcing and supporting technology to ensure that the coal slope keeps good bearing performance is an effective way for maintaining the stability of a roadway.
(3) Bearing coefficient k of gangue2
The key block B is supported by roadside gangue after rotating to a certain degree, and the gangue plays a role in limiting the rotation of the key block B. Angle of rotation theta1At 6 degrees, the bearing coefficient k of the gangue2When the pressure is increased from 0MPa to 0.3MPa, the support resistance follows the gangue bearing coefficient k2As shown in fig. 12.
As can be seen from FIG. 12, the support resistance is linearly reduced along with the increase of the gangue bearing coefficient, and the gangue bearing coefficient k2The bracing resistance is reduced by 481kN every 30kPa increase, and when the coefficient is increased to 300kPa, the bracing resistance is reduced to 1513 kN. The law shows that the gangue support can effectively control the rotation deformation of the key block B, shorten the gangue contact period of the key block B, and fully exert the gangue bearing performance to facilitate the drag reduction of the support body.
The beneficial effects of this embodiment include:
the development height of the upward cracks of the mining overburden rock on the working face can be reduced, the upward cracks and the downward cracks are quickly closed, the overall subsidence of the ground surface after mining is realized, the upward cracks are prevented from being communicated with the downward cracks, the water-resisting stability of a mining overburden rock water-resisting layer is ensured, and the water-retaining coal mining is realized.
The method can calculate the supporting resistance in the roadway of the non-pillar gob-side entry retaining water-retaining coal mining method, has simple operation and reliable result, can greatly improve the extraction rate of coal resources on the premise of realizing water-retaining coal mining and non-pillar safe mining, has wide practicability, and has certain guiding effect on the implementation process of the support in the roadway of the non-pillar gob-side entry retaining water-retaining coal mining method.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
It should be noted that the terms "first \ second \ third" referred to in the embodiments of the present application merely distinguish similar objects, and do not represent a specific ordering for the objects, and it should be understood that "first \ second \ third" may exchange a specific order or sequence when allowed. It should be understood that "first \ second \ third" distinct objects may be interchanged under appropriate circumstances such that the embodiments of the application described herein may be implemented in an order other than those illustrated or described herein.
The terms "comprising" and "having" and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product, or device that comprises a list of steps or modules is not limited to the listed steps or modules but may alternatively include other steps or modules not listed or inherent to such process, method, product, or device.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (6)
1. A method for determining water-retaining coal mining support equipment for a non-pillar gob-side entry retaining is characterized by comprising the following steps:
s10, according to the compression strength sigma of the rock mass measured on sitecAnd the ratio η of the crush strength of the rock at the corner end to the compressive strength of the rock, the thickness h of the substantially top-breaking block2Angle of revolution theta1And the length L of the block body, and calculating the equivalent stress P of the basic top breaking block bodyd；
S20, obtaining the volume weight gamma of the direct roof rock stratum1And the bulk density gamma of the basic top rock layer2Thickness h of direct roof broken block1And length l, calculating weight G of direct roof breaking block1And a basic crest broken block weight G2；
S30, obtaining the coal upper bearing coefficient k1Length l of load-bearing area of coal side1Calculating the first bearing capacity F of the roadside coal body1；
S40, obtaining a goaf gangue bearing coefficient k2And calculating the second bearing capacity F of the caving gangue in the goaf2；
S50, breaking the equivalent stress P of the block body according to the basic burstingdDirect roof breaking block weight G1Basic top broken block weight G2First bearing capacity F1And a second bearing force F2And calculating the in-tunnel supporting resistance P, and determining supporting parameters and supporting equipment for the non-pillar gob-side entry retaining water-retaining coal mining according to the in-tunnel supporting resistance P.
2. The method for determining the water-retaining coal mining support equipment for the coal pillar-free gob-side entry retaining according to claim 1, wherein the basic roof breaking block equivalent stress PdThe calculation process of (2) includes:
wherein, PdRepresenting the equivalent force of the basic bursting block, η representing the ratio of the extrusion strength to the compression strength of the rock block at the corner end, h2Denotes the base top thickness, θ1Representing the angle of gyration, L representing the length of the basic bursting block, σcIndicating the compressive strength of the rock mass.
3. The method for determining the water-retaining coal mining support equipment for the coal-pillar-free gob-side entry according to claim 1, wherein the weight G of the direct roof breaking block is1The calculation process of (2) includes: g1＝γ1h1l；
Weight of basic top broken block G2The calculation process of (2) includes: g2＝γ2h2L。
4. The method for determining the water-retaining coal mining support equipment for the coal-pillar-free gob-side entry retaining according to claim 1, wherein the first bearing force F is1The calculation process of (2) includes:
5. the method for determining the water-retaining coal mining support equipment for the coal-pillar-free gob-side entry retaining according to claim 1, wherein the second bearing force F is2The calculation process of (2) includes:
6. the method for determining the water-retaining coal mining support equipment for the coal pillar-free gob-side entry retaining according to any one of claims 1 to 5, wherein the calculation process of the in-lane support resistance P comprises the following steps:
P＝G1+G2-Pd-F2-F1。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010392131.4A CN111581703B (en) | 2020-05-11 | 2020-05-11 | Determination method of coal pillar-free gob-side entry retaining water-retaining coal mining supporting equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010392131.4A CN111581703B (en) | 2020-05-11 | 2020-05-11 | Determination method of coal pillar-free gob-side entry retaining water-retaining coal mining supporting equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111581703A true CN111581703A (en) | 2020-08-25 |
| CN111581703B CN111581703B (en) | 2024-06-18 |
Family
ID=72112212
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010392131.4A Active CN111581703B (en) | 2020-05-11 | 2020-05-11 | Determination method of coal pillar-free gob-side entry retaining water-retaining coal mining supporting equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111581703B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111963197A (en) * | 2020-08-28 | 2020-11-20 | 陕西煤业化工技术研究院有限责任公司 | Gob-side entry retaining roadway supporting method for three-soft coal seam coal pillar-free mining |
| CN113982626A (en) * | 2021-10-14 | 2022-01-28 | 中煤能源研究院有限责任公司 | Method for calculating supporting resistance of roof in gob-side entry retaining roadway without coal pillar roof cutting |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103573273A (en) * | 2013-11-14 | 2014-02-12 | 山东科技大学 | Method for suitability evaluation of high-strength material of roadside flexible-strength double-layer composite support in gob-side entry retaining |
| CN104358572A (en) * | 2014-09-11 | 2015-02-18 | 四川达竹煤电（集团）有限责任公司铁山南煤矿 | Non-pillar mining technology by spontaneous caving filling roadway at large inclined angle steeply inclined seam |
| CN106919744A (en) * | 2017-02-23 | 2017-07-04 | 陕西煤业化工技术研究院有限责任公司 | The determination method of shallow embedding mining of closed distance coal seam group first weight bracket support resistance |
| CN108678769A (en) * | 2018-05-16 | 2018-10-19 | 山东科技大学 | Deep Gateway anchor note cuts top master control and stays lane method |
| CN109236362A (en) * | 2018-11-13 | 2019-01-18 | 辽宁工程技术大学 | A method of it determines and comprehensive puts gob side entry retaining road-in packing supporting parameter |
| CN109779632A (en) * | 2019-01-15 | 2019-05-21 | 山东科技大学 | A kind of gob-side entry retaining support system coordination deformation quantifying design method |
| AU2020100227A4 (en) * | 2020-02-16 | 2020-03-26 | Xi'an University Of Science And Technology | Method for determining coal wall rib spalling of large mining-height fully-mechanized mining face of shallow coal seam |
| CN111079292A (en) * | 2019-12-18 | 2020-04-28 | 太原理工大学 | Method for determining support resistance of residual coal re-mining fully-mechanized caving face |
-
2020
- 2020-05-11 CN CN202010392131.4A patent/CN111581703B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103573273A (en) * | 2013-11-14 | 2014-02-12 | 山东科技大学 | Method for suitability evaluation of high-strength material of roadside flexible-strength double-layer composite support in gob-side entry retaining |
| CN104358572A (en) * | 2014-09-11 | 2015-02-18 | 四川达竹煤电（集团）有限责任公司铁山南煤矿 | Non-pillar mining technology by spontaneous caving filling roadway at large inclined angle steeply inclined seam |
| CN106919744A (en) * | 2017-02-23 | 2017-07-04 | 陕西煤业化工技术研究院有限责任公司 | The determination method of shallow embedding mining of closed distance coal seam group first weight bracket support resistance |
| CN108678769A (en) * | 2018-05-16 | 2018-10-19 | 山东科技大学 | Deep Gateway anchor note cuts top master control and stays lane method |
| CN109236362A (en) * | 2018-11-13 | 2019-01-18 | 辽宁工程技术大学 | A method of it determines and comprehensive puts gob side entry retaining road-in packing supporting parameter |
| CN109779632A (en) * | 2019-01-15 | 2019-05-21 | 山东科技大学 | A kind of gob-side entry retaining support system coordination deformation quantifying design method |
| CN111079292A (en) * | 2019-12-18 | 2020-04-28 | 太原理工大学 | Method for determining support resistance of residual coal re-mining fully-mechanized caving face |
| AU2020100227A4 (en) * | 2020-02-16 | 2020-03-26 | Xi'an University Of Science And Technology | Method for determining coal wall rib spalling of large mining-height fully-mechanized mining face of shallow coal seam |
Non-Patent Citations (10)
| Title |
|---|
| 候兰涛: "东峰煤矿综放沿空留巷巷旁支护结构与参数研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》, no. 2019, 15 January 2019 (2019-01-15), pages 021 - 102 * |
| 孔祥义 等: "煤矿沿空掘巷巷旁支护体参数设计", 《科技导报》, vol. 31, no. 20, 18 July 2013 (2013-07-18), pages 31 - 34 * |
| 左东霞: "锚索加密集支柱沿空成巷无煤柱开采研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》, no. 2015, 15 January 2015 (2015-01-15), pages 021 - 34 * |
| 张霖: "浅埋首采薄煤层无墙体沿空留巷围岩稳定机理与应用研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》, no. 2017, 15 February 2017 (2017-02-15), pages 021 - 142 * |
| 樊海亮: "近距离煤层群卸压区回采工作面开采技术研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》, no. 2015, 15 February 2015 (2015-02-15), pages 021 - 122 * |
| 王丹: "突出厚煤层顶分层膏体充填沿空留巷支护参数研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》, no. 2014, 15 January 2014 (2014-01-15), pages 021 - 24 * |
| 田卫东: "急倾斜特厚煤层水平分段综放开采沿空留巷技术研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》, no. 2008, 15 May 2008 (2008-05-15), pages 021 - 20 * |
| 蔡峰 等: "厚层灰岩直接顶沿空成巷切顶断裂条件及围岩移动规律研究", 《采矿与安全工程学报》, vol. 34, no. 3, 15 May 2017 (2017-05-15), pages 488 - 494 * |
| 谭云亮 等: "沿空巷旁支护适应性原理与支护方法", 《煤炭学报》, vol. 41, no. 02, 15 February 2016 (2016-02-15), pages 376 - 382 * |
| 赵萌烨 等: "无煤柱切顶沿空留巷矿压显现规律", 《西安科技大学学报》, vol. 39, no. 04, 31 July 2019 (2019-07-31), pages 597 - 602 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111963197A (en) * | 2020-08-28 | 2020-11-20 | 陕西煤业化工技术研究院有限责任公司 | Gob-side entry retaining roadway supporting method for three-soft coal seam coal pillar-free mining |
| CN111963197B (en) * | 2020-08-28 | 2023-02-21 | 陕西煤业化工技术研究院有限责任公司 | Gob-side entry retaining roadway supporting method for three-soft coal seam coal pillar-free mining |
| CN113982626A (en) * | 2021-10-14 | 2022-01-28 | 中煤能源研究院有限责任公司 | Method for calculating supporting resistance of roof in gob-side entry retaining roadway without coal pillar roof cutting |
| CN113982626B (en) * | 2021-10-14 | 2023-08-22 | 中煤能源研究院有限责任公司 | Calculation method for roof supporting resistance in gob-side entry retaining roadway without coal pillar roof cutting |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111581703B (en) | 2024-06-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108678769B (en) | Anchor grouting and roof cutting main control entry retaining method for deep mining tunnel | |
| CN108518222B (en) | Paste body filling combination top plate presplitting second mining super high seam stops the method for adopting line coal column | |
| CN105971606B (en) | A kind of thick sandstone coal wall recovery method | |
| CN103902780B (en) | Solid filling coal mining earth's surface Deformation prediction method | |
| Cai et al. | Roof filling control technology and application to mine roadway damage in small pit goaf | |
| CN104832178A (en) | A layering and partially filling coal mining method of thick seams | |
| CN102678121A (en) | Layered top-controlling filling mining method for residual ores in deep hole in diskless area | |
| CN111828007B (en) | Stoping method for residual studs in underground mine goaf | |
| CN106150545B (en) | A kind of method that the filling of goaf part is carried out according to roof caving feature | |
| CN104847406B (en) | Method for fracturing retained filled wall of adjacent coal face | |
| CN107191208A (en) | Rigid protection body Support Method in flexible support Ti Yu lanes by gob side entry retaining lane | |
| CN106150546B (en) | A kind of method that the filling of goaf part is carried out according to earth's surface subsidence | |
| CN105626071A (en) | Mining method for gently inclined thin ore body | |
| CN109899109B (en) | Grouting filling method for irregular goaf | |
| CN104100271B (en) | Pre-pick is led cave filling artificial side secondary multiplexing roadside support and is become lane method | |
| CN110030013B (en) | Gob-side entry retaining method for three-seam periodic roof cutting self-entry side of transition support area | |
| CN109236297A (en) | Split the coal-mining method filled and leave coal seam in conjunction with the residual exploiting field of uplink second mining tool post | |
| CN112377193B (en) | Deep well small coal pillar gob-side entry retaining method based on top breaking and pressure relief of lower key layer of top plate | |
| CN111581703A (en) | Method for determining water-retaining coal mining support equipment for non-pillar gob-side entry retaining | |
| CN110307034B (en) | Strip type grouting filling method for goaf | |
| WO2019062283A1 (en) | Method for determining feasibility of non-pillar gob-side roof-caving roadway formation | |
| CN110781597B (en) | Method for calculating roof cutting height based on roof cutting weakening of coal mine | |
| CN110158621A (en) | Pre-pouring grout reinforcing side slope country rock promotes the method for being cleaved into seam effect in advance | |
| CN106285677A (en) | Side back production subregion filling studding recovery method is expanded to route on Chao Qian | |
| Tian et al. | Study on the deformation failure mechanism and coupling support technology of soft rock roadways in strong wind oxidation zones |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant |