A method for determining the working resistance of the advance section unit support in a mining roadway

Abstract

A method for determining the working resistance of a unit support in the advance section of a mining roadway includes the following steps: S1, collecting geological parameters of the overlying strata in the advance section of the roadway to be tested and determining the load on the roadway; S2, classifying the roadway into six types based on the lithology of the roadway roof, the structure of the roadway roof, whether the roadway is affected by impact, and whether the roadway is along the goaf; S3, calculating the surrounding rock load in the advance section for each of the six types of roadways; S4, calculating the roadway bearing capacity for each of the six types of roadways; S5, calculating the rated working resistance of the unit support for each of the six types of roadways. The method described in this invention comprehensively considers all possible load sources that the unit support may bear, as well as the active support provided by the roadway anchor cables, maximizing the stability of the active support system for the roadway. It can accurately calculate the working resistance of the unit support under different roadway types and support conditions, providing systematic guidance for the scientific use of the unit support throughout the entire process, ensuring that the working space is in a safe zone, and reducing safety hazards.

Description

Technical Field

[0001] This invention relates to the field of coal mine roadway safety support technology, and in particular to a method for determining the working resistance of a unit support in the advanced section of a longwall roadway. Background Technology

[0002] The mining roadway ahead of the working face is located in the superimposed influence zone of the advance support pressure and the lateral support pressure. The support pressure has a significant impact on the roof integrity of the roadway's advance section, especially the roadway along the goaf side where stress concentration is obvious, making roadway maintenance difficult and posing a safety hazard to normal underground production. Therefore, in order to ensure the safe mining of the working face, it is necessary to adopt reinforcement support methods for the mining roadway to reduce the damage to the roadway roof caused by the advance pressure and mining-induced effects, and ensure the stability of the roadway's load-bearing system.

[0003] Traditional pre-run roadway reinforcement methods using single-pillar supports and steel frame roof beams have significant drawbacks, including low strength, low efficiency, high labor intensity for workers, and significant safety hazards, making them unsuitable for current integrated mechanized production. To address these issues, some mines have deployed stepping hydraulic supports in groups in the pre-run section. However, these supports repeatedly support and damage the roadway roof, frequently disturbing the surrounding rock, which is highly detrimental to roadway stability. Unit supports are a new type of roadway support and reinforcement equipment. They are independent, flexible, and easy to transport. During support work, they can avoid repeated support and damage to the roof, making them an effective support and reinforcement method.

[0004] The geological conditions of the surrounding rock in coal mine roadways are complex and varied. The deformation characteristics and failure modes of the surrounding rock vary under different geological and mining conditions. In order to achieve better reinforcement and support effects, it is necessary to quantitatively determine the working resistance of the unit support under the optimal working state, based on the differences in engineering conditions such as roadway overburden movement, roof structure, burial depth, and mining layout, from the perspective of improving the stress and deformation state of the original surrounding rock, effectively improving the overall strength of the surrounding rock, and increasing the integrity of the roadway surrounding rock.

[0005] Currently, due to the complex stress conditions of the surrounding rock in the advance support section and the immaturity of relevant theories, the design and parameter selection of unit supports in the field are still mainly based on experience. A significant number of roadway roof accidents are caused by either the unit supports exerting too much force on the roof, damaging the original active support of the anchor cables, or the unit supports exerting too little force on the roof, failing to play their due role. This exposes a serious lack of scientific calculation and determination methods for the selection of various parameters of the current advance unit supports. Therefore, it is urgent to propose a method for determining the working resistance of unit supports in the advance section of mining roadways, to standardize the determination of the support effectiveness of unit supports on the roadway roof in different mining roadway operating areas, and to assist in the selection of unit supports. Summary of the Invention

[0006] To address the problems existing in the prior art, the present invention provides a method for determining the working resistance of the advance section unit support in a longwall mining roadway, comprising the following specific technical solutions:

[0007] A method for determining the working resistance of a unit support in the advance section of a mining roadway includes the following steps:

[0008] S1, collect geological parameters of the overlying rock of the tunnel under test, and determine the lithology of the tunnel roof, the structure of the tunnel roof, and the load formed on the tunnel by impact.

[0009] S2. Based on the lithology of the roadway roof, the roadway roof structure, and whether the roadway is affected by impact, and depending on whether the roadway is along the goaf, the roadways to be tested are classified into the following types: Type I roadway: Solid coal roadway without impact; Type II roadway: Solid coal roadway affected by impact; Type III roadway: Goaf-side roadway affected by impact with the basic roof fracture line located above the solid coal; Type IV roadway: Goaf-side roadway affected by impact with the basic roof fracture line located above the roadway (coal pillar); Type V roadway: Goaf-side roadway affected by impact with the basic roof fracture line located above the goaf; Type VI roadway: Goaf-side roadway affected by impact with the basic roof prematurely broken.

[0010] S3, calculate the surrounding rock load of the tunnel advance section for each of the Type I to Type VI tunnels;

[0011] S4. Calculate the bearing capacity of roadways from Type I to Type VI respectively. The bearing capacity of the roadway includes the active support bearing capacity of the anchor cable, and / or the coal face bearing capacity, and / or the coal pillar bearing capacity, and / or the bearing capacity absorbed by the unit support equipment.

[0012] S5, calculate the rated working resistance P of the unit support for Type I to Type VI roadways using the following formula. m :

[0013]

[0014] Furthermore, the geological parameters include the rock mechanics properties of the surrounding rock, the location of roof delamination, the spatial occurrence morphology of the coal seam, in-situ stress, and the deformation of the surrounding rock; the lithology of the roadway roof includes the rock mechanics properties of the surrounding rock and the location of roof delamination. After the roadway is excavated, the roof forms a loosening load due to the effect of rock strata delamination; the roadway roof structure includes in-situ stress. According to the roadway determination measures, during the mining process, the advanced section of the roadway forms a mining load due to mining activity; whether the roadway is affected by impact includes the deformation of the surrounding rock. When the advanced section of the roadway is affected by the fracturing of the overlying strata, a dynamic load is formed; the load of the surrounding rock in the advanced section of the roadway is calculated using the following formula:

[0015] When there is no impact on the tunnel, including Type I tunnels:

[0016] Q c无冲击 =Q1+Q2

[0017] When roadways are affected by impacts, including Type II to Type VI roadways:

[0018] Q c受冲击 =Q1+Q2+Q3

[0019] In the formula, Q c无冲击 Q represents the surrounding rock load in the lead section of the roadway when there is no impact; kN. c受冲击 Q1 is the surrounding rock load in the leading section of the roadway when the roadway is affected by impact, kN; Q2 is the loosening load of the surrounding rock, kN; Q3 is the mining load, kN; Q4 is the dynamic load, kN.

[0020] Furthermore, the calculation formula for the loosening load of the surrounding rock is as follows:

[0021] Q1=B×D×L′×γ

[0022] In the formula, Q1 is the loosening load of the surrounding rock, kN; B is the cross-sectional width of the roadway, m; D is the spacing between unit supports, m; L' is the effective anchorage length of the anchor cable, m; and γ is the unit weight of the rock, kN / m³. 3 ;

[0023] The formula for calculating the mining load is as follows:

[0024] Type I and Type II tunnels:

[0025]

[0026] Type III and Type IV tunnels:

[0027]

[0028] Type V tunnel:

[0029]

[0030] Type VI tunnels:

[0031]

[0032] In the above formula,

[0033] B′=B+B m +B s

[0034]

[0035] Q2 is the mining load, kN; η is the roof breaking efficiency; C0 is the basic roof periodic breaking step distance, m; m is the coal seam thickness, m; mE is the basic roof thickness, m; mz is the immediate roof thickness, m; γE is the average unit weight of the basic roof strata, kN / m³. 3 γZ is the average unit weight of the immediate top rock layer, kN / m³. 3 B' is the roadway bearing width, in meters; K F K is the load distribution coefficient; C B is the rock weight distribution coefficient; B is the tunnel cross-sectional width, in meters. m B is the width of the coal pillar, in meters. s L is the elastic-plastic boundary length of the coal face, in meters; L is the working face length, in meters. S The basic overhang distance is in meters (m); K is the stress concentration factor; μ is the Poisson's ratio of the coal seam. The internal friction angle of the coal seam, °; γ' is the average unit weight of the overlying strata, kN / m³. 3 H is the roadway depth, m; PZ is the roadway coal seam support resistance, MPa; N0 is the coal body cohesion, MPa.

[0036] The formula for calculating the dynamic load Q3 is as follows:

[0037] Q3=B×D×ρ×CP×vP

[0038] In the formula, Q3 is the dynamic load, kN; B is the width of the roadway cross-section, m; D is the unit support spacing, m; ρ is the medium density, kg / m³. 3 C P V is the wave velocity of the P-wave, in m / s; P The peak vibration velocity (m / s) is the vibration wave formed above the roadway after transmission and attenuation caused by the fracture of the overlying strata.

[0039] Furthermore, for Type I and Type II roadways, the roadway bearing capacity includes the active support bearing capacity and the coal face bearing capacity; for Type III-VI roadways, the roadway bearing capacity includes the active support bearing capacity, the coal face bearing capacity, and the coal pillar bearing capacity; the formula for calculating the active support bearing capacity is:

[0040] F 主动 =KZnSQS

[0041] In the formula, F 主动 For the active support bearing capacity of the tunnel; K Z n represents the influence coefficient of active or passive support on active support. S Q represents the number of anchor cables within the controlled top area within the unit support spacing; S The value is the working load of the anchor cable, in kN.

[0042] Furthermore, the formula for calculating the rated working resistance of the unit support of the Type I roadway is as follows:

[0043] P m / Ⅰ =(Q c无冲击 -2F s / Ⅰ / Ⅱ -F 主动 ) / n J

[0044] The formula for calculating the rated working resistance of the unit support of the Type II roadway is as follows:

[0045] P m / Ⅱ =(Q c受冲击 -2F s / Ⅰ / Ⅱ -F 主动 ) / n J

[0046] In the formula, P m / Ⅰ The working resistance of the Type I roadway unit support; P m / Ⅱ The working resistance of the Type II roadway unit support; Q c无冲击 Q represents the surrounding rock load in the lead section of the roadway when there is no impact; kN. c受冲击 F represents the surrounding rock load in the leading section of the roadway when it is subjected to impact, in kN. s / Ⅰ / Ⅱ For coal seam support loads in Type I and Type II roadways, kN; F 主动 To enhance the bearing capacity of the active support system for the tunnel; n J This refers to the number of supports within the unit support spacing.

[0047] Furthermore, the formulas for calculating the coal seam bearing capacity of Type I and Type II roadways are as follows:

[0048]

[0049] In the formula, F s / Ⅰ / Ⅱ The coal seam support load for Type I and Type II roadways is given in kN / m. E The basic top thickness is in meters (m). z For direct top thickness, m; γ E The average unit weight of the basic top rock layer is kN / m³. 3 ;γ Z The average unit weight of the immediate top rock stratum is given in kN / m³. 3 D is the unit support spacing, in meters; B is the tunnel cross-sectional width, in meters; B s The length of the elastic-plastic boundary of the coal seam is in meters (m).

[0050] Furthermore, for Type III-VI roadways, the surrounding rock load in the advance section includes loosening load, mining load, and dynamic load. The rated working resistance of the unit support for Type III-VI roadways is calculated using the following formula:

[0051] P m / x =(Qc受冲击 -F m / x -F S / x -F 主动 ) / n J

[0052] In the formula, P m / x The working resistance of the support unit for type III-VI roadways; Q c受冲击 F represents the surrounding rock load in the leading section of the roadway when it is subjected to impact, in kN. m / x The coal pillar support forces (kN) for Type III to Type VI roadways respectively; F S / x The coal seam support forces (kN) for Type III to Type VI roadways respectively; F 主动 To enhance the bearing capacity of the active support system for the tunnel; n J This refers to the number of supports within the unit support spacing.

[0053] Furthermore, the formula for calculating the coal seam bearing capacity of Type III to Type VI roadways is as follows:

[0054]

[0055] F S / Ⅳ =B S (m E γ E +m Z γ Z )·D

[0056]

[0057] In the formula, F S / Ⅲ The coal seam support capacity of a type III roadway is given in kN; F. S / Ⅳ The coal seam support force for a type IV roadway is given in kN; F. S / Ⅴ F represents the coal seam support force in a type V roadway, in kN. s / Ⅵ l1 represents the coal seam support force of type VI roadway (kN); l2 represents the lateral fracture span of the critical block of type III roadway (m); l3 represents the lateral fracture span of the critical block of type V roadway (m); L s θ1 is the basic top-to-top distance, in meters; θ3 is the critical block rotation angle of type III roadway; θ4 is the critical block rotation angle of type V roadway, in degrees; G Z B is the weight of the broken basic roof rock block, kN; B is the width of the tunnel cross section, m; B m G is the width of the coal pillar, in meters; g The weight of the directly overhead rock strata above the tunnel's bearing width, in kN; F C B represents the supporting force of the goaf on the critical block, in kN; s B is the elastic-plastic boundary length of the coal face, in meters; D is the unit support spacing, in meters; P The distance from the basic roof fracture location to the coal pillar, in meters; EThe basic top thickness is in meters (m). z For direct top thickness, m; γ E The average unit weight of the basic top rock layer is kN / m³. 3 ;γ Z The average unit weight of the immediate top rock stratum is given in kN / m³. 3 .

[0058] Furthermore, the formula for calculating the coal pillar bearing capacity of Type III to Type VI roadways is as follows:

[0059]

[0060] In the formula, F m / Ⅲ The coal pillar support force for a type III roadway is expressed in kN; F m / Ⅳ The coal pillar support force for a type IV roadway is given in kN; F. m / Ⅴ F represents the coal pillar support force in a type V roadway, in kN. m / Ⅵ l1 represents the coal pillar support force of type VI roadway, kN; l2 represents the lateral fracture span of the critical block of type III roadway, m; l3 represents the lateral fracture span of the critical block of type IV roadway, m; l4 represents the lateral fracture span of the critical block of type V roadway, m; L s θ1 is the basic top-to-top distance, in meters; θ2 is the critical block rotation angle of type III roadway; θ3 is the critical block rotation angle of type IV roadway, in degrees; G is the critical block rotation angle of type V roadway, in degrees. Z B is the weight of the broken basic roof rock block, kN; B is the width of the tunnel cross section, m; B m G is the width of the coal pillar, in meters; g The weight of the directly overhead rock strata above the tunnel's bearing width, in kN; F C B represents the supporting force of the goaf on the critical block, in kN; s B is the elastic-plastic boundary length of the coal face, in meters; D is the unit support spacing, in meters; P The distance from the basic roof fracture location to the coal pillar, in meters; E The basic top thickness is in meters (m). z For direct top thickness, m; γ E The average unit weight of the basic top rock layer is kN / m³. 3 ;γ Z The average unit weight of the immediate top rock stratum is given in kN / m³. 3 .

[0061] Furthermore, the rated working resistance P of the unit support for Type I to Type VI roadways m The calculation formula is:

[0062]

[0063] Based on the above technical solution, the present invention has the following beneficial effects:

[0064] 1. This invention describes a method for systematically quantifying the working resistance of a unit support, taking into account all possible load sources that the unit support may bear, while also taking into account the active support provided by the roadway anchor cables, to ensure the stability of the roadway active support system to the greatest extent, and at the same time play a role in reinforcing the support.

[0065] 2. This invention can accurately calculate the working resistance of unit supports under different roadway types and support conditions. It can systematically and scientifically classify different types of roadways and calculate reasonable working resistance of unit supports throughout the entire process, effectively control roadway roof subsidence, and guide the scientific use of unit supports.

[0066] 3. This invention describes a quantitative calculation method for the working resistance of a unit support in a mining roadway at any roof fracture location. It expands the calculation principles for the bearing capacity of the solid coal side and the coal pillar side. The obtained working resistance can prevent the entire roadway section from being crushed in extreme situations, ensuring that the working space is in a safe zone and reducing safety hazards. Attached Figure Description

[0067] Figure 1 : A schematic flowchart of the method of the present invention;

[0068] Figure 2 Schematic diagram showing the relationship between the working resistance of the unit support and the surrounding rock of the roadway;

[0069] Figure 3 : Schematic diagram showing the fault line along the goaf roadway located above the solid coal;

[0070] Figure 4 : Schematic diagram showing the fault line along the goaf located above the goaf (coal pillar);

[0071] Figure 5 : Schematic diagram showing the fault line of the goaf roadway located above the goaf area;

[0072] Figure 6 : Schematic diagram of early roof cut-off along the tunnel;

[0073] Figure 7 A comparison chart of the working resistance and actual working resistance of the advanced unit support in the 2412 working face of a certain coal mine. Detailed Implementation

[0074] It should be noted that:

[0075] Certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. Unless otherwise defined, the technical or scientific terms used in this disclosure should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains.

[0076] The following is in conjunction with the appendix Figure 1 To be continued Figure 6 The present invention will be described in detail by way of examples.

[0077] This embodiment describes a method for determining the working resistance of a unit support in the advance section of a mining roadway, including the following steps:

[0078] S1, Collect geological parameters of the overlying strata in the leading section of the roadway to be tested. The geological parameters include, but are not limited to:

[0079] Rock mechanics properties of the surrounding rock in the tunnel, such as Poisson's ratio μ, unit weight γ, and friction angle within the coal and rock mass. wait;

[0080] Location of top slab separation;

[0081] The spatial occurrence of coal seams, such as the thickness of the coal seam (m) and the thickness of the immediate roof (m). z The basic roof thickness of the coal seam is m. E wait;

[0082] Geostress, such as seismic waves caused by the fracturing of overlying rock strata. P The basic top cycle is used to press the step distance C0, etc.

[0083] Deformation of the surrounding rock in the tunnel.

[0084] S2 determines the lithology of the roadway roof, the structure of the roadway roof, and whether the roadway is affected by impact, thus determining the load on the roadway.

[0085] The lithology of the roadway roof includes geological parameters such as the mechanical properties of the roadway roof rock and the location of the roof delamination. When the roadway is excavated, the roof is affected by the delamination of the rock strata, resulting in a loosening load on the surrounding rock.

[0086] The roadway roof structure includes geological parameters such as ground stress and roadway determination measures. During the mining process, the advanced section of the roadway is affected by mining and forms a mining load.

[0087] Whether a tunnel is affected by impact includes geological parameters such as the deformation of the surrounding rock. When the deformation of the surrounding rock changes drastically in a short period of time, and when it is affected by the fracturing of the overlying strata, dynamic loads are formed.

[0088] S3. Based on the lithology of the roadway roof, the structure of the roadway roof, and whether the roadway is affected by impact, and depending on whether the roadway runs along a goaf, the roadways to be tested are classified into the following types:

[0089] Type I roadways: Solid coal roadways without impact effects;

[0090] Type II roadways: Solid coal roadways affected by impact;

[0091] Type III roadway: a roadway along the gob that is affected by impact and whose basic roof fracture line is located above solid coal;

[0092] Type IV roadway: A roadway along the goaf that is affected by impact and whose basic roof fracture line is located above the roadway (coal pillar);

[0093] Type V roadway: a roadway along the goaf that is affected by impact and whose basic roof fracture line is located above the goaf.

[0094] Type VI roadway: a roadway along the goaf that has been impacted and whose main roof has collapsed prematurely.

[0095] S4, calculate the surrounding rock load of the tunnel advance section using the following formula:

[0096] When there is no impact on the tunnel, Q c =Q1 + Q2;

[0097] When the tunnel is affected by an impact, Q c =Q1 + Q2 + Q3;

[0098] In the formula,

[0099] Q c Q1 is the surrounding rock load of the advanced section of the roadway, kN; Q2 is the loosening load of the surrounding rock, kN; Q3 is the mining load, kN; Q4 is the dynamic load, kN.

[0100] The following steps are used to calculate the loosening load Q1, mining load Q2, and dynamic load Q3 of the surrounding rock.

[0101] S401, the surrounding rock loosening load Q1 is determined based on the lithology and structure of the roadway roof, and is applied to Type I-VI roadways. The calculation formula is:

[0102] Q1=B×D×L′×γ

[0103] In the formula,

[0104] Q1 is the loosening load of the surrounding rock, kN; B is the cross-sectional width of the tunnel, m; D is the spacing between unit supports, m; L' is the effective anchorage length of the anchor cable, m; γ is the unit weight of the rock, kN / m³. 3 .

[0105] S402, the mining load Q2 is determined based on whether the roadway roof is along the goaf:

[0106] For Type I and Type II roadways, the calculation formula is as follows:

[0107]

[0108] For Type III and Type IV roadways, the calculation formula is as follows:

[0109]

[0110] For type V roadways, the calculation formula is:

[0111]

[0112] For type VI roadways, the calculation formula is:

[0113]

[0114] In the above formula,

[0115] B′=B+B m +B s

[0116]

[0117] Q2 is the mining load, kN; η is the roof breaking efficiency; C0 is the basic roof breaking step distance, m; m is the coal seam thickness, m; m E The basic top thickness is in meters (m). z For direct top thickness, m; γ E The average unit weight of the basic top rock layer is kN / m³. 3 ;γ Z The average unit weight of the immediate top rock stratum is given in kN / m³. 3 B' is the roadway bearing width, m; KF is the load distribution coefficient; KC is the rock weight distribution coefficient; B is the roadway cross-sectional width, m; B m B is the width of the coal pillar, in meters. s L is the elastic-plastic boundary length of the coal face, in meters; L is the working face length, in meters. S The basic overhang distance is in meters (m); K is the stress concentration factor; μ is the Poisson's ratio of the coal seam. The internal friction angle of the coal seam, °; γ' is the average unit weight of the overlying strata, kN / m³. 3 H represents the tunnel depth in meters (m); P Z N0 is the resistance of the coal seam support in the roadway, MPa; N0 is the coal body cohesion, MPa.

[0118] S403, the dynamic load Q3 is determined based on the roadway impact conditions and is applied to Type II-VI roadways. The calculation formula is:

[0119] Q3=B×D×ρ×CP ×v P

[0120] In the formula,

[0121] Q3 is the dynamic load, kN; B is the roadway cross-sectional width, m; D is the unit support spacing, m; ρ is the medium density, kg / m³. 3 C P V is the wave velocity of the P-wave, in m / s; P The peak vibration velocity (m / s) is the vibration wave formed above the roadway after transmission and attenuation caused by the fracture of the overlying strata.

[0122] S5, calculate the bearing capacity of the roadway, including the active support bearing capacity of the anchor cables, and / or the coal face bearing capacity, and / or the coal pillar bearing capacity, and / or the bearing capacity absorbed by the unit support equipment.

[0123] S501, the active support bearing capacity of the anchor cables in the advance section of Type I to Type VI roadways is calculated using the following formula:

[0124] F 主动 =K Z n S Q S

[0125] In the formula,

[0126] F 主动 For the active support bearing capacity of the tunnel; K Z n represents the influence coefficient of active or passive support on active support. S Q represents the number of anchor cables within the controlled top area within the unit support spacing; S The value is the working load of the anchor cable, in kN.

[0127] S502, for Type I and Type II roadways, namely solid coal roadways without impact and solid coal roadways affected by impact, the roadway bearing capacity includes the active support bearing capacity and the coal face bearing capacity.

[0128] The formula for calculating the bearing capacity of the coal seam is as follows:

[0129]

[0130] In the formula,

[0131] F s / Ⅰ / Ⅱ The coal seam support load for Type I and Type II roadways is given in kN / m. E The basic top thickness is in meters (m). z For direct top thickness, m; γ E The average unit weight of the basic top rock layer is kN / m³. 3 ;γ Z The average unit weight of the immediate top rock stratum is given in kN / m³.3 D is the unit support spacing, in meters; B is the tunnel cross-sectional width, in meters; B s The length of the elastic-plastic boundary of the coal seam is in meters (m).

[0132] S503, for type III roadways, which are roadways affected by impact and whose basic roof fracture line is located above solid coal, the roadway bearing capacity includes the active support bearing capacity, the coal side bearing capacity, and the coal pillar bearing capacity.

[0133] in,

[0134] The formula for calculating the bearing capacity of a coal pillar is:

[0135]

[0136] The formula for calculating the bearing capacity of coal seams is:

[0137]

[0138] In the formula,

[0139] F m / Ⅲ The coal pillar support force for a type III roadway is expressed in kN; F S / Ⅲ The coal seam support capacity of a type III roadway is given in kN; G. Z B is the weight of the broken basic roof rock block, kN; B is the width of the tunnel cross section, m; B m G is the width of the coal pillar, in meters; g The weight of the directly overhead rock strata above the tunnel's bearing width, in kN; F C B represents the supporting force of the goaf on the critical block, in kN; l1 represents the lateral fracture span of the critical block in a type III roadway, in meters; θ1 represents the rotation angle of the critical block in a type III roadway; B s denoted as _t_, representing the elastic-plastic boundary length of the coal face, in meters; and _d_, representing the unit support spacing, in meters.

[0140] S504, for type IV roadways, which are roadways along the goaf that are affected by impact and whose basic roof fracture line is located above the roadway (coal pillar), the roadway bearing capacity includes the active support bearing capacity, the coal side bearing capacity, and the coal pillar bearing capacity.

[0141] in,

[0142] The formula for calculating the bearing capacity of a coal pillar is:

[0143]

[0144] The formula for calculating the bearing capacity of coal seams is:

[0145] F S / Ⅳ =B S (m E γ E +m Z γ Z )·D

[0146] In the formula,

[0147] F m / Ⅳ The coal pillar support force for a type IV roadway is given in kN; F. S / Ⅳ The coal seam support force of type IV roadway is kN; G Z The weight of the basic top rock block that breaks off, kN; B P B is the distance from the basic roof fracture location to the coal pillar, in meters. m G is the width of the coal pillar, in meters; g The weight of the directly overhead rock strata above the tunnel's bearing width, in kN; F C θ1 is the support force of the goaf on the critical block, kN; l2 is the lateral fracture span of the critical block in the type IV roadway, m; θ2 is the rotation angle of the critical block in the type IV roadway, °; B s The elastic-plastic boundary length of the coal seam, in meters; E The basic top thickness is in meters (m). z For direct top thickness, m; γ E The average unit weight of the basic top rock layer is kN / m³. 3 ;γ Z The average unit weight of the immediate top rock stratum is given in kN / m³. 3 D represents the unit support spacing, in meters.

[0148] S505, for type V roadways, which are roadways affected by impact and whose basic roof fracture line is located above the goaf, the roadway bearing capacity includes the active support bearing capacity, the coal side bearing capacity, and the coal pillar bearing capacity.

[0149] in,

[0150] The formula for calculating the bearing capacity of a coal pillar is:

[0151]

[0152] The formula for calculating the bearing capacity of coal seams is:

[0153]

[0154] In the formula,

[0155] F m / Ⅴ F represents the coal pillar support force in a type V roadway, in kN. S / Ⅴ The coal seam support force for a type V roadway is given in kN / m. E The basic top thickness is in meters (m). z For direct top thickness, m; γ E The average unit weight of the basic top rock layer is kN / m³. 3 ;γ Z The average unit weight of the immediate top rock stratum is given in kN / m³. 3; l3 is the lateral fracture span of the key block in type V roadway, in meters; G Z θ3 is the weight of the basic roof rock block that breaks, in kN; θ3 is the rotation angle of the key block in type V roadway, in °; B s B is the elastic-plastic boundary length of the coal seam, in meters; B is the cross-sectional width of the roadway, in meters. m L is the width of the coal pillar, in meters (m). s The distance between the top and bottom is the basic top-to-bottom distance, in meters (m).

[0156] S506, for type VI roadways, which are roadways affected by impact and whose basic roof has collapsed in advance, the roadway bearing capacity includes the active support bearing capacity, the coal side bearing capacity, and the coal pillar bearing capacity.

[0157] in,

[0158] The formula for calculating the bearing capacity of a coal pillar is:

[0159]

[0160] The formula for calculating the bearing capacity of coal seams is:

[0161]

[0162] In the formula,

[0163] F m / Ⅵ F represents the coal pillar support force in type VI roadway, in kN. S / Ⅵ The coal seam support force for type VI roadway is given in kN / m. E The basic top thickness is in meters (m). z For direct top thickness, m; γ E The average unit weight of the basic top rock layer is kN / m³. 3 ;γ Z The average unit weight of the immediate top rock stratum is given in kN / m³. 3 B s B is the elastic-plastic boundary length of the coal seam, in meters; B is the cross-sectional width of the roadway, in meters. m denoted as , where is the width of the coal pillar (m); D is the spacing between unit supports (m).

[0164] S6, calculate the rated working resistance of the unit support for Type I to Type VI roadways using the following steps:

[0165] S601, for Type I roadways, the surrounding rock load of the advance section includes the loosening load and mining load. The rated working resistance of the unit support of a Type I roadway, i.e., a solid coal roadway without impact, is calculated using the following formula:

[0166] P m / Ⅰ = (Q1+Q2-2F) s / Ⅰ / Ⅱ -K Z n S Q S) / n J

[0167] In the formula,

[0168] P m / Ⅰ Q1 is the working resistance of the Type I roadway unit support; Q2 is the surrounding rock loosening load; F is the mining load; s / Ⅰ / Ⅱ For coal seam support loads in Type I and Type II roadways, kN; K Z n represents the influence coefficient of active or passive support on active support. S Q represents the number of anchor cables within the controlled top area within the unit support spacing; S The anchor cable working load is kN; n J This refers to the number of supports within the unit support spacing.

[0169] For S602, for Type II roadways, the surrounding rock load in the advance section includes the loosening load, mining load, and dynamic load. The rated working resistance of the unit support for Type II roadways, i.e., solid coal roadways affected by impact, is calculated using the following formula:

[0170] P m / Ⅱ = (Q1+Q2+Q3-2F) s / Ⅰ / Ⅱ -Q 卸 -K Z n S Q S ) / n J

[0171] Considering the most dangerous scenario, Q 卸 Due to various reasons such as failure or sudden pressure damage, Q is taken in the calculation for the sake of support safety. 卸 The value is 0, therefore,

[0172] P m / Ⅱ = (Q1+Q2+Q3-2F) s / Ⅰ / Ⅱ -K Z n S Q S ) / n J

[0173] In the formula,

[0174] P m / Ⅱ Q1 is the working resistance of the Type II roadway unit support; Q2 is the loosening load of the surrounding rock; Q3 is the mining load; Q4 is the dynamic load; Q5 is the working resistance of the support unit of the roadway ... 卸 The load-bearing capacity absorbed by the unit support equipment; Fs / Ⅰ / Ⅱ For coal seam support loads in Type I and Type II roadways, kN; K Z n represents the influence coefficient of active or passive support on active support. S Q represents the number of anchor cables within the controlled top area within the unit support spacing; SThe anchor cable working load is kN; n J This refers to the number of supports within the unit support spacing.

[0175] S603, for Type III-VI roadways, the surrounding rock load in the advance section includes loosening load, mining load, and dynamic load. The rated working resistance of the unit support for Type III-VI roadways is calculated using the following formula:

[0176] P m / x = (Q1+Q2+Q3-F) m / x -F S / x -Q 卸 -K Z n S Q S ) / n J

[0177] Considering the most dangerous scenario, Q 卸 Due to various reasons such as failure or sudden pressure damage, Q is taken in the calculation for the sake of support safety. 卸 The value is 0, therefore,

[0178] P m / x = (Q1+Q2+Q3-F) m / x -F S / x -K Z n S Q S ) / n J

[0179] In the formula,

[0180] P m / x Q1 is the working resistance of the support unit for type III-VI roadways; Q2 is the loosening load of the surrounding rock; Q3 is the mining load; Q4 is the dynamic load; Q5 is the working resistance of the support unit for type III-VI roadways. 卸 The load-bearing capacity absorbed by the unit support equipment; F m / x The coal pillar support forces (kN) for Type III to Type VI roadways respectively; F S / x The coal seam support forces corresponding to Type III to Type VI roadways are given in kN and K, respectively. Z n represents the influence coefficient of active or passive support on active support. S Q represents the number of anchor cables within the controlled top area within the unit support spacing; S The anchor cable working load is kN; n J This refers to the number of supports within the unit support spacing.

[0181] The following case study, based on a specific construction site of the 2412 working face of a coal mine, demonstrates the method for calculating the rated working resistance of the advanced unit support in the aforementioned roadway working face:

[0182] I. Basic Information on Tunnel Support

[0183] 1. The active support anchor cable adopts a steel strand anchor cable with a model of Φ21.8×8500mm, uses MSK2850 type resin anchoring agent, and has a drilling diameter of Φ32mm.

[0184] Roof anchor spacing: transport roadway, 1600×2700mm; return airway, 2000×1800mm.

[0185] The effective anchorage length L′ of the anchor cable, which is "anchor cable length - anchor cable anchorage end length - anchor cable exposed end length", is 6.45m for both the transport roadway and the return airway.

[0186] 2. Roadway cross-sectional width B: 6m for transport roadways and 5.2m for return air roadways; coal pillar width B m =6m, width B of the plastic zone of the solid coal face S =8.15m, tunnel burial depth H=600m.

[0187] 3. Unit support spacing D: 5m for both roadways; coal seam thickness m = 11.3m; immediate roof thickness m Z =2.4m, basic top thickness m E =1.3m; Basic top periodic failure step C0 = 4.89m; Solid coal bulk density γ: 13kN / m³ 3 The basic top average bulk density γ E =25kN / m 3 Direct top average bulk density γ Z =25kN / m 3 The average unit weight of the overlying strata is γ' = 25 kN / m³. 3 Poisson's ratio of the coal seam μ = 0.25; internal friction angle of the coal seam Coal seam cohesion N0 = 1.87 MPa; roadway coal seam support resistance P Z =0.

[0188] 4. The seismic energy is taken as 1.62 × 10⁻⁶. 4 J, medium density ρ = 25 kg / m³ 3 P-wave velocity C P =5.8×10 3 m / s, vibration velocity v P =1.32m / s.

[0189] In the aforementioned 2412 working face:

[0190] The return air roadway is a type VI roadway supported by pre-roof collapse unit supports under impact conditions, meaning it is a type VI roadway. The formula for calculating the rated resistance of its unit supports is as follows:

[0191] P m / x = (Q1+Q2+Q3-F) m / x-F S / x -K Z n S Q S ) / n J

[0192] Right now:

[0193] P m / Ⅵ = (Q1+Q2+Q3-F) m / Ⅵ -F S / Ⅵ -K Z n S Q S ) / n J

[0194]

[0195] The transport roadway is a solid coal roadway supported by unit supports under impact, i.e., this transport roadway is a Type II roadway. The formula for calculating the rated resistance of its unit supports is:

[0196] P m / Ⅱ = (Q1+Q2+Q3-2F) s / Ⅰ / Ⅱ -K Z n S Q S ) / n J

[0197]

[0198] II. Verification of Rated Working Resistance of Advanced Unit Support

[0199] 1. Return air roadway

[0200] ①Rock loosening load

[0201] Q1 = B × D × L′ × γ = 2180 kN

[0202] ②Mining load

[0203]

[0204] In the formula, η is the roof breaking efficiency, taken as 1.45; B' is the roadway bearing width, B'=B+B m +B S =19.35m; K F The load distribution factor is D / 0.5C0.

[0205] ③ Dynamic load

[0206] Q3=B×D×ρ×CP×vP=4976KN

[0207] ④ Active support strength

[0208] K Z n S Q S =0.9×8×553.07=3982KN

[0209] In the formula, K Z The influence coefficient of active or passive support on active support is taken as 0.9; n S The number of anchor cables within the controlled top area of ​​the unit support spacing is 8; Q S The anchor cable working load is 553.07 kN.

[0210] ⑤ Coal pillar support force F m

[0211]

[0212] ⑥ Coal wall support force F S

[0213]

[0214] Therefore, the working resistance of the unit support of the return air roadway in the 2412 working face is

[0215] P m = (Q1+Q2+Q3-F) m -F s -K Z n S Q S ) / n J =3601KN

[0216] Where, n J The number of supports within the unit support spacing is 2.

[0217] The calculated result of 3601kN refers to the rated working resistance of the unit support when the unit support is arranged in a double row on site.

[0218] 2. Transport roadway

[0219] ①Rock loosening load

[0220] Q1=B×D×L′×γ=2516KN

[0221] ②Mining load

[0222]

[0223] In the formula, B' is the width of the roadway dip, B' = B + 2B S =22.3m; K F The load distribution factor is D / 0.5C0.

[0224] ③ Dynamic load

[0225] Q3=B×D×ρ×CP×vP=5742KN

[0226] ④ Active support strength

[0227] K Z n S Q S =0.9×9×553.07=4480KN

[0228] In the formula, K Z The influence coefficient of active or passive support on active support is taken as 0.9; n S The number of anchor cables within the controlled top area within the unit support spacing is 9; Q S The anchor cable working load is 553.07 kN.

[0229] ⑤ Coal side support force

[0230]

[0231] Therefore, the working resistance of the unit support of the transport roadway at the 2412 working face is

[0232] P m = (Q1+Q2+Q3-2F) s -K Z n S Q S ) / n J =3778KN

[0233] In the formula, n J The number of supports within the unit support spacing is 1.

[0234] The calculated result of 3778kN refers to the rated working resistance of the unit support when the unit support is arranged in a single row on site.

[0235] Appendix Figure 7 The diagram shows a comparison between the working resistance and the actual working resistance of the advanced unit support for the two roadways on the 2412 working face. From this comparison, it can be seen that the required working resistance of the unit support varies depending on the spacing of the unit support. Different working resistances should be selected according to the actual site conditions.

[0236] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for determining the working resistance of a unit support in the advance section of a mining roadway, characterized in that, Includes the following steps: S1, collect geological parameters of the overlying rock of the tunnel under test, and determine the lithology of the tunnel roof, the structure of the tunnel roof, and the load formed on the tunnel by impact. S2. Based on the lithology of the roadway roof, the roadway roof structure, and whether the roadway is affected by impact, and depending on whether the roadway is along the goaf, the roadways to be tested are classified into the following types: Type I roadway: Solid coal roadway without impact; Type II roadway: Solid coal roadway affected by impact; Type III roadway: Goaf-side roadway affected by impact with the basic roof fracture line located above the solid coal; Type IV roadway: Goaf-side roadway affected by impact with the basic roof fracture line located above the roadway; Type V roadway: Goaf-side roadway affected by impact with the basic roof fracture line located above the goaf; Type VI roadway: Goaf-side roadway affected by impact with the basic roof prematurely broken. S3, calculate the surrounding rock load of the tunnel advance section for each of the Type I to Type VI tunnels; S4. Calculate the bearing capacity of roadways from Type I to Type VI respectively. The bearing capacity of the roadway includes the active support bearing capacity of the anchor cable, and / or the coal face bearing capacity, and / or the coal pillar bearing capacity, and / or the bearing capacity absorbed by the unit support equipment. S5, calculate the rated working resistance P of the unit support for Type I to Type VI roadways using the following formula. m : The geological parameters include the rock mechanical properties of the surrounding rock of the roadway, the location of the roof delamination, the spatial occurrence morphology of the coal seam, the in-situ stress, and the deformation of the surrounding rock of the roadway. The lithology of the roadway roof includes the rock mechanical properties of the roadway surrounding rock and the location of roof delamination. When the roadway is excavated, the roof forms a loosening load on the surrounding rock due to the effect of rock strata delamination. The roadway roof structure includes ground stress. According to the roadway determination measures, during the mining process at the working face, the advanced section of the roadway will form a mining load due to mining. Whether the roadway is affected by impact includes the deformation of the surrounding rock. When the leading section of the roadway is affected by the fracturing of the overlying strata, a dynamic load is formed. The surrounding rock load of the advanced section of the tunnel is calculated using the following formula: When there is no impact on the tunnel, including Type I tunnels: Q c无冲击 =Q1+Q2 When roadways are affected by impacts, including Type II to Type VI roadways: Q c受冲击 Q1+Q2+Q3 In the formula, Q c无冲击 Q represents the surrounding rock load in the lead section of the roadway when there is no impact; kN. c受冲击 Q1 is the surrounding rock load in the leading section of the roadway when the roadway is affected by impact, kN; Q2 is the loosening load of the surrounding rock, kN; Q3 is the mining load, kN; Q4 is the dynamic load, kN.

2. The method for determining the working resistance of a unit support in the advance section of a mining roadway according to claim 1, characterized in that, The formula for calculating the loosening load of the surrounding rock is: Q1=B×D×L'×γ In the formula, Q1 is the loosening load of the surrounding rock, kN; B is the cross-sectional width of the roadway, m; D is the spacing between unit supports, m; L' is the effective anchorage length of the anchor cable, m; and γ is the unit weight of the rock, kN / m³. 3 ; The formula for calculating the mining load is as follows: Type I and Type II tunnels: Type III and Type IV tunnels: Type V tunnel: Type VI tunnels: In the above formula, B'=B+B m +B s Q2 is the mining load, kN; η is the roof breaking efficiency; C0 is the basic roof breaking step distance, m; m is the coal seam thickness, m; m E The basic top thickness is in meters (m). z For direct top thickness, m; γ E The average unit weight of the basic top rock layer is kN / m³. 3 ;γ Z The average unit weight of the immediate top rock stratum is given in kN / m³. 3 B' is the roadway bearing width, in meters; K F K is the load distribution coefficient; C B is the rock weight distribution coefficient; B is the tunnel cross-sectional width, in meters. m B is the width of the coal pillar, in meters. s L is the elastic-plastic boundary length of the coal face, in meters; L is the working face length, in meters. S The basic overhang distance is in meters (m); K is the stress concentration factor; μ is the Poisson's ratio of the coal seam. γ' is the internal friction angle of the coal seam, °; γ' is the average unit weight of the overlying strata, kN / m³. 3 H represents the tunnel depth in meters (m); P Z N0 is the resistance of the coal seam support in the roadway, MPa; N0 is the coal body cohesion, MPa. The formula for calculating the dynamic load Q3 is as follows: Q3=B×D×ρ×C P ×v P In the formula, Q3 is the dynamic load, kN; B is the width of the roadway cross section, m; D is the unit support spacing, m; ρ is the density of the medium, kg / m³ 3 C P V is the wave velocity of the P-wave, in m / s; P The peak vibration velocity (m / s) is the vibration wave formed above the roadway after transmission and attenuation caused by the fracture of the overlying strata.

3. The method for determining the working resistance of a unit support in the advance section of a mining roadway according to claim 2, characterized in that, Type I and Type II roadways have roadway bearing capacity including active support bearing capacity and coal seam bearing capacity; Type III to Type VI roadways have a roadway bearing capacity that includes active support bearing capacity, coal side bearing capacity, and coal pillar bearing capacity. The formula for calculating the bearing capacity of the active support is as follows: F 主动 =K Z n S Q S In the formula, F 主动 For the active support bearing capacity of the tunnel; K Z n represents the influence coefficient of active or passive support on active support. S Q represents the number of anchor cables within the controlled top area within the unit support spacing; S The value is the working load of the anchor cable, in kN.

4. The method for determining the working resistance of a unit support in the advance section of a mining roadway according to claim 3, characterized in that, The formula for calculating the rated working resistance of the unit support of the Type I roadway is as follows: P m / Ⅰ =(Q c无冲击 -2F s / Ⅰ / Ⅱ -F 主动 ) / n J The formula for calculating the rated working resistance of the unit support of the Type II roadway is as follows: P m / Ⅱ =(Q c受冲击 -2F s / Ⅰ / Ⅱ -F 主动 ) / n J In the formula, P m / Ⅰ The working resistance of the Type I roadway unit support; P m / Ⅱ The working resistance of the Type II roadway unit support; Q c无冲击 Q represents the surrounding rock load in the lead section of the roadway when there is no impact; kN. c受冲击 F represents the surrounding rock load in the leading section of the roadway when it is subjected to impact, in kN. s / Ⅰ / Ⅱ For coal seam support loads in Type I and Type II roadways, kN; F 主动 To enhance the bearing capacity of the active support system for the tunnel; n J This refers to the number of supports within the unit support spacing.

5. The method for determining the working resistance of a unit support in the advance section of a mining roadway according to claim 4, characterized in that, The formulas for calculating the coal seam bearing capacity of Type I and Type II roadways are as follows: In the formula, F s / Ⅰ / Ⅱ The coal seam support load for Type I and Type II roadways is given in kN / m. E The basic top thickness is in meters (m). z For direct top thickness, m; γ E The average unit weight of the basic top rock layer is kN / m³. 3 ;γ Z The average unit weight of the immediate top rock stratum is given in kN / m³. 3 D is the unit support spacing, in meters; B is the tunnel cross-sectional width, in meters; B s The length of the elastic-plastic boundary of the coal seam is in meters (m).

6. The method for determining the working resistance of a unit support in the advance section of a mining roadway according to claim 3, characterized in that, For Type III-VI roadways, the surrounding rock load in the advance section includes loosening load, mining load, and dynamic load. The rated working resistance of the unit support for Type III-VI roadways is calculated using the following formula: P m / x =(Q c受冲击 -F m / x -F S / x -F 主动 ) / n J In the formula, P m / x The working resistance of the support unit for type III-VI roadways; Q c受冲击 F represents the surrounding rock load in the leading section of the roadway when it is subjected to impact, in kN. m / x The coal pillar support forces (kN) for Type III to Type VI roadways respectively; F S / x The coal seam support forces (kN) for Type III to Type VI roadways respectively; F 主动 To enhance the bearing capacity of the active support system for the tunnel; n J This refers to the number of supports within the unit support spacing.

7. The method for determining the working resistance of a unit support in the advance section of a mining roadway according to claim 6, characterized in that, The formula for calculating the coal seam bearing capacity of Type III to Type VI roadways is: F S / Ⅳ =B S (m E c E +m Z c Z )·D In the formula, F S / Ⅲ The coal seam support capacity of a type III roadway is given in kN; F. S / Ⅳ The coal seam support force for a type IV roadway is given in kN; F. S / Ⅴ F represents the coal seam support force in a type V roadway, in kN. S / Ⅵ The coal seam support force for type VI roadway is given in kN. l1 is the lateral fracture span of the critical block in a type III roadway, in meters; l3 is the lateral fracture span of the critical block in a type V roadway, in meters; L s The basic top-to-bottom distance is in meters (m). θ1 is the critical block rotation angle of type III roadway; θ3 is the critical block rotation angle of type V roadway, °; G Z B is the weight of the broken basic roof rock block, kN; B is the width of the tunnel cross section, m; B m G is the width of the coal pillar, in meters; g The weight of the directly overhead rock strata above the tunnel's bearing width, in kN; F C B represents the supporting force of the goaf on the critical block, in kN; s B is the elastic-plastic boundary length of the coal face, in meters; D is the unit support spacing, in meters; P The distance from the basic roof fracture location to the coal pillar, in meters; E The basic top thickness is in meters (m). z For direct top thickness, m; γ E The average unit weight of the basic top rock layer is kN / m³. 3 ;γ Z The average unit weight of the immediate top rock stratum is given in kN / m³. 3 .

8. The method for determining the working resistance of a unit support in the advance section of a mining roadway according to claim 6, characterized in that, The formula for calculating the coal pillar bearing capacity of Type III to Type VI roadways is as follows: In the formula, F m / Ⅲ The coal pillar support force for a type III roadway is expressed in kN; F m / Ⅳ The coal pillar support force for a type IV roadway is given in kN; F. m / Ⅴ F represents the coal pillar support force in a type V roadway, in kN. m / Ⅵ The coal pillar support force for type VI roadway, kN; l1 is the lateral fracture span of the critical block in a type III roadway, in meters; l2 is the lateral fracture span of the critical block in a type IV roadway, in meters; l3 is the lateral fracture span of the critical block in a type V roadway, in meters; L s The basic top-to-bottom distance is in meters (m). θ1 is the critical block rotation angle of type III roadway; θ2 is the critical block rotation angle of type IV roadway, °; θ3 is the critical block rotation angle of type V roadway, °; G Z B is the weight of the broken basic roof rock block, kN; B is the width of the tunnel cross section, m; B m G is the width of the coal pillar, in meters; g The weight of the directly overhead rock strata above the tunnel's bearing width, in kN; F C B represents the supporting force of the goaf on the critical block, in kN; s B is the elastic-plastic boundary length of the coal face, in meters; D is the unit support spacing, in meters; P The distance from the basic roof fracture location to the coal pillar, in meters; E The basic top thickness is in meters (m). z For direct top thickness, m; γ E The average unit weight of the basic top rock layer is kN / m³. 3 ;γ Z The average unit weight of the immediate top rock stratum is given in kN / m³. 3 .

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