Method for determining lateral roof hanging stratum position and maximum hanging roof length in gob area

Abstract

The present invention provides a method for determining the hanging position and maximum hanging length of the lateral roof in a goaf. The method includes, for a coal mining face and a goaf where coal mining has been completed, obtaining the roof rock strata structure of the roof caving range based on the coal mining height of the coal mining face and the roof borehole columnar section of the goaf; determining the set of possible hanging positions of the lateral roof based on the loads of each layer in the roof rock strata structure; calculating the caving step distance of each possible hanging position, and screening the set of possible hanging positions based on the caving step distance to obtain the target set of hanging positions; constructing two directional boreholes in the adjacent roadway on one side of the goaf, with the borehole openings of the two directional boreholes spaced a set distance apart along the driving direction, and each directional borehole extending horizontally towards the goaf after reaching the uppermost target hanging position; arranging electromagnetic wave detection devices in the two directional boreholes to obtain the absorption coefficient of the detection area, and determining the maximum hanging length based on the comparison result between the absorption coefficient and the set absorption threshold.

Description

Technical Field

[0001] The present invention relates to the technical field of roof strata control, and particularly to a method for determining the hanging roof layer position and the maximum hanging roof length on the side of a gob area. Background Art

[0002] Affected by the lateral abutment pressure in the gob area, the gob-side entry is often the main area where rock bursts, large deformations and strong mine pressures occur, and the main source of the lateral abutment pressure is the lateral hanging roof in the gob area. For the lateral hanging roof in the gob area, before the working face is mined, the roof can be weakened by means of roof blasting or hydraulic fracturing in advance to reduce the hanging roof length in the gob area. However, some mines did not take measures in advance before the gob area was formed. When starting to drive or use the gob-side entry, facing the influence of the lateral abutment pressure, at this time, roof weakening and pressure relief measures are taken on the side of the gob-side entry towards the gob area. At this time, for the unclear lateral hanging roof layer position and unknown hanging roof length in the gob area, there are great safety hazards in using roof blasting, and hydraulic fracturing is difficult to play a role because the fracturing layer position cannot be determined. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to some extent.

[0004] To this end, the first object of the present invention is to propose a method for determining the hanging roof layer position and the maximum hanging roof length on the side of a gob area, so as to more accurately determine the hanging roof layer position and the hanging roof length.

[0005] The second object of the present invention is to propose a system for determining the hanging roof layer position and the maximum hanging roof length on the side of a gob area.

[0006] The third object of the present invention is to propose an electronic device.

[0007] The fourth object of the present invention is to propose a computer-readable storage medium.

[0008] To achieve the above object, the first aspect of the present invention proposes a method for determining the hanging roof layer position and the maximum hanging roof length on the side of a gob area, including:

[0009] For a coal mining face and a gob area where the mining has been completed, based on the obtained coal mining height of the coal mining face and the roof borehole columnar diagram of the gob area, obtain the roof strata structure of the roof caving range;

[0010] Based on the loads of each layer in the roof strata structure, determine the set of possible hanging roof layer positions of the lateral roof;

[0011] Calculate the caving step distance of each possible hanging roof layer position in the set of possible hanging roof layer positions, and screen the set of possible hanging roof layer positions based on the caving step distance to obtain the set of target hanging roof layer positions;

[0012] Construct two directional boreholes in the adjacent roadway on one side of the goaf. The borehole openings of the two directional boreholes are separated by a set distance along the driving direction. Each directional borehole extends horizontally towards the goaf after reaching the topmost target suspended roof horizon.

[0013] Arrange an electromagnetic wave detection device in the two directional boreholes to obtain the absorption coefficient of the detection area, and determine the maximum suspended roof length based on the comparison result between the absorption coefficient and the set absorption threshold.

[0014] In the method of the first aspect of the present invention, the roof rock stratum structure for obtaining the roof caving range based on the coal mining height of the coal mining face and the roof borehole histogram of the goaf includes: calculating the roof caving height based on the coal mining height of the coal mining face and the initial swelling coefficient of the roof rock stratum; determining the roof rock stratum structure of the roof caving range corresponding to the roof caving height based on the roof borehole histogram of the goaf.

[0015] In the method of the first aspect of the present invention, the determining the set of possible suspended roof horizons of the lateral roof based on the loads of each layer in the roof rock stratum structure includes: for the roof rock stratum structure of the roof caving range, starting from the bottommost first layer, taking the first layer as the bearing layer and calculating the loads of each layer above the bearing layer on the bearing layer to obtain the target layer that meets the suspended roof load condition; taking the target layer as the new bearing layer and calculating the load on the new bearing layer to obtain a new target layer, repeating the update of the bearing layer until the number of layers reaches the total number of layers of the roof rock stratum structure, where each obtained target layer forms the set of possible suspended roof horizons.

[0016] In the method of the first aspect of the present invention, the meeting the suspended roof load condition means that the load of the current calculated layer on the bearing layer is less than the load of the previous layer of the current calculated layer on the bearing layer.

[0017] In the method of the first aspect of the present invention, the calculating the caving step distance of each possible suspended roof horizon in the set of possible suspended roof horizons includes: calculating the corresponding caving step distance based on the thickness, tensile strength and bearing load of each possible suspended roof horizon.

[0018] In the method of the first aspect of the present invention, the step of screening the set of possible suspended roof strata positions based on the caving step distance to obtain the target set of suspended roof strata positions includes: sorting each possible suspended roof strata position in the set of possible suspended roof strata positions from bottom to top according to its position in the roof rock stratum structure; screening any two adjacent possible suspended roof strata positions, and the screening process includes: when the caving step distance of the upper possible suspended roof strata position is less than that of the lower possible suspended roof strata position, adding the load borne by the upper possible suspended roof strata position to the lower possible suspended roof strata position to recalculate the caving step distance of the lower possible suspended roof strata position, and deleting the upper possible suspended roof strata position from the set of possible suspended roof strata positions; after screening all groups of two adjacent possible suspended roof strata positions, the final set of possible suspended roof strata positions is the target set of suspended roof strata positions.

[0019] In the method of the first aspect of the present invention, when each directional borehole extends horizontally towards the goaf, the length exceeding the goaf boundary of the adjacent roadway is a set length, and the set length is less than the caving step distance of the uppermost target suspended roof strata position.

[0020] To achieve the above object, the second aspect of the present invention proposes a system for determining the lateral roof suspended roof strata positions and the maximum suspended roof length in the goaf, including:

[0021] A caving range determination module, configured to obtain the roof rock stratum structure of the roof caving range for a coal mining face and a goaf that have been mined out, based on the coal mining height of the coal mining face and the roof borehole columnar diagram of the goaf obtained;

[0022] A possible suspended roof strata position determination module, configured to determine a set of possible suspended roof strata positions of the lateral roof based on the loads of each layer in the roof rock stratum structure;

[0023] A target suspended roof strata position determination module, configured to calculate the caving step distance of each possible suspended roof strata position in the set of possible suspended roof strata positions, and screen the set of possible suspended roof strata positions based on the caving step distance to obtain the target set of suspended roof strata positions;

[0024] A directional borehole arrangement module, configured to construct two directional boreholes in the adjacent roadway on one side of the goaf, with the borehole openings of the two directional boreholes spaced apart by a set distance along the driving direction, and each directional borehole extends to the uppermost target suspended roof strata position and then extends horizontally towards the goaf;

[0025] A suspended roof length calculation module, configured to arrange electromagnetic wave detection devices in the two directional boreholes to obtain the absorption coefficient of the detection area, and determine the maximum suspended roof length based on the comparison result between the absorption coefficient and the set absorption threshold.

[0026] To achieve the above object, a third aspect of the present invention provides an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method provided in the first aspect of the present invention.

[0027] To achieve the above object, a fourth aspect of the present invention provides a computer-readable storage medium storing computer-executable instructions, which are used to implement the method provided in the first aspect of the present invention when executed by a processor.

[0028] The method, system, electronic device and storage medium for determining the hanging roof layer position and maximum hanging roof length of the gob-side lateral roof provided by the present invention are as follows: for a coal mining face and a gob that have been mined out, based on the coal mining height of the coal mining face and the roof borehole columnar section of the gob, the roof rock stratum structure of the roof caving range is obtained; based on the loads of each layer in the roof rock stratum structure, a set of possible hanging roof layer positions of the lateral roof is determined; the caving step distances of each possible hanging roof layer position in the set of possible hanging roof layer positions are calculated, and the set of possible hanging roof layer positions is screened based on the caving step distances to obtain a set of target hanging roof layer positions; two directional boreholes are constructed in the adjacent roadway on the gob side, the borehole openings of the two directional boreholes are separated by a set distance along the driving direction, and each directional borehole extends to the uppermost target hanging roof layer position and then extends horizontally towards the gob; electromagnetic wave detection devices are arranged in the two directional boreholes to obtain the absorption coefficient of the detection area, and the maximum hanging roof length is determined based on the comparison result between the absorption coefficient and the set absorption threshold. In this case, considering that the roof of the caving range has the most direct influence on the gob-side entry, the roof rock stratum structure of the roof caving range is determined based on the coal mining height and the roof borehole columnar section. For the roof rock stratum structure of the roof caving range, the set of target hanging roof layer positions is obtained by using the load and the caving step distance, and then combined with the absorption coefficient collected by the electromagnetic wave detection devices arranged in the two directional boreholes in the adjacent roadway to obtain the hanging roof length, so that the determination of the hanging roof layer position and the hanging roof length is more accurate.

[0029] The additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0030] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the drawings, wherein:

[0031] Figure 1 is a schematic flow chart of a method for determining the hanging roof layer position and maximum hanging roof length of the gob-side lateral roof provided by an embodiment of the present invention;

[0032] Figure 2 Schematic diagram of the layout of directional drilling provided by an embodiment of the present invention;

[0033] Figure 3 Block diagram of a system for determining the hanging roof layer position and maximum hanging roof length of the side roof in a goaf provided by an embodiment of the present invention. Detailed implementation manners

[0034] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention.

[0035] The method and system for determining the hanging roof layer position and maximum hanging roof length of the side roof in a goaf according to the embodiments of the present invention will be described below with reference to the drawings.

[0036] The embodiments of the present invention provide a method for determining the hanging roof layer position and maximum hanging roof length of the side roof in a goaf to more accurately determine the hanging roof layer position and hanging roof length.

[0037] Figure 1 Schematic flow chart of a method for determining the hanging roof layer position and maximum hanging roof length of the side roof in a goaf provided by an embodiment of the present invention.

[0038] As Figure 1 shown, the method for determining the hanging roof layer position and maximum hanging roof length of the side roof in a goaf includes the following steps:

[0039] Step S101, for a coal mining face and a goaf where coal mining has ended, obtain the roof rock stratum structure of the roof caving range based on the coal mining height of the coal mining face and the roof borehole columnar section of the goaf.

[0040] Specifically, in step S101, first determine a coal mining face where coal mining has ended. For this coal mining face and the goaf where this coal mining face is located, obtain the coal mining height of the coal mining face and the roof borehole columnar section of the side roof of the goaf.

[0041] In step S101, obtaining the roof rock stratum structure of the roof caving range based on the coal mining height of the coal mining face and the roof borehole columnar section of the goaf includes: calculating the roof caving height based on the coal mining height of the coal mining face and the initial swelling coefficient of the roof rock stratum; determining the roof rock stratum structure of the roof caving range corresponding to the roof caving height based on the roof borehole columnar section of the goaf.

[0042] The roof caving height satisfies formula (1):

[0043]

[0044] In the formula, H is the caving height of the roof. M is the coal mining height of the coal mining face, with the unit of m. K P is the initial bulking coefficient of the roof rock stratum, and it can take values from 1.1 to 1.4.

[0045] Among them, if the full caving of the roof corresponding to the caving height of the roof can fill the goaf, and only the full caving can reduce the influence of the lateral stress in the goaf.

[0046] According to the obtained caving height of the roof, referring to the roof borehole columnar section, obtain the roof rock stratum structure within the caving range corresponding to the caving height of the roof. The roof rock stratum structure within the caving range includes the stratum distribution information of the roof within the caving range.

[0047] In step S101, after obtaining the roof rock stratum structure of the roof caving range, drill rock cores from the rock strata within the roof rock stratum structure for mechanical parameter testing. The tested mechanical parameters include but are not limited to parameters such as uniaxial compressive strength, tensile strength, elastic modulus, and Poisson's ratio.

[0048] Step S102, determine the set of possible hanging roof layers of the lateral roof based on the loads of each layer in the roof rock stratum structure.

[0049] In step S102, determining the set of possible hanging roof layers of the lateral roof based on the loads of each layer in the roof rock stratum structure includes: for the roof rock stratum structure of the roof caving range, starting from the bottommost first layer, take the first layer as the bearing layer and calculate the loads of each layer above the bearing layer on the bearing layer to obtain the target layer that meets the hanging roof load condition; take the target layer as the new bearing layer and calculate the load on the new bearing layer to obtain a new target layer, and repeat updating the bearing layer until the number of layers reaches the total number of layers of the roof rock stratum structure, where each obtained target layer forms the set of possible hanging roof layers. Among them, meeting the hanging roof load condition means that the load of the current calculated layer on the bearing layer is less than the load of the previous layer of the current calculated layer on the bearing layer.

[0050] Specifically, consider the roof rock stratum structure within the caving range from bottom to top as the 1st layer, the 2nd layer,..., the Nth layer respectively. N is the total number of rock strata in the roof rock stratum structure within the caving range. According to the mechanical parameters of the rock strata measured in step S101, calculate the loads of each rock stratum within the roof rock stratum structure within the caving range. The formula for calculating the loads of each rock stratum is as shown in formula (2):

[0051]

[0052] In the formula, q is the load of the nth layer on the 1st layer, with the unit of MPa. E i (i = 1, 2,... n) is the elastic modulus of the ith layer, with the unit of MPa; h i(i = 1, 2, … n) is the thickness of the i-th layer, with the unit of m; ρ i (i = 1, 2, … n) is the bulk density of the i-th layer, with the unit of kg / m 3 ; g is the acceleration due to gravity, with the unit of N / kg. If the cumulative terms in the numerator and denominator of Equation (2) are respectively cumulated to the (n + 1)-th layer, the calculated value is the load of the (n + 1)-th layer on the 1st layer.

[0053] When the load of the (n + 1)-th layer on the 1st layer is less than the load of the n-th layer on the 1st layer, the calculation stops, and the load of the n-th layer on the 1st layer is taken as the load of the 1st layer. The load calculations of other layers can be analogized to the load of the 1st layer.

[0054] Taking the 1st layer as the bearing layer, calculate the loads of each layer above the 1st layer on the 1st layer. When the current calculation layer is the (n + 1)-th layer, if the load of the (n + 1)-th layer on the 1st layer is less than the load of the n-th layer on the 1st layer, the (n + 1)-th layer meets the caving roof load condition. At this time, the (n + 1)-th layer is the required target layer (i.e., the possible caving roof position of the lateral roof). Taking the (n + 1)-th layer as the new bearing layer, calculate the loads of the rock layers above the (n + 1)-th layer on the (n + 1)-th layer to obtain a new target layer, and repeat the update of the bearing layer until the number of layers reaches the total number of layers of the roof rock layer structure (for example, reaching the N-th layer), where each obtained target layer forms a set of possible caving roof positions.

[0055] It should be noted that the total number of layers of the rock layers in the roof rock layer structure within the caving range is limited. If there are no layers that meet the caving roof load condition between a certain target layer and the highest rock layer in the roof rock layer structure within the caving range during the repeated update process, then this target layer is the possible caving roof position of the uppermost layer. The load of this possible caving roof position of the uppermost layer can be calculated based on the remaining rock layers above it.

[0056] In step S102, while determining the set of possible caving roof positions of the lateral roof, the loads of each possible caving roof position are also obtained.

[0057] Step S103, calculate the caving step distances of each possible caving roof position in the set of possible caving roof positions, and screen the set of possible caving roof positions based on the caving step distances to obtain a set of target caving roof positions.

[0058] In step S103, calculating the caving step distances of each possible caving roof position in the set of possible caving roof positions includes: calculating the corresponding caving step distances based on the thickness, tensile strength, and bearing load of each possible caving roof position.

[0059] The formula for calculating the caving step distances of each possible caving roof position is as shown in Equation (3):

[0060]

[0061] In the formula, L jis the caving step distance of the j-th possible suspended roof layer, h j is the thickness of the j-th possible suspended roof layer, R T,j is the tensile strength of the j-th possible suspended roof layer, q j is the load of the j-th possible suspended roof layer. j takes values from 1 to J, and J is the number of possible suspended roof layers in the set of possible suspended roof layers.

[0062] In step S103, the set of possible suspended roof layers is screened based on the caving step distance to obtain the set of target suspended roof layers, including: sorting each possible suspended roof layer in the set of possible suspended roof layers from bottom to top according to its position in the roof rock stratum structure; screening any two adjacent possible suspended roof layers in a group, and the screening process includes: if the caving step distance of the upper possible suspended roof layer is less than that of the lower possible suspended roof layer, adding the load borne by the upper possible suspended roof layer to the lower possible suspended roof layer to recalculate the caving step distance of the lower possible suspended roof layer, and deleting the upper possible suspended roof layer from the set of possible suspended roof layers; after screening all groups of two adjacent possible suspended roof layers, the final set of possible suspended roof layers is the set of target suspended roof layers.

[0063] In step S103, referring to the roof rock stratum structure within the caving range, the uppermost target suspended roof layer among all the target suspended roof layers included in the set of target suspended roof layers can be determined.

[0064] Step S104, construct two directional boreholes in the adjacent roadway on the goaf side. The borehole openings of the two directional boreholes are separated by a set distance along the driving direction, and each directional borehole extends to the uppermost target suspended roof layer and then extends horizontally towards the goaf.

[0065] In step S104, the set distance is, for example, 20 - 30 m.

[0066] In step S104, when each directional borehole extends horizontally towards the goaf, the length exceeding the goaf boundary of the adjacent roadway is a set length, and the set length is less than the caving step distance of the uppermost target suspended roof layer. Among them, in the embodiments of the present invention, the goaf boundary of the adjacent roadway refers to the interface between the goaf and the coal pillar.

[0067] Specifically, Figure 2 is the layout schematic diagram of the directional boreholes provided by the embodiments of the present invention. As Figure 2As shown in the figure, a directional borehole is first constructed in the adjacent roadway on the goaf side. The directional borehole is drilled until it reaches the uppermost target hanging roof layer determined in step S103, and then continues to drill horizontally along the uppermost target hanging roof layer towards the goaf, with the drilling exceeding the set length beyond the goaf boundary (i.e., the interface between the goaf and the coal pillar). Another borehole opening is made at intervals of 20 - 30 m along the driving direction of the adjacent roadway, and a similar directional borehole is constructed in the same way as the above-mentioned directional borehole.

[0068] Step S105: Arrange electromagnetic wave detection devices in the two directional boreholes to obtain the absorption coefficient of the detection area, and determine the maximum hanging roof length based on the comparison result between the absorption coefficient and the set absorption threshold.

[0069] Specifically, in step S105, electromagnetic wave detection devices are arranged in the two directional boreholes for electromagnetic wave CT (Computed Tomography) detection. An excitation device is installed in one hole, and a receiving device is installed in the other hole. The installation position can be, for example, any position within the directional borehole section corresponding to the set length (see Figure 2 ). The detection range is the area of the uppermost target hanging roof layer between the two directional boreholes. The electromagnetic wave absorption coefficient of this area is detected through the arranged electromagnetic wave detection devices. The electromagnetic wave absorption coefficient can be simply referred to as the absorption coefficient.

[0070] According to the distribution of the electromagnetic wave absorption coefficient, when the absorption coefficient is higher than the set absorption threshold, it can be considered that there is a fracture space in this area, that is, the roof of this area has been damaged. When the absorption coefficient is less than the set absorption threshold, it can be considered that the rock formation in this area is dense, with fewer fractures and no fracture has occurred. Therefore, based on the distribution of the electromagnetic wave absorption coefficient detected by the arranged electromagnetic wave detection devices, determine the positions where the absorption coefficient is higher than the set absorption threshold. The length from each position to the goaf boundary is the hanging roof length, and the maximum value selected from all the hanging roof lengths is the required maximum hanging roof length. It should be noted that the set distance is determined based on experience. The hanging roof conditions between the directional boreholes at intervals of the set distance are basically the same. Therefore, by arranging electromagnetic wave detection devices in two directional boreholes separated by the set distance, the maximum hanging roof length of the side roof of the goaf can be obtained.

[0071] To implement the above embodiments, the present invention also proposes a system for determining the hanging roof layer position and maximum hanging roof length of the side roof of the goaf.

[0072] Figure 3 It is a block diagram of a system for determining the hanging roof layer position and maximum hanging roof length of the side roof of the goaf provided by the embodiments of the present invention.

[0073] As Figure 3As shown in the figure, the system for determining the hanging roof layer position and the maximum hanging roof length on the side of the goaf includes a caving range determination module 11, a possible hanging roof layer position determination module 12, a target hanging roof layer position determination module 13, an orientation drilling arrangement module 14, and a hanging roof length calculation module 15, where:

[0074] The caving range determination module 11 is used to obtain the roof rock stratum structure of the roof caving range for the coal mining face and the goaf that have been mined out, based on the coal mining height of the coal mining face and the roof borehole columnar section of the goaf.

[0075] The possible hanging roof layer position determination module 12 is used to determine the set of possible hanging roof layer positions of the side roof based on the loads of each layer in the roof rock stratum structure.

[0076] The target hanging roof layer position determination module 13 is used to calculate the caving step distance of each possible hanging roof layer position in the set of possible hanging roof layer positions, and screen the set of possible hanging roof layer positions based on the caving step distance to obtain the set of target hanging roof layer positions.

[0077] The orientation drilling arrangement module 14 is used to construct two orientation drill holes in the adjacent roadway on one side of the goaf. The drill hole openings of the two orientation drill holes are separated by a set distance along the driving direction, and each orientation drill hole extends horizontally along the goaf after extending to the topmost target hanging roof layer position.

[0078] The hanging roof length calculation module 15 is used to arrange electromagnetic wave detection devices in the two orientation drill holes to obtain the absorption coefficient of the detection area, and determine the maximum hanging roof length based on the comparison result between the absorption coefficient and the set absorption threshold.

[0079] Further, in a possible implementation manner of the embodiment of the present invention, the caving range determination module 11 is specifically used to: calculate the roof caving height based on the coal mining height of the coal mining face and the initial swelling coefficient of the roof rock stratum; determine the roof rock stratum structure of the roof caving range corresponding to the roof caving height based on the roof borehole columnar section of the goaf.

[0080] Further, in a possible implementation manner of the embodiment of the present invention, the possible hanging roof layer position determination module 12 is specifically used to: for the roof rock stratum structure of the roof caving range, starting from the bottommost first layer, use the first layer as the bearing layer to calculate the loads of the layers above the bearing layer on the bearing layer to obtain the target layer that meets the hanging roof load condition; use the target layer as the new bearing layer, calculate the load on the new bearing layer to obtain the new target layer, and repeat updating the bearing layer until the number of layers reaches the total number of layers of the roof rock stratum structure, where each obtained target layer forms the set of possible hanging roof layer positions.

[0081] Further, in a possible implementation manner of the embodiment of the present invention, satisfying the caving roof load condition means that the load of the current calculation layer on the bearing layer is less than the load of the previous layer of the current calculation layer on the bearing layer.

[0082] Further, in a possible implementation manner of the embodiment of the present invention, the target caving roof layer position determination module 13 calculates the caving step distance of each possible caving roof layer position in the set of possible caving roof layer positions, including: calculating the corresponding caving step distance based on the thickness, tensile strength, and bearing load of each possible caving roof layer position.

[0083] Further, in a possible implementation manner of the embodiment of the present invention, the target caving roof layer position determination module 13 screens the set of possible caving roof layer positions based on the caving step distance to obtain the set of target caving roof layer positions, including: sorting each possible caving roof layer position in the set of possible caving roof layer positions from bottom to top according to its position in the roof rock stratum structure; screening any two adjacent possible caving roof layer positions in a group, and the screening process includes: when the caving step distance of the upper possible caving roof layer position is less than the caving step distance of the lower possible caving roof layer position, adding the load borne by the upper possible caving roof layer position to the lower possible caving roof layer position to recalculate the caving step distance of the lower possible caving roof layer position, and deleting the upper possible caving roof layer position from the set of possible caving roof layer positions; the final set of possible caving roof layer positions after screening all groups of two adjacent possible caving roof layer positions is the set of target caving roof layer positions.

[0084] Further, in a possible implementation manner of the embodiment of the present invention, when each directional borehole in the directional borehole arrangement module 14 extends horizontally towards the gob area, the length exceeding the gob area boundary of the adjacent roadway is a set length, and the set length is less than the caving step distance of the topmost target caving roof layer position.

[0085] It should be noted that the foregoing explanation of the embodiment of the method for determining the caving roof layer position and the maximum caving roof length on the side of the gob area also applies to the system for determining the caving roof layer position and the maximum caving roof length on the side of the gob area of this embodiment, and will not be elaborated here.

[0086] In the embodiment of the present invention, for the coal mining face and the goaf where coal mining has been completed, the roof rock stratum structure of the roof caving range is obtained based on the coal mining height of the coal mining face and the roof borehole columnar section of the goaf; the possible suspended roof layer position set of the lateral roof is determined based on the loads of each layer in the roof rock stratum structure; the caving step distances of each possible suspended roof layer position in the possible suspended roof layer position set are calculated, and the possible suspended roof layer position set is screened based on the caving step distances to obtain the target suspended roof layer position set; two directional boreholes are constructed in the adjacent roadway on the goaf side, the borehole openings of the two directional boreholes are separated by a set distance along the driving direction, and each directional borehole extends horizontally towards the goaf after reaching the uppermost target suspended roof layer position; an electromagnetic wave detection device is arranged in the two directional boreholes to obtain the absorption coefficient of the detection area, and the maximum suspended roof length is determined based on the comparison result between the absorption coefficient and the set absorption threshold. In this case, considering that the roof of the caving range has the most direct impact on the gob-side entry, the roof rock stratum structure of the roof caving range is determined based on the coal mining height and the roof borehole columnar section. The target suspended roof layer position set is obtained by using the load and the caving step distance for the roof rock stratum structure of the roof caving range, and then the absorption coefficient collected by the electromagnetic wave detection device arranged in the two directional boreholes in the adjacent roadway is combined to obtain the suspended roof length, so that the determination of the suspended roof layer position and the suspended roof length is more accurate.

[0087] Considering that if the roof caving completely fills the goaf, the influence of the lateral roof is very small. Therefore, the method and system of the present invention only analyze the roof suspension in the caving zone, which is more clear and reasonable. After determining the suspended roof layer position, directional boreholes are constructed, and the roof is detected by electromagnetic wave CT. According to the magnitude of the absorption coefficient, the lateral suspended roof length is obtained. This has an important role in guiding the pre-splitting treatment of the lateral roof to protect the gob-side entry. Compared with the traditional on-site borehole drilling method, the method and system of the present invention can more conveniently obtain the roof suspended roof layer position and the suspended roof length, and are more practical in the prevention and control technology of rock bursts.

[0088] The method and system of the present invention have the following technical effects: 1) Analyze the roof in the caving zone that has the most direct impact on the gob-side entry, and the selection of the analysis object is more reasonable; 2) Determine the suspended roof layer position of the lateral roof by calculating the loads of each rock stratum, and the obtained result is more in line with the actual situation on site, and further clarifies the object of the roof pre-splitting weakening treatment, making the pressure relief measures more targeted; 3) Use electromagnetic wave detection to obtain the suspended roof length. Compared with the traditional drilling detection method, it saves the project volume, reduces the waste caused by blind construction, and the detection range of drilling construction is limited, and this method is more universal.

[0089] To implement the above embodiments, the present invention further provides an electronic device, including: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method provided in the foregoing embodiments.

[0090] To implement the above embodiments, the present invention further provides a computer-readable storage medium storing computer-executable instructions, which are used to implement the method provided in the foregoing embodiments when executed by a processor.

[0091] To implement the above embodiments, the present invention further provides a computer program product including a computer program, which implements the method provided in the foregoing embodiments when executed by a processor.

[0092] In the description of the foregoing embodiments, the descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0093] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0094] Any process or method description in the flowchart or described in other ways herein may be understood to represent a module, segment, or portion of code including one or more executable instructions for implementing a customized logical function or process, and the scope of the preferred embodiments of the present invention includes additional implementations, where the functions may be executed in a substantially simultaneous manner or in a reverse order according to the involved functions, rather than in the order shown or discussed, which should be understood by those skilled in the art to which the embodiments of the present invention pertain.

[0095] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a definable sequence list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or used in conjunction with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer disk cartridge (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other suitable processing as necessary, and then storing it in a computer memory.

[0096] It should be understood that various parts of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits having suitable combinational logic gate circuits, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0097] Those of ordinary skill in the art of this technology can understand that all or part of the steps carried by the method of the above-described embodiments can be completed by a program instructing relevant hardware, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0098] In addition, each functional unit in various embodiments of the present invention may be integrated into one processing module, may exist separately physically for each unit, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0099] The above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disc, etc. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for determining the lateral roof hanging layer position and the maximum hanging roof length in a gob area, characterized in that Comprising: For a coal mining face and a goaf where coal mining has ended, based on the obtained coal mining height of the coal mining face and the roof borehole columnar section of the goaf, obtain the roof rock stratum structure of the roof caving range; Based on the loads of each layer in the roof rock stratum structure, determine the set of possible hanging roof levels of the lateral roof; Calculate the caving step distance of each possible hanging roof level in the set of possible hanging roof levels, and based on the caving step distance, screen the set of possible hanging roof levels to obtain the target set of hanging roof levels; Construct two directional boreholes in the adjacent roadway on the goaf side. The borehole openings of the two directional boreholes are separated by a set distance along the driving direction. Each directional borehole extends to the topmost target hanging roof level and then extends horizontally towards the goaf; Arrange an electromagnetic wave detection device in the two directional boreholes to obtain the absorption coefficient of the detection area, and determine the maximum hanging roof length based on the comparison result between the absorption coefficient and the set absorption threshold.

2. The method for determining the position of the hanging roof layer on the side roof of the goaf and the maximum hanging roof length according to claim 1, wherein The obtaining the roof rock stratum structure of the roof caving range based on the obtained coal mining height of the coal mining face and the roof borehole columnar section of the goaf includes: Based on the coal mining height of the coal mining face and the initial swelling coefficient of the roof rock stratum, calculate the roof caving height; Based on the roof borehole columnar section of the goaf, determine the roof rock stratum structure of the roof caving range corresponding to the roof caving height.

3. The method for determining the lateral roof hanging layer position and maximum hanging roof length in the goaf according to claim 1, characterized in that, The determining the set of possible hanging roof levels of the lateral roof based on the loads of each layer in the roof rock stratum structure includes: For the roof rock stratum structure of the roof caving range, starting from the bottommost first layer, take the first layer as the bearing layer and calculate the loads of the layers above the bearing layer on the bearing layer to obtain the target layer that meets the hanging roof load condition; Take the target layer as the new bearing layer, calculate the load on the new bearing layer to obtain a new target layer, and repeat updating the bearing layer until the number of layers reaches the total number of layers of the roof rock stratum structure, where each obtained target layer forms the set of possible hanging roof levels.

4. The method for determining the lateral roof hanging stratum position and the maximum hanging roof length in a gob area according to claim 3, characterized in that The meeting the hanging roof load condition means that the load of the currently calculated layer on the bearing layer is less than the load of the previous layer of the currently calculated layer on the bearing layer.

5. The method for determining the lateral roof hanging layer position and maximum hanging roof length in a goaf according to claim 1, characterized in that, The calculating the caving step distance of each possible hanging roof level in the set of possible hanging roof levels includes: Based on the thickness, tensile strength, and bearing load of each possible hanging roof level, calculate the corresponding caving step distance.

6. The method for determining the lateral roof hanging layer position and maximum hanging roof length in a goaf according to claim 5, characterized in that The screening the set of possible hanging roof levels based on the caving step distance to obtain the target set of hanging roof levels includes: Sort each possible hanging roof level in the set of possible hanging roof levels from bottom to top according to its position in the roof rock stratum structure; Screen any two adjacent possible hanging roof levels in a group. The screening process includes: when the caving step distance of the upper possible hanging roof level is less than the caving step distance of the lower possible hanging roof level, add the load borne by the upper possible hanging roof level to the lower possible hanging roof level to recalculate the caving step distance of the lower possible hanging roof level, and delete the upper possible hanging roof level from the set of possible hanging roof levels; After screening all groups of two adjacent possible hanging roof levels, the final set of possible hanging roof levels is the target set of hanging roof levels.

7. The method for determining the lateral roof hanging layer position and maximum hanging roof length in a gob area according to claim 1, characterized in that When each directional borehole extends horizontally towards the goaf, the length exceeding the goaf boundary of the adjacent roadway is a set length, and the set length is less than the caving step distance of the topmost target caving strata position.

8. A system for determining the lateral roof hanging layer position and the maximum hanging roof length in a goaf, characterized in that, Comprising: A caving range determination module, configured to obtain the roof rock stratum structure of the roof caving range for a coal mining face and a goaf where coal mining has ended, based on the coal mining height of the coal mining face and the roof borehole columnar section of the goaf obtained. A possible caving strata position determination module, configured to determine a set of possible caving strata positions of the lateral roof based on the loads of each layer in the roof rock stratum structure. A target caving strata position determination module, configured to calculate the caving step distance of each possible caving strata position in the set of possible caving strata positions, and screen the set of possible caving strata positions based on the caving step distance to obtain a set of target caving strata positions. A directional borehole arrangement module, configured to construct two directional boreholes in the adjacent roadway on one side of the goaf, with the borehole openings of the two directional boreholes spaced a set distance apart along the driving direction, and each directional borehole extends horizontally towards the goaf after reaching the topmost target caving strata position. A roof hanging length calculation module, configured to arrange an electromagnetic wave detection device in the two directional boreholes to obtain the absorption coefficient of the detection area, and determine the maximum roof hanging length based on the comparison result between the absorption coefficient and a set absorption threshold.

9. An electronic device, characterized in that, Comprising: A processor, and a memory communicatively connected to the processor; The memory stores computer execution instructions; The processor executes the computer execution instructions stored in the memory to implement the method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, Computer execution instructions are stored in the computer-readable storage medium, and when the computer execution instructions are executed by the processor, they are used to implement the method according to any one of claims 1-7.

Images