Mine hard rock roadway tunneling blasting fragmentation control method

Abstract

The embodiment of the invention discloses a mine hard rock roadway tunneling blasting lumpiness control method, relates to a mine roadway blasting tunneling technology, and can effectively control the size of rock lumpiness after blasting. The method comprises the following steps: after blasting, measuring and analyzing the lumpiness of a muck pile, analyzing reasons for generating large rocks, and determining generation positions of blasting large blocks; for the blast hole with the large block area, a charging structure that the hole bottom is continuously charged and the hole opening is alternately charged is adopted for charging; after charging is completed, a multipoint detonation technology is adopted, orifices and bottoms of blast holes in a large area are detonated at the same time, superposition of multipoint stress waves is achieved, and the rock fragmentation lumpiness is improved.

Description

Technical Field

[0001] The invention relates to a hard rock blasting excavation technology in a mine, and in particular to a method for controlling the blasting block size in hard rock shaft and tunnel excavation in a mine. Background Art

[0002] As an important indicator for evaluating the blasting effect, rock blasting fragmentation directly affects the subsequent construction cost and construction efficiency of mine blasting projects. Blasting is a commonly used rock breaking method in the process of hard rock tunnel excavation in mines. However, traditional blasting methods often make it difficult to effectively control the blasting fragmentation, resulting in a high rate of large fragments, which not only affects the subsequent shoveling, transportation and crushing efficiency, increases production costs, but also may cause safety hazards.

[0003] As the main construction method for tunneling, the drilling and blasting method has paid more attention to the tunneling speed and the shape of the cross section after blasting, and less attention to the size of the blasting block in previous academic research and practical engineering applications. After some hard rock mines mixed and twisted the air intake shaft, they adopted the traditional charging structure, which made most of the explosives concentrated in the lower part of the blasthole, resulting in the blasting block being too large and requiring secondary crushing, which directly affected the efficiency of gangue discharge and further affected the entire construction progress. If the purpose of controlling the blasting block size is achieved by blasthole densification, but after the blasthole is densified, if the original charging length is continued, the charging amount will be too large, which is not economical and will aggravate the damage to the surrounding rock and even collapse the tunnel equipment; if the charging length is reduced, it will make it easier to produce large blocks in the hole mouth area. Therefore, in view of the rigid requirements of some hard rock mines such as mixed and twisted conversion that the block size of tunnel excavation blasting cannot exceed 300 mm, it is urgent to develop a technical solution for blasting block size control in hard rock tunnel excavation in mines.

[0004] In addition, to study the size of blasting blocks during shaft and tunnel excavation, it is necessary to determine the cause of excessive blasting blocks. In engineering practice, large blasting blocks often occur even when the utilization rate of blastholes is relatively reasonable. How to determine the location of large blocks and how to reduce the generation of large blocks without changing the workers' drilling habits are the problems that need to be solved at present. In existing research, some scholars have proposed setting up high-speed cameras on site for taking pictures, but there are problems such as poor lighting conditions and poor shooting effects on site, fast rock throwing speed and long throwing distance after blasting, and stress waves and shock waves after blasting that will damage the electronic components of the camera. This method has not been well applied in engineering.

[0005] Therefore, how to determine the location of large blocks produced during shaft and tunnel excavation blasting and adjust the blasting parameters to form an economical, safe and effective method for controlling the block size of hard rock shaft and tunnel excavation blasting in mines is a technical problem that urgently needs to be solved. Summary of the invention

[0006] In view of this, an embodiment of the present invention provides a method for controlling blasting fragmentation in hard rock shaft and tunnel excavation in a mine, which can effectively control the size of rock fragments after blasting, thereby facilitating improving mining efficiency and transportation efficiency, reducing secondary crushing costs, and ensuring the stability and safety of the tunnel surrounding rock.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] A method for controlling the blasting block size of hard rock shaft tunneling in a mine, comprising the steps of:

[0009] S10. After blasting, the size of the blasted pile is measured and analyzed to evaluate the blasting effect;

[0010] S20, if the rock size exceeds the set size threshold, analyze the cause of the large rock size and determine the location where the blasted large rock is generated; specifically including:

[0011] Check whether the blasting parameters of the slot hole area at the actual blasting site are consistent with the designed blasting parameters;

[0012] If they are consistent, it is further determined whether the blasthole utilization rate after blasting reaches the preset threshold;

[0013] If yes, it is determined that the blasted block is not generated by the cut hole area of ​​the actual blasting site;

[0014] Continue to determine whether the blasting block is generated from the peripheral hole area and the cave-in hole area;

[0015] Monitor whether there is "large piece shedding" of surrounding rock around the tunnel after blasting;

[0016] If it exists, it is determined whether the blasting block is caused by unreasonable design of blasting parameters of peripheral holes or cave-in holes;

[0017] Verify the charge amount and blasthole spacing of the peripheral holes and cave-in holes at the actual blasting site according to the design plan of the corresponding blasting parameters;

[0018] If they are consistent, the explosive charge positions, detonation methods and micro-difference time of the surrounding holes are adjusted, and the blasting effect after adjustment is monitored;

[0019] If after adjustment, there is no "large piece falling off" phenomenon in the surrounding rock, but there are large pieces of rock, it is determined that the blasting block is produced by the cave-in hole area, and the explosive bag position, detonation position and blasting parameters of the cave-in hole are adjusted and optimized;

[0020] S30, for blastholes with large areas, a charging structure of continuous charging at the bottom of the hole and interval charging at the hole mouth is used for charging;

[0021] S40. After the charge is loaded, a multi-point detonation technique is used to simultaneously detonate the orifice and the bottom of the blasthole to achieve the superposition of multi-point stress waves, so as to improve the fragmentation of the rock.

[0022] As a specific implementation method, after discovering the area where large pieces are produced, it also includes: adjusting the hole layout of the blastholes, adding shallow holes in the area where large pieces are prone to be produced at the hole mouth, and using a deep and shallow combination structure of alternating long and short blastholes to reduce the large piece rate after blasting.

[0023] As a specific implementation, in step S20, the design adjustment and optimization of blasting parameters includes: verifying and determining the rationality of the design of blasting parameters of the slot holes, auxiliary holes, and peripheral holes; wherein the total number of blast holes must comply with the formula: , where N is the total number of blastholes in the entire tunnel section; f is the rock strength coefficient; S is the tunnel excavation cross-sectional area, m 2 .

[0024] As a specific implementation, in step S20, it also includes: blastholes are evenly arranged in the entire tunnel excavation section so that the energy after explosion is effectively utilized, and the unit consumption of explosives must comply with the modified Proctor formula:

[0025]

[0026] Where q is the unit explosive consumption; k0: coefficient, k0=525 / p, p is the explosive force, unit mL;

[0027] The type of explosive is selected according to the properties of the rock; the blasthole diameter and the charge diameter are selected according to the on-site conditions, wherein the on-site conditions include: rock hardness coefficient, size and shape of the tunnel to be excavated and blasting equipment; the blasthole spacing is selected according to the metal mine tunnel blasting construction specifications and engineering experience; the blasting parameters of the slotting eye are designed and optimized according to the rock hardness coefficient and the cross-sectional size.

[0028] As a specific implementation manner, the superposition energy of the multi-point stress waves is greater than the sum of the shock waves generated by the respective detonations of multiple charging points.

[0029] As a specific implementation method, when smooth blasting is used, the charge amount of a single hole in the peripheral hole should satisfy the formula: ,in,

[0030] is the charge amount of the peripheral holes per hole, is the average charge factor, is the length of the medicine roll, in m, is the weight of the medicine roll, is the average blasthole depth.

[0031] As a specific implementation method, the charge amount of a single hole of a cave hole and a slot hole is adjusted by a charge coefficient, and the charge amount of a single hole of a cave hole should satisfy the formula:

[0032] ;in,

[0033] is the charge amount of a single cave hole, is the linear charge density per meter of borehole, , unit: kg / m, is the charge coefficient, take 0.7-0.8, is the average blasthole depth.

[0034] As a specific implementation method, after the charging is completed, a millisecond delayed detonation method is adopted for multiple blastholes to control the detonation time interval of each blasthole to reduce blasting vibration and excessive rock fragmentation.

[0035] As a specific implementation method, the method also includes: before detonation, checking the construction quality of the blasthole to ensure that the position, depth and diameter of the blasthole meet the design requirements, and charging, filling and connecting are carried out according to the design requirements.

[0036] As a specific implementation, before step S10, the method further includes: marking the entire cross section with pigments, using red, yellow and white pigments to mark the cutout area, the collapse area and the surrounding hole area respectively;

[0037] The step S20 also includes: after blasting, determining the area where the large block is produced according to the rocks marked with different pigments.

[0038] The method for controlling the fragmentation of hard rock tunnel excavation blasting provided by the embodiment of the present invention determines the location of large-block rock after tunnel blasting through steps S10 to S40 after blasting, and can timely find the location of large-block rock, solve the drawbacks of determining large-block areas by camera method, optimize the design of blasting parameters, charging structure and detonation method, and use the uniform pressure distribution provided by continuous charging at the bottom of the hole to make the shock wave formed after the detonation of the explosive at the bottom of the hole act evenly on the rock to weaken the formation of the foundation; and after the charging is completed, use the multi-point detonation technology to detonate the orifice and the bottom of the blasthole at the same time, realize the superposition of multi-point stress waves, and generate uniform pressure distribution at the orifice to break the rock. It can effectively control the distribution and release of blasting energy, reduce excessive rock fragmentation and the generation of large blocks. Therefore, the present invention can simply and efficiently determine the location where large-block rocks are produced, and effectively control the size of rock blocks after blasting by optimizing and adjusting blasting parameters, etc., which is beneficial to improving mining efficiency and transportation efficiency, reducing secondary crushing costs, and ensuring the stability and safety of the tunnel surrounding rock. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] FIG1 is a process flow chart of an embodiment of a method for controlling blasting block size in hard rock tunnel excavation in a mine according to the present invention;

[0041] FIG2 is a schematic diagram of the arrangement of blastholes in the present invention;

[0042] Figure 3a to Figure 3c It is a schematic diagram of the arrangement of multiple embodiments of the slotted holes in the present invention;

[0043] FIG4 a is a schematic diagram of an embodiment of a slot hole charging structure in the present invention;

[0044] FIG4 b is a schematic diagram of an embodiment of a charge structure of a cave-in hole in the present invention;

[0045] Figure 4c It is a schematic diagram of an embodiment of the peripheral hole charging structure of the present invention;

[0046] Figure 5 It is a schematic diagram of the blast hole detonation method in the present invention;

[0047] FIG6 is a schematic diagram of shock wave collision according to the present invention;

[0048] FIG7 is a flow chart of determining the location of the blasting block in the present invention;

[0049] Figure 8 is a schematic diagram of the superposition of stress waves excited by the detonator in the middle of the charge column;

[0050] FIG9 is a schematic diagram of rock fragmentation before and after blasting in a tunnel using the technology of the present invention;

[0051] Fig.10 It is a schematic diagram of the arrangement structure of the "long and short blast holes" of the present invention. DETAILED DESCRIPTION

[0052] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0053] It should be clear that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] See also Figures 1 to 10 As shown, an embodiment of the present invention provides a method for controlling the blasting block size of hard rock shaft tunneling in a mine, comprising the steps of:

[0055] S10. After blasting, the size of the blasted pile is measured and analyzed to evaluate the blasting effect;

[0056] S20, if the rock size exceeds the set size threshold, analyze the cause of the large rock size and determine the location where the blasted large rock is generated;

[0057] As a key link in evaluating the effectiveness of the technology for controlling blasting fragmentation, it is very important to determine the location where the large blasting fragments are produced. In some existing technologies, photography is used to determine the location where the large blasting fragments are produced, which is not suitable for actual engineering applications, and has high time and economic costs and poses safety hazards.

[0058] In this embodiment, step S20 specifically includes:

[0059] Check whether the blasting parameters of the slot hole area at the actual blasting site are consistent with the designed blasting parameters;

[0060] If they are consistent, it is further determined whether the blasthole utilization rate after blasting reaches the preset threshold;

[0061] If yes, it is determined that the blasted block is not generated by the cut hole area of ​​the actual blasting site;

[0062] Continue to determine whether the blasting block is generated from the peripheral hole area and the cave-in hole area;

[0063] Monitor whether there is "large piece shedding" of surrounding rock around the tunnel after blasting;

[0064] If it exists, it is determined whether the blasting block is caused by unreasonable design of blasting parameters of peripheral holes or cave-in holes;

[0065] Verify the charge amount and blasthole spacing of the peripheral holes and cave-in holes at the actual blasting site according to the design plan of the corresponding blasting parameters;

[0066] If they are consistent, the explosive charge positions, detonation methods and micro-difference time of the surrounding holes are adjusted, and the blasting effect after adjustment is monitored;

[0067] If after adjustment, there is no "large piece falling off" phenomenon in the surrounding rock, but there are large pieces of rock, it is determined that the blasting block is produced by the cave-in hole area, and the explosive bag position, detonation position and blasting parameters of the cave-in hole are adjusted and optimized;

[0068] For example, in this embodiment, the rationality of the slot hole arrangement of the existing blasting scheme is first determined. Through the quantitative standards for the design of the aforementioned blasting parameters, it can be ensured that the blasting parameters such as the number of blastholes, blasthole spacing, and charge amount are relatively reasonable. If the blasthole utilization rate is not less than 80%, it means that the on-site blasting plan is relatively reasonable, and the appearance of larger rocks after blasting is caused by other reasons.

[0069] If we know that the arrangement and charge of blastholes in the slot hole area are reasonable and the utilization rate of blastholes in the entire section is also relatively reasonable, it means that the slotting effect is relatively good and is not caused by the slotting area. In addition, in engineering practice, in order to ensure that the entire section can be excavated smoothly, the charge in the slotting area is increased to ensure that the slotting blasting can obtain a larger cavity, provide a large enough free surface for other blasthole blasting, and ensure the excavation of the entire section. Therefore, if the blasting parameters in the slot hole area are reasonable, large pieces of rock will generally not be produced after blasting.

[0070] After it has been determined that the slot hole area is not the cause of the large chunks, the large chunks may be generated in the peripheral hole area and the collapse hole area. It is necessary to further investigate the peripheral hole area and the collapse hole area to observe the surrounding rock of the tunnel after blasting. If there is a "large piece of detachment" phenomenon in the surrounding surrounding rock, it means that the blasting large chunks may be caused by unreasonable design of the blasting parameters of the peripheral holes. From the formula of the quantitative standard of blasting parameters provided above, it can be seen that the parameters such as the charge amount of the peripheral holes and the collapse holes, the spacing between the blast holes, etc. are relatively reasonable. At this time, it is necessary to adjust the charge position, detonation method, micro-difference time, etc. of the peripheral holes. It mainly involves the adjustment of the charge position and the detonation point.

[0071] If after adjusting the parameters of the surrounding holes and blasting, there is no "large piece falling off" of the surrounding rock, but there are still many large blocks of rock, it means that the large blocks are produced in the collapse hole area, and the explosive charge position, detonation position and blasting parameters of the collapse hole should be adjusted.

[0072] In this embodiment, the scheme for determining the location of large rock blocks after tunnel blasting can timely discover the location of large blocks, solving the drawback of determining large block areas by camera method.

[0073] The blasting parameters include: the total number of blastholes, blasthole arrangement, charge structure, explosive unit consumption, explosive parameters, blasthole diameter, blasthole depth and blasthole spacing;

[0074] In this embodiment, if the rock size exceeds the set size threshold, the cause of the large rock is analyzed, and the location of the blasting large rock is determined. By analyzing the cause of the large rock, the blasting parameters and process can be adjusted in a targeted manner to reduce the generation of large rocks and improve the blasting effect.

[0075] S30, for blastholes with large areas, a charging structure of continuous charging at the bottom of the hole and interval charging at the hole mouth is used for charging;

[0076] S40. After the charge is loaded, a multi-point detonation technique is used to simultaneously detonate the orifice and the bottom of the blasthole to achieve the superposition of multi-point stress waves, so as to improve the fragmentation of the rock.

[0077] In order to help understand the above technical solution, the following is an overall description: Figure 1 As shown, according to an embodiment of the method for controlling the blasting block size of hard rock shaft tunneling in a mine of the present invention, first, geological information of the hard rock mine tunnel area is obtained. The geological information includes the physical and mechanical properties of the rock and the distribution of joints and fissures. Next, blasting parameter design is performed. The blasting parameters include the total number of blastholes, blasthole arrangement, charge structure, explosive unit consumption, explosive parameters, blasthole diameter, blasthole depth, and blasthole spacing.

[0078] After blasting, the size of the blast pile is measured and analyzed to evaluate the blasting effect; if the rock size exceeds the set size threshold, the cause of the large rock is analyzed to determine the location of the large blasted rock. In this way, after blasting, the size of the blast pile is measured and analyzed to evaluate the blasting effect. According to the evaluation results, the blasting parameters and process are adjusted and optimized. By evaluating and optimizing the blasting effect, the blasting process can be continuously improved, the blasting effect can be improved, and problems can be found and adjusted in time after each blasting to ensure that the effect of each blasting can meet expectations and improve construction efficiency and quality.

[0079] For blastholes that produce large areas, in each blasthole, a charging structure of continuous charging at the bottom of the hole and interval charging at the hole mouth is used for charging. After charging is completed, a multi-point detonation technology is used, and each blasthole is detonated simultaneously at the hole mouth and the bottom of the hole. The uniform pressure distribution provided by the continuous charging at the bottom of the hole makes the shock wave formed after the explosion of the explosive at the bottom of the hole act evenly on the rock to weaken the formation of the foundation. Based on the multiple charging points formed by the interval charging at the hole mouth, the shock waves generated after the explosion of the explosive at the hole mouth collide with each other between different charging points, and superimpose between at least two adjacent charging points to form a stronger superposition of multi-point stress waves, and produce a uniform pressure distribution at the hole mouth to break the rock. It can significantly reduce the large pieces of rock produced during the blasting process, improve the efficiency of subsequent shoveling, transportation and crushing, reduce production costs, and reduce safety hazards.

[0080] The embodiment of the present invention provides a method for controlling the fragmentation of hard rock shaft and tunnel excavation blasting in a mine. Through steps S10 to S40, after blasting, a scheme for determining the location of large-block rock after tunnel blasting can be used to timely discover the location of large blocks, solve the disadvantage of determining large-block areas by camera method, and optimize the blasting parameter design, charging structure and detonation method. The uniform pressure distribution provided by continuous charging at the bottom of the hole is used to make the shock wave formed after the detonation of the explosives at the bottom of the hole act evenly on the rock to weaken the formation of the foundation; and after the charging is completed, the multi-point detonation technology is used to simultaneously detonate the orifice and the bottom of the blasthole to achieve the superposition of multi-point stress waves and generate uniform pressure distribution at the orifice to break the rock. The distribution and release of blasting energy can be effectively controlled to reduce excessive rock breakage and the generation of large blocks. Therefore, the present invention can simply and efficiently determine the location where large-block rocks are produced, and by optimizing and adjusting blasting parameters, etc., can effectively control the size of rock blocks after blasting, thereby helping to improve mining efficiency and transportation efficiency, reduce secondary crushing costs, and at the same time ensure the stability and safety of the tunnel surrounding rock.

[0081] In addition, as another embodiment, before step S10, the method further includes: marking the entire cross section with pigments, using red, yellow and white pigments to mark the cutout area, the collapse area and the surrounding hole area respectively;

[0082] The step S20 also includes: after blasting, determining the area where the large pieces are produced according to the rocks marked with different pigments. In this way, the area where the large pieces are produced can be determined simply and quickly by the pigment marking method.

[0083] Specifically, the pigment marking method for determining the bulk production area can also be used in combination with the aforementioned scheme.

[0084] See also Fig.10 As shown, after discovering the area where large blocks are produced, the method also includes: adjusting the hole layout of the blastholes, adding shallow holes in the area where large blocks are easily produced at the hole mouth, and using a deep and shallow combination structure of alternating long and short blastholes to reduce the large block rate, and to ensure continuous improvement and optimization of blasting block size control technology.

[0085] Specifically, the deep and shallow combination structure of the alternating arrangement of long and short blast holes includes: long blast holes, which are arranged along the direction of mine excavation and are used for blasting deep rocks.

[0086] Short blastholes are arranged in the direction of mine excavation, parallel to and spaced from the long blastholes, near the mouths of the long blastholes, and are used for blasting shallow or easy-to-blast rocks.

[0087] Long blastholes and short blastholes are arranged alternately in the direction of mine excavation to achieve continuity and integrity of the blasted rock.

[0088] In this embodiment, by adopting a deep and shallow combination structure in which long and short blastholes are alternately arranged, and utilizing the synergistic effect of long blasthole deep blasting and short blasthole shallow blasting, the continuity and integrity of the blasted rock are achieved, ensuring that deep and shallow rocks are effectively crushed at the same time, making the blasting process more stable and controllable. In addition, it can also significantly improve the quality of mine tunnel forming, reduce unnecessary impacts and vibrations on surrounding rocks, thereby improving the safety and efficiency of mining operations.

[0089] In step S20, it also includes: verifying and determining the rationality of the design of blasting parameters for the cut holes, auxiliary holes, and peripheral holes. Specifically, the total number of blast holes must meet the formula: ; Among them, N is the total number of blastholes in the entire section of the tunnel, f is the rock strength coefficient, and S is the cross-sectional area of ​​the tunnel excavation, in m².

[0090] In this embodiment, by providing a standard formula for designing the number of blastholes, the total number of designed blastholes can be made more reasonable, thereby ensuring effective use of blasting energy, reducing unnecessary waste of explosives, and avoiding damage to surrounding rocks caused by excessive blasting.

[0091] In some embodiments, in step S20, blast holes are evenly arranged in the entire tunnel excavation section so that the energy after blasting can be effectively utilized. The unit consumption of explosives must comply with the modified Proctor formula:

[0092] ; where q is the unit explosive consumption, is the coefficient, =525 / p, p is the explosive force, unit is mL.

[0093] The type of explosive is selected according to the rock properties; the blasthole diameter and charge diameter are selected according to the site conditions, including the rock hardness coefficient, the size and shape of the tunnel to be excavated, and the blasting equipment. The blasthole spacing is selected according to the metal mine tunnel blasting construction specifications and engineering experience. The blasting parameters of the slot hole are designed according to the rock hardness coefficient and the cross-section size.

[0094] In this embodiment, by optimizing the design of the above-mentioned blasting parameters and charge structure, etc., the blasting block size in hard rock mine tunneling can be effectively controlled, the generation of large blocks can be reduced, and the construction efficiency and safety can be improved.

[0095] In a hard rock mine tunnel excavation project, the method of the present invention was used for blasting construction. By surveying and analyzing the geological conditions of the tunnel area, the physical and mechanical properties of the rock and the distribution information of joints and fissures were obtained. Based on this information, reasonable blasting parameters were designed, including the total number of blastholes, blasthole arrangement, charge structure, etc.

[0096] In some mine blasting projects, it has been verified that the charging structure of continuous charging at the bottom of the hole and interval charging at the hole mouth is used for charging, and multi-point detonation technology is used for detonation. The results show that the rock block size after blasting is significantly reduced, the large block rate is reduced by about 30%, the efficiency of subsequent shoveling, transportation and crushing is increased by about 25%, and the production cost is reduced by about 15%.

[0097] In some embodiments, the energy of the composite shock wave is greater than the sum of the shock waves generated by the detonation of two adjacent charge points. Specifically, by reasonably designing the positions and charge amounts of the charge points, when the shock waves generated by the detonation of adjacent charge points collide and overlap with each other, the energy of the composite shock wave formed is greater than the sum of the shock waves generated by the separate detonation of the two adjacent charge points, thereby improving the blasting effect and further reducing the generation of large rocks.

[0098] It is worth mentioning that through the design of this blasting plan, the blasting efficiency can be significantly improved without increasing the total amount of explosives, reducing the generation of large rocks and improving the efficiency and safety of subsequent construction.

[0099] It is understandable that too much charge will lead to excessive crushing of the rock mass, and too little charge will lead to the generation of large pieces. In order to achieve a better blasting effect, while considering the charge structure, the charge amount per hole should be considered. In some embodiments, when smooth blasting is used, the charge amount per peripheral hole should satisfy the formula:

[0100] in, is the charge amount of the peripheral holes per hole, is the average charge factor, is the length of the medicine roll, in m, is the weight of the medicine roll, is the average blasthole depth.

[0101] In this embodiment, the above formula can be used to reasonably determine the charge amount of the peripheral holes, ensure the effect of smooth blasting, reduce the damage to the surrounding rocks, and improve the blasting quality. Furthermore, by controlling the charge amount of the peripheral holes, the damage to the surrounding rocks during the blasting process can be effectively reduced, ensuring the stability and safety of the tunnel.

[0102] In some embodiments, the charge amount of a single hole of a cave hole and a slot hole is adjusted by a charge coefficient, and the charge amount of a single hole of a cave hole should satisfy the formula:

[0103] ;in,

[0104] is the charge amount of a single cave hole, is the linear charge density per meter of borehole, , unit: kg / m, is the charge coefficient, take 0.7-0.8, is the average blasthole depth.

[0105] In this embodiment, by adjusting the charge coefficient, the charge amount of each hole of the cave-in hole and the slot hole can be reasonably controlled to ensure the blasting effect and reduce the generation of large rocks. It is worth noting that through this adjustment, the amount of explosives used can be reduced while ensuring the blasting effect, reducing costs and improving construction efficiency.

[0106] In some embodiments, in step S40, after the charging is completed, a millisecond delayed detonation method is adopted for multiple blast holes to control the detonation time interval of each blast hole to reduce blasting vibration and excessive rock fragmentation.

[0107] Specifically, high-precision detonating equipment is selected to ensure the accuracy and synchronization of detonation. The millisecond delayed detonation method is adopted to reasonably control the detonation time interval of each blast hole to reduce blasting vibration and excessive rock fragmentation.

[0108] In some embodiments, during detonation, a multi-point detonation technique is used, and the hole mouth and the hole bottom are detonated simultaneously to homogenize the explosion stress field, fully utilize the stress wave effect, and reduce the generation rate of large pieces at the hole mouth.

[0109] In some embodiments, the method further includes checking the construction quality of the blasthole before detonation to ensure that the position, depth and diameter of the blasthole meet the design requirements, and charging, filling and connecting are performed according to the design requirements. In this way, potential problems can be discovered and corrected before construction, the accuracy of blasting parameters can be ensured, and the blasting effect can be improved.

[0110] In order to help understand the technical solution and technical effects provided by the embodiments of the present invention, the following is an example of a specific A hard rock shaft tunneling engineering practice as an example for explanation as follows:

[0111] Geological exploration and analysis

[0112] First, the physical and mechanical parameters of the rock, such as compressive strength, tensile strength, elastic modulus, etc., are obtained through geological drilling and trenching. The rock hardness at the location of the A hard rock shaft is medium hard, and the joints and fissures are relatively developed. These geological information provides basic data for the subsequent blasting parameter design. Next, based on the geological parameters of the above-mentioned mine tunnel area, the blasting parameters are designed.

[0113] Blasting parameter design

[0114] In this specific implementation case, the blasting parameters are designed according to the geological survey. The blasthole arrangement adopts vertical grooving, the grooving hole depth is 3.5 meters, the auxiliary hole and peripheral hole depth is 3.3 meters, the blasthole diameter is 42 mm, the blasthole spacing is 0.6-0.7 meters, and the full-section blasthole arrangement is as follows: Figure 2 As shown in the figure, for different metal mine tunneling, the blasthole arrangement can be adjusted according to the rock properties.

[0115] The number of blastholes in one cycle can be calculated according to the above formula Calculation, but the specific number of blastholes should be determined according to the actual situation of the slot holes, collapse holes, and peripheral holes. In this case, the charge amount is calculated based on the rock characteristics and blasting experience formula. The charge amount for one cycle of shaft and tunnel blasting is Q=Q1+Q2+Q3, where Q1 is the charge amount for the slot holes, Q2 is the charge amount for the collapse holes, and Q3 is the charge amount for the peripheral holes. Still taking A iron ore as an example, through calculation and practice, it is concluded that the charge amount for a single slot hole is 3kg, the auxiliary hole is 2.7kg, and the peripheral hole is 1.2kg.

[0116] In order to achieve better blasting effect, the present invention provides a slotting arrangement for rocks of different hardness, as shown in Figure 3. When the hardness of the rock to be excavated is average, the "1+6" slotting form shown in Figure 3a is adopted; when the hardness of the rock is medium hard, the "1+8" slotting form shown in Figure 3b is adopted; when the hardness of the rock is relatively hard, the "1+8" slotting form shown in Figure 3b can be adopted. Figure 3c The "1+6" large hole groove form.

[0117] Optimization of charge structure

[0118] Next, the blasting scheme is further optimized from the perspective of charge structure. Specifically, continuous charge at the bottom of the hole is used to overcome the bottom resistance, eliminate the foundation, and ensure the smooth progress of a single cycle. Interval charge at the hole mouth can increase the explosive energy used to break or throw rocks and reduce the generation of large rocks. In a specific example, continuous charge is used in the slot hole, such as Figure 4a As shown in the figure, the cave-in holes and peripheral holes adopt the technology of continuous charging at the bottom of the hole and interval charging at the hole mouth, as shown in the figure. Figure 4b and Figure 4c As shown. In a specific implementation case, the hole mouth is charged with intervals, and the middle is separated by an air spacer or a plastic tube. Taking the charging of the slot hole of A iron ore as an example, 1.2kg of charge is charged at the bottom and 0.8kg is charged at the top, so that the ratio of the upper and lower charges is as close as possible, which can reduce the generation of large rocks at the hole mouth.

[0119] Detonation method selection

[0120] Use multi-point detonation in the hole, and use simultaneous detonation at the hole mouth and hole bottom for a single hole to homogenize the explosion stress field, make full use of the stress wave effect, and reduce the generation rate of large pieces at the hole mouth. Multi-point synchronous detonation mainly utilizes the interaction and superposition of detonation waves to enhance the power of detonation waves, such as Figure 6 As shown in the figure. The slot hole adopts the method of placing a detonating charge at the bottom and middle of the blast hole to increase the detonation energy. Figure 5 The detonator is placed in the middle of the explosive column, and the stress waves after the explosion are superimposed. The schematic diagram of the stress wave superposition excited by the detonator in the middle of the explosive column is shown in Figure 8 As shown. During the detonation process, high-precision electronic detonators are selected as detonating equipment, and the detonation error is controlled within 1 millisecond. The millisecond delayed detonation method is adopted, the groove eye is detonated first, the collapse eye is detonated after an interval of 50 milliseconds, and the surrounding eye is detonated after an interval of 50 milliseconds. By adopting the above-mentioned blasting parameter design and detonation method design, the size of the rock block after blasting can be effectively controlled, which is conducive to improving the mining efficiency and transportation efficiency, reducing the secondary crushing cost, and ensuring the stability and safety of the tunnel surrounding rock.

[0121] Before and after detonation, blasting site quality control is required.

[0122] Before blasting, the depth, diameter, angle, etc. of the blastholes are checked to ensure that they meet the design requirements. During the charging process, the charge density and filling quality are strictly controlled to ensure the safety and reliability of the blasting. After the blasting, the blasting effect evaluation and blasting technology optimization are required.

[0123] Specifically, the blast pile is measured after blasting, and the size of the blocks is counted using an image method. In a specific case, if there are many large blocks generated after blasting, the location where the large blocks are generated needs to be determined according to the solution of one of the embodiments mentioned above. Figure 7 The flowchart for determining the location of large blocks can be used to determine the location of large blocks by using the aforementioned scheme for determining the location of large blocks, and to correct the problems existing in the original blasting plan to ensure the feasibility of the entire blasting plan and achieve the purpose of controlling the blasting block size.

[0124] In a specific case, the block size is counted according to the image method. If the statistical large block rate is less than 10%, it means that precise control of the blasting block size has been achieved. Fig. 9 a is an image of a cycle of blasting rock in A iron mine before blasting block size control. There are 15 large blocks exceeding 300 mm, and the large block rate can reach 30%; Fig. 9 b is the result of image processing using the technology of the present invention. There is almost no rock block larger than 300 mm, and the large block rate is less than 10%. Therefore, the present invention can achieve the control of rock block size in metal mine tunnel excavation blasting to a certain extent.

[0125] According to the verification of the above specific cases, the method for controlling the blasting block size in metal mine tunnel excavation provided by the embodiment of the present invention can effectively control the blasting block size in metal mine tunnel excavation, reduce the generation of large blocks, and improve construction efficiency and safety.

[0126] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0127] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0128] In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0129] For the convenience of description, the above device is described by dividing the functions into various units / modules. Of course, when implementing the present invention, the functions of each unit / module can be implemented in the same or multiple software and / or hardware.

[0130] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for controlling the blasting block size of hard rock shaft tunneling in a mine, characterized in that: Includes steps: S10. After blasting, the size of the blasted pile is measured and analyzed to evaluate the blasting effect; S20, if the rock size exceeds the set size threshold, analyze the cause of the large rock size and determine the location where the blasted large rock is generated; specifically including: Check whether the blasting parameters of the slot hole area at the actual blasting site are consistent with the designed blasting parameters; If they are consistent, it is further determined whether the blasthole utilization rate after blasting reaches the preset threshold; If so, it is determined that the blasted block is not generated by the cut hole area of ​​the actual blasting site; Continue to determine whether the blasting block is generated from the peripheral hole area and the cave-in hole area; Monitor whether there is "large piece shedding" of surrounding rock around the tunnel after blasting; If it exists, it is determined whether the blasting block is caused by unreasonable design of blasting parameters of peripheral holes or cave-in holes; Verify the charge amount and blasthole spacing of the peripheral holes and cave-in holes at the actual blasting site according to the design plan of the corresponding blasting parameters; If they are consistent, the explosive charge positions, detonation methods and micro-difference time of the surrounding holes are adjusted, and the blasting effect after adjustment is monitored; If after adjustment, there is no "large piece falling off" phenomenon in the surrounding rock, but there are large pieces of rock, it is determined that the blasting block is generated in the cave hole area, and the explosive bag position, detonation position and blasting parameters of the cave hole are adjusted and optimized; The blasting parameters include: the total number of blastholes, blasthole arrangement, charge structure, explosive unit consumption, explosive parameters, blasthole diameter, blasthole depth and blasthole spacing; S30, for blastholes with large areas, a charging structure of continuous charging at the bottom of the hole and interval charging at the hole mouth is used for charging; S40. After the charge is loaded, a multi-point detonation technique is used to simultaneously detonate the orifice and the bottom of the blasthole to achieve the superposition of multi-point stress waves, so as to improve the fragmentation of the rock.

2. The method according to claim 1, characterized in that: After discovering the area where large pieces are produced, the following steps are also included: adjusting the hole layout of the blastholes, adding shallow holes in the area where large pieces are easily produced at the hole mouth, and using a deep and shallow combination structure of alternating long and short blastholes to reduce the rate of large pieces after blasting.

3. The method according to claim 1, characterized in that In step S20, the design adjustment and optimization of blasting parameters includes: verifying and determining the rationality of the design of blasting parameters of the slot holes, auxiliary holes, and peripheral holes; wherein the total number of blast holes must comply with the formula: , where N is the total number of blastholes in the entire tunnel section; f is the rock strength coefficient; S is the tunnel excavation cross-sectional area, m 2 .

4. The method according to claim 2 or 3, characterized in that: In step S20, it also includes: arranging the blast holes evenly in the entire tunnel excavation section so that the energy after the explosion can be effectively utilized, and the unit consumption of explosives must comply with the modified Proctor formula: ； Among them, q is the unit explosive consumption; k0 is the coefficient, k0=525 / p, p is the explosive force, unit is mL; The type of explosive is selected according to the properties of the rock; the blasthole diameter and the charge diameter are selected according to the on-site conditions, wherein the on-site conditions include: rock hardness coefficient, size and shape of the tunnel to be excavated and blasting equipment; the blasthole spacing is selected according to the mining hard rock shaft blasting construction specifications and engineering experience; the blasting parameters of the slotting eye are designed and optimized according to the rock hardness coefficient and the cross-sectional size.

5. The method according to claim 1, characterized in that The superposition energy of the multi-point stress waves is greater than the sum of the shock waves generated by the respective detonations of multiple charge points.

6. The method according to claim 1, characterized in that When smooth blasting is used, the charge amount of each peripheral hole should satisfy the formula: ,in, is the charge amount of the peripheral holes per hole, is the average charge factor, is the length of the medicine roll, in m, is the weight of the medicine roll, is the average blasthole depth.

7. The method according to claim 1, characterized in that The charge amount of a single hole of a cave hole and a slot hole is adjusted by the charge coefficient. The charge amount of a single hole of a cave hole should satisfy the formula: ;in, is the charge amount of a single cave hole, is the linear charge density per meter of borehole, , unit: kg / m, is the charge coefficient, take 0.7-0.8, is the average blasthole depth.

8. The method according to claim 7, characterized in that After the charging is completed, the millisecond delayed detonation method is adopted for multiple blast holes to control the detonation time interval of each blast hole to reduce the blasting vibration and excessive rock fragmentation.

9. The method according to claim 7 or 8, characterized in that: The method also includes: before detonation, checking the construction quality of the blasthole to ensure that the position, depth and diameter of the blasthole meet the design requirements, and charging, filling and connecting are carried out according to the design requirements.

10. The method according to claim 1, characterized in that Before step S10, the method further includes: marking the entire cross section with pigments, using red, yellow and white pigments to mark the cutout area, the collapse area and the surrounding hole area respectively; The step S20 also includes: after blasting, determining the area where the large blocks are produced according to the rocks marked with different pigments.

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