Multi-stage presplitting blasting construction method

Abstract

The invention discloses a multistage presplitting blasting construction method. The method comprises the steps of construction preparation, hole arrangement and drilling, cartridge processing and charging blocking, blasting construction and post-blasting inspection. The method is reasonable in step design, the number of the damping pre-cracks is increased, the quality of the permanent pre-cracks is improved, blasting vibration of the main blasting hole is effectively reduced, surrounding rock is fully protected, and therefore the stability of a permanent slope is improved, the safety of the slope is not affected during construction operation, and the service life of the slope is prolonged. Compared with the prior art, the method has the advantages that the time and the cost of slope regulation before later acceptance are saved, the acceptance work of mine open-pit mining is accelerated, the damage to the retained rock mass of the slope during the blasting of the main blasting area can be effectively weakened, and the flatness of the excavation contour and the stability of the protected rock mass are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of pre-splitting blasting, and in particular to a multi-stage pre-splitting blasting construction method. Background Art

[0002] Pre-splitting blasting means that when excavating rock, a through crack of a certain width is first blasted along the designed contour line before blasting in the main blasting area. This is to buffer and reflect the vibration wave of the excavation blasting, control its destructive effect on the retained rock mass, and obtain a smoother excavation contour. Pre-splitting blasting is not only widely used on vertical and inclined excavation walls, but also on regular curved surfaces, twisted surfaces, and horizontal foundation surfaces. Pre-splitting blasting is suitable for weak rock formations with poor stability but requiring control of the excavation contour.

[0003] The characteristics of pre-splitting blasting are mainly reflected in the following aspects: (1) The pre-splitting holes are arranged on the excavation edge, and their hole spacing and resistance line are much smaller than those of the main blastholes; (2) The pre-splitting hole is detonated before the main blasting hole. Its design control parameters include hole diameter, hole spacing, line charge density, plugging length, etc. (3) The bottom charge should be strengthened, the hole mouth can be unblocked, the unblocked length is 1 / 4 of the hole depth, and the charge length is 3 / 4 of the hole depth; (4) The distance between the pre-splitting surface and the nearest row of main gun holes is generally half the distance between the rows of main gun holes; (5) Pre-splitting blasting design is mainly based on empirical methods and engineering analogy methods, which can be combined with theoretical calculation methods to make the best design that conforms to reality; (6) The effect of simultaneous detonation of pre-crack holes is better. However, when too many pre-crack holes are detonated at the same time, segmented micro-difference detonation can be used to prevent excessive blasting vibration.

[0004] According to the characteristics of pre-splitting blasting, reasonable pre-splitting blasting design should achieve slope safety and stability at the lowest cost.

[0005] The existing pre-splitting blasting mostly adopts single-stage pre-splitting blasting, but in the area where the surrounding rock is broken, the single-stage pre-splitting blasting does not protect the surrounding rock of the slope enough, because the blasting vibration of the main blast hole is large, which causes the surrounding rock of the slope to break, affecting the safety of the slope, especially in open-pit mining projects, seriously affecting the acceptance of mining, and adding a lot of cost and time to the later slope regulation. To this end, we proposed a multi-stage pre-splitting blasting construction method. Summary of the invention

[0006] The purpose of the present invention is to provide a multi-stage pre-splitting blasting construction method to overcome the technical problems existing in the prior art.

[0007] In order to achieve the above technical objectives and the above technical effects, the present invention provides the following technical solutions: A multi-stage pre-splitting blasting construction method comprises the following steps: Step 1: Construction preparation; A. Site survey: Conduct a detailed survey of the construction site and determine the blasting area, crack location and length based on the survey results; B. Drawing: According to the ground characteristics and engineering requirements, design parameters such as blasthole diameter, hole spacing, hole depth, charge amount, etc., draw construction drawings according to the design parameters, and the supervision unit organizes the design unit and the construction unit to review the drawings. The review minutes together with the construction drawings are included in the project files as the basis for construction; C. Construction guidance: The construction unit shall prepare a construction plan, and after approval by the supervision unit, targeted guidance and training shall be provided to the construction personnel and management personnel; D. Equipment preparation: prepare drilling equipment, check equipment maintenance records to ensure that all parts are in good working order, prepare blasting agents to ensure that the performance of the agents meets the requirements, prepare safety protection equipment, and construction personnel must wear them according to the specifications; E. Data preparation: prepare the construction record acceptance form and arrange relevant record personnel to make corresponding records after the construction steps are completed; Step 2: hole arrangement and drilling; A. Hole layout: According to the specific requirements of blasting design, carry out detailed hole layout planning to determine the location, quantity and arrangement of holes; B. Drilling: Drill holes according to the hole layout plan, and use appropriate drilling equipment and technology to ensure the accuracy and quality of the holes; C. Inspection and acceptance: Inspect and accept the drilling quality to ensure that the drilling quality meets the blasting design requirements, and check whether the hole position and size are accurate and consistent with the position on the design drawing; Step 3: drug package processing and drug loading and blocking; A. Material selection: Choose appropriate types of explosives and auxiliary materials such as plastic tubes, detonating cords, and bamboo strips; B. Processing of explosive packages: Put the explosives into a plastic tube of a certain diameter, and run a detonating cord through the entire tube hole to ensure smooth detonation and transmission. Tie the explosives to the detonating cord continuously or at intervals to form a string of explosives, and then tie the string of explosives to the bamboo strips; C. Check the charge: Check the quality of the processed explosive packages, and slowly put the qualified explosive packages into the borehole to ensure that the explosives are evenly distributed in the blasthole; D. Blocking the blast hole: put the blocking material into the lower part of the blocking section, and then gradually block it upward to the blast hole mouth. After the blocking is completed, the blast hole mouth should be checked to ensure that there is no leakage; Step 4: Blasting construction; A. Safety protection: clear personnel from the site before blasting, set up safety warning signs, ensure that no personnel stay within the safety range, and that construction personnel wear appropriate protective equipment for construction operations; B. Network design: Design a reasonable blasting network according to the predetermined detonation sequence to ensure that each blast hole can be detonated in sequence; C. Detonation construction: Detonation work shall be carried out according to the predetermined detonation sequence, and the detonation time difference of the pre-splitting holes shall be strictly controlled to ensure the pre-splitting effect; Step 5: Post-explosion inspection; A. Site cleaning: After the blasting is completed and safety conditions are met, the site will be cleaned up to eliminate potential safety hazards; B. Effect inspection: Check the effect of the blasting area, adjust the blasting design parameters in time for existing problems, and conduct additional drilling and blasting in time if there are any unqualified areas; C. Quality assessment: Conduct quality assessment on the blasting effect, adjust and optimize construction parameters according to the assessment results, ensure that the blasting effect meets the design requirements, and improve the blasting quality.

[0008] Preferably, in a multi-stage pre-splitting blasting construction method, the detonation sequence of the detonation construction in step 4 is first-stage pre-splitting detonation, second-stage pre-splitting detonation and main blasthole detonation.

[0009] Preferably, in a multi-stage pre-splitting blasting construction method, in step one, the diameter of the blasthole is 50 to 200 mm, the spacing between the blastholes is 8 to 12 times the hole diameter, and the hole depth is 2 to 3 times the hole diameter.

[0010] Preferably, in a multi-stage pre-splitting blasting construction method, during the on-site survey in step 1, a detailed analysis of the ground properties is performed, and the construction parameters are adjusted according to the analysis results.

[0011] Preferably, in a multi-stage pre-splitting blasting construction method, the depth, hole diameter and hole spacing of the boreholes are monitored in real time during drilling in step 2 to ensure that the design requirements are met.

[0012] Preferably, in a multi-stage pre-splitting blasting construction method, the inspection and acceptance items in step 2 include the integrity of the drilled hole, the smoothness of the hole wall, and the accuracy of the hole depth and hole diameter.

[0013] Preferably, in a multi-stage pre-splitting blasting construction method, the type of explosive in step three is selected from explosives with low detonation velocity and good explosion transmission performance, such as rock explosives or ammonium nitrate explosives.

[0014] Preferably, in a multi-stage pre-splitting blasting construction method, the plugging material in step three is selected from sand, clay mixture, kraft paper or woven bags, and during the plugging process, it is ensured that the plugging is tight and has no gaps.

[0015] Preferably, in a multi-stage pre-splitting blasting construction method, detonating cords, detonating caps or electric detonators are used in conjunction with the detonation construction in step 4.

[0016] Preferably, in a multi-stage pre-splitting blasting construction method, the quality assessment items of the blasting effect in step five include the width, flatness and blasthole trace retention rate of the pre-cracks.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The steps of the present invention are reasonably designed. In the surrounding rock broken section, multi-stage pre-splitting blasting construction technology is adopted, which increases the number of shock-absorbing pre-cracks, improves the quality of permanent pre-cracks, effectively reduces the blasting vibration of the main blast hole, and fully protects the surrounding rock, thereby improving the stability of the permanent slope; 2. The invention will not affect the safety of the slope during construction and operation, thus saving the time and cost of slope regulation before the later acceptance, and speeding up the acceptance of open-pit mining; 3. After the primary pre-crack is detonated, a blasting crack is formed in the surrounding rock mass along the direction of the center line of the pre-crack hole. After the primary pre-crack is formed, the secondary pre-crack is detonated. During the detonation of the secondary pre-crack, the surrounding rock moves toward the direction of the minimum resistance line under the action of the blasting vibration. The primary pre-crack creates a micro-free surface for the secondary pre-crack, making the secondary pre-crack wider and more effective. It can effectively reduce the damage to the rock mass retained on the slope during blasting in the main blasting area, ensuring the flatness of the excavation contour and the stability of the protected rock mass. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the description of the specific implementation methods 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.

[0019] Figure 1 It is a flowchart of multi-stage pre-splitting blasting construction; Figure 2 It is the plan layout of blastholes for multi-stage pre-splitting blasting construction; Figure 3 This is the elevation layout of the blastholes for multi-stage pre-splitting blasting construction. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the 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.

[0021] See also Figure 1-3 As shown, this embodiment is a multi-stage pre-splitting blasting construction method, comprising the following steps: Step 1: Construction preparation; A. Site survey: Conduct a detailed survey of the construction site and determine the blasting area, crack location and length, surrounding environment and safety conditions based on the survey results; B. Drawing: According to the ground characteristics and engineering requirements, design parameters such as blasthole diameter, hole spacing, hole depth, charge amount, etc., draw construction drawings according to the design parameters, and the supervision unit organizes the design unit and the construction unit to review the drawings. The review minutes together with the construction drawings are included in the engineering files as the basis for construction; C. Construction guidance: The construction unit shall prepare a construction plan, and after approval by the supervision unit, targeted guidance and training shall be provided to the construction personnel and management personnel; D. Equipment preparation: prepare drilling equipment (such as drilling machine, drill bit, wrench, etc.), check equipment maintenance records to ensure that all parts are in good working order, prepare blasting agents to ensure that the performance of the agents meets the requirements, prepare safety protection equipment (such as safety helmets, safety shoes, protective glasses, etc.), and construction workers must wear them according to the specifications; E. Data preparation: prepare the construction record acceptance form and arrange relevant record personnel to make corresponding records after the construction steps are completed; Step 2: hole arrangement and drilling; D. Hole layout: According to the specific requirements of the blasting design, carry out detailed hole layout planning to determine the location, number and arrangement of holes. When arranging holes, factors such as geological conditions, blasting targets and safety distances should be fully considered to ensure that the hole layout plan meets the design requirements and can ensure blasting effect and safety; E. Drilling: Drill holes according to the hole layout plan. Use appropriate drilling equipment and technology to ensure the accuracy and quality of the holes. The hole position should be accurate during drilling, and the hole depth, hole diameter and hole spacing should meet the design requirements. F. Inspection and acceptance: Inspect and accept the quality of the drilled holes to ensure that they meet the blasting design requirements. Check whether the hole position and size are accurate and consistent with the position on the design drawing. Only drilled holes that meet the requirements can be used for subsequent blasting operations. Step 3: drug package processing and drug loading and blocking; E. Material selection: Choose appropriate types of explosives and auxiliary materials such as plastic tubes, detonating cords, and bamboo strips; F. Processing of explosive packages: Put the explosives into a plastic tube of a certain diameter, and run a detonating cord through the entire tube hole to ensure smooth detonation and transmission. Tie the explosives to the detonating cord continuously or at intervals to form a string of explosives, and then tie the string of explosives to the bamboo strips. This method can make the explosives more evenly distributed in the blast hole and reduce the squeezing effect of the explosives on the blast hole; G. Check charging: Check the quality of the processed explosive packages, and slowly deliver the qualified explosive packages into the borehole to ensure that the explosives are evenly distributed in the blasthole. Only qualified explosive packages can be transported to the construction site for charging operations; H. Blocking the blasthole: put the blocking material into the lower part of the blocking section, and then gradually block it upward to the blasthole mouth. After the blocking is completed, the blasthole mouth should be checked to ensure that there is no leakage. If there is leakage, it should be repaired quickly to prevent the explosives from getting damp or affecting the blasting effect; Step 4: Blasting construction; A. Safety protection: clear personnel from the site before blasting, set up safety warning signs, ensure that no personnel stay within the safety range, and that construction personnel wear appropriate protective equipment for construction operations; B. Network design: Design a reasonable blasting network according to the predetermined detonation sequence to ensure that each blast hole can be detonated in sequence, connect the detonating cord and detonator according to the design requirements to form a complete blasting network; C. Detonation construction: Detonation work shall be carried out according to the predetermined detonation sequence, and the detonation time difference of the pre-splitting holes shall be strictly controlled to ensure the pre-splitting effect; Step 5: Post-explosion inspection; A. Site cleaning: After the blasting is completed and safety conditions are met, the site will be cleaned up to eliminate potential safety hazards; B. Effect inspection: Check the effect of the blasting area, adjust the blasting design parameters in time for existing problems, and conduct additional drilling and blasting in time if there are any unqualified areas; C. Quality assessment: Conduct quality assessment on the blasting effect, adjust and optimize construction parameters according to the assessment results, ensure that the blasting effect meets the design requirements, and improve the blasting quality.

[0022] The detonation sequence of the detonation construction in step 4 is first-level pre-splitting detonation, second-level pre-splitting detonation and main blasting hole detonation, wherein during the first-level pre-splitting detonation, a row of pre-splitting holes is added between the pre-splitting holes and the main blasting hole, so that the row of pre-splitting holes is detonated first, and during the second-level pre-splitting detonation, the second-level pre-splitting holes are the final slope opening line, and after the first-level pre-splitting holes are detonated to form cracks, the row of pre-splitting holes is detonated, and when the main blasting hole is detonated, the main blasting hole is detonated after the first-level and second-level pre-splitting holes are detonated, to ensure that the two shock-absorbing cracks between the main blasting hole and the permanent slope play a full role, so that the blasting vibration damage is minimized.

[0023] In step one, the diameter of the blasthole is 50 to 200 mm, the spacing between blastholes is 8 to 12 times the hole diameter, and the hole depth is 2 to 3 times the hole diameter, which is convenient for subsequent charging and detonation.

[0024] During the on-site survey in step one, a detailed analysis of the ground properties is conducted, and the construction parameters are adjusted based on the analysis results to meet the construction requirements of the blasting area.

[0025] During drilling in step 2, the depth, hole diameter and hole spacing of the drilling holes are monitored in real time to ensure that they meet the design requirements.

[0026] The inspection and acceptance items in step two include the integrity of the borehole, the smoothness of the hole wall, the accuracy of the hole depth and hole diameter. Only the boreholes that meet the requirements can be used for subsequent blasting operations.

[0027] In step three, the type of explosives used should be those with low detonation velocity and good explosion transmission performance, such as rock explosives or ammonium nitrate explosives, to ensure the detonation effect.

[0028] In step three, the plugging material is selected from sand, clay mixture, kraft paper or woven bags. During the plugging process, ensure that the plugging material is tight and has no gaps to prevent the high-pressure gas generated by the explosion of the explosives from leaking from the blast hole.

[0029] During the detonation construction in step 4, detonating cords, detonating caps or electric detonators are used to carry out detonation to ensure that the pre-crack holes can be detonated in sequence and accurately.

[0030] The quality assessment items of the blasting effect in step five include the width, flatness and retention rate of the pre-cracks, so as to adjust and optimize the construction parameters according to the assessment results and improve the blasting effect.

[0031] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0032] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A multi-stage pre-splitting blasting construction method, characterized in that: The following steps are involved: Step 1: Construction preparation; A. Site survey: Conduct a detailed survey of the construction site and determine the blasting area, crack location and length based on the survey results; B. Drawing: According to the ground characteristics and engineering requirements, design parameters such as blasthole diameter, hole spacing, hole depth, charge amount, etc., draw construction drawings according to the design parameters, and the supervision unit organizes the design unit and the construction unit to review the drawings. The review minutes together with the construction drawings are included in the engineering files as the basis for construction; C. Construction guidance: The construction unit shall prepare a construction plan, and after approval by the supervision unit, targeted guidance and training shall be provided to the construction personnel and management personnel; D. Equipment preparation: prepare drilling equipment, check equipment maintenance records to ensure that all parts are in good working order, prepare blasting agents to ensure that the performance of the agents meets the requirements, prepare safety protection equipment, and construction personnel must wear them according to the specifications; E. Data preparation: prepare the construction record acceptance form and arrange relevant record personnel to make corresponding records after the construction steps are completed; Step 2: hole arrangement and drilling; A. Hole layout: According to the specific requirements of blasting design, carry out detailed hole layout planning to determine the location, quantity and arrangement of holes; B. Drilling: Drill holes according to the hole layout plan, and use appropriate drilling equipment and technology to ensure the accuracy and quality of the holes; C. Inspection and acceptance: Inspect and accept the drilling quality to ensure that the drilling quality meets the blasting design requirements, and check whether the hole position and size are accurate and consistent with the position on the design drawing; Step 3: drug package processing and drug loading and blocking; A. Material selection: Choose appropriate types of explosives and auxiliary materials such as plastic tubes, detonating cords, and bamboo strips; B. Processing of explosive packages: Put the explosives into a plastic tube of a certain diameter, and run a detonating cord through the entire tube hole to ensure smooth detonation and transmission. Tie the explosives to the detonating cord continuously or at intervals to form a string of explosives, and then tie the string of explosives to the bamboo strips; C. Check the charge: Check the quality of the processed explosive packages, and slowly put the qualified explosive packages into the borehole to ensure that the explosives are evenly distributed in the blasthole; D. Blocking the blasthole: put the blocking material into the lower part of the blocking section, and then gradually block it upward to the blasthole mouth. After the blocking is completed, the blasthole mouth should be checked to ensure that there is no leakage; Step 4: Blasting construction; A. Safety protection: clear personnel from the site before blasting, set up safety warning signs, ensure that no personnel stay within the safety range, and that construction personnel wear appropriate protective equipment for construction operations; B. Network design: Design a reasonable blasting network according to the predetermined detonation sequence to ensure that each blast hole can be detonated in sequence; C. Detonation construction: Detonation work shall be carried out according to the predetermined detonation sequence, and the detonation time difference of the pre-splitting holes shall be strictly controlled to ensure the pre-splitting effect; Step 5: Post-explosion inspection; A. Site cleaning: After the blasting is completed and safety conditions are met, the site will be cleaned up to eliminate potential safety hazards; B. Effect inspection: Check the effect of the blasting area, adjust the blasting design parameters in time for existing problems, and conduct additional drilling and blasting in time if there are any unqualified areas; C. Quality assessment: Conduct quality assessment on the blasting effect, adjust and optimize construction parameters based on the assessment results, ensure that the blasting effect meets the design requirements, and improve the blasting quality.

2. A multi-stage pre-splitting blasting construction method according to claim 1, characterized in that: The detonation sequence of the detonation construction in step 4 is first-level pre-splitting detonation, second-level pre-splitting detonation and main blasthole detonation.

3. A multi-stage pre-splitting blasting construction method according to claim 1, characterized in that: In step 1, the diameter of the blasthole is 50 to 200 mm, the spacing between the blastholes is 8 to 12 times the hole diameter, and the hole depth is 2 to 3 times the hole diameter.

4. A multi-stage pre-splitting blasting construction method according to claim 1, characterized in that: During the on-site survey in step one, the ground properties are analyzed in detail and the construction parameters are adjusted based on the analysis results.

5. A multi-stage pre-splitting blasting construction method according to claim 1, characterized in that: During drilling in step 2, the depth, hole diameter and hole spacing of the drilling holes are monitored in real time to ensure that they meet the design requirements.

6. A multi-stage pre-splitting blasting construction method according to claim 1, characterized in that: The inspection and acceptance items in step 2 include the integrity of the drilled hole, the smoothness of the hole wall, the accuracy of the hole depth and hole diameter.

7. A multi-stage pre-splitting blasting construction method according to claim 1, characterized in that: In step 3, the type of explosive selected is an explosive with low detonation velocity and good explosion transmission performance, such as rock explosive or ammonium nitrate explosive.

8. A multi-stage pre-splitting blasting construction method according to claim 1, characterized in that: In step three, the plugging material is sand, clay mixture, kraft paper or woven bag. During the plugging process, ensure that the plugging is tight and has no gaps.

9. A multi-stage pre-splitting blasting construction method according to claim 1, characterized in that: During the detonation construction in step 4, detonating cord, detonating detonator or electric detonator is used for detonation.

10. A multi-stage pre-splitting blasting construction method according to claim 1, characterized in that: The quality assessment items of the blasting effect in step five include the width, flatness and retention rate of the pre-cracks.

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