An efficient blasting method for similar cut in rock roadway

Abstract

An embodiment of the present invention discloses an efficient blasting method for similar cut in rock roadways, which relates to the technical field of rock roadway tunneling. By adjusting the arrangement of cut holes to optimize the burden of blast holes, reduce the number of drill holes and improve the cut efficiency. The method includes the steps of: drilling: drilling a center hole, lower cut holes, upper cut holes, auxiliary holes and peripheral holes in the roadway construction section area; charging: filling explosives into the center hole, the lower cut holes, the upper cut holes, the auxiliary holes and the peripheral holes; blasting: adopting a millisecond delay initiation method to sequentially blast the following blast holes to complete a one-time full-section blasting. The present invention is applicable to the construction scenario of the drill-and-blast method.

Description

Technical Field

[0001] The present invention relates to the technical field of rock roadway tunneling, and particularly to an efficient blasting method for similar cut in rock roadway. Background Art

[0002] The drill and blast method is a traditional tunneling method, which is widely used in shaft and tunnel tunneling construction, especially more commonly used in rock roadway tunneling. However, at present, the drill and blast method has problems such as shallow drilling, a large number of blast holes, and a long construction period. These problems make the efficiency of the traditional drill and blast method very low, and the average monthly advance is between 60 - 70m. However, the demand for coal in China increases year by year. Since rock roadways play an important role in personnel passage, equipment transportation, and ventilation and dust reduction, the tunneling construction efficiency seriously restricts the coal mining efficiency. Therefore, improving the rock roadway tunneling efficiency is of great significance for alleviating the contradiction between excavation and mining, increasing coal production capacity, and shortening the working cycle of workers.

[0003] In a single drill and blast method construction operation, drilling, charging, and connection occupy 60 - 80% of the construction period. At present, manual drilling is generally used in China, and the equipment is a handheld pneumatic hammer. This equipment is easy to operate, but the drilling is shallow and the drilling efficiency is low. In addition, the cross-section of the rock roadway in mines that meet China's standardization construction is usually large, and the number of blast holes is about 120. This greatly increases the drilling time and also causes an increase in the subsequent charging and connection time, prolonging the operation cycle. Although the equipment gradually adopts mechanized methods, such as using a drill and pile integrated machine can slightly increase the drilling speed, for large cross-section roadways, the large number of blast holes is the most basic problem affecting the entire operation cycle. Summary of the Invention

[0004] In view of this, the embodiment of the present invention provides an efficient blasting method for similar cut in rock roadway, which optimizes the blast hole burden by adjusting the arrangement of cut holes, reduces the number of blast holes, and improves the cut efficiency.

[0005] In a first aspect, an efficient blasting method for similar cut in a rock roadway provided by an embodiment of the present invention includes the following steps: Drilling: Drilling in the roadway construction section area: a center hole, lower cut holes, upper cut holes, auxiliary holes, and peripheral holes; the center hole is in the middle of the section area, the lower cut holes are respectively on both sides of the center hole, the lower cut holes are located in the lower part of the section area, the upper cut holes are located in the upper part of the section area, the auxiliary holes are located outside the lower cut holes and the upper cut holes, and the peripheral holes are arranged along the contour edge of the section area; Charging: Loading explosives into the center hole, the lower cut holes, the upper cut holes, the auxiliary holes, and the peripheral holes; the center hole is filled with center hole explosives, both the lower cut holes and the upper cut holes are filled with upper section explosives and lower section explosives, the lower section explosives are located at the bottom of the holes, the auxiliary holes are filled with auxiliary hole explosives, and the peripheral holes are filled with peripheral hole explosives; Blasting: Adopting a millisecond delay initiation method, sequentially blasting the following blast holes to complete a one-time full-section blasting: First-stage blasting: Initiating the lower section explosives in the lower cut holes; Second-stage blasting: Simultaneously initiating the lower second-stage explosives in the lower cut holes and the center hole explosives in the center hole; Third-stage blasting: Initiating the upper section explosives in the upper cut holes; Fourth-stage blasting: Initiating the upper second-stage explosives in the upper cut holes; Fifth-stage initiation: Initiating the auxiliary hole explosives in the auxiliary holes; Sixth-stage initiation: Initiating the peripheral hole explosives in the peripheral holes.

[0006] Optionally, the center hole, the lower cut holes, the upper cut holes, the auxiliary holes, and the peripheral holes are all perpendicular to the free face of the rock roadway.

[0007] Optionally, the area of the roadway construction section area is greater than 15 m 2 .

[0008] Optionally, the center hole is located on the central axis of the section area, and the distance between adjacent center holes is 0.4 - 0.6 m; the lower cut holes are located in the lower straight wall part of the section area, and the distance between adjacent lower cut holes is 1.6 - 1.8 m; the upper cut holes are located in the upper semi-circular arch part of the section area, and the upper cut holes are arranged in a semi-circular arc shape, and the distance between adjacent upper cut holes is 0.4 - 0.6 m.

[0009] Optionally, the arrangement of the auxiliary holes adjusts the number of auxiliary holes according to the size of the on-site section.

[0010] Optionally, the depths of the center hole, the lower cut holes, the upper cut holes, the auxiliary holes, and the peripheral holes are all greater than 2 m, and the diameters are all greater than 40 mm.

[0011] Optionally, the mass of the center hole explosive is 0.5 to 0.75 times the mass of the explosive in the lower cut hole or the upper cut hole.

[0012] Optionally, the drilling arrangement of the lower cut hole, the upper cut hole and the center hole is as follows: drill the lower cut hole in the lower straight wall area of the cross-section area, and the area surrounded by the lower cut holes is rectangular; drill the upper cut hole in the upper semi-circular arch area of the cross-section area, and the area surrounded by the upper cut holes is a semi-circular arc; drill the center hole in the middle of the area surrounded by the lower cut hole and the upper cut hole; the shape of the area surrounded by the lower cut hole and the upper cut hole is basically similar to the shape of the cross-section area.

[0013] Optionally, the charging arrangement of the lower cut hole is as follows: insert the second-stage detonator into the explosive, place it at the bottom of the lower cut hole, continue charging to form the next section of explosive; carry out stemming sealing, and the stemming length is not less than 0.55 m; put the first-stage detonator into the explosive, place it in the lower cut hole, continue charging to form the next second section of explosive; carry out stemming sealing and tamp the stemming tightly with a stemming rod.

[0014] Optionally, the charging arrangement of the upper cut hole is as follows: insert the third-stage detonator into the explosive, place it at the bottom of the upper cut hole, continue charging to form the first section of the upper explosive; carry out stemming sealing, and the stemming length is not less than 0.55 m; put the fourth-stage detonator into the explosive, place it in the upper cut hole, continue charging to form the second section of the upper explosive; carry out stemming sealing and tamp the stemming tightly with a stemming rod.

[0015] Optionally, the length ratio of the next section of explosive to the next second section of explosive is 1.2 to 1.5; the length ratio of the first section of the upper explosive to the second section of the upper explosive is 1.2 to 1.5.

[0016] Optionally, the millisecond delay blasting method uses coal mine permitted digital electronic detonators for initiation, and the detonator delay setting is carried out according to specific needs.

[0017] A high-efficiency blasting method for similar cut in rock roadways provided by an embodiment of the present invention adopts a similar cut hole layout method, a sectional charging method and a coal mine permitted digital electronic detonator delay method, increases the cut area range, improves the cavity volume generated by the blasting of the cut holes, reduces the minimum resistance line of the auxiliary holes and makes it uniform, reduces the number of auxiliary holes and perimeter holes, reduces the drilling time and the amount of explosive used, and at the same time, multi-section delay initiation can reduce the vibration effect generated by blasting and improve the roadway stability. Description of the Drawings

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the attached drawings required for description in the embodiments or the prior art. Obviously, the attached drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other attached drawings can be obtained based on these drawings.

[0019] Figure 1 Schematic diagram of the similar cut high-efficiency blasting method for rock roadway in the embodiment of the present invention;

[0020] Figure 2 Layout drawing of the blast holes in the construction section area of the rock roadway in the embodiment of the present invention;

[0021] Figure 3 For Figure 2 Charge loading schematic diagram of each blast hole in

[0022] Figure 4 For Figure 2 Schematic diagram of the cavity formed after blasting of the cut holes and the center hole in

[0023] Figure 5 Blasting design drawing of the on-site application example of another embodiment of the present invention.

[0024] In the figure: 1 - center hole; 11 - center hole explosive; 2 - lower cut hole; 21 - next-section explosive; 22 - second-next-section explosive; 3 - upper cut hole; 31 - previous-section explosive; 32 - second-previous-section explosive; 4 - auxiliary hole; 41 - auxiliary hole explosive; 5 - perimeter hole; 51 - perimeter hole explosive; 6 - stemming; 7 - stemming; 8 - stemming; 9 - stemming; 10 - free face of the rock roadway; 11 - cavity in the cut area. Detailed implementation manners

[0025] The following describes the embodiments of the present invention in detail with reference to the attached drawings.

[0026] It should be clear that the described embodiments are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0027] Embodiment 1

[0028] The embodiment of the present invention provides a similar cut high-efficiency blasting method for rock roadway, Figure 1 Schematic diagram of the similar cut high-efficiency blasting method for rock roadway in the embodiment of the present invention. The similar cut means that the cavity formed after cutting is similar to the cross-section structure of the rock roadway to be driven. Please refer to Figure 1 As shown, the similar cut high-efficiency blasting method for rock roadway mainly includes the following steps:

[0029] S110, Drilling: In the roadway construction section area, drill the following holes: center hole 1, lower cut hole 2, upper cut hole 3, auxiliary hole 4 and perimeter hole 5. The center hole 1 is in the middle of the section area. The center hole 1 is arranged at the middle position of the free face 10 of the rock roadway. The center hole can play a role in crushing rocks, reducing the block size of the blasted rocks, and reducing the time used for subsequent operations to break gangue. The lower cut holes 2 are respectively on both sides of the center hole 1. The lower cut holes 2 are located in the lower part of the section area. The upper cut holes 3 are located in the upper part of the section area. The auxiliary holes 4 are located outside the lower cut holes 2 and the upper cut holes 3. The perimeter holes 5 are arranged along the contour edge of the section area. The layout diagram of the blast holes in the rock roadway construction section area is as Figure 2 shown;

[0030] S120, Charging: Load explosives into the center hole 1, the lower cut holes 2, the upper cut holes 3, the auxiliary holes 4 and the perimeter holes 5. The center hole 1 is filled with center hole explosive 11. Both the lower cut holes 2 and the upper cut holes 3 are filled with upper section explosive and lower section explosive. The lower section explosive is located at the bottom of the hole. The auxiliary holes 4 are filled with auxiliary hole explosive 41. The perimeter holes 5 are filled with perimeter hole explosive 51. The charging schematic diagram of each blast hole is as Figure 3 shown;

[0031] S130, Blasting: Adopt the millisecond delay initiation method, and sequentially blast the following blast holes according to the charging schematic diagram of each blast hole shown in Figure 3 to complete the one-time full-section blasting:

[0032] First-stage blasting: Initiate the lower section explosive 21 in the lower cut hole 2;

[0033] Second-stage blasting: Simultaneously initiate the lower second-stage explosive 22 in the lower cut hole 2 and the center hole explosive 11 in the center hole 1;

[0034] Third-stage blasting: Initiate the upper section explosive 31 in the upper cut hole 3;

[0035] Fourth-stage blasting: Initiate the upper second-stage explosive 32 in the upper cut hole 3;

[0036] Fifth-stage initiation: Initiate the auxiliary hole explosive 41 in the auxiliary hole 4;

[0037] Sixth-stage initiation: Initiate the perimeter hole explosive 51 in the perimeter hole 5.

[0038] Among them, the "stage" refers to the stage of the explosive, which is divided by the stage number of the millisecond detonator used for initiation. There are several charging holes for the explosives in the same stage and they are initiated simultaneously. The initiation of the explosives in adjacent stages is separated by several milliseconds in time.

[0039] In some embodiments, as Figure 2 and Figure 3 shown, the central hole 1, the lower cut hole 2, the upper cut hole 3, the auxiliary hole 4 and the peripheral hole 5 are all perpendicular to the free face 10 of the rock roadway; the vertical hole layout method can increase the hole depth regardless of the section size, thereby increasing the single-blast tunneling depth. In addition, the vertical hole layout can effectively reduce the throwing distance of blasting flyrock, thereby protecting the on-site instruments and personnel and safety.

[0040] In some embodiments, the area of the roadway construction section area is greater than 15 m 2 . The area of the section given here is a value that can significantly exert the effect of this blasting technology, and as the section area increases, the effect becomes more obvious. The technology can also be used for sections with an area lower than this value.

[0041] In some embodiments, the central hole 1 is located on the central axis of the section area, and the spacing between adjacent central holes 1 is 0.4 - 0.6 m; the lower cut hole 2 is located in the lower straight wall part of the section area, and the spacing between adjacent lower cut holes 2 is 1.6 - 1.8 m; the upper cut hole 3 is located in the upper semi-circular arch part of the section area, and the upper cut hole 3 is arranged in a semi-circular arc shape, and the spacing between adjacent upper cut holes 3 is 0.4 - 0.6 m. The above hole spacing parameters can achieve better blasting effects, and can be adjusted according to the actual situation during specific construction.

[0042] Furthermore, on the free face 10 of the rock roadway, in the rock roadway construction section area, the lower cut hole 2 is located in the lower straight wall part of the section, and the upper cut hole 3 is located in the upper semi-circular arch part of the section. Setting cut holes in both the upper and lower parts of the section can increase the cut area and reduce the number of auxiliary holes.

[0043] In some embodiments, the layout of the auxiliary holes 4 adjusts the number of auxiliary holes according to the size of the on-site section. When the section area is large, multiple circles of auxiliary holes, usually 1 - 3 circles of auxiliary holes, are set between the peripheral holes and the cut area according to actual needs, so as to increase the rock fragmentation effect.

[0044] In some embodiments, the depths of the central hole 1, the lower cut hole 2, the upper cut hole 3, the auxiliary hole 4 and the peripheral hole 5 are all greater than 2 m, and the diameters are all greater than 40 mm. Parameters such as hole depth, hole diameter, and explosive amount will all affect the blasting effect. The embodiments of the present invention give the minimum values of the relevant parameters that can achieve better blasting effects, and can be adjusted according to the situation during actual operation.

[0045] In some embodiments, as Figure 3As shown, the depths of the central hole 1, the lower cut holes 2, and the upper cut holes 3 are the same. The depths of the auxiliary holes 4 and the perimeter holes 5 are the same. The depths of the central hole 1, the lower cut holes 2, and the upper cut holes 3 are 300 - 400 mm more than the depths of the auxiliary holes and the perimeter holes. This can increase the degree of rock fragmentation at the bottom of the holes after the blasting of the central hole 1, the lower cut holes 2, and the upper cut holes 3, increase the volume of the cut area, and provide a sufficient free face for the subsequent blasting of the auxiliary holes 4 and the perimeter holes 5.

[0046] In some embodiments, the mass of the explosive 11 in the central hole is 0.5 - 0.75 times the mass of the explosive in the lower cut hole or the upper cut hole. Loading a small amount of explosive in the central hole can improve the degree of rock fragmentation and reduce the amount of explosive used at the same time.

[0047] In some embodiments, during the drilling step, as Figure 2 shown, the drilling layout of the lower cut holes 2, the upper cut holes 3, and the central hole 1 is as follows: drill the lower cut holes 2 in the lower straight wall area of the cross-section area, and the area enclosed by the lower cut holes 2 is rectangular; drill the upper cut holes 3 in the upper semi-circular arch area of the cross-section area, and the area enclosed by the upper cut holes 3 is a semi-circular arc; drill the central hole 1 in the middle of the area enclosed by the lower cut holes 2 and the upper cut holes 3; the shape of the area enclosed by the lower cut holes 2 and the upper cut holes 3 is basically similar to the shape of the cross-section area.

[0048] Furthermore, as Figure 2 shown, in the embodiment of the present invention, adopting this cut hole layout method, after the blast holes in the cut hole area are detonated, a Figure 4 shown cavity 11 can be formed. At this time, the minimum resistance lines of all the auxiliary holes 4 are basically uniform, reducing the initiation difficulty of the auxiliary holes 4, increasing the blast hole blasting efficiency, and further increasing the blasting efficiency of the perimeter holes 5.

[0049] In some embodiments, during the charging step, as Figure 3 shown, the charging layout of the lower cut holes 2 is as follows:

[0050] Insert the two-stage detonator into the explosive, place it at the bottom of the lower cut hole 2, and continue charging to form the next section of explosive 21;

[0051] Carry out stemming sealing, and the sealing length is not less than 0.55 m; the minimum value of the stemming 8 is specified here. In order to prevent sympathetic detonation when the next section of explosive explodes, which may affect the next two sections of explosive, so when plugging, not only the length should be met, but also a wooden stemming rod should be used to plug it tightly;

[0052] Place a section of detonator into the explosive, and place it into the lower cut hole 2. Then continue charging to form the lower second section of explosive 22;

[0053] Perform stemming sealing, and use a stemming rod to tamp the stemming firmly.

[0054] Further, in the charging step, as Figure 3 shown, the charging arrangement of the upper cut hole 3 is as follows:

[0055] Insert a three-section detonator into the explosive, place it at the bottom of the upper cut hole 3, and continue charging to form the upper first section of explosive 31;

[0056] Perform stemming sealing, and the sealing length is not less than 0.55 m;

[0057] Place a four-section detonator into the explosive, place it into the upper cut hole 3, and continue charging to form the upper second section of explosive 32;

[0058] Perform stemming sealing, and use a stemming rod to tamp the stemming firmly.

[0059] In some embodiments, the length ratio of the lower first section of explosive 21 to the lower second section of explosive 22 is 1.2 - 1.5; the length ratio of the upper first section of explosive 31 to the upper second section of explosive 32 is 1.2 - 1.5. The length of the lower second section of explosive 22 is greater than that of the lower first section of explosive 21, and the length of the upper second section of explosive 32 is greater than that of the upper first section of explosive 31. The bottom of the blast hole is subjected to a large clamping action of the rock. Therefore, more explosives at the bottom of the blast hole can increase the cavity volume and the utilization rate of the explosives.

[0060] In some embodiments, in the blasting step, the millisecond delay blasting method uses coal mine permitted digital electronic detonators for initiation, and the detonator delay setting is carried out according to specific needs. Using coal mine permitted digital electronic detonators can break through the limitation of the five-section blasting of traditional electric detonators, so as to increase more delay times to meet the blasting sequence of different blast holes.

[0061] Further, during initiation, the following blast holes are detonated in sequence to complete the one-time full-section blasting:

[0062] First-stage blasting: Initiate the lower first section of explosive 21 in the lower cut hole 2;

[0063] Second-stage blasting: Simultaneously initiate the lower second section of explosive 22 in the lower cut hole 2 and the central hole explosive 11 in the central hole 1;

[0064] Third-stage blasting: Initiate the upper first section of explosive 31 in the upper cut hole 3;

[0065] Fourth-stage blasting: Initiate the upper second section of explosive 32 in the upper cut hole 3;

[0066] Five-stage initiation: Initiate the auxiliary hole explosive 41 in the auxiliary hole 4;

[0067] Six-stage initiation: Initiate the perimeter hole explosive 51 in the perimeter hole 5.

[0068] Specifically, as Figure 2 shown, first initiate the lower cut holes 2 and the center hole 1, which can create a lower cavity in a small area first, and then initiate the upper cut holes 3. Due to the existence of the lower cavity, it is easier to initiate the upper cut holes, and finally form Figure 4 a cavity 11 similar to the roadway cross-section as shown, which reduces the minimum resistance line of the auxiliary hole 4 and makes it uniform, and finally initiate the perimeter hole 5. In this way, the initiation direction from bottom to top and from inside to outside is formed. By multi-stage initiation, the initiation resistance is reduced, the volume of the cut area is increased, the initiation difficulty of other blast holes is reduced, and multi-stage one-time initiation is realized through digital electronic detonators, reducing the blasting vibration while reducing the blasting cost.

[0069] Embodiment 2

[0070] To better understand a high-efficiency blasting method for similar cuttings in rock roadways provided by the present invention, Embodiment 2 provides a specific case of using the high-efficiency blasting method for similar cuttings in rock roadways of the present invention. Figure 5 It is the blasting design drawing of the on-site application example.

[0071] The cross-sectional area of a certain coal mine rock roadway is 21.3 m 2 . The original blasting and tunneling scheme of this coal mine is the single-wedge cut blasting method, using coal mine permitted millisecond delay electric detonators, usually divided into five segments for blasting. The depth of the cut holes is 2.0 m, and the depth of other holes is 1.8 m. The actual number of blast holes during construction is about 120, and the single-pass driving depth is about 1.5 m.

[0072] Adopt a high-efficiency blasting method for similar cuttings in rock roadways provided by the invention. As Figure 4 shown, the depth of the cut holes and the center hole is 2.9 m, and the depth of other holes is 2.5 m. The coal mine permitted digital electronic detonators are used for delay initiation. Table 1 is the blast hole parameter table of the on-site application example. As shown in Table 1, the delay time can be arbitrarily set between 0 and 130 ms according to actual needs, the delay error is less than 1 ms, the number of drill holes is 74, which is 38.3% less than the original scheme, and the total time of drilling, charging and connection during construction is reduced by about 50%. The single-pass driving depth is 2.3 m. After adopting the new similar cut blasting technology, the number of drill holes is reduced, the construction period is greatly shortened, the driving efficiency is greatly improved, the cost is saved, and the production efficiency is improved.

[0073]

[0074] Table 1

[0075] In summary, a high-efficiency blasting method for similar cut in rock roadways provided by the embodiments of the present invention adopts a similar cut hole layout method, a sectional charging method, and a delay method of coal mine permitted digital electronic detonators, increases the range of the cut area, improves the volume of the cavity generated by the blasting of the cut holes, reduces the minimum resistance line of the auxiliary holes and makes it uniform, reduces the number of auxiliary holes and peripheral holes, reduces the drilling time and the amount of explosive used, and at the same time, multi-section delay initiation can reduce the vibration effect generated by the blasting and improve the roadway stability.

[0076] It should be understood that the terms "including / comprising", "consisting of...", or any other variant thereof are intended to cover non-exclusive inclusion, so that a product, device, process, or method including a series of elements not only includes those elements, but may also include other elements not explicitly listed when necessary, or further includes elements inherent to such product, device, process, or method. Without further limitation, the elements defined by the statement "including / comprising..." or "consisting of..." do not exclude the existence of additional identical elements in the product, device, process, or method including the said elements.

[0077] It should also be understood that the terms "installed", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0078] In the present invention, unless otherwise clearly defined and limited, the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device, component, or structure referred to must have a specific orientation, be constructed or operated in a specific orientation, and should not be construed as a limitation to the present invention.

[0079] 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 one or more of such features. In the description of the present invention, the meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0080] As described above, it is only the specific implementation manner 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 those skilled in the art within the technical scope disclosed by the present invention should be covered within 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 high-efficiency blasting method for similar cut in rock roadway, characterized in that, Including the steps: Drilling: Drill the following holes in the roadway construction section area: center hole, lower cut holes, upper cut holes, auxiliary holes and perimeter holes; the center hole is in the middle of the section area, the lower cut holes are respectively on both sides of the center hole, the lower cut holes are located in the lower part of the section area, the upper cut holes are located in the upper part of the section area, the auxiliary holes are located outside the lower cut holes and the upper cut holes, and the perimeter holes are arranged along the contour edge of the section area; Charging: Load explosives into the center hole, the lower cut holes, the upper cut holes, the auxiliary holes and the perimeter holes; the center hole is filled with center hole explosive, both the lower cut holes and the upper cut holes are filled with upper section explosive and lower section explosive, the lower section explosive is located at the bottom of the hole, the auxiliary holes are filled with auxiliary hole explosive, and the perimeter holes are filled with perimeter hole explosive; Blasting: Adopt the millisecond delay initiation method to detonate the following blast holes in sequence to complete the one-time full-section blasting: First-stage blasting: Detonate the lower section explosive in the lower cut holes; Second-stage blasting: Detonate the lower second-section explosive in the lower cut holes and the center hole explosive in the center hole simultaneously; Third-stage blasting: Detonate the upper section explosive in the upper cut holes; Fourth-stage blasting: Detonate the upper second-section explosive in the upper cut holes; Fifth-stage initiation: Detonate the auxiliary hole explosive in the auxiliary holes; Sixth-stage initiation: Detonate the perimeter hole explosive in the perimeter holes; The center hole is located on the central axis of the section area, and the distance between adjacent center holes is 0.4 - 0.6 m; the lower cut holes are located in the lower straight wall part of the section area, and the distance between adjacent lower cut holes is 1.6 - 1.8 m; the upper cut holes are located in the upper semi-circular arch part of the section area, and the upper cut holes are arranged in a semi-circular arc shape, and the distance between adjacent upper cut holes is 0.4 - 0.6 m; The depths of the center hole, the lower cut holes and the upper cut holes are the same, the depths of the auxiliary holes and the perimeter holes are the same, and the depths of the center hole, the lower cut holes and the upper cut holes are 300 - 400 mm more than the depths of the auxiliary holes and the perimeter holes; The drilling arrangements of the lower cut holes, the upper cut holes and the center hole are as follows: Drill lower cut holes in the lower straight wall area of the section area, and the area enclosed by the lower cut holes is rectangular; drill upper cut holes in the upper semi-circular arch area of the section area, and the area enclosed by the upper cut holes is semi-circular; drill a center hole in the middle of the area enclosed by the lower cut holes and the upper cut holes; the shape of the area enclosed by the lower cut holes and the upper cut holes is basically similar to the shape of the section area; after detonating in the cut hole area, a cavity similar to the shape of the section area can be formed, so that the minimum resistance lines of all auxiliary blast holes are uniform.

2. The blasting method according to claim 1, wherein The center hole, the lower cut holes, the upper cut holes, the auxiliary holes and the perimeter holes are all perpendicular to the free surface of the rock roadway.

3. The blasting method according to claim 1, characterized in that, The area of the roadway construction cross-section area is greater than 15 m 2 .

4. The blasting method according to claim 1, wherein The arrangement of the auxiliary holes adjusts the number of auxiliary holes according to the size of the on-site section.

5. The blasting method according to claim 1, characterized in that, The depths of the central hole, the lower cut holes, the upper cut holes, the auxiliary holes and the perimeter holes are all greater than 2 m, and the diameters are all greater than 40 mm.

6. The blasting method according to claim 1, wherein The mass of the explosive in the central hole is 0.5 to 0.75 times the mass of the explosive in the lower cut hole or the upper cut hole.

7. The blasting method according to claim 1, characterized in that, The charging arrangement of the lower cut holes is as follows: Insert the second-stage detonator into the explosive, place it at the bottom of the lower cut hole, and continue charging to form the next section of explosive; Perform stemming sealing, and the stemming length is not less than 0.55 m; Put the first-stage detonator into the explosive, place it in the lower cut hole, and continue charging to form the next second section of explosive; Perform stemming sealing, and tamp the stemming with a tamping rod.

8. The blasting method according to claim 1, characterized in that The charging arrangement of the upper cut holes is as follows: Insert the third-stage detonator into the explosive, place it at the bottom of the upper cut hole, and continue charging to form the first section of explosive; Perform stemming sealing, and the stemming length is not less than 0.55 m; Put the fourth-stage detonator into the explosive, place it in the upper cut hole, and continue charging to form the second section of explosive; Perform stemming sealing, and tamp the stemming with a tamping rod.

9. The blasting method according to claim 1, characterized in that, The length ratio of the next section of explosive to the next second section of explosive is 1.2 to 1.5; the length ratio of the first section of explosive to the second section of explosive is 1.2 to 1.

5.

10. The blasting method according to claim 1, characterized in that, The millisecond delay initiation method uses coal mine permitted digital electronic detonators for initiation, and the detonator delay setting is carried out according to specific needs.

Images