Blasting excavation method for short and shallow vertical shaft

Abstract

The invention discloses a blasting excavation method for a short and shallow vertical shaft, which comprises the following construction steps: step 1, firstly performing drilling construction, then filling explosive in a hole, then performing networking blasting, and excavating a pilot shaft at the central position of the section of the vertical shaft to be excavated; 2, drilling construction is carried out firstly, then the hole is filled with explosive, networking blasting is carried out, and the pilot shaft is excavated into a temporary vertical shaft in an expanding mode with the pilot shaft as the center; and 3, the whole section of the vertical shaft is layered from top to bottom with the temporary vertical shaft as the center, drilling construction is conducted on each layer, then the holes are filled with explosives, networking blasting is conducted, and the vertical shaft is layered, expanded, excavated and formed. The excavation method for rapid blasting of the short and shallow vertical shaft is low in construction cost, easy to operate, high in efficiency and convenient to apply and popularize. The problems that according to an existing vertical shaft excavation method, for a short and shallow vertical shaft excavation project, the construction difficulty is large, the construction period is too long, or the construction cost is too high are solved, and a good effect is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering construction and relates to a blasting excavation method for a short shallow vertical shaft. Background Art

[0002] In water conservancy and hydropower projects or other projects, shallow shaft excavation projects are often encountered, such as tailwater gate shafts and tailwater surge shafts in water conservancy and hydropower projects. Common shaft excavation generally adopts forward excavation method, reverse drilling rig well guide method and other methods. Among them, forward excavation method is the most traditional excavation method, but the forward slag discharge during excavation is relatively slow and the construction period will be longer; although the reverse drilling rig well guide method is more efficient and accurate, the reverse drilling rig equipment is expensive, and the installation and disassembly of the equipment is relatively complicated, time-consuming and labor-intensive, so the reverse drilling rig well guide method is generally used in deep and long shaft excavation projects. For excavating short and shallow shafts, its economy is insufficient. Therefore, on the one hand, in order to improve the construction speed of short and shallow shaft excavation and avoid affecting the progress of the entire project, on the other hand, in order to improve the economy of the construction of short and shallow shaft excavation projects, it is necessary to improve the construction plan of short and shallow shaft excavation projects in a targeted manner. Summary of the invention

[0003] The purpose of the present invention is to provide a blasting excavation method for short and shallow vertical shafts. For short and shallow vertical shaft excavation projects, the method has the advantages of high excavation efficiency and low project construction cost, and solves the problems of existing shaft excavation methods for short and shallow vertical shaft excavation projects, such as high construction difficulty, long construction period, or high construction cost.

[0004] The blasting excavation method for short shallow shafts disclosed in the present invention is only applicable to the excavation construction process of vertical shafts that penetrate from top to bottom, so that slag can be easily dropped during the blasting project, avoiding the difficulty of slag removal. The applicable shaft depth generally does not exceed 35m. Based on the principle of controlling construction costs and improving construction efficiency, the applicable shaft depth range in a specific project needs to be determined according to the drilling depth and drilling hole slope of the engineering drilling equipment in the project.

[0005] The blasting excavation method for a short shallow vertical shaft disclosed by the invention can be used in vertical shaft excavation construction projects with square, circular or other shaped cross sections.

[0006] The technical solution adopted by the present invention is a blasting excavation method for a short shallow shaft, comprising the following construction steps:

[0007] Step 1: Dig a pilot shaft at the center of the shaft section to be excavated, according to the following subdivision steps:

[0008] Step 1.1: Pilot well drilling construction

[0009] Determine the scope of pilot well construction. The diameter of the pilot well is generally greater than 130mm. If there is no large-diameter drill pipe, you can also use a small-diameter drill pipe to drill multiple holes (to form as many open surfaces as possible). Arrange the drilling positions of a hollow hole and several main blasting holes within the cross-sectional size of the pilot well; Use engineering drilling equipment to complete the drilling construction of each hollow hole and main blasting hole one by one;

[0010] Step 1.2: First hole filling and charging

[0011] First, backfill the bottom of each main blast hole with a set thickness of filling material. The thickness of the filling is calculated according to the formula: L = K*D, where L = the length of the filling; K = the filling coefficient, which is usually between 10 and 25, depending on the rock properties, the type of explosives, the blasting design, the construction conditions, etc. Softer rocks and weaker explosives require a larger filling coefficient, and vice versa; then, detonating cords and multiple explosive rolls arranged at a set interval are tied to several PVC sheets or nylon ropes, and tied to the required blasting positions in each main blast hole; finally, the set thickness of filling material is poured into each main blast hole again;

[0012] Step 1.3: First network attack

[0013] The detonating cords of each main blast hole are tied with detonators according to the set detonation network, and then the detonators and fuses are used for network detonation, controlling the explosive rolls in each main blast hole to blast the pilot well from bottom to top;

[0014] Step 2: Expand the pilot shaft into a temporary vertical shaft with the pilot shaft as the center, and proceed according to the following subdivision steps:

[0015] Step 2.1: Temporary shaft drilling construction

[0016] Determine the construction scope of the temporary shaft, arrange the drilling positions of several main blast holes within the cross-sectional size of the temporary shaft; use engineering drilling equipment to complete the drilling construction of each main blast hole one by one;

[0017] Step 2.2: Second hole filling and charging

[0018] First, backfill the bottom of each main blast hole with a set thickness of filler; then tie detonating cords and multiple cords arranged at set intervals on several PVC sheets or nylon ropes, and tie them to the locations to be blasted in each main blast hole; finally, backfill the main blast hole with a set thickness of filler again;

[0019] Step 2.3: Second network detonation

[0020] The detonating cords of each main blast hole are tied with detonators according to the set detonation network, and then the detonators and fuses are used for network detonation, controlling the explosive rolls in each main blast hole to blast the temporary shaft from bottom to top;

[0021] Step 3: With the temporary shaft as the center, the entire section of the shaft is excavated from top to bottom in layers. Considering that each layer needs to be excavated and supported, the number of layers should not be too high, and the height of shotcrete and anchor drilling needs to be considered. The construction of each layer is carried out according to the following subdivision steps:

[0022] Step 3.1: Single-layer drilling construction

[0023] Arrange the drilling positions of several main blasting holes and several pre-splitting blasting holes within the cross-sectional size of the shaft; use engineering drilling equipment to complete the drilling construction of each main blasting hole and pre-splitting blasting hole one by one at a time, and the drilling depth is the same as the set depth of the layer;

[0024] Step 3.2: Filling the hole with charge

[0025] Detonating cords and multiple explosive rolls arranged at set intervals are tied to several PVC sheets or nylon ropes, and are tied to the required blasting positions in each main blasting hole and pre-splitting blasting hole; then, a filling material of set thickness is poured into each main blasting hole and pre-splitting blasting hole again;

[0026] Step 3.3: Network detonation

[0027] The detonating cords of each main blast hole and pre-splitting blast hole are tied with detonators according to the set detonation network, and then the detonators and fuses are used for network detonation, and the explosive rolls in each main blast hole are controlled to blast the entire section of the shaft from top to bottom;

[0028] Step 3.4: Carry out final section excavation and support for the expanded vertical shaft.

[0029] The present invention is also characterized in that, when the vertical shaft to be excavated is a vertical shaft with a square cross section, in step 2.1, the construction cross section of the temporary vertical shaft is rectangular, the two short sides of the temporary vertical shaft cross section coincide with the straight line where the two opposite sides of the vertical shaft are located, and the drilling positions of a plurality of pre-splitting blasting holes are evenly arranged along the edges of the two short sides; the engineering drilling equipment is used to complete the drilling construction of each pre-splitting blasting hole one by one at a time;

[0030] In step 2.2, first, a filler of a set thickness is backfilled into the bottom of each pre-splitting blasting hole; then, detonating cords and a plurality of explosive rolls arranged at a set interval are tied to a plurality of PVC sheets or nylon ropes, and are respectively tied to the positions to be blasted in each pre-splitting blasting hole; finally, a filler of a set thickness is poured into each pre-splitting blasting hole again;

[0031] In step 2.3, the detonating cords of each pre-splitting blasting hole and the detonating cords of the main blasting hole are tied with detonators according to the set detonation network, and then the detonators and fuses are connected for detonation, and the explosive rolls in each pre-splitting blasting hole and the main blasting hole are controlled to blast the temporary shaft from bottom to top.

[0032] The present invention is also characterized in that, when the vertical shaft to be excavated is a vertical shaft with a circular cross section, in step 2.1, the construction cross section of the temporary vertical shaft is also circular.

[0033] The present invention is also characterized in that, after step 1.1 and before step 1.2, the first hole bottom protection is performed, the bottom of each main blast hole is blocked with a circular wooden wedge, and iron wire and the wooden wedge are respectively fixed, the iron wire is passed along the corresponding hole wall, and the iron wire is tightened above each hole so that the wooden wedge closes the bottom hole of the corresponding hole;

[0034] After step 2.1 and before step 2.2, the second hole bottom protection is performed. The bottom of each hole drilled in step 2.1 is blocked with a round wooden wedge, and fixed with iron wire and wooden wedge respectively. The iron wire is passed along the corresponding hole wall, and the iron wire is tightened above each hole so that the wooden wedge closes the bottom hole of the corresponding hole;

[0035] After step 3.1 of the last layer of excavation construction in step 3 and before step 3.2, the third hole bottom protection is carried out. The bottom of each hole drilled in step 3.1 is blocked with a round wooden wedge, and fixed with iron wire and wooden wedge respectively. The iron wire is passed along the corresponding hole wall, and the iron wire is tightened above each hole so that the wooden wedge closes the bottom hole of the corresponding hole.

[0036] The present invention is also characterized in that, in step 1.1, the hollow hole is located at the center of the pilot shaft section, and a plurality of main blast holes are evenly distributed along the circumferential direction of the hollow hole;

[0037] In step 2.1, a number of main blast holes are evenly distributed within the range between the cross-sectional dimensions of the temporary shaft and the cross-sectional dimensions of the pilot shaft;

[0038] In step 3.1, a plurality of pre-splitting blasting holes are evenly distributed along the edge of the shaft section, and a plurality of main blasting holes are evenly distributed within the range between the shaft section size and the temporary shaft section size.

[0039] The present invention is also characterized in that, in step 1.2, step 2.2 and step 3.2, while filling each hole, a gun rod is used for tamping, and damage to the detonating cords of each hole should be prevented during filling and tamping.

[0040] The present invention is also characterized in that in step 1.2, step 2.2 and step 3.2, the medicine rolls are all used Emulsion explosive production, line charge density is 110-950g / m, explosive unit consumption is 0.66-6.40kg / m 3 .

[0041] The present invention is also characterized in that, in step 1.3, step 2.3 and step 3.3, the blasting network is a segmented relay network, and the blasting detonators include non-electric detonators and fire detonators. One end of the non-electric detonator is bundled and connected with the detonating cord of each hole, and the other end is connected to the fire detonator, the fuse and the detonator in sequence; wherein the non-electric detonator adopts a non-electric millisecond detonator, and the fire detonator adopts a double detonator.

[0042] The present invention is also characterized in that the engineering drilling equipment adopts a geological drilling machine or other drilling equipment.

[0043] The present invention is also characterized in that the filling material is rock powder or fine sand.

[0044] The beneficial effects of the present invention are as follows: drilling is performed using engineering drilling equipment commonly used at construction sites, and then blasting is performed in the holes, and this can be repeated multiple times to excavate a short shallow vertical shaft. Without the need for other large equipment or too much manpower, the construction difficulty of the short shallow vertical shaft is greatly reduced, the excavation efficiency of the short shallow vertical shaft is improved, the construction period is shortened, and the project construction cost is reduced, thereby solving the problems of the existing shaft excavation methods being difficult to construct, the construction period being too long, or the construction cost being too high for short shallow vertical shaft excavation projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of the drilling construction of the engineering drilling equipment in the present invention;

[0046] Figure 2 is the drilling plan layout diagram in step 1.1 of the present invention;

[0047] Figure 3 It is a schematic diagram of the effect of filling the main blast hole with explosives in step 1.2 of the present invention;

[0048] Figure 4 is the drilling plan layout diagram in step 2.1 of the present invention;

[0049] Figure 5 It is a schematic diagram of the effect of filling the pre-splitting blasting hole with explosives in step 2.2 of the present invention;

[0050] Figure 6 It is a schematic diagram of the effect of filling the main blast hole with explosives in step 2.2 of the present invention;

[0051] Figure 7 is the drilling plan layout diagram in step 3.1 of the present invention;

[0052] Figure 8 It is a schematic diagram of the effect of filling the pre-splitting blasting hole with explosives in step 3.2 of the present invention;

[0053] Fig. 9It is a schematic diagram of the effect of filling the main blast hole with explosives in step 3.2 of the present invention; DETAILED DESCRIPTION

[0054] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] Embodiment 1:

[0056] Take the excavation construction project of the tailwater surge tank of a hydropower station with a depth of 24.75m, a cross-sectional size of 7.3m in length and 3.1m in width as an example. The tailwater surge tank is a vertical shaft that runs through from top to bottom. The blasting excavation method used for short and shallow vertical shafts, when excavating the tailwater surge tank, takes the following construction steps:

[0057] Step 1: Dig a pilot well with a diameter of φ1m at the center of the tailwater surge well section to be excavated, and proceed according to the following subdivision steps:

[0058] Step 1.1: Pilot well drilling construction

[0059] Determine the scope of pilot well construction, such as Figure 2 As shown in the figure, within the range of the pilot shaft section size of φ1m in diameter, one hollow hole and six main blast holes are arranged. The hollow hole is located at the center of the pilot shaft section, and its diameter is φ130mm. The six main blast holes are evenly distributed along the circumference of the hollow hole, and the diameter of the main blast holes is φ76mm. The distance between the main blast holes and the hollow holes is 500mm. Figure 1 As shown, a geological drill is used to complete the drilling construction of each hollow hole and the main blast hole one by one;

[0060] The bottom of each main blast hole is blocked with a round wooden wedge, and fixed with 8# iron wire and wooden wedge respectively. The iron wire is passed along the corresponding hole wall, and the iron wire is tightened above each hole so that the wooden wedge can close the bottom hole of the corresponding hole;

[0061] Step 1.2: First hole filling and charging

[0062] like Figure 3 As shown in the figure, firstly, fill the bottom of each main blast hole with 1m thick rock powder or fine sand as filling material; then use 6 PVC sheets to tie detonating cords and multiple cords in uncoupled interval charging mode, and tie them into the required blasting positions in each main blast hole; finally, fill each main blast hole with 1m thick rock powder or fine sand again; while filling the hole, use the gun rod for tamping, and prevent the detonating cords of each hole from being damaged during filling and tamping; the cords in the main blast hole are all used Emulsion explosive production, line charge density is 850-950g / m3, explosive unit consumption is 5.72-6.40kg / m3 3 ;

[0063] Step 1.3: First network attack

[0064] The detonating cords of each main blast hole are tied with detonators according to the segmented relay detonation network, and then the detonators and fuses are used for network detonation, so as to control the explosive rolls in each main blast hole to blast in two layers from bottom to top, and finally the pilot well is blasted into shape;

[0065] Step 2: With the pilot shaft as the center, expand the pilot shaft into a rectangular temporary shaft with a cross-section of 3.1m×1.6m, according to the following subdivision steps:

[0066] Step 2.1: Temporary shaft drilling construction

[0067] Determine the construction scope of the temporary shaft. The 1.6m side of the temporary shaft is located at the edge of the shaft. Therefore, in order to ensure the quality of the shaft wall, the designed shaft wall at this location must be pre-splitting blasted before blasting and excavation. Figure 4 As shown, 8 pre-splitting blasting holes are evenly arranged along the 1.6m long edge of the temporary shaft, with a diameter of φ76mm; 4 main blasting holes are evenly arranged within the range between the cross-sectional dimensions of the temporary shaft and the cross-sectional dimensions of the pilot shaft, with a diameter of φ76mm, and a hole spacing of 1.6m between the main blasting holes, 0.8m from the pre-splitting blasting holes, and a hole spacing of 0.8m between the pre-splitting holes. A geological drill is used to complete the drilling of each pre-splitting blasting hole and the main blasting hole one by one;

[0068] The bottom of each pre-splitting blasting hole and the main blasting hole are blocked with round wooden wedges, and fixed with 8# iron wire and wooden wedges respectively. The iron wire is passed along the corresponding hole wall, and the iron wire is tightened above each hole so that the wooden wedges can close the bottom of the corresponding hole.

[0069] Step 2.2: Second hole filling and charging

[0070] like Figure 5 and Figure 6 As shown in the figure, firstly, fill the bottom of each pre-splitting blasting hole and the main blasting hole with 1m thick rock powder or fine sand as filling material; then use 12 PVC sheets to tie the detonating cord and tie multiple cords in the uncoupled interval charging method, and tie them into the required blasting positions in each pre-splitting blasting hole and the main blasting hole respectively; finally, fill each pre-splitting blasting hole and the main blasting hole with 1m thick rock powder or fine sand again; while filling the hole, use the gun rod for tamping, and prevent the detonating cord of each hole from being damaged during filling and tamping; the cords in the pre-splitting blasting hole are all used Emulsion explosives are made, with a line charge density of 220-320g / m; the charge rolls in the main blast hole are all made of Emulsion explosive production, line charge density is 750-850g / m, explosive unit consumption is 0.68-0.8kg / m 3 ;

[0071] Step 2.3: Second network detonation

[0072] The detonating cords of each pre-splitting blasting hole and the main blasting hole are tied with detonators according to the segmented relay detonation network, and then the detonators and fuses are used for network detonation, so that the explosive rolls in each pre-splitting blasting hole are controlled to blast first, and the explosive rolls in the main blasting hole are blasted later. The explosive rolls in each hole are blasted into shape from bottom to top to form the temporary shaft;

[0073] Step 3: With the temporary shaft as the center, the entire shaft section is excavated from top to bottom in three layers, with the layer height controlled at 5.7m. The construction of each layer is carried out according to the following subdivision steps:

[0074] Step 3.1: Single-layer drilling construction

[0075] like Figure 7 As shown, in order to ensure the quality of the shaft wall, the shaft wall needs to be pre-splitting blasting before blasting excavation, so 18 pre-splitting blasting holes are evenly arranged at the edge of the shaft section, with a diameter of φ76mm; 8 main blasting holes are evenly arranged within the range between the shaft section size and the temporary shaft section size, with a diameter of φ76mm, the main blasting holes are 1.5m apart, 1m apart, 0.85m away from the pre-splitting blasting holes, and the pre-splitting holes are 0.7-0.9m apart; a geological drill is used to complete the drilling of each pre-splitting blasting hole and the main blasting hole one by one, and the drilling depth is the same as the set depth of the layer;

[0076] In addition, after the drilling of the last layer is completed, the bottom of each pre-splitting blasting hole and the main blasting hole is blocked with a round wooden wedge, and fixed with 8# iron wire and wooden wedge respectively, the iron wire is passed along the corresponding hole wall, and the iron wire is tightened above each hole so that the wooden wedge closes the bottom hole of the corresponding hole;

[0077] Step 3.2: Filling the hole with charge

[0078] like Figure 8 As shown, 18 PVC sheets are used to tie detonating cords and multiple explosive rolls in an uncoupled interval charging manner, and are tied into the required blasting positions in each pre-splitting blasting hole, such as Fig. 9 As shown in the figure, 8 PVC sheets are used to tie the detonating cords and multiple cords are tied in a continuous charging manner, and are respectively tied to the required blasting positions in each main blasting hole; then 1m thick rock powder or fine sand is poured into each pre-splitting blasting hole and the main blasting hole as a filling material; while filling the holes, the gun rod is used for tamping, and the detonating cords of each hole should be prevented from being damaged during filling and tamping; the cords in the pre-splitting blasting holes are all used Emulsion explosives are made. The bottom of the hole is 1m for the strengthening section, the line charge density is 880-1200g / m, the middle is the normal section, the charge density is initially planned to be 220-320g / m, and the 1m near the hole mouth is the weakening section, the line charge density is 110-160g / m; the explosive rolls in the main blast hole are all used Emulsion explosive production, explosive consumption per unit is 0.66-0.74kg / m 3 ;

[0079] Step 3.3: Network detonation

[0080] The detonating cords of each pre-splitting blasting hole and the main blasting hole are tied with detonators according to the segmented relay detonation network, and then the detonators and fuses are connected and detonated, so that the charge in each pre-splitting blasting hole is controlled to blast first, and the charge in the main blasting hole is blasted later, and finally the full section of the vertical shaft of the layer is blasted into shape; the soil and stone debris generated by the blasting needs to be manually cleaned, and the temporary vertical shaft slag can be used, which is convenient and quick;

[0081] Step 3.4: Carry out final section excavation and support for the expanded vertical shaft.

[0082] In this embodiment, in step 1 and step 2, a bottom-up blasting method is adopted to facilitate automatic slag falling during blasting, without having to deal with the slag discharge problem during the excavation process. This is efficient and fast, improves the efficiency of excavation construction, saves equipment and labor, and reduces construction costs.

[0083] In this embodiment, in step 1.3, step 2.3 and step 3.3, the detonating caps are tied according to the segmented relay detonation network, and the network connection is carried out on the surface. The detonating caps include non-electric detonators and fire detonators, wherein the non-electric detonators use non-electric millisecond detonators, and the fire detonators use double detonators. One end of the non-electric detonator is tied and connected with the detonating cord of each hole, and the other end is connected with the fire detonator, the fuse, and the detonator in sequence. The detonator and the fuse are used to detonate the detonating caps. Double detonators are preferably used for detonation outside the hole. The non-electric millisecond detonators are segmented to relay the detonation network, and then detonate the detonating cord in each main blasting hole and the pre-splitting blasting hole.

[0084] In this embodiment, in addition to rock powder or fine sand, other suitable materials may be used as the filler, but it is strictly prohibited to use coarse particles to prevent clogging of the hole.

[0085] In other embodiments of the present invention, the cross-sectional dimensions of the pilot shaft, the cross-sectional dimensions of the temporary shaft, the dimensions of the hollow holes, the main blasting holes and the pre-splitting blasting holes in each step shall all be determined according to the specific dimensions of the shaft to be excavated and the actual conditions of the construction project, and shall not be regarded as completely unified requirements.

[0086] In other embodiments of the present invention, when the shaft is expanded in layers, the number of layers and the height of the layers to be excavated into the shaft need to be controlled according to the actual situation of the construction project, and no unified requirement is made.

[0087] In other embodiments of the present invention, the specific model of the emulsion explosive used in the cartridge in each hole, the line charge density of the explosive in each hole, the unit consumption of explosive and other data shall all be determined according to the actual situation of the specific blasting construction project.

[0088] In other embodiments of the present invention, the iron wire used to fix the wooden wedge can be not only 8# iron wire, but also other suitable types of iron wire, or other rope-like materials that can be tied and fixed with the wooden wedge and can be pulled.

[0089] In other embodiments of the present invention, the number of hollow holes in step 1 can also be arranged as multiple, and several main blast holes are still arranged around the multiple hollow holes. In actual construction, the number of hollow holes needs to be determined according to the on-site conditions of the construction project.

[0090] Working principle of this embodiment: The present invention uses in-hole blasting to simply and efficiently excavate short shallow vertical shafts, and adopts a layered blasting construction method, which can not only ensure the construction quality of short shallow vertical shafts, but also improve the excavation efficiency of short shallow vertical shafts and reduce the construction cost of short shallow vertical shaft excavation projects. The present invention adopts an excavation method of short shallow vertical shafts with rapid blasting. The tailwater surge well can be excavated and formed by drilling and blasting. No other large equipment is required, and too much manpower is not required. The overall construction cost is low, easy to operate, and efficient. It can effectively shorten the construction period and is easy to promote and apply. It solves the problems of existing shaft excavation methods for short shallow vertical shaft excavation projects, such as high construction difficulty, long construction period, or high construction cost, and achieves better results.

[0091] The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technical solution obtained by any technician familiar with the field within the technical scope disclosed by the present invention by equivalent replacement or change based on the technical concept of the present invention should be included in the protection scope of the present invention.

Claims

1. A blasting excavation method for a short shallow shaft, characterized in that: The construction steps include: Step 1: Dig a pilot shaft at the center of the shaft section to be excavated, according to the following subdivision steps: Step 1.1: Pilot well drilling construction Determine the scope of pilot well construction, arrange the drilling positions of a hollow hole and several main blast holes within the cross-sectional size of the pilot well; use engineering drilling equipment to complete the drilling construction of each hollow hole and main blast hole one by one at a time; Step 1.2: First hole filling and charging First, backfill the bottom of each main blast hole with a set thickness of filler; then, respectively tie detonating cords and multiple cords arranged at set intervals on a plurality of PVC sheets or nylon ropes, and respectively tie them to the positions to be blasted in each main blast hole; finally, fill each main blast hole with a set thickness of filler again; Step 1.3: First network attack The detonating cords of each main blast hole are tied with detonating caps according to the set detonation network, and then the detonators and fuses are used for network detonation, so as to control the explosive rolls in each main blast hole to blast the pilot well into shape from bottom to top; Step 2: Expand the pilot shaft into a temporary vertical shaft with the pilot shaft as the center, and proceed according to the following subdivision steps: Step 2.1: Temporary shaft drilling construction Determine the construction scope of the temporary shaft, arrange the drilling positions of several main blast holes within the cross-sectional size of the temporary shaft; use engineering drilling equipment to complete the drilling construction of each main blast hole one by one; Step 2.2: Second hole filling and charging First, backfill the bottom of each main blast hole with a set thickness of filler; then, respectively tie detonating cords and multiple cords arranged at set intervals on a plurality of PVC sheets or nylon ropes, and respectively tie them to the positions to be blasted in each main blast hole; finally, fill each main blast hole with a set thickness of filler again; Step 2.3: Second network detonation The detonating cords of the main blast holes are tied with detonating caps according to the set detonation network, and then the detonators and fuses are used for network detonation, so as to control the explosive rolls in the main blast holes to blast the temporary shaft from bottom to top; Step 3: With the temporary shaft as the center, the entire section of the shaft is excavated layer by layer from top to bottom. The construction of each layer is carried out according to the following subdivision steps: Step 3.1: Single-layer drilling construction Arrange the drilling positions of several main blasting holes and several pre-splitting blasting holes within the cross-sectional size of the shaft; use engineering drilling equipment to complete the drilling construction of each main blasting hole and pre-splitting blasting hole one by one at a time, and the drilling depth is the same as the set depth of the layer; Step 3.2: Filling the hole with charge Detonating cords and multiple explosive rolls arranged at set intervals are tied to several PVC sheets or nylon ropes, and are tied to the required blasting positions in each main blasting hole and pre-splitting blasting hole; then, a filling material of set thickness is poured into each main blasting hole and pre-splitting blasting hole; Step 3.3: Network detonation The detonating cords of the main blast holes and pre-splitting blast holes are tied with detonators according to the set detonation network, and then the detonators and fuses are used for network detonation, and the explosive rolls in the main blast holes are controlled to blast the entire section of the shaft from top to bottom; Step 3.4: Carry out final section excavation and support for the expanded vertical shaft.

2. The blasting excavation method for a short shallow shaft according to claim 1, characterized in that: The vertical shaft to be excavated is a vertical shaft with a square cross section. In step 2.1, the construction cross section of the temporary vertical shaft is rectangular, the two short sides of the temporary vertical shaft cross section coincide with the straight line where the two opposite sides of the vertical shaft are located, and the drilling positions of a plurality of pre-splitting blasting holes are evenly arranged along the edges of the two short sides; the engineering drilling equipment is used to complete the drilling construction of each pre-splitting blasting hole one by one at a time; In step 2.2, first, backfill the bottom of each pre-splitting blasting hole with a set thickness of filler; then, detonating cords and multiple explosive rolls arranged at a set interval are tied to a plurality of PVC sheets or nylon ropes, and are respectively tied to the positions to be blasted in each pre-splitting blasting hole; finally, the filler of the set thickness is poured into each pre-splitting blasting hole again; In step 2.3, the detonating cords of each pre-splitting blasting hole and the detonating cords of the main blasting hole are tied to the detonating caps according to the set detonation network, and then the detonators and fuses are connected and detonated, and the explosive rolls in each pre-splitting blasting hole and the main blasting hole are controlled to blast the temporary shaft from bottom to top.

3. The blasting excavation method for a short shallow shaft according to claim 1, characterized in that: The vertical shaft to be excavated is a vertical shaft with a circular cross section. In step 2.1, the construction cross section of the temporary vertical shaft is also circular.

4. The blasting excavation method for a short shallow shaft according to any one of claims 1 to 3, characterized in that: After step 1.1 and before step 1.2, perform the first bottom hole protection The bottom of each main blast hole is blocked with a circular wooden wedge, and the wooden wedge is fixed with iron wire, the iron wire is passed along the corresponding hole wall, and the iron wire is tightened above each hole so that the wooden wedge closes the bottom hole of the corresponding hole; After step 2.1 and before step 2.2, perform the second hole bottom protection. The bottom of each hole drilled in step 2.1 is blocked with a round wooden wedge, and the wooden wedge is fixed with a wire, the wire is passed along the corresponding hole wall, and the wire is tightened above each hole so that the wooden wedge closes the bottom of the corresponding hole; After step 3.1 of the last layer of excavation in step 3 and before step 3.2, the third hole bottom protection is carried out The bottom of each hole drilled in step 3.1 is blocked with a circular wooden wedge, and the wooden wedge is fixed with a wire. The wire is passed along the corresponding hole wall, and the wire is tightened above each hole so that the wooden wedge closes the bottom of the corresponding hole.

5. The blasting excavation method for a short shallow shaft according to claim 4, characterized in that: In step 1.1, the hollow hole is located at the center of the pilot well section, and a plurality of main blast holes are evenly distributed along the circumference of the hollow hole; In step 2.1, a number of main blast holes are evenly distributed within the range between the cross-sectional dimensions of the temporary shaft and the cross-sectional dimensions of the pilot shaft; In step 3.1, a plurality of pre-splitting blasting holes are evenly distributed along the edge of the shaft section, and a plurality of main blasting holes are evenly distributed within a range between the shaft section size and the temporary shaft section size.

6. The blasting excavation method for a short shallow shaft according to claim 4, characterized in that: In step 1.2, step 2.2 and step 3.2, while filling each hole, the gun rod is used for tamping. During filling and tamping, damage to the detonating cord of each hole should be prevented.

7. The blasting excavation method for a short shallow shaft according to claim 4, characterized in that: In step 1.2, step 2.2 and step 3.2, the medicine rolls are all made of Emulsion explosive production, line charge density is 110-950g / m, explosive unit consumption is 0.66-6.40kg / m 3 .

8. The blasting excavation method for a short shallow shaft according to claim 4, characterized in that: In step 1.3, step 2.3 and step 3.3, the detonation network is a segmented relay network, the detonating caps include non-electric detonators and fire detonators, one end of the non-electric detonators is connected to the detonating cords of each hole, and the other end is connected to the fire detonator, the fuse and the detonator in sequence; The non-electric detonator adopts a non-electric millisecond detonator; the fire detonator adopts a double detonator.

9. The blasting excavation method for a short shallow shaft according to claim 4, characterized in that: The engineering drilling equipment adopts a geological drilling rig.

10. The blasting excavation method for a short shallow shaft according to claim 4, characterized in that: The filler is rock powder or fine sand.

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