A method of blasting and excavating a cylindrical chamber

Abstract

The application discloses a blasting excavation method suitable for a cylindrical tank chamber, and steps are as follows: excavating a lower branch channel to a tank body edge; excavating an upper branch channel to a tank chamber dome end head forming; blasting and excavating the dome into multiple areas to an upper tank chamber forming; continuing to excavate along the lower branch channel to the tank body direction to exceed a position of a slag vertical shaft; blasting and excavating the vertical shaft from top to bottom; blasting and excavating a tank body central part, dividing the dome to the tank body bottom into n layers from top to bottom, taking the vertical shaft as a free surface, taking the tank body central point as a circle, expanding multiple circular rings from inside to outside, sequentially performing cylindrical excavation, and excavating to 1.5-2 m away from the tank chamber edge; for the area 1.5-2 m away from the tank chamber edge, sequentially excavating from top to bottom into n layers and from each layer into m areas until the tank body is formed. The application controls the dome and the tank body to be excavated in areas respectively, is helpful to control over-excavation and under-excavation, can be adjusted in time according to specific construction conditions during construction, and guarantees construction safety.

Description

Technical Field

[0001] This invention relates to the field of underground tank chamber excavation technology, specifically to a blasting excavation method suitable for cylindrical tank chambers. Background Technology

[0002] In today's era of globalization and rapid development across industries, most businesses rely heavily on land use and planning. This has led to a scarcity of land resources and a surge in tunnel and underground engineering projects. More and more buildings are extending underground, but due to limitations imposed by surrounding buildings and terrain, most underground structures are primarily hexagonal in shape and their size is significantly constrained. This results in a lack of systematic designs for cylindrical and semi-circular dome warehouses, with few custom-designed construction methods available. Furthermore, these designs are hampered by factors such as high construction costs, high labor costs, poor coordination between manual and mechanical work, and over- or under-excavation. Additionally, the removal and transportation of slag from large caverns presents a significant challenge. Slag removal channels cannot be too large due to economic constraints, while excessively small channels negatively impact construction efficiency. Finding a balance is crucial. Summary of the Invention

[0003] To address the shortcomings of the prior art, this invention provides a blasting excavation method suitable for cylindrical tank chambers, designed to meet the construction requirements of such chambers.

[0004] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for blasting excavation suitable for cylindrical tank chambers, comprising the following steps:

[0006] Step 1: Excavate the lower support channel to the edge of the tank and complete the reinforcement measures for the opening;

[0007] Step 2: Excavate the upper support passage to the top of the tank chamber dome and complete the reinforcement measures for the opening;

[0008] Step 3: Using the upper support channel, the dome is divided into multiple zones and blasted and excavated until the upper tank chamber is formed;

[0009] Step 4: After the dome excavation is completed, continue excavating the lower branch channel towards the tank body, extending the channel beyond the slag discharge shaft.

[0010] Step 5: Excavate the vertical shaft by blasting from top to bottom, connecting the upper tank chamber with the lower branch passage extension;

[0011] Step 6: Blasting excavation of the central part of the tank. The area from the dome to the bottom of the tank is excavated in n layers from top to bottom, where n is a natural number. The vertical shaft is used as the free surface. Taking the center point of the tank as the circle, multiple rings are expanded from the inside to the outside. Cylindrical excavation is carried out from the inside to the outside. Each layer is blasted twice to remove slag. Excavation is carried out to a distance of 1.5 to 2m from the edge of the tank chamber.

[0012] Step 7: Blasting excavation at the edge of the tank. For the area 1.5 to 2m away from the edge of the tank chamber, the excavation is divided into n layers from top to bottom. Each layer is divided into m zones for excavation. A maximum of 3 zones can be excavated at a time. The excavation is carried out in a skip-slot manner until the tank body is excavated and shaped.

[0013] Furthermore, in step S3, the dome blasting construction adopts a zoned excavation method, which is divided into seven zones. Zone A is excavated first. After the excavation of Zone A is completed, the right and left sides of Zone A are excavated in the order of Zone B → Zone C → Zone D. The advance per cycle of the tank chamber dome excavation is controlled within 2m. Zone A extends radially from the edge of the tank chamber at the upper branch passage to the opposite edge of the tank chamber. Using the radial line perpendicular to the boundary of Zone A as the dividing line, Zone A is divided into Zone B and Zone C on the same side. Zones B and C extend along the dividing line to a distance of 1.5 to 2m from the edge of the tank chamber. Zone C is close to the upper branch passage. The remaining part is Zone D.

[0014] Furthermore, in step S3, when excavating area A, the excavation cross-section is expanded when the upper support passage is excavated to 0.5m from the edge of the tank chamber, increasing the excavation width from 4.3m to 6m. During the excavation of area A, the dome position is over-excavated by 20cm. The excavation height is increased from 4.35m to 5.93m and then reduced to 2.38m according to the shape of the dome. The full-section method and the step method are used for excavation according to the excavation height.

[0015] Furthermore, in step S3, when the excavation height is less than 4.5m, the full-section excavation method is used, and when the excavation height is greater than 4.5m, the bench excavation method is used.

[0016] Furthermore, in step S3, the excavation of areas B and C adopts the step-by-step method, and area D is carried out after the excavation of areas B and C is completed. Area D adopts full-section excavation, with an excavation advance of 1m to 2m per cycle until the excavation is completed.

[0017] Furthermore, in step S3, during the dome blasting, the blasting-related parameters are set as follows:

[0018] ① The excavation advance of each blast hole cycle shall not exceed 2m;

[0019] ② The slotting hole is a wedge-shaped slot, and the amount of medicine in a single hole is controlled within 1.8 kg;

[0020] ③ The spacing between auxiliary holes should be controlled between 0.6 and 0.8 m, and adjusted according to the actual situation on site; the amount of chemical per hole should be controlled within 1.2 kg.

[0021] ④ The spacing between the perimeter holes is controlled at 0.5m, the charge per hole is controlled at less than 0.6kg, interval charging is adopted, detonating cord is used for connection, and the distance between the flash blasting layer and the second ring hole is controlled at 0.6m;

[0022] ⑤ The spacing between holes in the bottom plate should be controlled between 0.6 and 0.8 m, and the amount of explosive in a single hole should be controlled within 1.5 kg;

[0023] ⑥ For cases where the borehole depth is not less than 2m, adjust the pressure by 0.5 to 0.6 kg / m.

[0024] Furthermore, in step S5, the blasting excavation method for the shaft is as follows: a 90mm diameter through hole is drilled from top to bottom using a down-the-hole drill. The through hole is connected to the extension channel of the lower support channel. Four slotting holes are arranged around the through hole, evenly distributed along the center. Six to eight peripheral holes are evenly distributed along the excavation line. The bottom of the shaft is inclined towards the edge of the tank body at an inclination angle of 2 to 3°.

[0025] Furthermore, in steps S6 and S7, the blasting excavation of the central and edge parts of the tank adopts the shallow hole bench blasting method, with a blast hole depth of 2 to 2.5 m, a distance of 1 to 1.5 m between two adjacent blast holes, a distance of 1 to 1.2 m between two adjacent rings of blast holes, and a single hole charge of ≤1.3 KG.

[0026] Furthermore, in step S7, the area 1.5 to 2m from the edge of the tank chamber is divided into 18 zones for excavation on each layer. When excavating by skipping trenches, the two ends of the same arch frame cannot be excavated at the same time.

[0027] Furthermore, in step S7, a spiral passage is constructed inside the tank. The spiral passage is arranged circumferentially along the side wall of the tank in a spiral shape. The upper part of the spiral passage is connected to the upper branch passage, and the lower part of the spiral passage is connected to the lower branch passage.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1) The tank body is equipped with upper support channels, lower support channels and vertical shafts, and the excavation of the dome and tank body is controlled in separate sections. The excavation is divided into sections, which helps to control over-excavation and under-excavation. During construction, adjustments can be made in a timely manner according to the specific construction situation. Based on the construction problems of the previous section, the next construction section can be strictly prevented or modified. Strict control of the excavation area at the same time helps to reduce the impact of vibration waves on the adjacent structure and ensure construction safety.

[0030] 2) Excavate a vertical shaft in the middle of the tank to connect the upper and lower support channels, which will facilitate subsequent construction, reduce construction difficulty, establish a smooth blasting free face, and excavate radially around the tank in a regular manner to facilitate geological exploration and safety inspection. Peel off layer by layer and slide the slag from the vertical shaft to the lower support channel, where a slag remover and dump truck will transport it away.

[0031] 3) Construct a winding access road inside the tank for excavators, loaders, etc. to reduce the slope, ensure the safety of personnel and machinery, ensure smooth operation, eliminate the need to turn back, detect some geological conditions in advance, facilitate subsequent construction, make reasonable use of the tank height, and facilitate layer-by-layer construction.

[0032] 4) By using a construction operation platform and equipped with large-scale machinery with corresponding functions, and determining the cyclic advance according to certain design and specifications, drilling is carried out on the outline of the channel design section and inside the outline according to the design layout. The explosive energy is used to blast and shape it in one go, which can effectively reduce the labor force, reduce the working intensity of the workers, and improve work efficiency. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a map showing the zoning of the dome excavation.

[0035] Figure 2 This is a schematic diagram of the layout of the blast holes for the dome excavation;

[0036] Figure 3 This is a schematic diagram of the layout of blast holes for vertical shaft blasting excavation;

[0037] Figure 4 This is a top view of the tank excavation;

[0038] Figure 5 yes Figure 4 A cross-sectional view along XX;

[0039] Figure 6 This is a cross-sectional view of the spiral sidewalk.

[0040] Attached diagram labels: 1-vertical shaft, 2-upper branch passage, 3-lower branch passage, 4-winding access road, 7-arch frame, 8-boundary line, 9-through hole, 10-cut hole, 11-peripheral hole. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0042] A method for blasting excavation suitable for cylindrical tank chambers, comprising the following steps:

[0043] Step 1: Excavate the lower support channel 3 to the edge of the tank and complete the reinforcement measures for the opening.

[0044] Step 2: Excavate the upper support passage 2 to the top of the tank chamber dome and complete the reinforcement measures for the opening.

[0045] Step 3: The dome is divided into seven or nine zones and excavated by blasting until the upper tank chamber is formed.

[0046] Step 4: After the dome excavation is completed, continue excavating the lower branch channel 3 towards the tank body, extending the channel beyond the slag discharge shaft 1.

[0047] Step 5: Excavate shaft 1 by blasting from top to bottom. Shaft 1 connects the upper tank chamber with the lower branch passage extension.

[0048] Step 6: Excavate the center of the tank by blasting. The area from the dome to the bottom of the tank is divided into n layers from top to bottom, where n is a natural number. Using shaft 1 as the free surface, multiple rings are expanded from the center of the tank outwards. Cylindrical excavation is carried out from the inside outwards. Each layer is blasted twice to remove slag. Excavate to a distance of 1.5 to 2 meters from the edge of the tank chamber.

[0049] Step 7: Blasting excavation at the edge of the tank. For the area 1.5 to 2m away from the edge of the tank chamber, the excavation is divided into n layers from top to bottom. Each layer is divided into m zones for excavation. A maximum of 3 zones can be excavated at a time. The excavation is done by skipping trenches and the excavation depth is 3m until the tank body is excavated and shaped.

[0050] Specifically, in step 3, the dome blasting excavation adopts a zoned and layered excavation method, divided into seven zones. Zone A is excavated first. After the excavation of Zone A is completed, the right and left sides of Zone A are excavated in the order of Zone B → Zone C → Zone D. Figure 1As shown, the excavation advance per cycle during the tank chamber dome excavation should be controlled within 2m. When the surrounding rock deteriorates during construction, the excavation advance should not exceed 1m and should not exceed the spacing of one arch frame. Zone A extends radially from the edge of the tank chamber to the opposite edge. Using the radial line perpendicular to the boundary of Zone A as the dividing line 8, Zone A is divided into Zone B and Zone C on the same side. Zones B and C extend along the dividing line 8 to a distance of 1.5 to 2m from the edge of the tank chamber, with Zone C being closer to the upper support passage; the remaining area is Zone D.

[0051] Step 3.1 Excavation of Area A

[0052] When the upper support passage 2 is excavated to 0.5m from the edge of the tank chamber, the excavation cross-section will be expanded, increasing the excavation width from 4.3m to 6m. Since two layers of steel arch frames are required in Area A, the dome will be over-excavated by 20cm during excavation in Area A to facilitate the completion of the first layer of support. Excavation will proceed directly upwards from the shaft wall to the edge of the tank chamber. The excavation width in Area A is 6m, and the excavation height will increase from 4.35m to 5.93m (middle of the dome) and then decrease to 2.38m (opposite edge of the tank chamber) depending on the dome shape. The full-face method and the step method will be used depending on the excavation height. The full-face method will be used when the excavation height is less than 4.5m, and the step method will be used when the excavation height is greater than 4.5m. When excavating down a step, the left and right sides of the step should be staggered by 3m. Each cycle of excavation should not exceed the spacing of two arch frames, and both sides of the same arch frame should not be suspended simultaneously.

[0053] After the excavation of Area A is completed, the installation of the double radial arch frame 7 and the additional installation of 6m anchor rods in Area A must be completed first, and the anchor plates should be installed in a timely manner. The anchor plates should be tightly attached to the shotcrete surface and welded to the rod body.

[0054] Step 3.2 Excavation on the right side of Zone A

[0055] After excavation of Zone A is completed, excavation of Zone B to the right of Zone A begins. Zone B is excavated to B-5 before excavation of Zone C begins, in order to establish a complete load-bearing system as soon as possible. Zones B and C are excavated using a stepped excavation method. Zone D is excavated after Zones B and C are completed, using full-section excavation. Each excavation cycle advances 1-2 meters until the excavation is complete. During construction, a set of 2.5m long anchor bolts is added at each arch joint. To facilitate connection, shotcrete application should be temporarily suspended within 50cm of the joint location.

[0056] Step 3.3 Excavation on the left side of area A

[0057] After the right side of area A is excavated, the left side of area A is excavated using the same construction method, i.e., area B' → area C' → area D', to complete the excavation of the entire dome.

[0058] Full-face excavation emphasizes fully utilizing the self-supporting function of the rock mass (surrounding rock) structure, minimizing repeated disturbance and damage to the surrounding rock. It employs a construction platform equipped with appropriate large-scale machinery, and follows a predetermined cyclic advance according to design specifications. Holes are drilled along and within the designed cross-sectional outline of the passage, and explosive energy is used for a single blast to form the tunnel. This method effectively reduces labor requirements, lowers worker intensity, and improves work efficiency. Specific parameters for full-face excavation blasting of the passage should be referenced.

[0059] During the dome blasting, to control over- and under-excavation, the locations of each blast hole on the excavation section were marked with spray paint during the surveying and layout process. Figure 2 As shown, the blasting-related parameters are set as follows:

[0060] ① The excavation advance of each blast hole cycle shall not exceed 2m;

[0061] ② The initial design of the slotting hole is a wedge-shaped slot (level 2), and the amount of medicine per hole is controlled within 1.8 kg;

[0062] ③ Auxiliary holes: the spacing between holes should be controlled between 0.6 and 0.8 m, and adjusted according to the actual situation on site; the amount of explosive per hole should be controlled within 1.2 kg.

[0063] ④ For the peripheral holes, the hole spacing should be controlled at 0.5m, and the charge per hole should be controlled within 0.6kg. It is recommended to use interval charging, detonating cord connection, and control the thickness of the flash blast layer (distance from the second ring hole) at 0.6m.

[0064] ⑤ For the bottom plate holes, the hole spacing should be controlled between 0.6 and 0.8 m, and the amount of medicine per hole should be controlled within 1.5 kg;

[0065] ⑥ For cases where the borehole depth is not less than 2m, the adjustment can be made at 0.5~0.6kg / m.

[0066] Step 4: Excavate the lower branch passage to extend the passage.

[0067] After the tank chamber dome is formed, continue excavating along the lower support channel to extend the channel. The excavation distance should be no less than 6m until it exceeds the position of one side of the vertical shaft.

[0068] Step 5: Shaft blasting excavation

[0069] Drill a through hole from top to bottom using a down-the-hole drill to connect with the extension channel of the lower branch channel, which serves as the blasting face. Then drill holes around the through hole and blast to form a vertical shaft. To avoid the shaft from being blocked, the holes are slightly tilted towards the edge of the tank at an angle of 2 to 3 degrees to form a funnel shape, ensuring that the diameter of the shaft is not less than 2m.

[0070] Specifically, the cross-sectional dimension of the shaft excavation is Ф2m. First, a 90mm diameter through hole 9 is drilled using a down-the-hole drill. Then, four cut holes 10 are arranged around the through hole, evenly distributed along the center. Six peripheral holes 11 are evenly distributed along the excavation line, with the bottom of each hole inclined outwards by 5cm. The drilling is done using a down-the-hole drill. The shaft excavation should be completed in one operation. The hole layout diagram is shown below. Figure 3 As shown.

[0071] The blasting parameters for the vertical shaft are shown in Table 1:

[0072]

[0073] Note: The parameters listed in this article are preliminary design parameters and should be adjusted appropriately based on on-site test explosions, cross-sectional dimensions, and other factors during construction.

[0074] Table 1 Parameters of Vertical Shaft Blasting Holes

[0075] Step 6: Blasting and excavating the central part of the tank.

[0076] The excavation from the dome to the bottom of the tank is divided into n layers, where n is a natural number. The first layer is excavated using shaft 1 as the free face. Figure 4 , Figure 5 As shown, taking the center point of the tank as a circle, multiple rings expand outward from the inside, such as Zone VI, Zone VIII, and Zone VIII. Cylindrical excavation is carried out sequentially from the inside out, with each layer being blasted twice. Excavation is carried out to a distance of 1.5 to 2 meters from the edge of the tank chamber. 1.5 meters is taken when the surrounding rock is good and 2 meters is taken when the surrounding rock is poor. Down-the-hole drills are used to drill vertically. After blasting, the blast debris is directly transferred to the lower branch passage through the vertical shaft. A 50-ton loader is used to shovel the debris and transport it to the passing lane for loading. Single-axle dump trucks are used to transport it away, completing the excavation of the central part of the tank.

[0077] Step 7: Blasting and excavating the edge of the tank.

[0078] The edge area of ​​the tank (zone IX) (1.5-2m from the edge of the tank chamber) is excavated in n layers from top to bottom, such as... Figure 4 , Figure 5 As shown, from top to bottom, the zones are IX-1 to IX-4, with each layer divided into 18 zones for excavation. For example, the 18 zones of the first layer are IX-1-1 to IX-1-18. A maximum of 3 zones can be excavated at a time, using a skip-slot excavation method. Each zone can have no more than 3 arch frames, and both ends of the same closed arch frame cannot be excavated simultaneously. The excavation depth is 3m. Drilling is done manually using a YT-28 pneumatic drill. Initial support construction is carried out promptly after excavation. To ensure that workers and machinery can enter and exit the tank chamber, 2 zones at the upper support passage entrance are reserved for temporary non-excavation or slag removal operations are not carried out after blasting. The slag generated during excavation is hauled to the bottom of the tank chamber using an excavator and loaded onto trucks for removal through the lower support passage until the tank body is excavated and formed.

[0079] Preferably, a spiral access road 4 is constructed inside the tank for excavators, loaders, etc. to travel on, such as... Figure 6 As shown, the spiral access road 4 is arranged circumferentially along the side wall of the tank in a spiral shape. During the excavation of the first few layers (two layers in the example), access is via the spiral access road constructed from the upper branch passage 2. Before excavating the last few layers, the lower branch passage 3 leading to the spiral access road 4 is constructed first. Then, the upper spiral access road is dismantled in 3-meter increments, with timely support provided, until the entire upper excavation and support are completed (6 meters in the example). The lower branch passage is promptly addressed. During the excavation of the last few layers (two layers in the example), a temporary access road is constructed from the lower branch passage for access.

[0080] The tank body was excavated using a shallow-hole bench blasting method, with the vertical shaft serving as the free face, layer by layer from top to bottom. A protection scheme combining blast zone coverage and near-zone shielding was adopted, along with controlled blasting by rationally selecting the blasting direction, appropriately increasing the density of blast holes, and controlling the maximum single-explosive charge, in order to keep blasting vibration, flyrock, and fragment size within permissible ranges.

[0081]

[0082] Table 2. Parameters of blasting holes for tank steps

[0083] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A method for blasting excavation of cylindrical tank chambers, characterized in that: The steps are as follows: Step 1: Excavate the lower support channel to the edge of the tank and complete the reinforcement measures for the opening; Step 2: Excavate the upper support passage to the top of the tank chamber dome and complete the opening reinforcement measures; Step 3: Using the upper support passage, the dome is divided into multiple zones for blasting and excavation until the upper tank chamber is formed. The dome blasting construction adopts a zoned excavation method, which is divided into seven zones. Zone A is excavated first. After the excavation of Zone A is completed, the right and left sides of Zone A are excavated in the order of Zone B → Zone C → Zone D. The advance per cycle of tank chamber dome excavation is controlled within 2m. Zone A extends radially from the edge of the tank chamber at the upper support passage to the opposite edge of the tank chamber. Using the radial line perpendicular to the boundary of Zone A as the dividing line, Zone B and Zone C are divided on the same side of Zone A. Zones B and C extend along the dividing line to 1.5-2m from the edge of the tank chamber. Zone C is close to the upper support passage. The remaining part is Zone D. Step 4: After the dome excavation is completed, continue excavating the lower branch channel towards the tank body, extending the channel beyond the slag discharge shaft. Step 5: Excavate the shaft from top to bottom using blasting. The shaft connects the upper tank chamber with the extended lower support passage. The blasting method for the shaft is as follows: Drill a 90mm diameter through hole from top to bottom using a down-the-hole drill. The through hole connects to the extended lower support passage. Arrange four slotting holes around the through hole, evenly distributed along the center. Arrange six to eight peripheral holes evenly along the excavation line. The bottom of the shaft is inclined towards the edge of the tank body at an angle of 2 to 3°. Step 6: Blasting excavation of the central part of the tank. The area from the dome to the bottom of the tank is excavated in n layers from top to bottom, where n is a natural number. The vertical shaft is used as the free surface. Taking the center point of the tank as the circle, multiple rings are expanded from the inside to the outside. Cylindrical excavation is carried out from the inside to the outside. Each layer is blasted twice to remove slag. Excavation is carried out to a distance of 1.5 to 2m from the edge of the tank chamber. Step 7: Blasting excavation at the edge of the tank. For the area 1.5 to 2m away from the edge of the tank chamber, the excavation is divided into n layers from top to bottom. Each layer is divided into m zones for excavation. A maximum of 3 zones can be excavated at a time. The excavation is carried out in a skip-slot manner until the tank body is excavated and shaped.

2. The blasting excavation method for cylindrical tank chambers according to claim 1, characterized in that: In step S3, when excavating area A, the excavation cross-section is expanded when the upper support passage is excavated to 0.5m from the edge of the tank chamber, increasing the excavation width from 4.3m to 6m. During the excavation of area A, the dome position is over-excavated by 20cm. The excavation height is increased from 4.35m to 5.93m and then reduced to 2.38m according to the shape of the dome. The full-section method and the step method are used for excavation according to the excavation height.

3. The blasting excavation method for cylindrical tank chambers according to claim 2, characterized in that: In step S3, when the excavation height is less than 4.5m, the full-section method is used for excavation; when the excavation height is greater than 4.5m, the bench method is used for excavation.

4. The blasting excavation method for cylindrical tank chambers according to claim 1, characterized in that: In step S3, the excavation of areas B and C adopts the step-by-step method. Area D is carried out after the excavation of areas B and C is completed. Area D adopts full-section excavation, with an excavation advance of 1m to 2m per cycle until the excavation is completed.

5. The blasting excavation method for cylindrical tank chambers according to claim 1, characterized in that: In step S3, during the dome blasting, the blasting-related parameters are set as follows: ① The excavation advance of each blast hole cycle shall not exceed 2m; ② The slotting hole is a wedge-shaped slot, and the amount of medicine in a single hole is controlled within 1.8 kg; ③ The spacing between auxiliary holes should be controlled between 0.6 and 0.8 m, and adjusted according to the actual situation on site; the amount of chemical per hole should be controlled within 1.2 kg. ④ The spacing between the perimeter holes is controlled at 0.5m, the charge per hole is controlled at less than 0.6kg, interval charging is adopted, detonating cord is used for connection, and the distance between the flash blasting layer and the second ring hole is controlled at 0.6m; ⑤ The spacing between holes in the bottom plate should be controlled between 0.6 and 0.8 m, and the amount of medicine per hole should be controlled within 1.5 kg; ⑥ For cases where the borehole depth is not less than 2m, adjust the pressure by 0.5 to 0.6 kg / m.

6. The blasting excavation method for cylindrical tank chambers according to claim 1, characterized in that: In steps S6 and S7, the blasting excavation of the central and edge parts of the tank adopts the shallow hole bench blasting method, with a blast hole depth of 2 to 2.5 m, a distance of 1 to 1.5 m between two adjacent blast holes, a distance of 1 to 1.2 m between two adjacent rings of blast holes, and a single hole charge of ≤1.3 KG.

7. The blasting excavation method for cylindrical tank chambers according to claim 1, characterized in that: In step S7, the area 1.5 to 2m from the edge of the tank chamber is divided into 18 zones for excavation on each layer. When excavating by skipping trenches, the two ends of the same arch frame cannot be excavated at the same time.

8. The blasting excavation method for cylindrical tank chambers according to claim 1, characterized in that: In step S7, a spiral passage is constructed inside the tank. The spiral passage is arranged circumferentially along the side wall of the tank in a spiral shape. The upper part of the spiral passage is connected to the upper branch passage, and the lower part of the spiral passage is connected to the lower branch passage.

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