Step-by-step tunneling method for shield and annular blasting of central small pilot tunnel in hard rock stratum vertical shaft

Abstract

The invention discloses a shield and annular blasting step-by-step tunneling method for a central small pilot tunnel in a vertical shaft of a hard rock stratum. The shield and annular blasting step-by-step tunneling method comprises the following steps: S1, excavating the central pilot tunnel in a tunnel face of the hard rock stratum in the vertical shaft by utilizing a cutter shield tunneling machine; s2, after excavation of the center pilot tunnel is completed, a driving assembly of the cutterhead shield tunneling machine is closed; s3, blast holes are formed in the hard rock stratum in the circumferential direction of the center pilot tunnel through the drilling skylight of the shield, and cartridges are installed in the blast holes; s4, the cutterhead shield tunneling machine is moved upwards, so that a cutterhead assembly of the cutterhead shield tunneling machine is moved to the tunnel face; s5, initiating the cartridge, and removing rock slag generated after the cartridge is blasted; and S6, the step S1 to the step S5 are repeated, and the next tunnel face is excavated till shaft excavation is completed. The method has the advantages that the small-diameter cutterhead shield is adopted to form the center pilot tunnel, then the blasting drill holes are formed in the small pilot tunnel towards the surrounding rock mass in the radial direction, the number of blasting cartridges can be reduced, over-break and under-break are controlled, and cost is saved.

Description

Technical Field

[0001] The invention belongs to the technical field of shaft construction, and in particular relates to a central small pilot hole shield and annular blasting step-by-step excavation method in a shaft of a hard rock formation. Background Art

[0002] my country's cities are developing rapidly, but in the process of decades of development, due to changes in development concepts at various stages, unreasonable urban planning, economic costs and population growth, urban space utilization and layout are unreasonable, as well as old and dilapidated renovation, urban development cannot meet people's needs, and urban renewal and transformation have become the future development trend. With the acceleration of urban renewal in my country, the problem of underground space utilization has become increasingly prominent. Major cities have built shaft garages to alleviate parking difficulties, underground storage pools to regulate flood disasters and recycle water resources, and shafts as underground energy storage and underground energy storage space, mountain tunnel ventilation shafts, etc. Shaft construction methods are divided into manual excavation construction, semi-mechanical excavation construction and mechanical excavation construction. Shield tunneling is widely used due to its advantages such as fast excavation speed, high safety and little impact on the surrounding environment.

[0003] Mechanized construction of large-diameter shafts has always been a difficult problem in the field of underground engineering. Currently, most construction methods use manually excavated shafts. After the shaft is built on the ground, it sinks as it is excavated. The construction speed is slow, and the shaft is prone to deflection, poor sinking, and the need to add sinking aids when sinking. In recent years, with the development of science and technology, some mechanized construction equipment has gradually emerged, but there are problems such as low mechanization and slow slag discharge speed that affect the construction progress. Especially for hard rock formations, a single drilling and blasting method or shield construction is usually used, which has problems such as low construction efficiency, safety of construction personnel, severe tool wear and frequent tool changes. It is impossible to comprehensively utilize the characteristics of shield tunneling, high safety, small impact on the surrounding environment, and high efficiency of drilling and blasting in hard rock excavation. Summary of the invention

[0004] The purpose of the present invention is to provide a method for step-by-step excavation of a central small guide hole shield and annular blasting in a hard rock formation shaft in accordance with the deficiencies of the above-mentioned prior art, which utilizes a cutterhead shield machine, which is composed of a cutterhead assembly, a drive assembly and a shield. The drive assembly is arranged in the shield and connected to the cutterhead assembly. The shield has a plurality of drilling skylights along its circumference, and the drive assembly drives the cutterhead assembly to rotate. First, a small-diameter cutterhead shield is used to form a central guide hole during the excavation of the hard rock shaft, which increases the blasting free surface for the large-diameter hard rock shaft drilling and blasting excavation. Then, blasting drill holes are arranged radially in the small guide hole toward the surrounding rock mass, which can reduce the number of blasting cartridges, control over-excavation and under-excavation, and save costs.

[0005] The purpose of the present invention is achieved by the following technical solutions: A method for tunneling in a hard rock formation using a central small pilot tunnel shield and annular blasting step-by-step tunneling method, the tunneling method comprising the following steps: S1: Use a cutterhead shield machine to excavate a central pilot tunnel on the tunnel face of the hard rock formation in the shaft; The cutterhead shield machine comprises a cutterhead assembly, a drive assembly and a shield, wherein the drive assembly is arranged in the shield and connected to the cutterhead assembly, and the shield is provided with a plurality of drilling skylights along its circumference; the drive assembly is started, and the drive assembly drives the cutterhead assembly to rotate, so that the cutterhead shield machine excavates the central guide hole downward; S2: After the excavation of the central pilot tunnel is completed, the drive assembly of the cutterhead shield machine is turned off; S3: using the drilled skylight of the shield, opening a blast hole on the hard rock formation around the central guide hole, and installing a charge in the blast hole; S4: moving the cutterhead shield machine upwards so that the cutterhead assembly of the cutterhead shield machine moves to the tunnel face; S5: detonating the explosive roll and removing rock slag generated after the explosive roll is exploded; S6: Repeat steps S1 to S5 to excavate the next tunnel face until the excavation of the shaft is completed.

[0006] The driving assembly includes a motor, a cutter head frame and a reaction frame. The base of the motor is installed on the reaction frame, and the motor shaft is connected to the cutter head assembly through the cutter head frame. The motor drives the cutter head assembly to rotate.

[0007] The reaction frame is composed of a fan-shaped support plate, a reaction plate, a radial rib plate and an arc-shaped rib plate. The reaction plate is circular, and a plurality of fan-shaped support plates are arranged along the circumference of the reaction plate. The radial rib plates and the arc-shaped rib plates are arranged along the radial direction and the arc-shaped rib plate respectively.

[0008] The cutter disc frame is composed of a connecting disc and a support foot. The connecting disc is in a circular ring shape. The two sides of the connecting disc are respectively connected to the motor shaft of the motor and the support foot. The support foot is inclined and arranged in multiple numbers along the circumference of the connecting disc. The support foot is connected to the cutter disc assembly.

[0009] The cutter disc assembly includes a cutter disc, a roller cutter and a scraper. The cutter disc includes a central circle cutter disc and a fan-shaped cutter disc. Multiple fan-shaped cutter discs are arranged along the circumference of the central circle cutter disc. A slag inlet is formed between adjacent fan-shaped cutter discs. Several groups of scrapers are arranged on both sides of the arc of the fan-shaped cutter disc, several groups of roller cutters are arranged in the middle of the fan-shaped cutter disc, and several groups of roller cutters are arranged on the central circle cutter disc.

[0010] The advantages of the present invention are: (1) First, a small-diameter cutterhead shield is used to form a central guide tunnel during the excavation of a hard rock shaft, which increases the blasting surface for the large-diameter hard rock shaft drilling and blasting excavation. Then, blasting holes are arranged radially in the small guide tunnel toward the surrounding rock mass, which can reduce the number of blasting cartridges, control over-excavation and under-excavation, and save costs. (2) Shield tunneling is highly safe, but there are problems with severe wear and tear of cutters in hard rock formations and high maintenance costs. The drilling and blasting method is low-cost but less safe. Combining the advantages and disadvantages of the shield method and the drilling and blasting method, only a small-diameter cutterhead shield is used to form a central guide hole to increase the blasting free surface, reduce the number of cutters and the length of use, reduce cutter wear, and save costs. (3) Using a small-diameter cutterhead shield machine to construct a large-diameter shaft can reduce the deformation of the shaft surrounding rock and ensure the safety of shaft construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of the cutterhead shield machine of the present invention; Figure 2 for Figure 1 AA section view; Figure 3 for Figure 2 BB cross-section diagram; Figure 4 for Figure 2 CC profile of ; Figure 5 for Figure 2 DD profile diagram; Figure 6 for Figure 2 EE profile of Figure 7 It is a schematic diagram of the construction process of the present invention; Figure 8 for Figure 7 FF cross-section diagram in; Fig. 9 for Figure 7 GG profile in; like Figures 1 to 9 As shown, the marks in the figure represent respectively: 1. Cutterhead shield machine, 2. Hard rock formation, 3. Vertical shaft, 4. Blast hole, 5. Charge roll; 11. Cutterhead assembly, 12. Drive assembly, 13. Shield, 14. Drilling skylight; 111. Cutter head, 112. Hob, 113. Scraper, 114. Slag inlet; 121. motor, 122. motor shaft, 123. cutter head frame, 124. reaction frame; 1231. Connecting plate, 1232. Support foot; 1241. fan-shaped support plate, 1242. reaction plate, 1243. radial rib plate, 1244. arc-shaped rib plate; 21. Palm face, 22. Center guide hole. DETAILED DESCRIPTION

[0012] The features of the present invention and other related features are further described in detail below through embodiments in conjunction with the accompanying drawings to facilitate understanding by those skilled in the art: Example: Figures 1 to 9 As shown, this embodiment specifically relates to a method for tunneling in a hard rock formation using a central small pilot tunnel shield and annular blasting step-by-step. The tunneling method mainly includes the following steps: S1: using the cutterhead shield machine 1 to excavate a central guide tunnel 22 on the tunnel face 21 of the hard rock stratum 2 in the shaft 3.

[0013] Among them, Figures 1 to 6 As shown, the cutterhead shield machine 1 includes a cutterhead assembly 11, a drive assembly 12 and a shield 13. The drive assembly 12 is arranged in the shield 13 and connected to the cutterhead assembly 11. The shield 13 is provided with a plurality of drilling skylights 14 along its circumference. The drilling skylights 14 can be used to drill blast holes for installing medicine rolls. The drive assembly 12 drives the cutterhead assembly 11 to rotate, thereby realizing the downward rotation of the cutterhead shield machine 1 to excavate the central guide hole 22.

[0014] The cutterhead assembly 11 includes a cutterhead 111, a roller cutter 112 and a scraper 113. The cutterhead 111 includes a central circular cutterhead and a fan-shaped cutterhead. Six fan-shaped cutterheads are arranged along the circumference of the central circular cutterhead. A slag inlet 114 is formed between adjacent fan-shaped cutterheads. Three groups of scrapers 113 are arranged on both sides of the arc of the fan-shaped cutterhead. Three groups of roller cutters 112 are arranged in the middle of the fan-shaped cutterhead. Two groups of roller cutters 112 are arranged on the central circular cutterhead, and the two groups of roller cutters 112 of the central circular cutterhead are in a cross shape. The roller cutters 112 and the scraper 113 are used for excavating the hard rock formation 2, thereby forming rock slag, and the rock slag can enter the shield 13 from the slag inlet 114.

[0015] The driving assembly 12 includes a motor 121, a cutter head frame 123 and a reaction frame 124. The base of the motor 121 is mounted on the reaction frame 124 (reaction plate 1242). The motor shaft 122 is connected to the fan-shaped cutter head of the cutter head assembly 11 through the cutter head frame 123. The motor 121 drives the cutter head assembly 11 to rotate. The cutter head frame 123 is composed of a connecting plate 1231 and a support foot 1232. The connecting plate 1231 is annular. Both sides of the connecting plate 1232 are connected to the motor shaft 122 of the motor 121 and the support foot 1232 respectively. The support foot 1232 is inclined and arranged 6 times along the circumference of the connecting plate 1231. The support foot 1232 is connected to the fan-shaped cutter head of the cutter head assembly 11. The reaction frame 124 is composed of a fan-shaped support plate 1241, a reaction plate 1242, radial ribs 1243 and arc-shaped ribs 1244. The reaction plate 1242 is circular. There are 6 fan-shaped support plates 1241 arranged along the circumference of the reaction plate 1242. The radial ends of the fan-shaped support plate 1241 are respectively connected to the reaction plate 1242 and the shield 13. The radial ribs 1243 and the arc-shaped ribs 1244 are respectively arranged along the radial direction and arc direction of the fan-shaped support plate 1241, so as to strengthen the fan-shaped support plate 1241.

[0016] When the cutterhead shield machine 1 is located on the tunnel face 21 , the motor 121 of the drive assembly 12 is started, and the motor 121 of the drive assembly 12 drives the cutterhead assembly 11 to rotate, so that the cutterhead shield machine 1 excavates the central guide tunnel 22 downward.

[0017] S2: After the excavation of the central guide hole 22 is completed, the motor 121 of the driving assembly 12 is turned off.

[0018] S3: using the drilled skylight 14 of the shield 13 , a blast hole 4 is opened on the hard rock stratum 2 in the circumferential direction of the central guide hole 22 , and a charge roll 5 is installed in the blast hole 4 .

[0019] The blast holes 4 (charge rolls 5) are arranged radially with the central guide hole 22 as the center.

[0020] S4: Move the cutterhead shield machine 1 upwards, so that the cutterhead assembly 11 of the cutterhead shield machine 1 moves to the tunnel face 21 .

[0021] S5: Detonating the explosive roll 5 and removing the rock slag produced after the explosive roll 5 is blasted.

[0022] S6: Repeat steps S1 to S5 to excavate the next tunnel face 21 until the excavation of the shaft 3 is completed.

[0023] The beneficial effects of this embodiment are: (1) First, a small-diameter cutterhead shield is used to form a central guide tunnel during the excavation of a hard rock shaft, which increases the blasting surface for the large-diameter hard rock shaft drilling and blasting excavation. Then, blasting holes are arranged radially in the small guide tunnel toward the surrounding rock mass, which can reduce the number of blasting cartridges, control over-excavation and under-excavation, and save costs. (2) Shield tunneling is highly safe, but there are problems with severe wear and tear of cutters in hard rock formations and high maintenance costs. The drilling and blasting method is low-cost but less safe. Combining the advantages and disadvantages of the shield method and the drilling and blasting method, only a small-diameter cutterhead shield is used to form a central guide hole to increase the blasting free surface, reduce the number of cutters and the length of use, reduce cutter wear, and save costs. (3) Using a small-diameter cutterhead shield machine to construct a large-diameter shaft can reduce the deformation of the shaft surrounding rock and ensure the safety of shaft construction.

[0024] Although the above embodiments have described in detail the concepts and embodiments of the present invention with reference to the accompanying drawings, ordinary technicians in this field can recognize that various improvements and changes can still be made to the present invention without departing from the scope of the claims, so they are not described one by one here.

Claims

1. A method for tunneling in a hard rock formation using a central small pilot tunnel shield and annular blasting step by step, characterized in that The excavation method comprises the following steps: S1: Use a cutterhead shield machine to excavate a central pilot tunnel on the tunnel face of the hard rock formation in the shaft; The cutterhead shield machine comprises a cutterhead assembly, a drive assembly and a shield, wherein the drive assembly is arranged in the shield and connected to the cutterhead assembly, and the shield is provided with a plurality of drilling skylights along its circumference; the drive assembly is started, and the drive assembly drives the cutterhead assembly to rotate, so that the cutterhead shield machine excavates the central guide hole downward; S2: After the excavation of the central pilot tunnel is completed, the drive assembly of the cutterhead shield machine is turned off; S3: using the drilled skylight of the shield, opening a blast hole on the hard rock formation around the central guide hole, and installing a charge in the blast hole; S4: moving the cutterhead shield machine upwards so that the cutterhead assembly of the cutterhead shield machine moves to the tunnel face; S5: detonating the explosive roll and removing rock slag generated after the explosive roll is exploded; S6: Repeat steps S1 to S5 to excavate the next tunnel face until the excavation of the shaft is completed.

2. A method for tunneling in a hard rock formation vertical shaft by shield tunneling and annular blasting in a central small pilot hole according to claim 1, characterized in that The driving assembly includes a motor, a cutter head frame and a reaction frame. The base of the motor is installed on the reaction frame, and the motor shaft is connected to the cutter head assembly through the cutter head frame. The motor drives the cutter head assembly to rotate.

3. A method for tunneling in a hard rock formation using a central small pilot tunnel shield and annular blasting step by step according to claim 2, characterized in that The reaction frame is composed of a fan-shaped support plate, a reaction plate, a radial rib plate and an arc-shaped rib plate. The reaction plate is circular, and a plurality of fan-shaped support plates are arranged along the circumference of the reaction plate. The radial rib plates and the arc-shaped rib plates are arranged along the radial direction and the arc-shaped rib plate respectively.

4. A method for tunneling in a hard rock formation using a central small pilot tunnel shield and annular blasting step by step according to claim 2, characterized in that The cutter disc frame is composed of a connecting disc and a support foot. The connecting disc is in a circular ring shape. The two sides of the connecting disc are respectively connected to the motor shaft of the motor and the support foot. The support foot is inclined and arranged in multiple numbers along the circumference of the connecting disc. The support foot is connected to the cutter disc assembly.

5. The method of tunneling in a hard rock formation vertical shaft by shield tunneling and annular blasting in a central small pilot hole according to claim 2, characterized in that The cutter disc assembly includes a cutter disc, a roller cutter and a scraper. The cutter disc includes a central circle cutter disc and a fan-shaped cutter disc. Multiple fan-shaped cutter discs are arranged along the circumference of the central circle cutter disc. A slag inlet is formed between adjacent fan-shaped cutter discs. Several groups of scrapers are arranged on both sides of the arc of the fan-shaped cutter disc, several groups of roller cutters are arranged in the middle of the fan-shaped cutter disc, and several groups of roller cutters are arranged on the central circle cutter disc.

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