Large-section tunnel peripheral hole anti-blocking protection and smooth blasting collaborative operation system

Abstract

The invention provides an anti-blocking hole protection and smooth blasting collaborative operation system for peripheral holes of a large-section tunnel, and belongs to the technical field of tunnel construction. The method comprises the following steps: S1, determining peripheral hole arrangement parameters based on tunnel geological survey data; s2, a combined type anti-blocking hole protecting device is adopted for conducting drilling protection on peripheral holes, the anti-blocking hole protecting device is synchronously installed in the drilling process, and after drilling is completed, residual rock powder in the holes is removed through cooperation of high-pressure airflow and a rock powder collecting assembly; s3, adjusting light explosion parameters according to the rock firmness coefficient; s4, adopting a partition collaborative detonation mode, and adopting millisecond millisecond detonation for the peripheral holes and the main detonation holes; and S5, flatness detection is conducted on the tunnel slope after blasting. According to the method, integrated cooperation of anti-blocking hole protection, smooth blasting parameter optimization, detonation control and parameter closed-loop adjustment is achieved, the peripheral hole drilling quality, the smooth blasting effect and the construction efficiency are improved, the construction cost is reduced, and tunnel construction safety and structural stability are guaranteed.

Description

TECHNICAL FIELD

[0001] The present application provides a large-section tunnel peripheral hole anti-blocking protection hole and light blasting coordinated operation system, which belongs to the technical field of tunnel construction. BACKGROUND

[0002] With the rapid advancement of China's transportation infrastructure construction, tunnel engineering gradually develops towards the trend of "large, deep and long". The drilling and blasting construction quality of large-section tunnels directly affects the safety and stability of tunnel structure and the subsequent construction efficiency, because the large-section tunnels have large cross-section width and weak self-stability of surrounding rock. As a key component of smooth blasting, the drilling quality, hole integrity and matching degree of light blasting parameters of peripheral holes are the key factors to determine the light blasting effect, control the flatness of tunnel slope and reduce overbreak and underbreak.

[0003] At present, there are two major technical problems in the construction process of large-section tunnel peripheral holes: first, the hole is prone to blockage after drilling. Due to the falling of rock debris during drilling, the infiltration of underground water, and the mechanical disturbance during construction, it is easy to cause the accumulation of residual rock powder in the hole and the collapse of the hole wall, causing difficulty in subsequent charging, and even requiring re-drilling, which seriously affects the construction progress and increases the construction cost; second, the anti-blocking protection hole is disconnected from the light blasting operation. In the existing technology, the anti-blocking protection hole is mostly a single protection measure, which is not designed in coordination with the light blasting parameters and detonation mode, resulting in poor protection effect, and the light blasting parameters cannot be adapted to the hole state, causing problems such as poor flatness of the slope after blasting and excessive disturbance of the surrounding rock, which cannot meet the construction quality requirements of large-section tunnels.

[0004] In the existing technology, some tunnel construction adopts a simple orifice plugging method for anti-blocking, such as paper, cloth or cork plugging, which not only has poor anti-blocking effect, but also the plugging materials are mostly disposable, causing serious waste, and cannot realize coordination with the light blasting operation; some other technologies focus on the optimization of light blasting parameters, but do not consider the influence of hole blockage on the light blasting effect, lack of dynamic adjustment mechanism, resulting in unstable light blasting effect. In addition, the existing peripheral hole arrangement parameters are mostly fixed values, which are not dynamically adapted to the geological conditions, and the matching degree of light blasting parameters and rock properties is insufficient, further affecting the blasting quality.

[0005] Therefore, in view of the above technical problems, it is urgent to develop a large-section tunnel peripheral hole anti-blocking protection hole and light blasting coordinated operation system which can realize the coordinated control of peripheral hole anti-blocking protection hole and light blasting operation, dynamically optimize parameters combined with geological conditions, and is convenient to operate, reliable in protection and stable in light blasting effect, in order to solve the deficiencies of the existing technology and promote the upgrading of large-section tunnel drilling and blasting construction technology. SUMMARY

[0006] The purpose of the present application is to overcome the defects in the prior art, such as the disconnection between the anti-blocking hole protection and the light blasting operation, the high hole jamming rate, the unstable light blasting effect, and the inability to dynamically adapt parameters, and to provide a large-section tunnel peripheral hole anti-blocking hole protection and light blasting collaborative operation system, which realizes the integration and collaboration of anti-blocking hole protection, light blasting parameter optimization, detonation control, and parameter closed-loop adjustment, improves the peripheral hole drilling quality, light blasting effect, and construction efficiency, reduces construction cost, and ensures the safety and structural stability of tunnel construction.

[0007] In order to solve the above problems, the technical scheme provided by the present application is as follows: a large-section tunnel peripheral hole anti-blocking hole protection and light blasting collaborative operation system, comprising the following steps: S1, determining peripheral hole arrangement parameters based on tunnel geological survey data, wherein the peripheral hole arrangement parameters include a hole diameter of 100 mm, a hole spacing of 0.8-1.2 m, a minimum resistance line of 0.77-1.43 m, and a hole depth calculated and determined by a formula L=H / sinα according to the tunnel slope ratio and the step height, wherein H is the step height and a is the drilling angle; S2, drilling and protecting the peripheral hole by using a combined anti-blocking hole protection device, wherein the combined anti-blocking hole protection device comprises a hole mouth protection cap, an anti-corrosion sleeve in the hole, and a bottom positioning mechanism, the anti-blocking hole protection device is installed synchronously during the drilling process, and the residual rock powder in the hole is removed by high-pressure airflow in cooperation with a rock powder collection assembly after the drilling is completed; S3, adjusting the light blasting parameters according to the rock firmness coefficient, controlling the linear charge density to be 0.22-0.48 kg / m, adopting a decoupling charge structure, and setting the decoupling coefficient of the cartridge diameter and the hole diameter to be 2-3, and the blocking length is not less than the minimum resistance line; S4, adopting a partition collaborative detonation mode, using millisecond differential detonation for the peripheral hole and the main blast hole, controlling the time difference of the peripheral hole detonation to be 25-50 ms, arranging the detonation sequence in a "Z" shape, and realizing the inter-hole collaborative transmission by a detonating cord triangular lap joint mode; S5, detecting the flatness of the tunnel slope after blasting, dynamically adjusting the peripheral hole arrangement parameters and the anti-blocking hole protection device installation process according to the detection results, and forming a closed-loop optimization mechanism.

[0008] Further, the anti-corrosion sleeve in the combined anti-blocking hole protection device in step S2 is made of high-strength wear-resistant composite material, the sleeve wall is provided with air holes, the bottom positioning mechanism is fixed to the hole bottom rock layer by an expansion anchoring method, and the hole mouth protection cap adopts an elastic sealing structure to prevent rock slag and underground water from entering the hole during the drilling process.

[0009] Further, the decoupling charge structure in step S3 adopts a spaced charge mode, the buffer material is filled between the cartridge and the hole wall, the buffer material is selected to be inert particles with a particle size of 5-10 mm, and the filling density is 1.2-1.5 g / cm³.

[0010] Furthermore, the zoned coordinated detonation mode in step S4 includes three stages: pre-splitting hole detonation, peripheral hole synchronous detonation, and main detonation hole segmented detonation. The time interval between pre-splitting hole detonation and peripheral hole detonation is 110-150ms. The main detonation hole is segmented according to the standard that the maximum single-shot charge does not exceed 17.28kg, and the charge amount of each segment is calculated and determined using the Sadovsky formula.

[0011] Furthermore, the closed-loop optimization mechanism in step S5 specifically includes: when the slope flatness deviation exceeds 5cm, adjusting the spacing of the surrounding holes to 0.8-0.9m; when the hole blockage rate exceeds 3%, optimizing the sleeve length and vent density of the anti-blockage protection device, and simultaneously increasing the high-pressure airflow hole clearing pressure to 0.6-0.8MPa.

[0012] Furthermore, the geological survey data in step S1 includes rock firmness coefficient, weathered layer thickness, and groundwater distribution. When the rock firmness coefficient f = 8-10, the minimum resistance line is taken as 1m and the hole spacing is taken as 1m. When the thickness of the strongly weathered layer exceeds 5m, the hole depth is increased by 1.2-1.5m for the ultra-deep section.

[0013] Furthermore, in step S2, the high-pressure airflow cleaning adopts a pulsed air supply mode with a supply frequency of 3-5 times / minute and a duration of 10-15 seconds for each supply. The rock powder collection component collects the rock powder discharged from the orifice through negative pressure adsorption, with a collection efficiency of not less than 95%.

[0014] Furthermore, in step S3, the plugging material is a mixture of drill rock powder and loess in a 3:1 ratio. The plugging process adopts a layered compaction process, with each layer having a compaction thickness of no more than 20cm and a total plugging length of no less than 1.0m.

[0015] Due to the adoption of the above technical solution, the beneficial effects of the large-section tunnel perimeter hole anti-blocking and protection hole and the light blasting collaborative operation system of the present invention are as follows: 1. Achieve coordinated operation of anti-blocking and protective hole protection with light blasting, breaking the current situation where the two are disconnected in the existing technology. The combined anti-blocking and protective hole protection device is designed in an integrated manner with light blasting parameters and blasting mode. This not only ensures the integrity of the surrounding holes and channels, but also improves the light blasting effect through precise matching of light blasting parameters, effectively controls the flatness of the tunnel slope, reduces over-excavation and under-excavation, and lowers the cost of subsequent support.

[0016] 2. The combined anti-clogging borehole protection device provides reliable protection. The combined action of the borehole opening protective cap, the anti-corrosion sleeve inside the borehole, and the bottom positioning mechanism can effectively prevent rock debris and groundwater from entering the borehole during the drilling process. At the same time, the anti-corrosion sleeve made of high-strength wear-resistant composite material can prevent borehole wall collapse. The bottom expansion anchoring method ensures that the device is firmly installed. The vent design facilitates high-pressure airflow to clean the borehole, further reducing the borehole blockage rate.

[0017] 3. The light blasting parameters are highly adaptable. The linear charge density, decoupling coefficient and other parameters are dynamically adjusted according to the rock firmness coefficient. The use of interval charging method and special buffer materials reduces the disturbance of the surrounding rock caused by blasting. At the same time, the reasonable plugging process ensures that the blasting energy is fully utilized, thereby improving the uniformity and stability of light blasting.

[0018] 4. The zoned coordinated detonation mode is optimized by combining millisecond micro-delay detonation with a “Z”-shaped detonation sequence. The triangular overlap of the detonating cord enables coordinated detonation between holes, effectively controlling the detonation time difference and avoiding interference from the detonation of surrounding holes. At the same time, the phased detonation of pre-splitting holes, surrounding holes, and main detonation holes further enhances the blasting effect and ensures the stability of the surrounding rock of the tunnel.

[0019] 5. Establish a closed-loop optimization mechanism. Through post-blasting slope flatness testing and borehole blockage statistics, dynamically adjust the surrounding borehole layout parameters, anti-blockage and protective borehole device installation process, and borehole cleaning pressure to achieve continuous optimization of the construction process, ensure the stability of operational results, and adapt to construction needs under different geological conditions. 6. Convenient operation and high efficiency: The anti-clogging protection device is installed simultaneously during the drilling process, eliminating the need for additional construction procedures. The combination of pulsed high-pressure airflow for hole cleaning and negative pressure rock powder collection not only provides excellent hole cleaning results but also reduces rock powder pollution. At the same time, the parameters are easy to adjust, which can effectively improve construction efficiency and shorten the construction cycle. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart of the system for coordinated operation of large-section tunnel perimeter hole anti-blocking protection hole and light blasting.

[0021] Figure 2 This is a schematic diagram of the reserved light blasting for the large-section tunnel perimeter hole anti-blocking protection hole and light blasting collaborative operation system of the present invention. Figure 1 .

[0022] Figure 3 This is a schematic diagram of the reserved light blasting for the large-section tunnel perimeter hole anti-blocking protection hole and light blasting collaborative operation system of the present invention. Figure 2 . Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0024] This embodiment is applied to the construction of a large-section highway tunnel. The tunnel has a maximum excavation width of 21m, a cross-sectional area of ​​240m², and geological conditions consisting of moderately weathered rock strata with a rock strength coefficient f=8-10, a strongly weathered layer thickness of 3m, limited groundwater distribution, a bench height H=3m, and a drilling angle α=75°. The specific steps using the operating system of this invention are as follows: S1. Determine the surrounding borehole layout parameters: Based on geological survey data, the rock firmness coefficient f=8-10, therefore the minimum resistance line is taken as 1m, the borehole spacing is taken as 1m, and the borehole diameter is determined to be 100mm; the borehole depth is calculated according to the formula L=H / sinα, H=3m, α=75°, sin75°≈0.966, therefore the borehole depth L=3 / 0.966≈3.11m, there is no need to add an ultra-deep section (the thickness of the strongly weathered layer is 3m<5m).

[0025] S2. Installation and Cleaning of the Combined Anti-Clogging and Protective Hole Device: A combined anti-clogging and protective hole device is adopted. The anti-corrosion sleeve inside the hole is made of high-strength wear-resistant composite material. The sleeve wall is equipped with 5mm diameter vent holes with a spacing of 50cm. The bottom positioning mechanism is fixed to the rock strata at the bottom of the hole through expansion anchors. The protective cap at the hole opening adopts a rubber elastic sealing structure. During the drilling process, the anti-corrosion sleeve inside the hole is inserted into the hole simultaneously, the bottom positioning mechanism is installed and fixed. After drilling is completed, pulsed high-pressure airflow is used for hole cleaning, with an air supply frequency of 4 times / minute and each air supply lasting 12 seconds. The initial cleaning pressure is set to 0.5MPa. With the help of the negative pressure adsorption rock powder collection component, the rock powder discharged from the hole opening is collected, with a collection efficiency of 96%, ensuring that there is no residual rock powder in the hole.

[0026] S3. Adjustment of blasting parameters and charging: Based on the rock strength coefficient f=8-10, the linear charge density is adjusted to 0.35kg / m; a decoupled charging structure is adopted, with a charge diameter of 35mm and an aperture of 100mm, and the decoupling coefficient = 100 / 35≈2.86 (within the range of 2-3); an intermittent charging method is adopted, with 5-10mm quartz sand (inert particles) filled between the charge and the borehole wall, and the filling density is 1.3g / cm³; the plugging material is a mixture of borehole rock powder and loess, with a mixing ratio of 3:1, and a layered compaction process is adopted, with each layer compacted to a thickness of 18cm, and a total plugging length of 1.2m (greater than the minimum resistance line by 1m).

[0027] S4. Zoned Coordinated Initiation: The zoned coordinated initiation mode is adopted, which is divided into three stages: pre-splitting hole initiation, peripheral hole synchronous initiation, and main blasting hole segmented initiation. The time interval between the pre-splitting hole initiation and the peripheral hole initiation is 130ms. The peripheral holes and the main blasting hole adopt millisecond micro-delay initiation, and the initiation time difference of the peripheral holes is controlled at 35ms. The initiation sequence is arranged in a "Z" shape, and the coordinated transmission of detonation between holes is achieved by the triangular overlapping of the detonating cord. The main blasting hole is divided into 4 segments according to the standard that the maximum single explosive charge does not exceed 17.28kg. The Sadovsky formula is used to calculate the explosive charge of each segment to ensure uniform release of blasting energy.

[0028] S5. Closed-loop optimization and adjustment: After blasting, a laser flatness detector was used to test the tunnel slope. The test results showed that the maximum slope flatness deviation was 3.2cm (less than 5cm) and the hole blockage rate was 1.5% (less than 3%). Therefore, the next round of construction does not require adjustment of the surrounding hole layout parameters and the anti-blocking hole protection device installation process. Construction can continue with the existing parameters.

[0029] After the completion of this embodiment, the tunnel slope flatness rate reached 98%, the over-excavation and under-excavation were controlled within the allowable range of the specifications, the hole blockage rate was only 1.5%, there was no need for re-drilling, the construction efficiency was improved by 30% compared with the traditional process, and there was no significant disturbance to the surrounding rock after blasting, with good stability. Example

[0030] This embodiment is applied to the construction of a large-section railway tunnel. The tunnel has a maximum excavation width of 23m, a cross-sectional area of ​​260m², and geological conditions consisting of strongly weathered rock layers with a rock strength coefficient f=6-7, a strongly weathered layer thickness of 6m, relatively abundant groundwater, a bench height H=3.5m, and a drilling angle α=70°. The specific steps using the operating system of this invention are as follows: S1. Determine the surrounding borehole layout parameters: Based on geological survey data, the rock firmness coefficient f=6-7, therefore the minimum resistance line is taken as 0.9m, the borehole spacing is taken as 1.1m, and the borehole diameter is determined to be 100mm; the borehole depth is calculated according to the formula L=H / sinα, H=3.5m, α=70°, sin70°≈0.940, therefore the borehole depth L=3.5 / 0.940≈3.72m; since the thickness of the strongly weathered layer is 6m>5m, the borehole depth is increased by 1.3m for the ultra-deep section, and the final borehole depth is 3.72+1.3=5.02m.

[0031] S2. Installation and Cleaning of the Combined Anti-Clogging and Protective Hole Protection Device: A combined anti-clogging and protective hole protection device is adopted. The anti-corrosion casing inside the hole is made of high-strength wear-resistant composite material. The casing wall is equipped with 6mm diameter vent holes with a spacing of 40cm. The bottom positioning mechanism is fixed to the bottom rock layer through expansion anchors. The hole opening protective cap adopts a silicone elastic sealing structure (suitable for scenarios with abundant groundwater). The anti-clogging and protective hole protection device is installed simultaneously during drilling. After drilling is completed, pulsed high-pressure airflow is used for hole cleaning, with an air supply frequency of 5 times / minute and each air supply lasting 15 seconds. The initial hole cleaning pressure is 0.5MPa. After hole cleaning, the hole blockage rate was found to be 3.8% (exceeding 3%). Therefore, the hole cleaning pressure was adjusted to 0.7MPa. After hole cleaning again, the hole blockage rate dropped to 2.2%, and the rock powder collection component achieved a collection efficiency of 95.5%.

[0032] S3. Adjustment of blasting parameters and charging: Based on the rock firmness coefficient f=6-7, the linear charge density is adjusted to 0.28kg / m; a decoupled charging structure is adopted, with a charge diameter of 33mm and an aperture of 100mm. The decoupling coefficient is approximately 100 / 33≈3.03 (close to 3, meeting the requirements); an intermittent charging method is adopted, with 5-10mm river sand (inert particles) filling the space between the charge and the borehole wall, with a filling density of 1.4g / cm³; the plugging material is a mixture of borehole rock powder and loess in a 3:1 ratio, using a layered compaction process, with each layer compacted to a thickness of 19cm, and a total plugging length of 1.1m (greater than the minimum resistance line of 0.9m).

[0033] S4. Zoned Coordinated Initiation: A zoned coordinated initiation mode is adopted, with a time interval of 140ms between the initiation of pre-splitting holes and the initiation of peripheral holes; the peripheral holes and the main blasting hole adopt millisecond micro-delay initiation, with the initiation time difference of peripheral holes controlled at 45ms. The initiation sequence is arranged in a "Z" shape, and the coordinated detonation between holes is achieved through the triangular overlapping of detonating cords; the main blasting hole is divided into 5 sections according to the standard that the maximum single-explosive charge does not exceed 17.28kg. The Sadovsky formula is used to calculate the amount of explosive charge for each section to avoid excessive blasting disturbance.

[0034] S5. Closed-loop optimization and adjustment: After blasting, a laser flatness detector was used to test the tunnel slope. The test results showed that the maximum slope flatness deviation was 5.8cm (exceeding 5cm). Therefore, in the next round of construction, the spacing of the surrounding holes was adjusted to 0.85m. At the same time, the hole blockage rate was 2.2% (less than 3%), so there was no need to adjust the sleeve length of the anti-blocking protection device and the density of the vent holes. The hole cleaning pressure was maintained at 0.7MPa, forming a closed-loop optimization.

[0035] In this embodiment, after adjusting the parameters in the next round of construction, the maximum deviation of the slope flatness was reduced to 4.1cm, the hole blockage rate was kept below 2.0%, the blasting effect was significantly improved, the influence of groundwater on the duct was effectively suppressed, and the construction efficiency was increased by 28% compared with the traditional process, effectively ensuring the construction quality and safety of large-section tunnels under strongly weathered rock conditions. Example

[0036] This embodiment is applied to the construction of a large-section municipal tunnel. The tunnel has a maximum excavation width of 19m, a cross-sectional area of ​​220m², and geological conditions consisting of slightly weathered rock layers with a rock strength coefficient f=10⁻¹², a strongly weathered layer thickness of 2m, very little groundwater, a step height H=2.8m, and a drilling angle α=80°. The specific steps using the operating system of this invention are as follows: S1. Determine the surrounding borehole layout parameters: Based on geological survey data, the rock firmness coefficient f=10-12, therefore the minimum resistance line is taken as 1.2m, the borehole spacing is taken as 1.2m, and the borehole diameter is determined to be 100mm; the borehole depth is calculated according to the formula L=H / sinα, H=2.8m, α=80°, sin80°≈0.985, therefore the borehole depth L=2.8 / 0.985≈2.84m, there is no need to add an ultra-deep section (the thickness of the strongly weathered layer is 2m<5m).

[0037] S2. Installation and Cleaning of Combined Anti-Clogging and Protective Hole Protection Device: A combined anti-clogging and protective hole protection device is adopted. The anti-corrosion casing inside the hole is made of high-strength wear-resistant composite material. The casing wall is equipped with 4mm diameter vent holes with a spacing of 60cm. The bottom positioning mechanism is fixed to the rock strata at the bottom of the hole through expansion anchors. The protective cap at the hole opening adopts a rubber elastic sealing structure. The anti-clogging and protective hole protection device is installed simultaneously during drilling. After drilling is completed, pulsed high-pressure airflow is used for hole cleaning, with an air supply frequency of 3 times / minute and each air supply lasting 10 seconds. The cleaning pressure is 0.5MPa. With the help of negative pressure adsorption rock powder collection components, the collection efficiency reaches 97%, and the hole blockage rate is 1.1%.

[0038] S3. Adjustment of blasting parameters and charging: Based on the rock strength coefficient f=10-12, the linear charge density is adjusted to 0.42kg / m; a decoupled charging structure is adopted, with a charge diameter of 38mm and an aperture of 100mm, and the decoupling coefficient = 100 / 38≈2.63 (within the range of 2-3); an intermittent charging method is adopted, with basalt particles (inert particles) with a particle size of 5-10mm filled between the charge and the borehole wall, and the filling density is 1.5g / cm³; the plugging material is a mixture of borehole rock powder and loess, with a mixing ratio of 3:1, and a layered compaction process is adopted, with each layer compacted to a thickness of 20cm, and a total plugging length of 1.3m (greater than the minimum resistance line of 1.2m).

[0039] S4. Zoned Coordinated Initiation: A zoned coordinated initiation mode is adopted, with a time interval of 120ms between the initiation of pre-splitting holes and the initiation of peripheral holes; the peripheral holes and the main blasting hole adopt millisecond micro-delay initiation, with the initiation time difference of peripheral holes controlled at 28ms. The initiation sequence is arranged in a "Z" shape, and the coordinated detonation between holes is achieved through the triangular overlapping of detonating cords; the main blasting hole is divided into 3 sections according to the standard that the maximum single-explosive charge does not exceed 17.28kg, and the charge of each section is calculated using the Sadovsky formula.

[0040] S5. Closed-loop optimization and adjustment: After blasting, the maximum deviation of slope flatness was 2.9cm (less than 5cm), and the hole blockage rate was 1.1% (less than 3%). Therefore, the next round of construction will maintain the existing parameters and continue stable construction.

[0041] After the completion of this embodiment, the tunnel slope flatness rate reached 99%, the over-excavation and under-excavation were far below the allowable range of the specifications, the surrounding rock integrity was good after blasting, and there was no collapse or rockfall. The construction efficiency was increased by 32% compared with the traditional process, and the overall construction cost was reduced by 18%.

[0042] The above three embodiments demonstrate that the large-section tunnel perimeter hole anti-blocking and protection hole and light blasting collaborative operation system of the present invention can be adapted to the construction of large-section tunnels with different geological conditions (moderate weathering, strong weathering, and slight weathering) and different cross-sectional sizes. Through the collaborative control and closed-loop optimization mechanism of anti-blocking and protection hole and light blasting, it effectively solves technical problems such as perimeter hole blockage and unstable light blasting effect, improves construction efficiency and construction quality, and has good practicality and promotion value.

[0043] The present invention and its embodiments have been described above. This description is not restrictive. In short, if a person skilled in the art is inspired by this description and designs a similar structure and embodiment without departing from the spirit of the present invention, such design should fall within the protection scope of the present invention.

Claims

1. A system for coordinated operation of perimeter hole sealing and blasting in large-section tunnels, comprising the following steps: S1. Determine the layout parameters of the surrounding holes based on the tunnel geological survey data. The layout parameters of the surrounding holes include a hole diameter of 100mm, a hole spacing of 0.8-1.2m, a minimum resistance line of 0.77-1.43m, and a hole depth calculated according to the tunnel slope ratio and step height using the formula L=H / sinα, where H is the step height and α is the drilling angle. S2. A combined anti-clogging hole protection device is used to protect the surrounding holes during drilling. The combined anti-clogging hole protection device includes a hole opening protection cap, an anti-corrosion sleeve inside the hole, and a bottom positioning mechanism. The anti-clogging hole protection device is installed simultaneously during the drilling process. After the drilling is completed, the residual rock powder inside the hole is removed by high-pressure airflow in conjunction with a rock powder collection component. S3. Adjust the blasting parameters according to the rock firmness coefficient, control the linear charge density to 0.22-0.48 kg / m, adopt a decoupled charge structure, the decoupling coefficient between the charge cartridge diameter and the aperture is 2-3, and the plugging length is not less than the minimum resistance line. S4. The zoned coordinated detonation mode is adopted. The peripheral holes and the main detonation hole are detonated with millisecond micro-delay. The detonation time difference of the peripheral holes is controlled at 25-50ms. The detonation sequence is arranged in a "Z" shape. Coordinated detonation between holes is achieved by the triangular overlapping of the detonating cord. S5. After blasting, the flatness of the tunnel slope is tested. Based on the test results, the layout parameters of the surrounding holes and the installation process of the anti-blocking protection hole device are dynamically adjusted to form a closed-loop optimization mechanism.

2. The system for coordinated operation of anti-blocking and protective holes for perimeter holes in large-section tunnels and light blasting as described in claim 1, characterized in that: In step S2, the in-hole anti-corrosion sleeve of the combined anti-blocking hole protection device is made of high-strength wear-resistant composite material. The sleeve wall is provided with vent holes. The bottom positioning mechanism is fixed to the bottom rock layer by expansion anchoring. The hole opening protective cap adopts an elastic sealing structure to prevent rock debris and groundwater from entering the hole during drilling.

3. The system for coordinated operation of anti-blocking and protective holes and light blasting for large-section tunnel perimeter holes according to claim 1, characterized in that: In step S3, the decoupled charge structure adopts an intermittent charge method, and the space between the charge cartridge and the hole wall is filled with a buffer material. The buffer material is selected as inert particles with a particle size of 5-10mm and a filling density of 1.2-1.5g / cm³.

4. The system for coordinated operation of anti-blocking and protective holes for perimeter holes in large-section tunnels and light blasting as described in claim 1, characterized in that: The partitioned coordinated detonation mode in step S4 includes three stages: pre-splitting hole detonation, peripheral hole detonation, and main detonation hole segmented detonation. The time interval between pre-splitting hole detonation and peripheral hole detonation is 110-150ms. The main detonation hole is segmented according to the standard that the maximum single-shot charge does not exceed 17.28kg. The charge amount for each segment is calculated using the Sadovsky formula.

5. The system for coordinated operation of anti-blocking and protective holes for perimeter holes in large-section tunnels and light blasting as described in claim 1, characterized in that: The closed-loop optimization mechanism in step S5 specifically includes: when the slope flatness deviation exceeds 5cm, adjusting the spacing of the surrounding holes to 0.8-0.9m; when the hole blockage rate exceeds 3%, optimizing the sleeve length and vent density of the anti-blockage protection device, and simultaneously increasing the high-pressure airflow hole clearing pressure to 0.6-0.8MPa.

6. The system for coordinated operation of anti-blocking and protective holes for perimeter holes in large-section tunnels and light blasting as described in claim 1, characterized in that: The geological survey data in step S1 includes rock firmness coefficient, weathered layer thickness, and groundwater distribution. When the rock firmness coefficient f = 8-10, the minimum resistance line is taken as 1m and the hole spacing is taken as 1m. When the thickness of the strongly weathered layer exceeds 5m, the hole depth is increased by 1.2-1.5m for the ultra-deep section.

7. The system for coordinated operation of anti-blocking and protective holes for perimeter holes in large-section tunnels and light blasting as described in claim 1, characterized in that: In step S2, the high-pressure airflow cleaning adopts a pulsed air supply mode with a supply frequency of 3-5 times / minute and a duration of 10-15 seconds for each supply. The rock powder collection component collects the rock powder discharged from the orifice through negative pressure adsorption, with a collection efficiency of not less than 95%.

8. The system for coordinated operation of anti-blocking and protective holes for perimeter holes in large-section tunnels and light blasting as described in claim 1, characterized in that: In step S3, the plugging material is a mixture of drill rock powder and loess in a 3:1 ratio. The plugging process adopts a layered compaction process, with each layer having a compaction thickness of no more than 20cm and a total plugging length of no less than 1.0m.

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