A tunnel blasting and shock reduction construction method

Abstract

The present invention discloses a tunnel tic-tac-toe method for blasting and exiting a tunnel with shock absorption. In a set mileage section from the tunnel exit, especially in a large span position of a variable cross section of the tunnel, the construction method is changed to the tic-tac-toe method, that is, the tunnel face is partitioned to form a plurality of blasting areas similar to a tic-tac-toe shape, the plurality of blasting areas are numbered, a vertical excavation support system is set between some blasting areas, and the partitions are detonated hole by hole in sequence according to the set blasting area number sequence, and micro-difference weak blasting is adopted hole by hole to control the disturbance of the blasting to the rock, and the construction is carried out in conjunction with mechanical excavation. The present invention not only ensures the construction quality and progress, but also reduces the influence of the tunnel blasting and exiting construction on itself and other structures.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel engineering construction, and more specifically, to a tunnel blasting and hole-exit shock-absorbing construction method. Background Art

[0002] With the need to build a strong transportation country, the requirements for tunnel capacity and transportation are becoming higher and higher. The span and excavation cross-sectional area of ​​newly built tunnels are showing an increasingly larger development trend. At present, in the construction of tunnels or tunnels, the commonly used construction method is blasting excavation, and the common construction methods are step method, full section, etc.

[0003] Conventional tunnel construction procedures, in order to save construction time and increase the working surface, often open a cross passage on the side of the mountain. This will result in the tunnel penetrating from the middle of the mountain to the slope. The rock strata and geological conditions encountered are complex, and the tunnel burial depth will also drop sharply. The rock strata are mostly broken zones or soil layers. Especially in the location of large spans with variable cross-sections in the tunnel, conventional blasting excavation methods have serious safety hazards. If you are not careful, tunnel collapse incidents may occur from time to time. It is particularly important to control the blasting vibration, which is particularly obvious in large-span tunnels. Therefore, new construction methods are urgently needed for large-span tunnels.

[0004] In the process of conventional tunnel exit blasting construction, some corresponding measures will also be taken, such as a large amount of advance support for the tunnel exit face in advance, including advance pipe sheds, small guide tubes, curtain grouting, etc., which not only increases construction costs and slows down construction period, but also has low operation efficiency. The blasting construction still uses traditional excavation methods, and uncontrolled blasting vibrations may have a destructive effect on existing tunnels, especially in the shallow mileage sections of the tunnel exit, which are prone to landslides. In order to reduce blasting vibrations and shorten the tunnel construction period during tunnel exit blasting construction, and meet the growing demand for fast-paced engineering construction, it is necessary to seek a construction method that not only ensures construction quality and progress, but also minimizes the impact of tunnel blasting construction on itself and other structures. Summary of the invention

[0005] One object of the present invention is to provide a tunnel blasting and hole-exit shock-absorbing construction method, which not only ensures the construction quality and progress, but also reduces the impact of the tunnel blasting and hole-exit construction on itself and other structures.

[0006] In order to solve the above technical problems, the present invention provides a tunnel tic-tac-toe blasting and shock-absorbing construction method. At a set mileage section away from the tunnel exit, especially at a large span position with a variable cross-section of the tunnel, the construction method is changed to the tic-tac-toe method, that is, the tunnel heading face is divided into multiple tic-tac-toe-shaped blasting areas, the multiple blasting areas are numbered, a vertical excavation support system is set between some of the blasting areas, and the partitions are detonated hole by hole in the set blasting area number sequence, and micro-difference weak blasting is used hole by hole to control the disturbance of the blasting to the rock, and mechanical excavation is coordinated for construction.

[0007] Preferably, the face is divided into seven blasting areas, that is, the face is divided into three parts from top to bottom, namely, upper, middle and lower parts, the upper part and the middle part form three blasting areas from left to right respectively, and the lower part forms one blasting area, the middle blasting areas in the upper part and the middle part are part ① and part ⑥ respectively, the left and right sides of part ① are part ② and part ③ respectively, the left and right sides of part ⑥ are part ④ and part ⑤ respectively, and the lower part is part ⑦, and detonation is carried out hole by hole in the order of part ①-part ⑦, and excavation construction is carried out.

[0008] Preferably, an excavation support system is provided on both sides of part ① close to part ② and part ③, which includes a vertical support and a vibration isolation plate arranged on the outside of the vertical support, and a steel mesh and shotcrete are also arranged between the vertical support and the vibration isolation plate; the excavation support system also includes a partition wall protection layer reserved when parts ② and ③ are excavated.

[0009] Preferably, when blasting and drilling blastholes one by one, vertical holes are drilled in section ⑥ and penetrate to section ⑦, and some horizontal holes are drilled in section ⑦.

[0010] Preferably, the method comprises the following steps:

[0011] Step S1, cleaning and protective construction of the tunnel exit;

[0012] Step S2, partitioning the tunnel face according to the set partitioning method to form seven blasting areas, and performing corresponding support;

[0013] Step S3, determining the excavation contour line of the partitioned part ①, and drilling the blastholes according to the blasthole design drawing, after the drilling is completed, the charge is connected to the network, and the blasting is initiated by micro-difference blasting hole by hole;

[0014] Step S4, after the blasting of part ① and the slag discharge are completed, an excavation support system is set up on both sides of part ①, and then part ① is excavated continuously according to the above steps;

[0015] Step S5, after the excavation of part ① reaches the set mileage, a certain safety layout is ensured, and parts ② and ③ are excavated alternately. When parts ② and ③ are excavated, the excavation contour close to the vertical support of part ① is retracted by a set spacing as a reserved partition wall protection layer. After the blastholes of part ② or part ③ are drilled according to the blasthole design drawing, part ② or part ③ is charged and networked, and detonated by hole-by-hole micro-difference blasting;

[0016] Step S6, after the blasting of part ② or part ③ and the slag discharge is completed, the reserved partition wall protective layer is mechanically broken, and the vibration isolation plate in the process of part ① is taken out for subsequent excavation of part ①. According to the above steps, a certain safety step distance is ensured between part ① and part ③, and part ② or part ③ is excavated alternately on both sides;

[0017] Step S7, after the excavation of section ①-section ③ reaches the set mileage, ensure that there is a reasonable safety step distance between section ③ and section ④ and section ⑤, and alternately excavate sections ④ and ⑤ close to the core soil side of section ⑥, and after drilling the blastholes according to the blasthole design drawing, use hole-by-hole micro-difference blasting to initiate the explosion;

[0018] Step S8, after the blasting of part ④ or part ⑤ and the slag discharge is completed, according to the above steps, a certain safe step distance is ensured between part ④ and part ⑤, and part ④ or part ⑤ is excavated alternately on both sides;

[0019] Step S9, according to the above steps, ensure that there is a safe step distance between each part of part ①-part ⑤, stagger excavate part ①-part ⑤, excavate part ⑥ and part ⑦ under the condition that the distance between part ⑥ and part ⑦ is not less than the set safe step distance of part ⑤, remove the vertical support of part ① in the single cycle footage area, and reuse it as the vertical support on both sides of the excavated part ① in front, according to the blasthole design drawing, drill vertical holes in the core soil of part ⑥ and extend to part ⑦, drill horizontal holes on both sides and contours of part ⑦, adopt hole-by-hole micro-difference blasting, and detonate part ⑥ and part ⑦ at one time;

[0020] Step S10: construct according to the above steps in sequence until the tunnel is penetrated inside the mountain.

[0021] Preferably, in step S5, when alternately excavating part ② and part ③, ensure that the excavation sections of part ①, part ② and part ③ are not in the same section and are at least 30m apart from each other by a safe step distance; when excavating parts ② and ③, the excavation outline of the vertical support close to part ① is retracted by 50cm as a rock wall interval to reserve a partition wall protection layer; in step S7, while meeting the requirement of the safe step distance between parts ① and ③ in step S5, ensure that the excavation sections of parts ④ and ⑤ are not in the same section and are at least 30m apart from each other by a safe step distance; in step S9, under the condition that parts ⑥ and ⑦ are not less than 50m away from part ⑤, the vertical support of part ① in the single-cycle footage area is removed, and then blasting excavation construction of parts ⑥ and ⑦ is carried out.

[0022] Preferably, the blast holes in the blasting area (1) are designed as follows: corresponding rows of slot holes A, auxiliary holes B and peripheral holes E are symmetrically arranged from the inside to the outside, and corresponding rows of bottom plate holes C are arranged below the (1) part, and corresponding rows of pressure holes D and peripheral holes E are arranged above the (1) part from the inside to the outside, and the detonation sequence is: according to A→B→C→D→E, and there is a time difference Tp between different columns and rows, and there is a time difference Tk between each row of blast holes, so as to ensure the micro-difference blasting of the blast holes on the face, and different columns and rows of the same category are detonated hole by hole from the inside to the outside, and the peripheral holes located in the column direction are detonated earlier than the peripheral holes located in the row direction; wherein, the slot hole spacing is 60 cm, the row spacing is 65 cm, the auxiliary hole spacing is 80 cm, the row spacing is 80 cm, the peripheral hole spacing is 40 cm, the light blasting layer thickness is 60 cm, and the blast hole angle is 50°~90°.

[0023] Preferably, the design of the blasting area ② and ③ blast holes is as follows: ② and ③ are fan-shaped structures, and corresponding rows of slot holes A, auxiliary holes B and peripheral holes E are arranged in sequence from the inside to the outside, and corresponding rows of bottom plate holes D are arranged below; between the auxiliary holes B and the peripheral holes E in ② and ③, corresponding rows of auxiliary holes B and auxiliary holes C are arranged in sequence from the inside to the outside along the contour line of the tunnel; the detonation sequence is: according to A→B→C→D→E, and there is a time difference Tp between different numbers of columns and rows There is a time difference Tk between each row of blastholes to ensure the slight difference blasting of each blasthole on the face. The same category with different columns and rows are detonated hole by hole from the inside to the outside. The auxiliary holes in the column direction are detonated earlier than the auxiliary holes in the row direction. Among them, the spacing between the slot holes in parts ② and ③ is 45cm and the row spacing is 60cm. The spacing between the auxiliary holes is 80~110cm and the row spacing is 60cm. The spacing between the peripheral holes is 40cm, the thickness of the light blasting layer is 50~60cm, and the blasthole angle is 60°~90°.

[0024] Preferably, the blasting area parts ④ and ⑤ are designed as follows: two rows of peripheral holes A are respectively arranged on both sides, and auxiliary holes B, auxiliary holes C, auxiliary holes D and bottom plate holes E of set numbers are arranged in sequence from top to bottom between the two rows of peripheral holes; pre-splitting blasting is adopted, and the peripheral hole A is detonated first to form an isolation vibration belt, and the detonation sequence is: according to A→B→C→D→E, and there is a time difference Tp between different columns and rows, and there is a time difference Tk between each row of blasting holes, so as to ensure the micro-difference blasting of the blasting holes on the face, and different columns and rows of the same category are detonated hole by hole from inside to outside; wherein, the main blasting holes of parts ④ and ⑤ are spaced 90-140cm apart, the row spacing is 110cm, the peripheral hole spacing is 50cm, and the thickness of the light blasting layer is 60cm.

[0025] Preferably, the design of the blasting area ⑥ and ⑦ is as follows: peripheral holes A are set at the contour line below ⑦, auxiliary holes B in the column direction and auxiliary holes C in the horizontal direction are set from the inside to the outside on both sides, and auxiliary holes D and auxiliary holes E in the vertical direction with a set number of rows are set; pre-splitting blasting is adopted, and the peripheral hole A is detonated first to form an isolation vibration belt, and the detonation order is: according to A→B→C→D→E, and there is a time difference Tp between different column numbers and row numbers, and there is a time difference Tk between each row of blasting holes , ensuring the micro-difference blasting of each blast hole on the face, the vertical auxiliary holes in the ⑥ part are detonated one by one from the outside to the inside between different rows; among them, vertical holes are drilled in the core soil of the ⑥ part, the main blasting hole spacing is 100cm, the row spacing is 80cm, the peripheral hole spacing is 50cm, and the thickness of the light blasting layer is 60~80cm. The depth of the holes drilled in the ⑥ part penetrates to the ⑦ part, and vertical holes are drilled. A protective layer with a thickness of 60~80cm is reserved from the bottom of the hole to the excavation contour of the ⑦ part, and horizontal holes are drilled in the remaining part of the ⑦ part.

[0026] The present invention has at least the following beneficial effects:

[0027] 1. The tunnel excavation method provided by the present invention has a simpler support structure than the conventional single (double) side wall pilot pit method, and the structure and connection method of the support system are simpler. Compared with the current technology, the construction safety is improved, the safety performance of the construction can be effectively guaranteed, and the workload and cost of tunnel exit are reduced.

[0028] 2. The tunnel excavation method provided by the present invention has a more regular regional division of the excavation area of ​​the face, which is easier for construction personnel to operate, reduces the cost of tunnel excavation, effectively improves economic benefits, and has less disturbance to the surrounding rock of the face.

[0029] 3. The shock-absorbing measure scheme provided by the present invention, the intermediate shock-absorbing insulation layer and the rock partition wall can effectively prevent the damage of the vertical support of part ①, and the micro-difference blasting of each hole can reduce the blasting vibration.

[0030] 4. The excavation methods of parts ⑥ and ⑦ provided by the present invention, the vertical holes are relative to the horizontal blasting excavation, which can reduce the impact of blasting on the undismantled support system, not only improving the safety of the overall structure, but also controlling the flying rocks caused by blasting.

[0031] 5. The present invention can be applied to the construction of mountain tunnels with large spans, broken rock layers, and rock and soil layers, especially to control blasting vibrations during the tic-tac-toe construction to ensure safe and rapid exit from the tunnel.

[0032] 6. The tunnel excavation method of the tic-tac-toe method provided by the present invention can divide the excavation area of ​​the heading face into more areas, and multiple working surfaces can exist at the same time. Under reasonable construction organization and arrangement, efficient construction can be easily achieved and the construction period can be shortened.

[0033] 7. The excavation method of parts ④, ⑤, ⑥, and ⑦ provided by the present invention has a detonation sequence of A→B→C→D→E, and adopts pre-splitting blasting. The peripheral hole A is detonated first to form an isolation vibration zone, which can further effectively reduce the impact of blasting vibration in this area.

[0034] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the tic-tac-toe method of the present invention for the partitioning of the face and the shock absorbing structure;

[0036] Figure 2 It is the layout diagram of blastholes in each zone of the tic-tac-toe method of the present invention;

[0037] Figure 3 This is the network diagram of hole-by-hole micro-difference initiation of the present invention;

[0038] Figure 4 This is the hole-by-hole micro-difference detonation network diagram of parts ② and ③ of the present invention;

[0039] Figure 5 This is the hole-by-hole micro-difference detonation network diagram of parts ④ and ⑤ of the present invention;

[0040] Figure 6 This is the hole-by-hole micro-difference initiation network diagram of parts ⑥ and ⑦ of the present invention. DETAILED DESCRIPTION

[0041] In order to better understand the purpose, structure and function of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement it according to the description.

[0042] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0043] The present invention provides a shock reduction measure and construction method for tunnel blasting exit by tic-tac-toe method. At an appropriate mileage section of tunnel exit, especially at a large span position of tunnel variable cross section, the construction method is changed to tic-tac-toe method, steel is used as vertical support in the middle, the face is divided, and micro-difference weak blasting is used for zoning blasting excavation. At the same time, vibration isolation plates, reserved partition wall protection layers and other measures are used to further reduce the impact on surrounding rocks and vertical supports, which can effectively prevent safety accidents such as collapse of the face, further optimize the construction process and working environment, and promote the quality improvement of tunnel engineering construction.

[0044] The present invention proposes a tunnel crisscross method blasting and hole-exit shock-absorbing construction method, which divides the tunnel face into 7 blasting areas for multiple micro-difference blasting. At the same time, the tunnel excavation support system and the advance system are composed of vibration isolation plates, steel vertical supports, steel meshes, advance small guide tubes, advance pipe racks, etc., wherein the vibration isolation plates and steel meshes are attached to the outer wall of the vertical support of the crisscross method, and the vibration isolation plates are made of lightweight rubber materials. At the same time, the vibration isolation plates and the vertical steel supports of the crisscross method can be reused, which greatly reduces the material cost of construction.

[0045] The present invention provides a tunnel blasting and hole construction shock-absorbing structure and a construction method thereof, comprising the following steps:

[0046] Step 1: According to the tic-tac-toe tunnel entrance design, the tunnel exit slope entrance engineering is first constructed before the tunnel exits, vegetation is cleared, and dangerous rocks and fallen stones at the entrance are removed by micro-vibration controlled blasting or mechanical methods. Dangerous rocks and fallen stones are treated by pile-slab stone retaining walls, active protection nets and reinforced piles. The total station is used for positioning, and a reinforced concrete arch is set at the entrance of the tunnel to cooperate with the construction of an advanced large pipe shed into the tunnel.

[0047] Step 2: Use advanced geological forecast to find out the surrounding rock conditions in front of the tunnel face before exiting the tunnel. When the surrounding rock geology deteriorates significantly or the tunnel burial depth is lower than the upper limit of the step method excavation, use the tic-tac-toe method to excavate the tunnel. Figure 1 As shown in the figure, the tunnel face is divided into 7 excavation areas, ①-⑦, which are the ①-⑦ parts of the tic-tac-toe method. The small holes are mainly excavated by blasting and mechanical excavation. Among them, the steel arches 1 are connected by a quick-release plate structure; the two sides of part ① are vertical steel supports, and the outer side of the vertical support 2 is provided with a vibration isolation plate 3, which is a shock-absorbing insulation layer made of lightweight rubber material, and between the vertical support 2 and the vibration isolation plate 3 is a steel mesh and shotcrete 4.

[0048] Step 3: Advance support of the rock formation outside the contour of the tunnel face, and design of the tunnel face area division according to the tic-tac-toe method. The tic-tac-toe method blasthole design diagram is as follows: Figure 2As shown in the figure, after the advanced horizontal support of the face is completed, the excavation contour line of the middle area ① is first determined according to the partition, and the total station is used to measure and lay out the area ①. The peripheral holes and auxiliary holes are drilled according to the blasthole design requirements. The middle slot holes are arranged symmetrically, with a slot hole spacing of 60cm and a row spacing of 65cm, an auxiliary hole spacing of 80cm and a row spacing of 80cm, a peripheral hole spacing of 35~40cm, a light blasting layer thickness of 60cm, and a blasthole angle of 50°~90°. After the slot holes and auxiliary holes of part ① are drilled, the area ① is charged and networked, and after charging and networking, micro-difference blasting is used hole by hole.

[0049] like Figure 3 As shown, the design of the blast holes in part ① of the blasting area is as follows: corresponding rows of slot holes A, auxiliary holes B and peripheral holes E are symmetrically arranged from the inside to the outside, and corresponding rows of bottom plate holes C are arranged below part ①, and corresponding rows of pressure holes D and peripheral holes E are arranged above part ① from the inside to the outside. The same category with different rows and between rows are detonated hole by hole from the inside to the outside, and the peripheral holes located in the row direction are detonated earlier than the peripheral holes located in the row direction.

[0050] The hole-by-hole differential blasting initiation network is as follows Figures 3 to 6 As shown in the figure, firstly, the blast holes are classified and arranged into rows. The slot holes are marked as A, and the row numbers of detonation at different times are marked as A0, A1...A n The auxiliary hole is marked as B, and the number of rows detonated at different times is marked as B0, B1...B n The bottom plate hole is denoted as C, and the number of rows detonated at different times is denoted as C0, C1...C n The pressure hole is recorded as D, and the number of rows detonated at different times is D0, D1...D n ; The peripheral holes are marked as E, and the number of rows detonated at different times is marked as E0, E1...E n ; The order of detonation for different types of blasting is A→B→C→D→E, and there is a time difference T between different rows of the same type p , the time difference between each row of holes is T k , to ensure the micro-difference blasting of each blast hole in the tunnel face, and the actual time difference between rows on site T p and the time difference between holes T k The specific values ​​are determined according to the on-site rock formation conditions and blasting tests. A, B, C, D, and E can also be other holes according to the actual area. When blasting, always follow A→B→C→D→E.

[0051] Step 4: After the blasting of area ① is completed and the slag is removed by backhoe excavator, vibration isolation plates are laid on the side walls on both sides and simply fixed with glue. Steel mesh is hung on the outside of the vibration isolation plates, and vertical supports and arch frames are erected. After the arch frame of part ① is closed, mortar is sprayed, and the above process is repeated to continue excavating area ① from both sides of the tunnel entrance and exit.

[0052] Step 5: After the footage of part ① reaches a certain mileage, preferably more than 60m, use the total station to measure and lay out the area of ​​part ②, drill the peripheral holes and auxiliary holes according to the design requirements, and flexibly arrange the middle slot holes according to the excavation area. The slot hole spacing is 45cm and the row spacing is 60cm. The auxiliary hole spacing is 80~110cm and the row spacing is 60cm. The peripheral hole spacing is 40cm, the thickness of the light blasting layer is 50~60cm, and the blast hole angle is 60°~90°. After the charging is networked, micro-difference blasting is adopted hole by hole. The order of detonation of different categories of blasting is A→B→C→D→E, and there is a time difference Tp between different rows of the same category, and a time difference Tk between each row of holes, to ensure the micro-difference blasting of the blast holes on the face. After the advance of part ② exceeds 30m safety step, use total station to measure and stake out part ③, and carry out drilling and blasting according to design requirements. The hole layout parameters and detonation network are the same as part ②. Parts ② and ③ are excavated alternately. At the same time, it is ensured that the excavation sections of parts ①, ② and ③ are not in the same section, and there is at least 30m safety step between them. The excavation contour of parts ② and ③ is retracted 50cm near the vertical support excavation contour of part ① as rock wall interval 5, and peripheral holes are mechanically drilled with a spacing of 40cm between peripheral holes. After the drilling of slot holes and auxiliary holes in parts ② or ③ is completed, the charging network of parts ② or ③ is connected. According to the blasthole design and the hole-by-hole micro-difference detonation network, hole-by-hole micro-difference blasting is adopted. The order of blasting detonation of different categories is A→B→C→D→E, and there is a time difference Tp between different rows of the same category, and a time difference Tk between each row of holes, to ensure hole-by-hole micro-difference blasting of the blastholes on the face.

[0053] like Figure 4 As shown, the design of the blast holes in parts ② and ③ of the blasting area is as follows: parts ② and ③ are fan-shaped structures, and corresponding rows of slot holes A, auxiliary holes B and peripheral holes E are arranged from the inside to the outside, and corresponding rows of bottom plate holes D are arranged below. Corresponding rows of auxiliary holes B and auxiliary holes C are also arranged from the inside to the outside along the contour line of the tunnel between the auxiliary holes B and peripheral holes E in parts ② and ③. Different rows of the same category and between rows are detonated hole by hole from the inside to the outside, and the auxiliary holes located in the row direction are detonated before the auxiliary holes located in the row direction.

[0054] Step 6: After blasting of area ② or ③ is completed and slag is removed by backhoe excavator, rock wall intervals of area ② or ③ are broken mechanically, and the vibration isolation plate used in the operation of area ① is taken out for subsequent excavation of area ①. After the arch frame of area ② or ③ is closed, mortar is sprayed to complete the single cycle operation of the area, and area ② or ③ is excavated alternately on both sides according to the above steps.

[0055] Step 7: After the footage of ①-③ reaches a certain distance, ④ and ⑤ are excavated alternately with a slope of 1:0.3 near the core soil of part ⑥. Under the condition of meeting the requirements of the safe step distance between parts ①-③ in step 5, ensure that the excavation sections of parts ④ and ⑤ are not in the same section, and are at least 30m apart from each other. Use the free surface of the excavation of parts ② and ③ to improve the quality of contour forming by pre-splitting blasting. The spacing between the main blasting holes is 90-140cm, the row spacing is 110cm, the spacing between the peripheral holes is 50cm, and the thickness of the light blasting layer is 60cm. According to the blasting hole design and the hole-by-hole micro-difference detonation network, hole-by-hole micro-difference blasting is adopted after charging and networking. Pre-splitting blasting is adopted, and the peripheral hole A is detonated first to form an isolation vibration zone. The detonation sequence of different categories of blasting is A→B→C→D→E, and there is a time difference Tp between different rows of the same category, and a time difference Tk between each row of holes, to ensure the micro-difference blasting of each hole in the face.

[0056] like Figure 5 As shown, the design of the blasting area ④ and ⑤ parts blast holes is: two rows of peripheral holes A are set on both sides, and between the two rows of peripheral holes, a set number of rows of auxiliary holes B, auxiliary holes C, auxiliary holes D and bottom plate holes E are arranged in sequence from top to bottom. The same category with different numbers of columns and rows are detonated hole by hole from the inside to the outside.

[0057] Step 8: After blasting of area ④ or ⑤ is completed and slag is removed by backhoe, mortar is sprayed after the arch frame of part ④ or ⑤ is closed to complete the single cycle operation of the area. Excavation of area ④ or ⑤ is carried out alternately on both sides according to the above steps.

[0058] Step 9: After the footage of ①-⑤ reaches a certain distance, under the condition that the distance between ⑥ and ⑦ is not less than 50m from ⑤, the vertical support of part ① in the single-cycle footage area is removed, and the single-cycle footage does not exceed 2 arch frames, which are reused as the vertical supports on both sides of the front excavation part ①. Vertical holes are drilled in the core soil of part ⑥, with the main blasting hole spacing of 100cm, the row spacing of 80cm, the peripheral hole spacing of 50cm, and the thickness of the light blasting layer of 60~80cm. The depth of the hole drilled in part ⑥ runs through part ⑦, and vertical holes are drilled, with the bottom of the hole reserved at a distance from the excavation outline of part ⑦. A 60~80cm thick protective layer was built. Horizontal holes were drilled on both sides and the contour of the remaining part of part ⑦. The blastholes were designed according to the schematic diagram. According to the blasthole design and the hole-by-hole micro-difference blasting network, the peripheral holes were spaced 50cm apart. Micro-difference blasting was adopted for hole-by-hole. Parts ⑥ and ⑦ were detonated at one time with pre-splitting blasting. The peripheral hole A was detonated first to form an isolation vibration zone. The detonation sequence of different categories of blasting was A→B→C→D→E. There was a time difference Tp between different rows of the same category and a time difference Tk between each row of holes to ensure hole-by-hole micro-difference blasting of the blastholes on the face.

[0059] like Figure 6As shown, the design of the blasting area ⑥ and ⑦ holes is as follows: peripheral holes A are set along the contour line below ⑦, longitudinal auxiliary holes B and transverse auxiliary holes C are set on both sides from the inside to the outside, and auxiliary holes D and auxiliary holes E with a set number of rows are set vertically in ⑥, and the vertical auxiliary holes in ⑥ are detonated one by one from the outside to the inside between different rows.

[0060] Step 10: Implement shock reduction measures and construction methods by blasting the tunnel both inside the tunnel and at the exit simultaneously, and penetrate the inside of the mountain according to the above steps.

[0061] It is understood that the present invention is described by some embodiments, and those skilled in the art are aware that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation mode, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, other modifications can be easily implemented, so without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrations shown and described here.

Claims

1. A tunnel blasting and shock absorption construction method, It is characterized in that At the set mileage section from the tunnel exit, the construction method is changed to the tic-tac-toe method, that is, the tunnel face is divided into multiple blasting areas similar to the tic-tac-toe shape, and the multiple blasting areas are numbered. A vertical excavation support system is set between some blasting areas, and the blasting is carried out hole by hole in the set blasting area number sequence. The micro-difference weak blasting is used hole by hole to control the disturbance of the blasting to the rock, and the construction is carried out in conjunction with mechanical excavation; The face is divided into seven blasting areas, that is, the face is divided into three parts from top to bottom, namely, upper, middle and lower. The upper and middle parts form three blasting areas from left to right respectively, and the lower part forms one blasting area. The middle blasting areas in the upper and middle parts are respectively Part ① and Part ⑥, the left and right sides of Part ① are respectively Part ② and Part ③, the left and right sides of Part ⑥ are respectively Part ④ and Part ⑤, and the lower part is Part ⑦. Detonation is carried out hole by hole in the order of Part ①-Part ⑦, and excavation construction is carried out.

2. The tunnel blasting and shock absorption construction method according to claim 1, It is characterized in that Excavation support systems are arranged on both sides of part ① near part ② and part ③, which include vertical supports and vibration isolation plates arranged outside the vertical supports, and steel meshes and shotcrete are arranged between the vertical supports and the vibration isolation plates; the excavation support system also includes a partition wall protection layer reserved when parts ② and ③ are excavated.

3. The tunnel blasting and shock absorption construction method according to claim 1, It is characterized in that When drilling blast holes one by one, vertical holes are drilled in section ⑥ and penetrate to section ⑦, and some horizontal holes are drilled in section ⑦.

4. The tunnel blasting and shock absorption construction method according to claim 2, It is characterized in that The specific steps include: Step S1, cleaning and protective construction of the tunnel exit; Step S2, partitioning the tunnel face according to the set partitioning method to form seven blasting areas, and performing corresponding support; Step S3, determining the excavation contour line of the partitioned part ①, and drilling the blastholes according to the blasthole design drawing, after the drilling is completed, the charge is connected to the network, and the blasting is initiated by micro-difference blasting hole by hole; Step S4, after the blasting of part ① and the slag discharge are completed, an excavation support system is set up on both sides of part ①, and then part ① is excavated continuously according to the above steps; Step S5, after the excavation of part ① reaches the set mileage, a certain safety layout is ensured, and parts ② and ③ are excavated alternately. When parts ② and ③ are excavated, the excavation contour close to the vertical support of part ① is retracted by a set spacing as a reserved partition wall protection layer. After the blastholes of part ② or part ③ are drilled according to the blasthole design drawing, part ② or part ③ is charged and networked, and detonated by hole-by-hole micro-difference blasting; Step S6, after the blasting of part ② or part ③ and the slag discharge is completed, the reserved partition wall protective layer is mechanically broken, and the vibration isolation plate in the process of part ① is taken out for subsequent excavation of part ①. According to the above steps, a certain safety step distance is ensured between part ① and part ③, and part ② or part ③ is excavated alternately on both sides; Step S7, after the excavation of section ①-section ③ reaches the set mileage, ensure that there is a reasonable safety step distance between section ③ and section ④ and section ⑤, and alternately excavate sections ④ and ⑤ close to the core soil side of section ⑥, and after drilling the blastholes according to the blasthole design drawing, use hole-by-hole micro-difference blasting to initiate the explosion; Step S8, after the blasting of part ④ or part ⑤ and the slag discharge is completed, according to the above steps, a certain safe step distance is ensured between part ④ and part ⑤, and part ④ or part ⑤ is excavated alternately on both sides; Step S9, according to the above steps, ensure that there is a safe step distance between each part of part ①-part ⑤, stagger excavate part ①-part ⑤, excavate part ⑥ and part ⑦ under the condition that the distance between part ⑥ and part ⑦ is not less than the set safe step distance of part ⑤, remove the vertical support of part ① in the single cycle footage area, and reuse it as the vertical support on both sides of the excavated part ① in front, according to the blasthole design drawing, drill vertical holes in the core soil of part ⑥ and extend to part ⑦, drill horizontal holes on both sides and contours of part ⑦, adopt hole-by-hole micro-difference blasting, and detonate part ⑥ and part ⑦ at one time; Step S10: construct according to the above steps in sequence until the tunnel is penetrated inside the mountain.

5. The tunnel blasting and shock absorption construction method according to claim 4, It is characterized in that In the step S5, when excavating part ② and part ③ alternately, ensure that the excavation sections of part ①, part ② and part ③ are not in the same section and are at least 30m apart from each other by a safe step distance; when excavating part ② and part ③, the excavation outline of the vertical support close to part ① is retracted by 50cm as a rock wall interval to reserve a partition wall protection layer; in the step S7, while meeting the requirement of the safe step distance between parts ① and ③ in step S5, ensure that the excavation sections of part ④ and part ⑤ are not in the same section and are at least 30m apart from each other by a safe step distance; in the step S9, under the condition that the distance between parts ⑥ and ⑦ is not less than 50m from part ⑤, remove the vertical support of part ① in the single-cycle footage area, and then carry out blasting excavation construction of parts ⑥ and ⑦.

6. The tunnel blasting and shock absorption construction method according to claim 4, It is characterized in that The design of the blast holes in the blasting area ① is as follows: corresponding rows of slot holes A, auxiliary holes B and peripheral holes E are symmetrically arranged from the inside to the outside, and corresponding rows of bottom plate holes C are arranged below the ① part, and corresponding rows of pressure holes D and peripheral holes E are arranged above the ① part from the inside to the outside. The detonation sequence is: according to A→B→C→D→E, and there is a time difference Tp between different columns and rows, and there is a time difference Tk between each row of blast holes to ensure the slight difference blasting of each hole in the face. Different columns and rows of the same category are detonated hole by hole from the inside to the outside, and the peripheral holes in the column direction are detonated earlier than the peripheral holes in the row direction; among them, the slot hole spacing is 60cm and the row spacing is 65cm, the auxiliary hole spacing is 80cm and the row spacing is 80cm, the peripheral hole spacing is 40cm, the light blasting layer thickness is 60cm, and the blast hole angle is 50°~90°.

7. The tunnel blasting and shock absorption construction method according to claim 4, It is characterized in that The design of the blast holes in the blasting area ② and ③ is as follows: ② and ③ are fan-shaped structures, with corresponding rows of slot holes A, auxiliary holes B and peripheral holes E arranged from the inside to the outside, and corresponding rows of bottom plate holes D arranged below. Between the auxiliary holes B and peripheral holes E in ② and ③, corresponding rows of auxiliary holes B and auxiliary holes C are arranged from the inside to the outside along the contour line of the tunnel; the detonation sequence is: A→B→C→D→E, and there is a time difference Tp between different numbers of columns and rows, and each There is a time difference Tk between rows of blast holes to ensure the slight difference blasting of each blast hole on the face. The same category with different rows and rows are detonated hole by hole from the inside to the outside, and the auxiliary holes located in the row direction are detonated earlier than the auxiliary holes located in the row direction. Among them, the spacing between the slot holes in parts ② and ③ is 45cm and the row spacing is 60cm, the spacing between the auxiliary holes is 80~110cm and the row spacing is 60cm, the spacing between the peripheral holes is 40cm, the thickness of the light blasting layer is 50~60cm, and the blast hole angle is 60°~90°.

8. The tunnel blasting and shock absorption construction method according to claim 4, It is characterized in that The design of the blasting holes in the blasting area ④ and ⑤ is as follows: two rows of peripheral holes A are set on both sides, and the auxiliary holes B, auxiliary holes C, auxiliary holes D and bottom plate holes E are set in a set number of rows from top to bottom between the two rows of peripheral holes; pre-splitting blasting is adopted, and the peripheral hole A is detonated first to form an isolation vibration belt. The detonation sequence is: according to A→B→C→D→E, and there is a time difference Tp between different columns and rows, and there is a time difference Tk between each row of blasting holes to ensure the slight difference blasting of each hole on the face, and different columns and rows of the same category are detonated hole by hole from inside to outside; among them, the spacing between the main blasting holes in parts ④ and ⑤ is 90~140cm, the row spacing is 110cm, the spacing between the peripheral holes is 50cm, and the thickness of the light blasting layer is 60cm.

9. The tunnel blasting and shock absorption construction method according to claim 4, It is characterized in that The design of the blasting holes in the blasting area ⑥ and ⑦ is as follows: peripheral holes A are set at the contour line below the ⑦ part, and auxiliary holes B and horizontal auxiliary holes C are set from the inside to the outside on both sides. Auxiliary holes D and auxiliary holes E with a set number of rows are set vertically in the ⑥ part; pre-splitting blasting is adopted, and the peripheral hole A is detonated first to form an isolation vibration belt. The detonation sequence is: according to A→B→C→D→E, and there is a time difference Tp between different numbers of columns and rows, and there is a time difference Tk between each row of blasting holes, ensuring The blast holes on the face are blasted hole by hole, and the vertical auxiliary holes in part ⑥ are detonated one by one from the outside to the inside in different rows. Among them, vertical holes are drilled in the core soil of part ⑥, with a main blasting hole spacing of 100cm, a row spacing of 80cm, a peripheral hole spacing of 50cm, and a smooth blasting layer thickness of 60~80cm. The depth of the holes in part ⑥ penetrates to part ⑦, and vertical holes are drilled. A protective layer with a thickness of 60~80cm is reserved from the bottom of the holes to the excavation outline of part ⑦. Horizontal holes are drilled in the remaining part of part ⑦.

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