Large-section tunnel benching excavation blasting method

Abstract

The application discloses a large-section tunnel upper step tunneling blasting method and relates to the technical field of tunneling blasting. In order to solve the problem that when the middle area of a door-shaped gantry exceeds 8m in the large-section tunnel upper step tunneling blasting, it is inconvenient to arrange holes, drill holes, charge, block and connect a network for the middle area of the gantry, the following technical scheme is provided: according to the form and size of the gantry, the upper step excavation surface is divided into a bottom area, a middle area and a top area; the bottom area and the top area adopt conventional tunneling blasting parameters and construction design; the middle area is not provided with blast holes corresponding to the position of the inner layer of the undercut hole in the bottom area, other blast holes are designed as fan-shaped caving holes by imitating the blast holes in the bottom area, and the charge structure, blast hole blocking and initiation network design are carried out. The application has the beneficial effects that the arrangement of holes, drilling of holes, charging, blocking and network connection are convenient to realize safe construction operation and good blasting effect, and the blasting vibration and flying stones can be effectively controlled.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tunnel excavation blasting, in particular to a large-section tunnel upper bench excavation blasting method. BACKGROUND

[0002] In tunnel excavation blasting, the arrangement of blast holes on the excavation surface is a very important link, which not only affects the excavation footage, blasting volume and peripheral contour, but also affects the hole arrangement, drilling, charging, plugging, network connection and other operation procedures, and further affects the safety, efficiency and economy of the entire construction operation.

[0003] When a manual rock drill is currently used to excavate a tunnel, a construction bench is an essential operation platform for hole arrangement, drilling, charging, plugging, network connection, anchor rod installation, mesh installation, and arch installation, among which a door-type bench is the most commonly used. In combination with the structure and size of the door-type bench, the tunnel excavation blasting cut method usually adopts the arrangement of 3-4 pairs of double cut holes at the bottom and middle regions of the bench. However, for a large-section tunnel with a single hole and three or four lanes, when the middle region of the door-type bench exceeds 8.0 m, if 3-4 pairs of double cut holes are also arranged in the middle region of the bench, the distance from the cut hole to the bench column will exceed 1.0 m, especially for the inner cut hole, which is not convenient for the workers to arrange holes, drill, charge, plug, and connect the network, greatly affecting the operation safety and construction efficiency. SUMMARY

[0004] The purpose of the present application is to provide a large-section tunnel upper bench excavation blasting method to solve the problem that when the middle region of the door-type bench exceeds 8.0 m, the arrangement of cut holes in the middle region of the bench is not convenient for manual hole arrangement, drilling, charging, plugging, and network connection.

[0005] The technical solution of the present application to solve the above technical problems is as follows:

[0006] A large-section tunnel upper bench excavation blasting method, characterized in that it comprises the following steps:

[0007] S1, according to the form and size of the bench, the upper bench excavation surface is divided into a bottom region, a middle region, and a top region;

[0008] S2, the bottom and top regions adopt conventional tunnel excavation blasting parameters and construction design;

[0009] S3, the middle region does not set a blast hole corresponding to the position of the inner cut hole in the bottom region, and other blast holes are designed as fan-shaped caving holes by imitating the blast holes in the bottom region, and the charging structure, blast hole plugging, and initiation network design are performed.

[0010] Further, the parameter design in step S2 includes: blast hole diameter, round footage, unit consumption of explosive, explosive consumption of single round of excavation blasting.

[0011] Further, the parameter design in step S2 further includes: angle of cut hole, up and down row distance of cut hole, hole mouth distance and hole bottom distance of cut hole, hole depth and hole length of cut hole, unit charge of cut hole and stemming length, hole distance and row distance of heading hole and top caving hole, unit charge of heading hole and top caving hole.

[0012] Further, the parameter design in step S2 further includes: hole distance and minimum resistance line of light hole, line charge density and stemming length of light hole.

[0013] Further, the parameter design in step S3 includes: blast hole distance, row distance, hole depth, hole length, distance from bottom cut hole, distance from top caving hole, hole mouth distance and hole bottom distance of inner side blast hole of bench, inclination angle, line charge density, stemming length.

[0014] Further, the construction design in step S2 includes: arrangement position, form, number and inclination angle of cut hole, arrangement position and inclination angle of heading hole and top caving hole, arrangement position and extrapolation angle of light hole.

[0015] Further, the construction design in step S2 further includes: charge structure form of each blast hole, initiation mode and stemming material.

[0016] Further, the construction design in step S3 includes: no blast hole is arranged in the position corresponding to the inner layer cut hole of the bottom region in the middle region of the bench, other blast holes are arranged in the form of fan-shaped caving hole imitating the cut hole, slot hole and heading hole of the bottom region, the distance between the inner side blast hole of the bench and the bench column is within 50 cm, except for the outer circle heading hole, other blast holes are inclined blast holes arranged in a fan shape; the charge structure adopts continuous charge structure, and the charge length is designed alternately long and short.

[0017] Further, the initiation network design includes that the same sub-segment initiation is adopted for the upper step, the initiation sequence is: from the middle cut hole to the outer side auxiliary cut hole, heading hole, caving hole, bottom hole, light hole, and the micro-difference initiation is performed row by row, the minimum interval of the micro-difference time between adjacent rows is 50 ms, and the micro-difference time of the last row of heading hole and light hole is not less than 100 ms; the light hole adopts series initiation of detonating cord, and other blast holes adopt digital electronic detonator initiation.

[0018] Further, the caving hole in the middle region adopts digital electronic detonator row-by-row down pressure initiation.

[0019] Further, step S2 further includes blasting material statistics, and the blasting material statistics includes explosive dosage, detonator dosage and detonating cord dosage.

[0020] The present application has the following beneficial effects:

[0021] The present application has the following beneficial effects: on one hand, the middle region of the excavation bench is convenient for manual hole arrangement, drilling, charging, plugging and network connection operation to realize safe construction operation and good blasting effect; on the other hand, since the middle region of the excavation bench is not provided with a slotting hole, the blasting vibration and blasting flyrock can be effectively controlled. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a partition diagram for the upper step operation of the present application;

[0023] Figure 2 is a vertical section view of the arrangement of the upper step tunneling blasting hole of the present application;

[0024] Figure 3 is an A-A section view of the arrangement of the upper step tunneling blasting hole of the present application;

[0025] Figure 4 is a B-B section view of the arrangement of the upper step tunneling blasting hole of the present application;

[0026] Figure 5 is a charging structure diagram of the A-A section of the arrangement of the upper step tunneling blasting hole of the present application;

[0027] Figure 6 is a charging structure diagram of the B-B section of the arrangement of the upper step tunneling blasting hole of the present application;

[0028] Figure 7 is a blasting network diagram of the upper step tunneling blasting hole of the present application;

[0029] Figure 8 is a flow chart of the present application. DETAILED DESCRIPTION

[0030] The technical solutions of the present application are described below in detail with reference to the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort belong to the scope of protection of the present application.

[0031] Please refer to Figures 1-7 The present application discloses a method for tunnel upper step tunneling blasting, which mainly aims at the improvement method for the current situation that the middle region of the portal bench exceeds 8.0m in the process of tunnel upper step tunneling blasting, and the bench middle region is not convenient for manual hole arrangement, drilling, charging, plugging and network connection.

[0032] The present application does not set blast hole in the position corresponding to the inner layer slot hole in the bottom area of the bench middle area, and other blast holes are arranged in the form of fan-shaped caving hole imitating the slot hole, slot hole and driving hole in the bottom area, and the initiation method is row-by-row down pressure blasting (minimum resistance line downward), which can solve the problems of inconvenient manual hole arrangement, drilling, charging, plugging and network connection, and achieve good blasting effect and ensure ideal excavation footage.

[0033] The present application solves the technical problems by the following technical scheme: The present application is suitable for III-IV grade surrounding rock large section tunnel upper bench excavation, does not set blast hole in the position corresponding to the inner layer slot hole in the bottom area of the bench middle area, and other blast holes are arranged in the form of fan-shaped caving hole imitating the slot hole, slot hole and driving hole in the bottom area, and the initiation method is row-by-row down pressure blasting, which can solve the problems of inconvenient manual hole arrangement, drilling, charging, plugging and network connection, and includes the following steps:

[0034] (1) According to the form and size of the bench, the tunnel upper bench excavation surface is divided into three areas: the bottom area, the middle area and the top area of the bench.

[0035] (2) The blast hole diameter, cycle footage, explosive unit consumption, explosive consumption of single cycle excavation blasting of the whole upper bench excavation area are designed.

[0036] (3) The bottom area and the top area of the bench are designed according to the conventional tunnel excavation blasting parameters and construction design. The parameter design includes: the angle of the slot hole, the up and down row distance of the slot hole, the hole distance and the hole bottom distance of the slot hole, the blast hole depth and length of the slot hole, the single hole charge and the plugging length of the slot hole, the hole distance and row distance of the driving hole and the top caving hole, the single hole charge and the plugging length of the driving hole and the top caving hole, the hole distance and the light blasting layer thickness of the light blasting hole, the line charge density and the plugging length of the light blasting hole. The construction design includes: first, blast hole arrangement, including the arrangement position, form, logarithm and inclination angle of the slot hole, the arrangement position and inclination angle of the driving hole and the top caving hole, and the arrangement position and external insertion angle of the light blasting hole; second, charge structure and blast hole plugging design, including the charge structure form, initiation method and plugging material of the slot hole, the driving hole, the floor hole, the top caving hole and the light blasting hole; third, initiation network design, including the same sub-segment initiation of the upper bench, and the initiation sequence is: from the middle slot hole to the outer auxiliary slot hole, the driving hole, the caving hole, the floor hole and the light blasting hole, and the row-by-row millisecond initiation. The minimum interval of the adjacent row is 50ms, and the millisecond time of the last row of driving hole and light blasting hole is not less than 100ms. The light blasting hole adopts series initiation of detonating cord, and other blast holes adopt digital electronic detonator initiation. Fourth, blasting material statistics, including the amount of explosive, detonator and detonating cord.

[0037] (4) For the middle region of the bench, the parameters design and construction design of other blastholes are improved except the light blasthole and the outer circle driving hole. The blastholes are not set corresponding to the position of the inner layer cut hole in the bottom region. The fan-shaped caving holes are arranged in the form of cut hole, slot hole and driving hole in the bottom region. The distance between the inner side blasthole of the bench and the bench column is within 50 cm. Except the outer circle driving hole, other blastholes are inclined blastholes arranged in a fan shape. The continuous charging structure is adopted for the charging structure, and the charging length is designed alternately long and short. The digital electronic detonator is used for row-by-row down pressure initiation of the initiation network.

[0038] Please refer to Figure 1 , the component, part name and corresponding mark in the figure are upper step STJ, construction bench TJ, excavation area boundary FJX, bottom excavation region I, middle excavation region II, top excavation region III.

[0039] Please refer to Figure 2 , the component, part name and corresponding mark in the figure are blasthole diameter D = 40 mm, upper step height h = 7.0-8.0 m, upper step bottom plate width b = 16.0-19.0 m, corner hole jk, light blasthole gk, bottom plate hole dk, inner layer cut hole tk1, outer layer cut hole tk2, auxiliary cut hole tk3, driving hole jjk, outer circle driving hole wjk, caving hole bk, inner layer cut hole hole distance a11 = 5.0-6.0 m, inner layer and outer layer cut hole spacing a12 = 50-60 cm, outer layer cut hole and auxiliary cut hole spacing a13 = 30-40 cm, inner and outer layer cut hole upper and lower row distance b11 = 40-50 cm, auxiliary cut hole upper and lower row distance b12 = 50-60 cm, inner layer cut hole distance from the bottom plate b13 = 70-80 cm, outer layer and auxiliary cut hole distance from the bottom plate b14 = 50-60 cm, driving hole hole distance a21 = 120-130 cm, driving hole row distance b21 = 90-110 cm, bench top region caving hole hole distance a22 = 130-140 cm, row distance b22 = 100-110 cm, outer circle driving hole hole distance a23 = 120-130 cm, bottom plate hole spacing a24 = 100-110 cm, bench middle region caving hole hole distance a31 = 50-80 cm, bench middle region caving hole distance from the cut hole b32 = 100-110 cm, bench middle region caving hole row distance b31 = 90-100 cm, innermost layer bench middle region caving hole hole distance a32 = 6.5-7.0 m, bench middle region caving hole distance from the top caving hole b33 = 100-110 cm, light blasthole spacing a41 = 45-55 cm, light blasthole layer thickness w41 = 60-70 cm.

[0040] Please refer to Figure 3, the part, position name and corresponding mark in the figure are blast hole depth kh=300-350cm, super depth ch=20-30cm, inner layer cut hole depth th1=250-270cm, cut hole bottom distance kd=20-30cm, cut hole angle α=45°-55°, tunneling hole angle β=60°-90°, and the light blasting hole outer insertion angle φ=2°-3°.

[0041] Please refer to Figure 4 , the part, position name and corresponding mark in the figure are inner layer caving hole distance a31=50-80cm in the middle area of the bench, inner layer hole depth bh1=230-250cm, hole bottom distance bkd=80-110cm, and angle bβ=45°-90°.

[0042] Please refer to Figure 5 , the part, position name and corresponding mark in the figure are charge section length yl and blocking section length dl, inner and outer cut hole linear charge density ρ=0.6-0.7kg / m, auxiliary cut hole linear charge density ρ=0.5-0.6kg / m, tunneling hole linear charge density ρ=0.5-0.6kg / m, top caving hole linear charge density ρ=0.4-0.5kg / m, floor hole linear charge density ρ=0.55-0.6kg / m, and light blasting hole linear charge density ρ=0.15-0.18kg / m; the cut blasting hole, auxiliary cut hole and tunneling hole adopt continuous charge structure, and the blocking length is not less than 0.8m; the light blasting hole adopts axial air interval charge structure, and the blocking length is not less than 0.4m.

[0043] Please refer to Figure 6 , the part, position name and corresponding mark in the figure are charge section length yl and blocking section length dl, wherein the caving hole linear charge density ρ=0.4-0.6kg / m in the middle area of the bench, and the caving hole adopts continuous charge structure, and the blocking length is not less than 0.8m.

[0044] Figure 7 , the detonating cord corresponding mark is dbs, and the initiation order is ①→⑩.

[0045] Figure 8 The figure is a flow chart of the blasting method.

[0046] The above only describes the preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for bench excavation and blasting of extra-large cross-section tunnels, characterized in that, Includes the following steps: S1. Based on the form and size of the platform, the upper step excavation face is divided into the bottom, middle and top areas of the platform; S2. Conventional tunnel boring blasting parameters and construction design are used for the bottom and top areas of the platform. S3. In the middle area of ​​the test platform, corresponding to the middle slotting hole in the bottom area, no blast holes are set. Other blast holes are arranged in a fan-shaped collapse hole pattern, similar to the slotting hole, enlargement hole, and excavation hole in the bottom area. The charging structure, blast hole plugging, and detonation network are designed. The distance between the blast holes on the inner side of the test platform and the test platform column is within 50cm. Except for the outer ring excavation hole, the other blast holes are fan-shaped inclined blast holes. The charging structure adopts a continuous charging structure with alternating charge lengths. The collapse holes in the middle area are detonated by digital electronic detonators in a row-by-row downward pressure.

2. The method for bench excavation and blasting of extra-large cross-section tunnels according to claim 1, characterized in that, The parameter design in step S2 includes: borehole diameter, cycle advance, explosive consumption per unit, and explosive consumption per cycle of excavation blasting.

3. The method for bench excavation and blasting of extra-large cross-section tunnels according to claim 1, characterized in that, The parameter design in step S2 also includes: the angle of the slotting hole, the upper and lower row spacing of the slotting hole, the hole opening distance and hole bottom distance of the slotting hole, the hole depth and hole length of the slotting hole, the single hole charge and plugging length of the slotting hole, the hole spacing and row spacing of the excavation hole and the top collapse hole, and the single hole charge and plugging length of the excavation hole and the top collapse hole.

4. The method for bench excavation and blasting of extra-large cross-section tunnels according to any one of claims 1 to 3, characterized in that, The parameter design in step S2 also includes: the hole spacing and minimum resistance line of the blast holes, the linear charge density of the blast holes, and the plugging length.

5. The method for bench excavation and blasting of extra-large cross-section tunnels according to claim 1, characterized in that, The parameter design in step S3 includes: borehole spacing, row spacing, borehole depth, borehole length, distance from bottom cut hole, distance from top collapse hole, borehole opening distance and bottom distance on the inner side of the platform, inclination angle, linear charge density, and plugging length.

6. The method for bench excavation and blasting of extra-large cross-section tunnels according to claim 4, characterized in that, The construction design in step S2 includes: the layout, form, number and inclination angle of the cut holes, the layout and inclination angle of the excavation holes and the top collapse holes, the layout and insertion angle of the blasting holes, and the charging structure, detonation method and plugging material of each blast hole.

7. The method for bench excavation and blasting of extra-large cross-section tunnels according to claim 6, characterized in that, The upper step adopts the same segmented initiation. The initiation sequence is as follows: from the middle slotting hole to the outer auxiliary slotting hole, tunneling hole, collapse hole, bottom plate hole, and smooth blasting hole, the micro-delay initiation is carried out row by row. The minimum micro-delay time interval between adjacent rows is 50ms. The micro-delay time between the last row of tunneling holes and smooth blasting holes is not less than 100ms. The smooth blasting holes are initiated by detonating cord in series, and the other blasting holes are initiated by digital electronic detonators.

8. The method for bench excavation and blasting of extra-large cross-section tunnels according to claim 1, characterized in that, Step S2 also includes statistics on explosive materials, which includes the amount of explosives used, the amount of detonators used, and the amount of detonating cord used.

Images