CN111912307A - Blasting excavation method of V-level surrounding rock large-section granite tunnel - Google Patents
Blasting excavation method of V-level surrounding rock large-section granite tunnel Download PDFInfo
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- CN111912307A CN111912307A CN202010716875.7A CN202010716875A CN111912307A CN 111912307 A CN111912307 A CN 111912307A CN 202010716875 A CN202010716875 A CN 202010716875A CN 111912307 A CN111912307 A CN 111912307A
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- 238000005422 blasting Methods 0.000 title claims abstract description 66
- 238000009412 basement excavation Methods 0.000 title claims abstract description 61
- 238000000034 method Methods 0.000 title claims abstract description 59
- 239000011435 rock Substances 0.000 title claims abstract description 20
- 239000010438 granite Substances 0.000 title claims abstract description 16
- 238000007600 charging Methods 0.000 claims abstract description 50
- 238000005553 drilling Methods 0.000 claims abstract description 25
- 230000002093 peripheral effect Effects 0.000 claims description 51
- 239000002360 explosive Substances 0.000 claims description 39
- 239000003814 drug Substances 0.000 claims description 21
- 238000009423 ventilation Methods 0.000 claims description 21
- 238000005474 detonation Methods 0.000 claims description 19
- 239000002893 slag Substances 0.000 claims description 15
- 238000009826 distribution Methods 0.000 claims description 14
- 238000005429 filling process Methods 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 230000000903 blocking effect Effects 0.000 claims description 4
- 235000017166 Bambusa arundinacea Nutrition 0.000 claims description 3
- 235000017491 Bambusa tulda Nutrition 0.000 claims description 3
- 241001330002 Bambuseae Species 0.000 claims description 3
- 235000015334 Phyllostachys viridis Nutrition 0.000 claims description 3
- 239000002390 adhesive tape Substances 0.000 claims description 3
- 239000011425 bamboo Substances 0.000 claims description 3
- 239000004927 clay Substances 0.000 claims description 3
- 238000004140 cleaning Methods 0.000 claims description 3
- 238000007599 discharging Methods 0.000 claims description 3
- 238000003754 machining Methods 0.000 claims description 3
- 238000005259 measurement Methods 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 3
- 238000012545 processing Methods 0.000 claims description 3
- 150000003839 salts Chemical class 0.000 claims description 3
- 239000004576 sand Substances 0.000 claims description 3
- 239000002699 waste material Substances 0.000 claims description 3
- 239000000839 emulsion Substances 0.000 claims 1
- 238000010276 construction Methods 0.000 abstract description 14
- 238000001125 extrusion Methods 0.000 abstract description 3
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42D—BLASTING
- F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
- E21D9/006—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries by making use of blasting methods
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42D—BLASTING
- F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
- F42D1/08—Tamping methods; Methods for loading boreholes with explosives; Apparatus therefor
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42D—BLASTING
- F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
- F42D1/08—Tamping methods; Methods for loading boreholes with explosives; Apparatus therefor
- F42D1/18—Plugs for boreholes
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42D—BLASTING
- F42D3/00—Particular applications of blasting techniques
- F42D3/04—Particular applications of blasting techniques for rock blasting
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/20—Hydro energy
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- Drilling And Exploitation, And Mining Machines And Methods (AREA)
Abstract
The invention discloses a blasting excavation method of a V-level surrounding rock large-section granite tunnel, which is used for excavating a tunnel with an elliptic section; the blasting excavation method divides the section of the tunnel into seven parts, namely a left pilot tunnel upper step, a left pilot tunnel lower step, a right pilot tunnel upper step, a right pilot tunnel lower step, a main tunnel upper part, a main tunnel middle part and a main tunnel lower part; the blasting excavation step sequence is as follows: left side pilot upper step → right side pilot upper step → main hole upper portion → main hole middle portion → left side pilot lower step → right side pilot lower step → main hole lower portion; the seven-part blasting excavation comprises the following steps: measuring, setting out, drilling, charging, blasting, ventilating, deslagging and transporting. The blasting excavation method of the tunnel can not only keep the stability of the tunnel face, reduce the transverse extrusion, accelerate the sealing and looping of the tunnel, improve the construction efficiency, but also reduce the cost, improve the construction safety and reduce the influence of blasting disturbance and vibration on surrounding buildings.
Description
Technical Field
The invention relates to a blasting excavation method of a V-level surrounding rock large-section granite tunnel.
Background
Tunnels and underground engineering play an important role in national economic construction. The tunnel is the key and key project for the construction of roads, railways and the like. With the rapid development of urban highway construction, tunnel engineering construction is more and more required to solve the problems of rapidness, good quality and economy. For this reason, in addition to the provision of advanced mechanical equipment, modern blasting technology for tunnels needs to be addressed. Blasting excavation is the first procedure of tunnel construction, and the success or failure and the quality of the blasting excavation directly influence the stability of surrounding rocks, and the normal running and construction speed of subsequent procedures, so tunnel blasting is a very important component of tunnel construction. If tunnel body section country rock is mainly apoplexy metaplasia granite mixed rock, the rock mass is more complete, is block column structure, and the country rock is from steady ability better, and the tunnel uses a small amount of morals and manners crack water as the main, and the water yield is less, and the section field is located the hills top, and the relief is higher, and the topography is undulant great, is unfavorable for the emergence of surface water, only has short earth's surface rivers in rainy season. Under this kind of environment, the degree of difficulty of blasting excavation is more obvious, if adopt the excavation preface of conventional double-wall pilot tunnel method, promptly: the tunnel is characterized in that the tunnel comprises a left pilot tunnel upper step → a left pilot tunnel lower step → a right pilot tunnel upper step → a right pilot tunnel lower step → a main tunnel upper part → a main tunnel middle part → a main tunnel lower part, and the tunnel is slow in ring formation due to the fact that the excavation section size of each part is small, deformation is large after excavation, lateral pressure is high, the side wall is easy to collapse, and blasting needs to be supplemented frequently.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a blasting excavation method of a V-level surrounding rock large-section granite tunnel, which not only can keep the stability of the tunnel face, reduce the transverse extrusion, accelerate the closing and ring formation of the tunnel, improve the construction efficiency, but also can reduce the cost, improve the construction safety and reduce the influence of blasting disturbance and vibration on surrounding buildings.
One technical scheme for achieving the purpose of the invention is as follows: a blasting excavation method of V-level surrounding rock large-section granite tunnels is used for excavating tunnels with elliptic sections; the blasting excavation method divides the section of the tunnel into seven parts, namely a left pilot tunnel upper step, a left pilot tunnel lower step, a right pilot tunnel upper step, a right pilot tunnel lower step, a main tunnel upper part, a main tunnel middle part and a main tunnel lower part; the blasting excavation steps are as follows: left side pilot upper step → right side pilot upper step → main hole upper portion → main hole middle portion → left side pilot lower step → right side pilot lower step → main hole lower portion;
when the upper step of the left pilot tunnel is excavated, blast holes are distributed on the section of the upper step of the left pilot tunnel, wherein 4 inner cut holes are distributed in the middle of the section of the upper step of the left pilot tunnel, the connecting line of the 4 inner cut holes is square, the distance between the orifices of the adjacent inner cut holes is 60cm, the hole depth of each inner cut hole is 90cm, the vertical included angle is 75 degrees, and the explosive loading of each inner cut hole is 0.3 Kg; 8 outer cut holes are distributed on the periphery of the 4 inner cut holes, the distance between the openings of the adjacent outer cut holes is 60cm, the depth of each outer cut hole is 160cm, the vertical included angle is 75 degrees, and the medicine loading amount of each outer cut hole is 0.45 Kg; 9 right auxiliary holes are distributed on the right side boundary of the section of the step on the left side pilot hole; 3 upper auxiliary holes which are arranged in a line are distributed above the 8 outer cut holes; 7 lower auxiliary holes are distributed at the left lower parts of the 8 outer cut holes; 9 right auxiliary holes are distributed on the right side boundary of the section of the step on the left side pilot hole; 12 peripheral holes are distributed on the left side boundary of the section of the upper step of the left side pit; 6 bottom holes are distributed on the bottom boundary of the section of the upper step of the left pilot tunnel; the hole depths of all the auxiliary holes, all the peripheral holes and all the bottom holes are all 80 cm; the pitch of all the auxiliary holes is 60-80 cm, the loading amount of all the auxiliary holes is 0.3Kg, the pitch of the peripheral holes is 45cm, the loading amount of each peripheral hole is 0.25Kg, the pitch of the bottom holes is 80-90 cm, and the loading amount of each bottom hole is 0.3 Kg; the footage per cycle is 0.5 m; the peripheral holes adopt an interval charging structure, and the rest blast holes all adopt a continuous charging structure;
when the step on the right pilot tunnel is excavated, arranging blast holes on the section of the step on the right pilot tunnel, wherein the type, the number and the charge of the blast holes are the same as those of the blast holes on the section of the step on the left pilot tunnel, and the arrangement structure of the blast holes is symmetrical to that of the blast holes on the section of the step on the left pilot tunnel;
when the upper part of the main tunnel is excavated, blast holes are distributed on the section of the upper part of the main tunnel, wherein 4 inner cut holes are distributed in the middle of the section of the upper part of the main tunnel, the connecting lines of the 4 inner cut holes are square, the hole spacing of the adjacent inner cut holes is 60cm, the hole depth of each inner cut hole is 90cm, the vertical included angle is 75 degrees, and the explosive loading of each inner cut hole is 0.25 Kg; 8 outer cut holes are distributed on the periphery of the 4 inner cut holes, the distance between the openings of the adjacent outer cut holes is 60cm, the depth of each outer cut hole is 160cm, the vertical included angle is 75 degrees, and the medicine loading amount of each outer cut hole is 0.25 Kg; respectively arranging 4 inner-row auxiliary holes, 4 middle-row auxiliary holes and 4 outer-row auxiliary holes on the left side and the right side of the 8 outer cut holes from inside to outside, wherein the medicine loading of each inner-row auxiliary hole and each middle-row auxiliary hole is 0.25Kg, and the medicine loading of each outer-row auxiliary hole is 0.15 Kg; distributing 20 peripheral holes on the top boundary of the section at the upper part of the main hole, wherein the medicine loading of each peripheral hole is 0.1 Kg; 8 bottom holes are distributed on the bottom boundary of the section of the upper part of the main hole, and the medicine loading of each bottom hole is 0.25 Kg; the hole depths of all the auxiliary holes, 20 peripheral holes and 8 bottom holes are all 80 cm; the pitch of all the auxiliary holes is 60-80 cm, the pitch of the peripheral holes is 45cm, and the pitch of the bottom holes is 80-90 cm; the footage per cycle is 0.5 m; the peripheral holes adopt an interval charging structure, and the rest blast holes all adopt a continuous charging structure;
when the middle part of the main tunnel is excavated, blast holes are distributed on the section of the middle part of the main tunnel, wherein 7 auxiliary holes at the uppermost row, 7 auxiliary holes at the secondary upper row, 7 auxiliary holes at the secondary lower row and 7 auxiliary holes at the lowermost row are distributed in the middle of the section of the middle part of the main tunnel; 7 bottom holes are distributed on the bottom boundary of the section in the middle of the main hole; the hole depths of all the auxiliary holes and all the bottom holes are 80 cm; the hole pitch of all the auxiliary holes is 60-80 cm, and the loading amount of all the auxiliary holes is 0.4 Kg; the hole pitch of the bottom holes is 80-90 cm, and the medicine loading of each bottom hole is 0.4 Kg; the footage per cycle is 0.5 m; all auxiliary holes and all bottom holes adopt a continuous charging structure;
when the left pilot tunnel lower step is excavated, blast holes are distributed on the section of the left pilot tunnel lower step, wherein 5 upper row auxiliary holes, 5 middle row auxiliary holes and 5 lower row auxiliary holes are distributed in the middle of the section of the left pilot tunnel lower step; 5 right auxiliary holes are distributed on the right side boundary of the section of the left pit guiding lower step; 8 peripheral holes are distributed on the left side boundary of the section of the lower step of the left side pilot tunnel; 5 bottom holes are distributed on the bottom boundary of the section of the lower step of the left pilot tunnel; the hole depths of all blast holes are 80 cm; the pitch of all the auxiliary holes is 60-80 cm, the loading amount of all the auxiliary holes is 0.25Kg, the pitch of the peripheral holes is 45cm, the loading amount of each peripheral hole is 0.15Kg, the pitch of the bottom holes is 80-90 cm, and the loading amount of each bottom hole is 0.25 Kg; the footage per cycle is 0.5 m; the peripheral holes adopt an interval charging structure, and the rest blast holes all adopt a continuous charging structure;
when the right side pilot tunnel lower step is excavated, blast holes are distributed on the section of the right side pilot tunnel lower step, the type, the number and the charge of the blast holes are the same as those of the blast holes on the section of the left side pilot tunnel lower step, and the distribution structure of the blast holes is symmetrical to that of the blast holes on the section of the left side pilot tunnel lower step;
when the lower part of the main tunnel is excavated, blast holes are distributed on the section of the lower part of the main tunnel, wherein 7 auxiliary holes at the uppermost row, 7 auxiliary holes at the secondary upper row, 7 auxiliary holes at the secondary lower row and 7 auxiliary holes at the lowermost row are distributed in the middle of the section of the lower part of the main tunnel; 8 bottom holes are distributed on the bottom boundary of the section at the lower part of the main hole; the hole depths of all the auxiliary holes and all the bottom holes are 80 cm; the hole pitch of all the auxiliary holes is 60-80 cm, and the loading amount of all the auxiliary holes is 0.4 Kg; the hole pitch of the bottom holes is 80-90 cm, and the medicine loading of each bottom hole is 0.4 Kg; the footage per cycle is 0.5 m; all auxiliary holes and all bottom holes adopt a continuous charging structure;
the seven-part blasting excavation comprises the following steps: measuring paying-off and hole distribution, drilling, charging, blasting, ventilating, deslagging and transporting;
when the step of measuring the paying-off and hole distribution is carried out, the method comprises the following steps:
(1) measuring a wire releasing process, performing the next cycle of excavation contour line lofting in time after each cycle, measuring the center line, the pile number and the elevation of the tunnel by adopting a total station prism-free method, releasing the excavation contour line according to the calculated excavation radius, wherein the excavation contour line is a designed excavation contour line, reserved deformation, trolley machining error and measurement error;
(2) a hole distribution procedure, namely drawing the excavation outline of the whole tunnel according to the lofting line points, marking the holes from the peripheral holes of the section, and marking other hole sites;
the drilling step comprises the following steps:
(1) drilling, namely drilling by adopting a hand pneumatic drill, wherein the diameter of a drill rod is 42 mm; firstly drilling a blast hole, and plugging the hole opening by using a woven bag to prevent sundries from blocking the blast hole; when drilling, firstly running at low speed, and then drilling at full speed after drilling at a certain depth;
(2) a hole cleaning procedure, wherein an air compressor jetting method is adopted, and slag bodies in holes are blown out by airflow;
when the charging step is carried out, the method comprises the following working procedures:
(1) the charging process comprises a continuous charging structure and an intermittent charging structure;
the continuous charging structure is used for uninterruptedly charging the explosive rolls with the calculated explosive quantity into the blast holes section by section;
the intermittent explosive loading structure is used for dividing an explosive cartridge with the calculated explosive quantity into a plurality of sections of small explosive cartridges and binding the small explosive cartridges on the detonating cord at uniform intervals to form an intermittent explosive string, the bottom of a hole of the detonating cord is bundled with a detonating cap, and then the detonating cap is loaded into the blast hole through a wooden or bamboo stick ignition tape;
(2) a filling process, wherein stemming is filled at an orifice, after each section of stemming roll is placed, a stemming roll is mashed and compacted by a stemming roller, and then the stemming roll is placed into the stemming roll and mashed and compacted by the stemming roll until filling is completed, wherein the filling length is not less than 20 cm;
the blasting step includes the following steps:
(1) a network connection procedure, wherein a non-electric millisecond detonator is adopted, and when the detonating tube is tightly bound with the detonator by adhesive tapes, the detonating tube is uniformly and tightly laid around the detonator and grows out of the detonator by 10 cm; when the detonating tube is bound with the detonator, the energy-gathering hole of the detonator is required to face to the detonating direction of the detonating cord, and when the detonating tubes are mutually lapped, the included angle between the main tube and the branch tube in the detonating direction is less than 90 degrees, and the lapping length is not less than 15 cm;
(2) and (3) a detonation procedure, wherein the detonation sequence is as follows: inner undercut hole → outer undercut hole → auxiliary hole → peripheral hole → bottom hole;
(3) the blind shot processing procedure is processed by original explosive loading personnel, and only after the blasting circuit, the blasting fuse and the blasting fuse in the blind shot hole are checked to be intact, the blind shot can be detonated again;
when the ventilation step is carried out, the following ventilation mode is adopted after blasting:
(1) the ventilator is adopted for ventilation, so that the wind speed and the wind volume of wind entering the tunnel meet the following requirements: when the full-section is excavated, the total-section depth is not less than 0.15m/s, the inner diameter of the tunnel is not less than 0.25m/s, but not more than 6 m/s;
(2) ventilating by using a ventilating pipe, arranging a press-in air inlet pipe orifice or a suction-out air outlet pipe orifice outside the tunnel, and making the tunnel type air inlet pipe orifice or the suction-out air outlet pipe orifice to prevent polluted air from flowing back into the tunnel; the distance between the air outlet of the press-in type ventilation pipe and the working surface is not more than 15m, and the air suction inlet of the suction type ventilation pipe is not more than 5 m;
(4) adopting mixed ventilation, wherein when one group of ventilators moves forwards, the pipelines of the other group of ventilators are correspondingly lengthened, and the adjacent ends of the two groups of pipelines are always staggered by not less than 20-30 m; when local ventilation is carried out, the air outlet of the suction type air pipe is introduced into the return air flow of the main air flow circulation;
when the slag discharging and transporting steps are carried out, digging the waste slag on the upper half section of the main tunnel to the lower half section of the main tunnel by using a digging machine, and loading the slag by using a loader; the lower half section is directly filled with slag by a digging machine.
The blasting excavation method of the V-level surrounding rock large-section granite tunnel comprises the following steps of when the upper step and the lower step of the left pilot tunnel and the upper step and the lower step of the right pilot tunnel are constructed, the distance between the upper step of the left pilot tunnel and the lower step of the left pilot tunnel and the distance between the upper step of the right pilot tunnel and the lower step of the right pilot tunnel are both 5-10 m; the distance between the upper step of the left pit guide and the upper step of the right pit guide is not less than 15 m; the distance between the left pit guiding lower step and the right pit guiding lower step is not less than 15 m.
The blasting excavation method of the V-level surrounding rock large-section granite tunnel comprises the step of loading powder, wherein the emulsified explosive with the specification of phi 32mm multiplied by 180g is adopted.
The blasting excavation method of the V-level surrounding rock large-section granite tunnel comprises the following steps of, when the filling process of the charging step is carried out, manufacturing stemming by using a stemming machine, wherein the mixing ratio of the stemming is 1: 3 clay and sand, and then adding water containing 2-3% of salt.
The blasting excavation method of the V-level surrounding rock large-section granite tunnel has the following characteristics:
(1) the excavation step sequence of the conventional double-side-wall pit guiding method is optimized, and the step sequence of an optimizer is as follows: left side pilot upper step → right side pilot upper step → main hole upper portion → main hole middle portion → left side pilot lower step → right side pilot lower step → main hole lower portion; can keep the stability of tunnel face, reduce horizontal extrusion for the tunnel seals the cyclization, improves the efficiency of construction, can also reduce cost and improve the construction security.
(2) The design and construction principles of large inclined hole cutting, small footage, small-spacing smooth blasting and small-diameter explosive cartridge charging are adopted; the use of explosives can be reduced, and the field control is more convenient;
(3) the blast hole arrangement adopts a plurality of sections of detonators, so that the maximum explosive-aligning quantity of a single section is reduced, and the influence of blasting disturbance and vibration on surrounding buildings is reduced;
(4) the blast hole ensures enough blocking length and prevents accidents such as blasting and the like.
Drawings
Fig. 1 is a cross-sectional view of a double-sidewall pilot tunnel excavation employed in the blasting excavation method of a tunnel according to the present invention;
FIG. 2 is a structural diagram of arrangement of blast holes when blasting excavation of a bench on a left pilot tunnel is carried out according to the invention;
FIG. 3 is an axial sectional view of the inner and outer cut holes of the present invention during blasting excavation of the upper step of the left pilot tunnel and the upper portion of the main tunnel;
FIG. 4 is a structural diagram of arrangement of blast holes when blasting excavation is carried out on the upper part of a main tunnel;
FIG. 5 is a structural diagram of arrangement of blast holes during blasting excavation of the middle part of a main tunnel according to the invention;
FIG. 6 is a structural diagram of arrangement of blast holes when blasting excavation is carried out on a left pilot tunnel lower bench of the invention;
fig. 7 is a structural view of arrangement of blast holes when blasting excavation is performed on the lower portion of the main tunnel according to the present invention.
Detailed Description
The invention will be further explained with reference to the drawings.
Referring to fig. 1 to 7, the blasting excavation method for the V-level surrounding rock large-section granite tunnel of the present invention is used for excavating a tunnel with an oval section, wherein the radius of the arch part of the tunnel profile is 10.08m, the radius of the side wall is 7.08m, and the arch height is 9.08 m.
According to the blasting excavation method, the section of a tunnel is divided into seven parts, namely a left pilot tunnel upper step 1, a left pilot tunnel lower step 5, a right pilot tunnel upper step 2, a right pilot tunnel lower step 6, a main tunnel upper part 3, a main tunnel middle part 4 and a main tunnel lower part 7; the blasting excavation step sequence of the invention is as follows: left side pit upper step 1 → right side pit upper step 2 → main pit upper portion 3 → main pit middle portion 4 → left side pit lower step 5 → right side pit lower step 6 → main pit lower portion 7.
When the left pilot tunnel upper step 1 is excavated, blast holes are distributed on the section of the left pilot tunnel upper step 1, wherein 4 inner cut holes 11 are distributed in the middle of the section of the left pilot tunnel upper step 1, the connecting line of the 4 inner cut holes 11 is square, the distance between the orifices of the adjacent inner cut holes 11 is 60cm, the hole depth of each inner cut hole 11 is 90cm, the vertical included angle is 75 degrees, and the explosive loading of each inner cut hole is 0.3 Kg; 8 outer cut holes 12 are distributed on the periphery of the 4 inner cut holes 11, the hole distance of the adjacent outer cut holes 12 is 60cm, the hole depth of each outer cut hole 12 is 160cm, the vertical included angle is 75 degrees, and the medicine loading amount of each outer cut hole is 0.45 Kg; 3 upper auxiliary holes 13 which are arranged in a line are arranged above the 8 outer cut holes; 7 lower auxiliary holes 14 are distributed at the left lower part of the 8 outer cut holes; 9 right auxiliary holes 15 are distributed on the right side boundary of the section of the step 1 on the left pit guide; 12 peripheral holes 16 are distributed on the left side boundary of the section of the step 1 on the left side pit; 6 bottom holes 17 are distributed on the bottom boundary of the section of the upper step 1 of the left pilot tunnel; the hole depths of all the auxiliary holes, all the peripheral holes and all the bottom holes are all 80 cm; the hole pitch of all the auxiliary holes is 60-80 cm, and the loading amount of all the auxiliary holes is 0.3 Kg; the pitch of the peripheral holes is 45cm, and the loading of each peripheral hole 17 is 0.25 Kg; the hole pitch of the bottom holes 17 is 80-90 cm, and the medicine loading of each bottom hole 17 is 0.3 Kg; the footage per cycle is 0.5 m; the peripheral holes 16 adopt a spaced charging structure, and the rest blast holes adopt a continuous charging structure.
When the right pilot tunnel upper step 2 is excavated, blast holes are distributed on the section of the right pilot tunnel upper step 2, the type, the number and the charge of the blast holes are the same as those of the blast holes on the section of the left pilot tunnel upper step 1, and the distribution structure of the blast holes is symmetrical to that of the blast holes on the section of the left pilot tunnel upper step 1;
when the upper part 3 of the main tunnel is excavated, blast holes are distributed on the section of the upper part 3 of the main tunnel, wherein 4 inner cut holes 31 are distributed in the middle of the section of the upper part 3 of the main tunnel, the connecting line of the 4 inner cut holes 31 is square, the distance between the orifices of the adjacent inner cut holes 31 is 60cm, the depth of each inner cut hole 31 is 90cm, the vertical included angle is 75 degrees, and the explosive loading of each inner cut hole 31 is 0.25 Kg; 8 outer cut holes 32 are distributed on the periphery of the 4 inner cut holes 31, the hole distance of the adjacent outer cut holes 32 is 60cm, the hole depth of each outer cut hole 32 is 160cm, the vertical included angle is 75 degrees, and the medicine loading of each outer cut hole 52 is 0.25 Kg; respectively arranging 4 inner auxiliary holes 33, 4 middle auxiliary holes 34 and 4 outer auxiliary holes 35 on the left side and the right side of the 8 outer cut holes 32 from inside to outside, wherein the medicine loading of each inner auxiliary hole 33 and each middle auxiliary hole 34 is 0.25Kg, and the medicine loading of each outer auxiliary hole 55 is 0.15 Kg; 20 peripheral holes 36 are distributed on the top boundary of the section of the upper part 3 of the main hole, and the loading amount of each peripheral hole 36 is 0.1 Kg; 8 bottom holes 37 are distributed on the bottom boundary of the section of the upper part 3 of the main hole, and the loading amount of each bottom hole is 0.25 Kg; all the auxiliary holes, 20 peripheral holes 36 and 8 bottom holes 37 have a hole depth of 80 cm; the pitch of all the auxiliary holes is 60-80 cm; the pitch of the peripheral holes 36 is 45 cm; the pitch of the bottom holes 37 is 80-90 cm; the footage per cycle is 0.5 m; the peripheral holes 36 adopt an interval charging structure, and the rest blast holes adopt a continuous charging structure;
when the middle part 4 of the main tunnel is excavated, blast holes are distributed on the section of the middle part 4 of the main tunnel, wherein 7 auxiliary holes 41 in the uppermost row, 7 auxiliary holes 42 in the secondary upper row, 7 auxiliary holes 43 in the secondary lower row and 7 auxiliary holes 44 in the lowermost row are distributed in the middle of the section of the middle part 4 of the main tunnel; 7 bottom holes 45 are distributed on the bottom boundary of the section of the middle part 4 of the main hole; the hole depths of all the auxiliary holes and all the bottom holes are 80 cm; the hole pitch of all the auxiliary holes is 60-80 cm, and the loading amount of all the auxiliary holes is 0.4 Kg; the pitch of the bottom holes 45 is 80-90 cm; the footage per cycle is 0.5m, and the loading of each bottom hole 45 is 0.4 Kg; all auxiliary holes and all bottom holes 45 adopt a continuous charging structure;
when the left pilot tunnel lower step 5 is excavated, blast holes are distributed on the section of the left pilot tunnel lower step 5, wherein 5 upper row auxiliary holes 51, 5 middle row auxiliary holes 52 and 5 lower row auxiliary holes 53 are distributed in the middle of the section of the left pilot tunnel lower step 5, and 5 right side auxiliary holes 54 are distributed on the right side boundary of the section of the left pilot tunnel lower step 2; 8 peripheral holes 55 are distributed on the left side boundary of the section of the left pit guiding lower step 5; 5 bottom holes 56 are distributed on the bottom boundary of the section of the lower step of the left pit guide; the hole depths of all blast holes are 80 cm; the pitch of all the auxiliary holes is 60-80 cm, the loading of all the auxiliary holes is 0.25Kg, the pitch of the peripheral holes 55 is 45cm, and the loading of each peripheral hole 55 is 0.15 Kg; the hole pitch of the bottom holes 56 is 80-90 cm, and the loading amount of each bottom hole 56 is 0.25 Kg; the footage per cycle is 0.5 m; the peripheral holes 55 adopt an interval charging structure, and the rest blast holes all adopt a continuous charging structure;
when the right-side pilot tunnel lower step 6 is excavated, blast holes are distributed on the section of the right-side pilot tunnel lower step 6, the type, the number and the charge of the blast holes are the same as those of the blast holes on the section of the left-side pilot tunnel lower step 5, and the distribution structure of the blast holes is symmetrical to that of the blast holes on the section of the left-side pilot tunnel lower step 5;
when excavating the lower part 7 of the main tunnel, arranging blast holes on the section of the lower part 7 of the main tunnel, wherein 7 auxiliary holes 71 in the uppermost row, 7 auxiliary holes 72 in the secondary upper row, 7 auxiliary holes 73 in the secondary lower row and 7 auxiliary holes 74 in the lowermost row are arranged in the middle of the section of the lower part 7 of the main tunnel; 8 bottom holes 75 are distributed on the bottom boundary of the section of the lower part 7 of the main hole; the hole depths of all the auxiliary holes and all the bottom holes are 80 cm; the hole pitch of all the auxiliary holes is 60-80 cm, and the loading amount of all the auxiliary holes is 0.4 Kg; the pitch of the bottom holes 75 is 80-90 cm; the footage per cycle is 0.5m, and the loading of each bottom hole 75 is 0.4 Kg; all the auxiliary holes and all the bottom holes 75 adopt a continuous charging structure;
when the left side pit guiding upper step 1, the left side pit guiding lower step 5, the right side pit guiding upper step 2 and the right side pit guiding lower step 6 are constructed, the distance between the left side pit guiding upper step 1 and the left side pit guiding lower step 5 and the distance between the right side pit guiding upper step 2 and the right side pit guiding lower step 6 are both 5-10 m; the distance between the left pit guiding upper step 1 and the right pit guiding upper step 2 is not less than 15 m; the distance between the left pit guiding lower step 5 and the right pit guiding lower step 6 is not less than 15 m.
The seven-part blasting excavation comprises the following steps: measuring, setting out, drilling, charging, blasting, ventilating, deslagging and transporting.
When the step of measuring the paying-off and hole distribution is carried out, the method comprises the following steps:
(1) measuring a wire releasing process, performing the next cycle of excavation contour line lofting in time after each cycle, measuring the center line, the pile number and the elevation of the tunnel by adopting a total station prism-free method, releasing the excavation contour line according to the calculated excavation radius, wherein the excavation contour line is a designed excavation contour line, reserved deformation, trolley machining error and measurement error;
(2) and in the hole distribution process, the accumulated soil and the broken layer on the surface of the blasting body are firstly removed before hole distribution, the excavation outline of the whole tunnel is drawn according to the lofting line points, then the marks are started from the peripheral holes of the section, then the marks of other hole positions are carried out, the hole distribution is finished and then is carefully checked, and the actual minimum resistance line basically conforms to the designed minimum resistance line.
The drilling step comprises the following steps:
(1) drilling, namely drilling by adopting a hand pneumatic drill, wherein the diameter of a drill rod is 42 mm; firstly drilling a blast hole, and plugging the hole opening by using a woven bag to prevent sundries from blocking the blast hole; when drilling, firstly running at low speed, and then drilling at full speed after drilling at a certain depth;
(2) and in the hole cleaning process, an air compressor jetting method is adopted, and slag bodies in the holes are blown out by utilizing air flow.
When the explosive charging step is carried out, the emulsified explosive with the specification of phi 32mm multiplied by 180g is adopted and comprises the following working procedures:
(1) the charging process comprises a continuous charging structure and an intermittent charging structure;
the continuous charging structure is used for uninterruptedly charging the explosive rolls with the calculated explosive quantity into the blast holes section by section;
the intermittent explosive loading structure is used for dividing an explosive cartridge with the calculated explosive quantity into a plurality of sections of small explosive cartridges and binding the small explosive cartridges on the detonating cord at uniform intervals to form an intermittent explosive string, the bottom of a hole of the detonating cord is bundled with a detonating cap, and then the detonating cap is loaded into the blast hole through a wooden or bamboo stick ignition tape;
(2) a filling process, wherein stemming is filled at an orifice, after each section of stemming roll is placed, a stemming roll is mashed and compacted by a stemming roller, and then the stemming roll is placed into the stemming roll and mashed and compacted by the stemming roll until filling is completed, wherein the filling length is not less than 20 cm; the stemming is manufactured by a stemming machine, and the mixing ratio of the stemming is 1: 3 clay and sand, and then adding water containing 2-3% of salt.
The blasting step includes the following steps:
(1) a network connection procedure, wherein a non-electric millisecond detonator is adopted, and when the detonating tube is tightly bound with the detonator by adhesive tapes, the detonating tube is uniformly and tightly laid around the detonator and grows out of the detonator by 10 cm; when the detonating tube is bound with the detonator, the energy-gathering hole of the detonator is required to face to the detonating direction of the detonating cord, so that the phenomenon of explosion rejection caused by the fact that the energy-gathering flow breaks the detonating tube is prevented, when the detonating tubes are mutually lapped, the included angle between the main tube and the branch tube in the detonating direction is smaller than 90 degrees, and the lapping length is not smaller than 15 cm;
(2) and (3) a detonating process, wherein the detonating sequence of the blast holes is as follows: inner undercut hole → outer undercut hole → auxiliary hole → peripheral hole → bottom hole;
the detonation sequence of blast holes on the upper step 1 of the left pilot tunnel is as follows: the inner cut holes 11 are detonated first, the outer cut holes 12 are detonated after 25ms of detonation of the inner cut holes 11, all the auxiliary holes are detonated after 50ms of detonation of the inner cut holes 11, the peripheral holes are detonated after 75ms of detonation of the inner cut holes 11, and the bottom holes are detonated after 110ms of detonation of the inner cut holes 11.
The detonation sequence of the blast holes on the upper step 2 of the right pilot tunnel is the same as that of the blast holes on the upper step 1 of the left pilot tunnel.
The detonation sequence of the blast holes on the upper part 3 of the main hole is as follows: the inner cut hole 31 is initiated first, the outer cut hole 32 is initiated after 25ms of initiation of the inner cut hole 31, the inner-row auxiliary hole 53 is initiated after 50ms of initiation of the inner cut hole 31, the middle-row auxiliary hole 34 is initiated after 75ms of initiation of the inner cut hole 31, the outer-row auxiliary hole 35 is initiated after 110ms of initiation of the inner cut hole 31, the peripheral hole 36 is initiated after 130ms of initiation of the inner cut hole 31, and the bottom hole 37 is initiated after 200ms of initiation of the inner cut hole 31.
The detonation sequence of the blast holes in the middle part 4 of the main hole is as follows: the uppermost row of auxiliary holes 41 is initiated first, the second upper row of auxiliary holes 42 is initiated after 25ms of initiation of the uppermost row of auxiliary holes 41, the second lower row of auxiliary holes 43 is initiated after 50ms of initiation of the uppermost row of auxiliary holes 41, the lowermost row of auxiliary holes 44 is initiated after 75ms of initiation of the uppermost row of auxiliary holes 41, and the bottom holes 45 are initiated after 110ms of initiation of the uppermost row of auxiliary holes 41.
The detonation sequence of the blast holes on the left pilot tunnel lower step 5 is as follows: the upper row of pilot holes 51 is detonated first, the middle row of pilot holes 52 is detonated after 25ms of detonation of the upper row of pilot holes 51, the lower row of pilot holes 53 is detonated after 50ms of detonation of the upper row of pilot holes 51, the right side pilot holes 54 and the peripheral holes 55 are detonated after 75ms of detonation of the upper row of pilot holes 51, and the bottom holes 56 are detonated after 110ms of detonation of the upper row of pilot holes 51.
The detonation sequence of the blast holes on the right pilot tunnel lower step 6 is the same as that of the blast holes on the left pilot tunnel lower step 5.
The detonation sequence of the blast holes on the lower part 7 of the main hole is as follows: the uppermost row of auxiliary holes 71 is initiated first, the second upper row of auxiliary holes 72 is initiated after 25ms of initiation of the uppermost row of auxiliary holes 71, the second lower row of auxiliary holes 73 is initiated after 50ms of initiation of the uppermost row of auxiliary holes 71, the lowermost row of auxiliary holes 74 is initiated after 75ms of initiation of the uppermost row of auxiliary holes 71, and the bottom holes 75 are initiated after 110ms of initiation of the uppermost row of auxiliary holes 71.
(3) The blind shot processing procedure is processed by original explosive loading personnel, and only after the blasting circuit, the blasting fuse and the blasting fuse in the blind shot hole are checked to be intact, the blind shot can be detonated again.
When the ventilation step is carried out, the following ventilation mode is adopted after blasting:
(1) the ventilator is adopted for ventilation, so that the wind speed and the wind volume of wind entering the tunnel meet the following requirements: when the full-section is excavated, the total-section depth is not less than 0.15m/s, the inner diameter of the tunnel is not less than 0.25m/s, but not more than 6 m/s;
(2) ventilating by using a ventilating pipe, arranging a press-in air inlet pipe orifice or a suction-out air outlet pipe orifice outside the tunnel, and making the tunnel type air inlet pipe orifice or the suction-out air outlet pipe orifice to prevent polluted air from flowing back into the tunnel; the distance between the air outlet of the press-in type ventilation pipe and the working surface is not more than 15m, and the air suction inlet of the suction type ventilation pipe is not more than 5 m;
(4) adopting mixed ventilation, wherein when one group of ventilators moves forwards, the pipelines of the other group of ventilators are correspondingly lengthened, and the adjacent ends of the two groups of pipelines are always staggered by not less than 20-30 m; when local ventilation is carried out, the air outlet of the suction type air pipe is introduced into the return air flow of the main air flow circulation.
When the slag discharging and transporting steps are carried out, digging the waste slag on the upper half section of the main tunnel to the lower half section of the main tunnel by using a digging machine, and loading the slag by using a loader; the lower half section is directly filled with slag by a digging machine.
The above embodiments are provided only for illustrating the present invention and not for limiting the present invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and therefore all equivalent technical solutions should also fall within the scope of the present invention, and should be defined by the claims.
Claims (4)
1. A blasting excavation method of V-level surrounding rock large-section granite tunnels is used for excavating tunnels with elliptic sections; the blasting excavation method divides the section of the tunnel into seven parts, namely a left pilot tunnel upper step, a left pilot tunnel lower step, a right pilot tunnel upper step, a right pilot tunnel lower step, a main tunnel upper part, a main tunnel middle part and a main tunnel lower part; the method is characterized in that the blasting excavation steps are as follows: left side pilot upper step → right side pilot upper step → main hole upper portion → main hole middle portion → left side pilot lower step → right side pilot lower step → main hole lower portion;
when the upper step of the left pilot tunnel is excavated, blast holes are distributed on the section of the upper step of the left pilot tunnel, wherein 4 inner cut holes are distributed in the middle of the section of the upper step of the left pilot tunnel, the connecting line of the 4 inner cut holes is square, the distance between the orifices of the adjacent inner cut holes is 60cm, the hole depth of each inner cut hole is 90cm, the vertical included angle is 75 degrees, and the explosive loading of each inner cut hole is 0.3 Kg; 8 outer cut holes are distributed on the periphery of the 4 inner cut holes, the distance between the openings of the adjacent outer cut holes is 60cm, the depth of each outer cut hole is 160cm, the vertical included angle is 75 degrees, and the medicine loading amount of each outer cut hole is 0.45 Kg; 9 right auxiliary holes are distributed on the right side boundary of the section of the step on the left side pilot hole; 3 upper auxiliary holes which are arranged in a line are distributed above the 8 outer cut holes; 7 lower auxiliary holes are distributed at the left lower parts of the 8 outer cut holes; 9 right auxiliary holes are distributed on the right side boundary of the section of the step on the left side pilot hole; 12 peripheral holes are distributed on the left side boundary of the section of the upper step of the left side pit; 6 bottom holes are distributed on the bottom boundary of the section of the upper step of the left pilot tunnel; the hole depths of all the auxiliary holes, all the peripheral holes and all the bottom holes are all 80 cm; the pitch of all the auxiliary holes is 60-80 cm, the loading amount of all the auxiliary holes is 0.3Kg, the pitch of the peripheral holes is 45cm, the loading amount of each peripheral hole is 0.25Kg, the pitch of the bottom holes is 80-90 cm, and the loading amount of each bottom hole is 0.3 Kg; the footage per cycle is 0.5 m; the peripheral holes adopt an interval charging structure, and the rest blast holes all adopt a continuous charging structure;
when the step on the right pilot tunnel is excavated, arranging blast holes on the section of the step on the right pilot tunnel, wherein the type, the number and the charge of the blast holes are the same as those of the blast holes on the section of the step on the left pilot tunnel, and the arrangement structure of the blast holes is symmetrical to that of the blast holes on the section of the step on the left pilot tunnel;
when the upper part of the main tunnel is excavated, blast holes are distributed on the section of the upper part of the main tunnel, wherein 4 inner cut holes are distributed in the middle of the section of the upper part of the main tunnel, the connecting lines of the 4 inner cut holes are square, the hole spacing of the adjacent inner cut holes is 60cm, the hole depth of each inner cut hole is 90cm, the vertical included angle is 75 degrees, and the explosive loading of each inner cut hole is 0.25 Kg; 8 outer cut holes are distributed on the periphery of the 4 inner cut holes, the distance between the openings of the adjacent outer cut holes is 60cm, the depth of each outer cut hole is 160cm, the vertical included angle is 75 degrees, and the medicine loading amount of each outer cut hole is 0.25 Kg; respectively arranging 4 inner-row auxiliary holes, 4 middle-row auxiliary holes and 4 outer-row auxiliary holes on the left side and the right side of the 8 outer cut holes from inside to outside, wherein the medicine loading of each inner-row auxiliary hole and each middle-row auxiliary hole is 0.25Kg, and the medicine loading of each outer-row auxiliary hole is 0.15 Kg; distributing 20 peripheral holes on the top boundary of the section at the upper part of the main hole, wherein the medicine loading of each peripheral hole is 0.1 Kg; 8 bottom holes are distributed on the bottom boundary of the section of the upper part of the main hole, and the medicine loading of each bottom hole is 0.25 Kg; the hole depths of all the auxiliary holes, 20 peripheral holes and 8 bottom holes are all 80 cm; the pitch of all the auxiliary holes is 60-80 cm, the pitch of the peripheral holes is 45cm, and the pitch of the bottom holes is 80-90 cm; the footage per cycle is 0.5 m; the peripheral holes adopt an interval charging structure, and the rest blast holes all adopt a continuous charging structure;
when the middle part of the main tunnel is excavated, blast holes are distributed on the section of the middle part of the main tunnel, wherein 7 auxiliary holes at the uppermost row, 7 auxiliary holes at the secondary upper row, 7 auxiliary holes at the secondary lower row and 7 auxiliary holes at the lowermost row are distributed in the middle of the section of the middle part of the main tunnel; 7 bottom holes are distributed on the bottom boundary of the section in the middle of the main hole; the hole depths of all the auxiliary holes and all the bottom holes are 80 cm; the hole pitch of all the auxiliary holes is 60-80 cm, and the loading amount of all the auxiliary holes is 0.4 Kg; the hole pitch of the bottom holes is 80-90 cm, and the medicine loading of each bottom hole is 0.4 Kg; the footage per cycle is 0.5 m; all auxiliary holes and all bottom holes adopt a continuous charging structure;
when the left pilot tunnel lower step is excavated, blast holes are distributed on the section of the left pilot tunnel lower step, wherein 5 upper row auxiliary holes, 5 middle row auxiliary holes and 5 lower row auxiliary holes are distributed in the middle of the section of the left pilot tunnel lower step; 5 right auxiliary holes are distributed on the right side boundary of the section of the left pit guiding lower step; 8 peripheral holes are distributed on the left side boundary of the section of the lower step of the left side pilot tunnel; 5 bottom holes are distributed on the bottom boundary of the section of the lower step of the left pilot tunnel; the hole depths of all blast holes are 80 cm; the pitch of all the auxiliary holes is 60-80 cm, the loading amount of all the auxiliary holes is 0.25Kg, the pitch of the peripheral holes is 45cm, the loading amount of each peripheral hole is 0.15Kg, the pitch of the bottom holes is 80-90 cm, and the loading amount of each bottom hole is 0.25 Kg; the footage per cycle is 0.5 m; the peripheral holes adopt an interval charging structure, and the rest blast holes all adopt a continuous charging structure;
when the right side pilot tunnel lower step is excavated, blast holes are distributed on the section of the right side pilot tunnel lower step, the type, the number and the charge of the blast holes are the same as those of the blast holes on the section of the left side pilot tunnel lower step, and the distribution structure of the blast holes is symmetrical to that of the blast holes on the section of the left side pilot tunnel lower step;
when the lower part of the main tunnel is excavated, blast holes are distributed on the section of the lower part of the main tunnel, wherein 7 auxiliary holes at the uppermost row, 7 auxiliary holes at the secondary upper row, 7 auxiliary holes at the secondary lower row and 7 auxiliary holes at the lowermost row are distributed in the middle of the section of the lower part of the main tunnel; 8 bottom holes are distributed on the bottom boundary of the section at the lower part of the main hole; the hole depths of all the auxiliary holes and all the bottom holes are 80 cm; the hole pitch of all the auxiliary holes is 60-80 cm, and the loading amount of all the auxiliary holes is 0.4 Kg; the hole pitch of the bottom holes is 80-90 cm, and the medicine loading of each bottom hole is 0.4 Kg; the footage per cycle is 0.5 m; all auxiliary holes and all bottom holes adopt a continuous charging structure;
the seven-part blasting excavation comprises the following steps: measuring paying-off and hole distribution, drilling, charging, blasting, ventilating, deslagging and transporting;
when the step of measuring the paying-off and hole distribution is carried out, the method comprises the following steps:
(1) measuring a wire releasing process, performing the next cycle of excavation contour line lofting in time after each cycle, measuring the center line, the pile number and the elevation of the tunnel by adopting a total station prism-free method, releasing the excavation contour line according to the calculated excavation radius, wherein the excavation contour line is a designed excavation contour line, reserved deformation, trolley machining error and measurement error;
(2) a hole distribution procedure, namely drawing the excavation outline of the whole tunnel according to the lofting line points, marking the holes from the peripheral holes of the section, and marking other hole sites;
the drilling step comprises the following steps:
(1) drilling, namely drilling by adopting a hand pneumatic drill, wherein the diameter of a drill rod is 42 mm; firstly drilling a blast hole, and plugging the hole opening by using a woven bag to prevent sundries from blocking the blast hole; when drilling, firstly running at low speed, and then drilling at full speed after drilling at a certain depth;
(2) a hole cleaning procedure, wherein an air compressor jetting method is adopted, and slag bodies in holes are blown out by airflow;
when the charging step is carried out, the method comprises the following working procedures:
(1) the charging process comprises a continuous charging structure and an intermittent charging structure;
the continuous charging structure is used for uninterruptedly charging the explosive rolls with the calculated explosive quantity into the blast holes section by section;
the intermittent explosive loading structure is used for dividing an explosive cartridge with the calculated explosive quantity into a plurality of sections of small explosive cartridges and binding the small explosive cartridges on the detonating cord at uniform intervals to form an intermittent explosive string, the bottom of a hole of the detonating cord is bundled with a detonating cap, and then the detonating cap is loaded into the blast hole through a wooden or bamboo stick ignition tape;
(2) a filling process, wherein stemming is filled at an orifice, after each section of stemming roll is placed, a stemming roll is mashed and compacted by a stemming roller, and then the stemming roll is placed into the stemming roll and mashed and compacted by the stemming roll until filling is completed, wherein the filling length is not less than 20 cm;
the blasting step includes the following steps:
(1) a network connection procedure, wherein a non-electric millisecond detonator is adopted, and when the detonating tube is tightly bound with the detonator by adhesive tapes, the detonating tube is uniformly and tightly laid around the detonator and grows out of the detonator by 10 cm; when the detonating tube is bound with the detonator, the energy-gathering hole of the detonator is required to face to the detonating direction of the detonating cord, and when the detonating tubes are mutually lapped, the included angle between the main tube and the branch tube in the detonating direction is less than 90 degrees, and the lapping length is not less than 15 cm;
(2) and (3) a detonation procedure, wherein the detonation sequence is as follows: inner undercut hole → outer undercut hole → auxiliary hole → peripheral hole → bottom hole;
(3) the blind shot processing procedure is processed by original explosive loading personnel, and only after the blasting circuit, the blasting fuse and the blasting fuse in the blind shot hole are checked to be intact, the blind shot can be detonated again;
when the ventilation step is carried out, the following ventilation mode is adopted after blasting:
(1) the ventilator is adopted for ventilation, so that the wind speed and the wind volume of wind entering the tunnel meet the following requirements: when the full-section is excavated, the total-section depth is not less than 0.15m/s, the inner diameter of the tunnel is not less than 0.25m/s, but not more than 6 m/s;
(2) ventilating by using a ventilating pipe, arranging a press-in air inlet pipe orifice or a suction-out air outlet pipe orifice outside the tunnel, and making the tunnel type air inlet pipe orifice or the suction-out air outlet pipe orifice to prevent polluted air from flowing back into the tunnel; the distance between the air outlet of the press-in type ventilation pipe and the working surface is not more than 15m, and the air suction inlet of the suction type ventilation pipe is not more than 5 m;
(4) adopting mixed ventilation, wherein when one group of ventilators moves forwards, the pipelines of the other group of ventilators are correspondingly lengthened, and the adjacent ends of the two groups of pipelines are always staggered by not less than 20-30 m; when local ventilation is carried out, the air outlet of the suction type air pipe is introduced into the return air flow of the main air flow circulation;
when the slag discharging and transporting steps are carried out, digging the waste slag on the upper half section of the main tunnel to the lower half section of the main tunnel by using a digging machine, and loading the slag by using a loader; the lower half section is directly filled with slag by a digging machine.
2. The blasting excavation method of the V-grade surrounding rock large-section granite tunnel according to claim 1, characterized in that when the upper and lower steps of the left pilot tunnel and the upper and lower steps of the right pilot tunnel are constructed, the distance between the upper step of the left pilot tunnel and the lower step of the left pilot tunnel and the distance between the upper step of the right pilot tunnel and the lower step of the right pilot tunnel are both 5-10 m; the distance between the upper step of the left pit guide and the upper step of the right pit guide is not less than 15 m; the distance between the left pit guiding lower step and the right pit guiding lower step is not less than 15 m.
3. The blasting excavation method of the V-grade surrounding rock large-section granite tunnel according to claim 1, characterized in that in the charging step, emulsion explosive with the specification of phi 32mm x 180g is adopted.
4. The blasting excavation method of the V-level surrounding rock large-section granite tunnel according to claim 1, wherein during the filling process of the charging step, stemming is adopted to be manufactured by a stemming machine, and the mixing ratio of the stemming is 1: 3 clay and sand, and then adding water containing 2-3% of salt.
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| CN114719698A (en) * | 2022-05-13 | 2022-07-08 | 中铁四局集团有限公司 | Ultra-long lower step blasting construction method based on blasting refinement analysis |
| CN115077315A (en) * | 2022-06-17 | 2022-09-20 | 山东多邦汇德信息技术有限公司 | Tunnel blast hole distribution scheme acquisition method based on rock drilling rack structure |
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