CN114754639A - Blasting method for improving single-cycle footage of V-level surrounding rock of high-speed rail tunnel - Google Patents
Blasting method for improving single-cycle footage of V-level surrounding rock of high-speed rail tunnel Download PDFInfo
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- 238000005422 blasting Methods 0.000 title claims abstract description 83
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- 229910000831 Steel Inorganic materials 0.000 claims description 17
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- 238000010276 construction Methods 0.000 abstract description 21
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
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- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
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Abstract
The invention provides a blasting method for improving single circulation footage of V-level surrounding rocks of a high-speed rail tunnel, which belongs to the technical field of underground engineering and comprises the following steps that S1, the V-level surrounding rocks of the tunnel are excavated on a section, the upper part of the V-level surrounding rocks are excavated first, the lower part of the V-level surrounding rocks are simultaneously followed, and the face of the upper part of the V-level surrounding rocks is 8-15 m ahead of the face of the lower part of the V-level surrounding rocks; excavating steps, namely excavating by changing a three-step method into a two-step method, and increasing the height of core soil to ensure the stability of the working face of an upper step; improving the design single-cycle footage; and the adoption of the unilateral cutting on two sides ensures that complete core soil is left behind each stubble of cannon. And S2, determining the number of the blast holes, arranging the blast holes at the upper part, and carrying out a blasting test, wherein the peripheral holes are subjected to smooth blasting. The invention improves the design single circulation footage, effectively reduces the cost and shortens the construction period.
Description
Technical Field
The invention belongs to the technical field of underground engineering, and relates to a blasting method for improving the single-cycle footage of V-level surrounding rocks of a high-speed rail tunnel.
Background
For the V-level surrounding rock tunnel of the high-speed railway, the construction technical rules specify: the excavation single-circulation footage is reasonably determined according to the geological conditions of surrounding rocks, the self-stability capability and the steel frame spacing of primary support, and the upper step circulation footage is not more than 1 steel frame design spacing. This has little effect on tunnels with only a few V-level surrounding rocks, but for long-distance tunnels with V-level surrounding rocks as the main, the single-cycle footage will determine the construction period of the whole tunnel, even the total construction period of the whole railway engineering.
Disclosure of Invention
The invention aims to provide a blasting method for improving the single-cycle footage of V-level surrounding rocks of a high-speed railway tunnel. The invention solves the problems in the background technology, improves the design single cycle footage, reduces the cost and shortens the construction period.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: the blasting method for reasonably improving the single-cycle footage of the V-level surrounding rock of the high-speed railway tunnel by researching and optimizing an excavation program and a blasting technology comprises the following steps,
s1, excavating the V-level surrounding rock section of the tunnel, excavating the V-level surrounding rock section by adopting an upper layer and a lower layer, wherein the upper part is firstly excavated, the lower part is simultaneously excavated, and the tunnel face of the upper part is 8-15 m ahead of the lower part;
excavating steps, namely excavating steps by changing a three-step method into a two-step method, and increasing the height of core soil to ensure the stability of the working face of the upper step; adopting two-side unidirectional cutting to ensure that complete core soil is left behind each stubble of cannon; improving the design single-cycle footage;
and S2, determining the number of the blast holes, arranging the blast holes at the upper part, and carrying out a blasting test, wherein the peripheral holes are subjected to smooth blasting.
Further, the number of blast holes is determined according to
The estimation is carried out in such a way that,
in the formula: f-the rock firmness coefficient; s-tunnel excavation section area, m 2。
Further, in step S1,
the excavation height of the upper step is increased to more than 6 m;
the height of the core soil is increased to more than 3.8m, and the width of the bottom is more than 5 m;
adopting one-way undermining on two sides of the core soil of the upper step, and arranging a plurality of undermining holes;
under the protection of V-level surrounding rock advance support and upper step core soil, the design single circulation footage is improved to more than 1.8 m.
Furthermore, the dip angle of the cut holes is 60-80 degrees, the cut holes comprise a main cut hole, an auxiliary cut hole 1, an auxiliary cut hole 2 and an auxiliary cut hole 3 which are sequentially arranged from the position close to the core soil, the dip angle is sequentially increased, and the single-hole dosage is sequentially reduced.
Further, the pitch of the main cut holes is smaller than the pitch of the auxiliary cut holes 1, the pitch of the auxiliary cut holes 1 and the auxiliary cut holes 2 is not larger than the pitch of the auxiliary cut holes 3, and the pitches of the auxiliary cut holes 1 and the auxiliary cut holes 2 are the same or different.
Further, the blast hole also comprises an inner ring collapse hole, an outer ring collapse hole, a bottom hole and a peripheral light explosion hole. The inner ring caving holes are positioned above the core soil, and the plurality of inner ring caving holes form an arc shape which is the same as that of the upper step; the outer ring burst holes are close to the peripheral light burst holes, the number of the outer ring burst holes is multiple, the outer ring burst holes and the inner ring burst holes are concentric and are arranged on the outer ring of the inner ring burst holes, and the outer ring burst holes on the two sides are arranged on the outer ring of the cut hole; the bottom hole is arranged on the horizontal plane at the lower end of the upper step; and the peripheral light blasting holes adopt smooth blasting.
Furthermore, the peripheral light explosion holes are uniformly distributed on the outer arc surface (designed excavation line) of the upper step, the distance between the peripheral light explosion holes is the minimum of the distances between all blast holes, and the single-hole explosive quantity is the minimum.
Further, in step S1, advance support protection is set within 140 ° of the crown arch during each cycle of excavation and blasting, and the advanced small guide tube is a hot-rolled seamless steel tube with a diameter of 42mm and a thickness of 3.5mm, the length of the tube is 3.5m, and the distance between the tubes is 35 cm; the central soil is reserved in the middle of the face of each cycle.
Further, the explosive for blasting comprises a cartridge with the diameter of phi 32mm, the weight of 300g, the length of 30cm and the density of 1.05-1.20 g/cm3The gap distance is more than or equal to 3 cm;
detonator: the charging in the hole adopts MS 1-MS 11 section non-electric millisecond detonator, the connection of the network outside the hole adopts MS1 section non-electric millisecond detonator, and the detonating adopts 8 number common industrial electric detonator.
Further, drilling a blast hole on a self-made drilling and blasting trolley, wherein the blast hole is drilled by a hand drill, and the diameter of the drilled hole is phi 42 mm; and (4) adopting a loader to load the slag of the dump truck.
Compared with the prior art, the invention has the following advantages and positive effects.
1. The invention changes a three-step method into a two-step method for excavation, expands the excavation height of the upper step, improves the height of the core soil, ensures the stability of the working face of the upper step, improves the design excavation single-cycle footage under the protection of V-level surrounding rock advance support and the core soil of the upper step, and further accelerates the excavation speed of the V-level surrounding rock. The construction technical specification of the high-speed rail tunnel specifies that the upper step excavation footage of the V-grade surrounding rock is not more than 1 steel frame design interval; the expert proves that: generally, the one-time excavation footage of the upper step of the V-grade surrounding rock is not more than 2 steel frame design intervals, and the one-time excavation footage of the middle step and the lower step is not more than 3 steel frame design intervals. The excavation single-cycle footage of the invention is increased by 2 times compared with the regulation; is 1.5 times of the expert demonstration that the excavation single-cycle footage is allowed.
2. The advanced small guide pipe constructed in each cycle effectively ensures the stability of the surrounding rock of the crown arch after the blasting, strives for time for subsequent steel support, net hanging and concrete spraying, and the peripheral holes of the tunnel adopt a smooth blasting technology, so that the disturbance of blasting on the surrounding rock is reduced.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a layout diagram of blast holes for upper bench excavation according to the present invention;
fig. 2 is a cross-sectional view a-a of the inventive slotted hole arrangement.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.
The following detailed description of specific embodiments of the invention refers to the accompanying drawings.
As shown in fig. 1-2, the blasting method for improving the single-cycle footage of the V-level surrounding rock of the high-speed railway tunnel comprises the following steps:
s1, excavating the V-level surrounding rock section of the tunnel, excavating the V-level surrounding rock section by adopting an upper layer and a lower layer, wherein the upper part is firstly excavated, the lower part is simultaneously excavated, and the tunnel face of the upper part is 8-15 m ahead of the lower part;
excavating steps, namely excavating steps by changing a three-step method into a two-step method, and increasing the height of core soil to ensure the stability of the working face of the upper step; improving the design single-cycle footage;
excavation was performed according to the following criteria.
1) And the number of steps to be excavated is reduced. According to regulations and design requirements, the V-level surrounding rock tunnel excavation is constructed by adopting a three-step method, and the more the number of steps is, the more complicated the excavation process is, and the more unfavorable the acceleration of the excavation speed is. Therefore, the three-step excavation is adjusted to the two-step excavation on the premise of strengthening the advance support and strengthening the tunnel face.
2) The height of the upper step is increased. After the three steps are changed into the two steps, the excavation height of the upper step is increased, so that the operation space is increased, the operation conditions of the working procedures of drilling, slag discharge, safety treatment, primary support and the like can be effectively improved, the excavation progress is accelerated, and the excavation height of the upper step is increased to more than 6 m;
3) the height of the core soil is increased. Along with the increase of the height of the excavation working surface of the upper step, in order to ensure the stability of the tunnel face, the height of the core soil is properly increased, the height of the core soil is increased to be more than 3.8m, and the width of the bottom of the core soil is more than 5 m.
4) Adopting one-way cut holes on two sides of the upper step core soil, and arranging a plurality of cut holes; unidirectional undercutting is rarely used in large section tunnel excavation blasting construction. In order to leave more complete core soil behind each stubble of cannon to ensure the stability of the tunnel face, two-side unidirectional cutting is considered.
5) And improving the single-cycle footage. Under the protection of V-level surrounding rock advance support and tunnel face core soil, the design single-cycle footage is improved to more than 1.8 m. The design distance between two steel frames with the single-circulation footage demonstrated by experts is 1.2m, and the design distance is properly increased to ensure that the monthly footage of the V-level surrounding rock excavation is more than 50 m.
And S2, determining the number of the blast holes, arranging the blast holes at the upper part, and carrying out a blasting test, wherein the peripheral holes are subjected to smooth blasting.
The number of blast holes is determined according to
The estimation is carried out in such a way that,
in the formula: f, a rock firmness coefficient; s-area of tunnel excavation section, m2。
Preferably, the dip angle of the cut holes is 60-80 degrees, the cut holes comprise a main cut hole, an auxiliary cut hole 1, an auxiliary cut hole 2 and an auxiliary cut hole 3 which are sequentially arranged from the position close to the core soil, the dip angle is sequentially increased, and the dosage of single holes is sequentially reduced.
Preferably, the pitch of the main cut holes is smaller than the pitch of the auxiliary cut holes 1, the pitch of the auxiliary cut holes 1 and the auxiliary cut holes 2 is not greater than the pitch of the auxiliary cut holes 3, and the pitches of the auxiliary cut holes 1 and the auxiliary cut holes 2 are the same or different.
Preferably, the blast hole further comprises an inner ring burst hole, an outer ring burst hole, a bottom hole and a peripheral light explosion hole. The inner ring caving holes are positioned above the core soil, and the plurality of inner ring caving holes form an arc shape which is the same as that of the upper step; the outer ring caving holes are close to the peripheral light explosion holes, the number of the outer ring caving holes is multiple, the outer ring caving holes and the inner ring caving holes are concentric and are arranged on the outer ring of the inner ring caving holes, and the outer ring caving holes on two sides are arranged on the outer ring of the cut hole; the bottom hole is arranged on the horizontal plane of the lower end of the upper step; and the peripheral light blasting holes adopt smooth blasting.
Preferably, the peripheral light blasting holes are uniformly distributed on the outer arc surface (designed excavation line) of the upper step, the distance between the peripheral light blasting holes is the minimum of the distances between all blast holes, and the single-hole explosive quantity is the minimum.
Conducting a blasting test
Through the research of tunnel excavation blasting tests, a blasting method for accelerating the excavation progress of the V-level surrounding rock and a reasonable single-cycle footage are found out, and the feasibility of the overall idea for accelerating the excavation progress is verified.
Test conditions
1) The blasting test is carried out in the excavation of the upper layer of the V-level surrounding rock at the outlet of the tunnel, and the two-step method is adopted for excavation, namely the number of the excavated steps is reduced, and the three-step method construction required by the technical regulations is changed into the two-step method construction.
2) The drilling work is carried out on a self-made drilling and blasting trolley, and the YT28 type hand pneumatic drill is adopted for drilling.
3) And each cycle of excavation and blasting is carried out, advance support protection is carried out within 140 degrees of the top arch, and the small advanced guide pipe is a hot-rolled seamless steel pipe with the diameter of 42mm and the thickness of 3.5mm, the length of the small advanced guide pipe is 3.5m, and the distance between the small advanced guide pipe and the hot-rolled seamless steel pipe is 35 cm.
4) The central soil is reserved in the middle of the face of each cycle.
Blasting equipment
1) Explosive: the method comprises the following steps of selecting a No. 2 rock emulsion explosive produced by Laizhou division of the Ore service Co., Ltd of BaolioryKa (Shandong): the diameter of the medicated roll is phi 32mm, the weight is 300g, the length is 30cm, and the density is 1.05-1.20 g/cm 3And the gap distance is more than or equal to 3 cm.
2) Detonator: the charging in the hole adopts MS 1-MS 11 section non-electric millisecond detonator, the connection of the network outside the hole adopts MS1 section non-electric millisecond detonator, and the detonating adopts 8 number common industrial electric detonator.
The embodiment is as follows: a large number of V-level surrounding rock tunnel sections exist at the entrance and the exit of the Weishan tunnel to the smoke bench high-speed railway, the flexible mountain tunnel is formally excavated into the tunnel at 1 month and 5 days in 2021, and the flexible mountain tunnel is excavated into the tunnel at 3 months and 5 days in 2021, but the flexible mountain tunnel is influenced by a plurality of things, so that the excavation construction period of the tunnel exit is dragged for 103 days, the entrance construction period is dragged for 44 days, and the total excavation construction period is seriously lagged.
The excavation work is finished 5 months and 27 days before 2022 according to the arrangement of the total construction period of the Lingshan tunnel. In order to ensure that the tunnel is completed according to the period, the monthly footage of V-level surrounding rock excavation must be more than 50m and the daily footage must be more than 1.67m through measurement and calculation, and the current situation is that the monthly footage of V-level surrounding rock excavation is only about 35m and the daily footage is about 1.2m, so that the completion of excavation work according to the period cannot be ensured at all. Therefore, the excavation speed of the V-level surrounding rock needs to be increased on the premise of ensuring the construction safety.
In order to solve the problems of late tunnel construction, lag construction period, slow excavation progress of a V-level surrounding rock tunnel section and the like, a series of V-level surrounding rock excavation blasting tests are developed and are carried out according to the steps, so that measures such as reducing excavation steps, changing an undermining mode, properly increasing single-cycle footage and the like are taken. The results show that: under the protection of advanced support and core soil, the single-cycle footage of the upper step of the V-level surrounding rock tunnel section can be increased to 2.0m from 1 steel frame spacing (0.6m) specified by regulations or 2 demonstrated steel frame spacing (1.2m), and the tunnel section surrounding rock after excavation and support is stable; the single-side monthly advance ruler for V-grade surrounding rock excavation is increased from 35m to 61.8m, so that the overall excavation progress is effectively accelerated, and the excavation cost is reduced.
The V-level surrounding rock excavation section of the Lingshan tunnel is 14.93m wide and 12.78m high, an upper layer and a lower layer are adopted for excavation in a subsection mode, the upper portion of the excavation scheme is firstly carried out, the lower portion of the excavation scheme is simultaneously followed, and the upper portion of the tunnel face is 8-15 m ahead of the lower portion of the tunnel face. Blasting test is carried out at the upper part, and peripheral holes are subjected to smooth blasting; the upper part and the lower part are drilled by YT28 hand pneumatic drills, and the diameter of the drilled hole is phi 42 mm; using a 3.0m3The loader loads 25t of the dump truck for slag tapping.
1) And (6) excavating steps. The three-step method is changed into the two-step method for excavation, and the excavation height of the upper step is increased from 3.2m to 6.7 m.
2) And (5) getting up the core soil of the step. In order to ensure the stability of the upper step tunnel face, the height of the core soil is increased from 1.8m to 4.0m in the case of three steps, and the width of the bottom is 5.5 m.
3) And (4) a cutting mode. In order to reserve the core soil, one-way undermining is adopted on two sides of the upper step core soil, and the inclination angle of the undermining hole is 60-80 degrees.
4) And improving the single-cycle footage. Under the protection of V-level surrounding rock advance support and upper step core soil, the design single circulation footage is improved to 2.0 m.
Blasting design
1) A typical shot hole arrangement is shown in figures 1 and 2.
2) Typical blast design parameters, see table 1.
Table 1 typical blasting design parameter table
In order to accelerate the excavation progress of V-grade surrounding rocks of the Weiwei-cigarette high-iron flexible mountain tunnel, an improvement single-cycle footage blasting test of 10 continuous cannons is carried out at a tunnel outlet DK96+ 979.1-DK 96+958.6, and specific test results are shown in Table 2.
TABLE 2 statistics table for single-cycle footage blasting test results
From the test condition of continuous 10-time cannons, the excavated tunnel surrounding rock is stable, the contour of the periphery of the tunnel is smooth and regular, the blasting efficiency reaches 102.5%, the average single-circulation footage is slightly larger than the average blast hole depth, and the top arch collapse phenomenon does not occur. The main reasons are as follows:
1) the core soil reserved in the middle of the face effectively ensures the stability of the face;
2) the advanced small guide pipe constructed in each cycle effectively ensures the stability of the surrounding rock of the crown arch behind the cannon, and strives for time for subsequent steel support, net hanging and concrete spraying;
3) the peripheral holes of the tunnel adopt a smooth blasting technology, so that the disturbance of blasting on surrounding rocks is reduced.
Consumption of blasting equipment
The number of the single-cycle evenly distributed holes for upper bench excavation and the consumption of blasting equipment are shown in table 3.
TABLE 3 consumption analysis of blasting equipment for bench excavation
The number of blast holes can be determined according to
An estimation is performed. In the formula: f-the rock firmness coefficient; s-tunnel excavation section area, m2. The surrounding rock of the test hole section is strongly weathered granite, belongs to IX-grade rock (Pogh grade) according to relevant documents and specifications, f is 8, and N is 119 estimated. As can be seen from Table 3, only 102 blast holes are less than 119 blast holes in the whole excavation face, and the density of the blast holes is 1.34 blast holes/m 2And the number of relative holes is small, so that the drilling operation time is effectively shortened.
According to the rated IX-grade rock detonator unit consumption of 0.90 rounds/m3And the unit consumption of explosive is 1.06kg/m3. The unit consumption of the detonator in the blasting test is 0.73 times/m3The specific consumption of explosive is 0.41kg/m3All are lower than the rated value, and the charging operation time is effectively reduced.
Under the protection of the core soil and the top arch advance support in the middle of the tunnel face, the single-cycle ruler feeding for V-level surrounding rock excavation of the Lingshan tunnel is feasible, and the construction safety can be guaranteed, wherein the distance between 1.2m and 2.0m is increased.
By 30 days at 4 months in 2021, excavating and supporting 28.5m of V-level surrounding rock on the entrance working face of the Lingshan tunnel, and remaining 74.5 m; and the V-level surrounding rock of the outlet working face is excavated and supported by 73.3m, and remains by 654.5 m. The inlet and the outlet are 729.2m in total. Excavating the cross section area of 76.38m according to the upper layer2Calculating the residual total amount of 55696.3m of the upper layer3The explosive can be saved by 16708.89kg compared with the rated explosive, and the detonator can be saved by 9469.
The blast ratio design of each blast of the upper layer excavation is estimated to reduce 17 blast holes, and according to the calculation of normal excavation single-cycle footage of 1.8m, each blast reduces 30.6m drill holes, 406 blast holes are needed for completing the V-level surrounding rock excavation, and 12423.6m drill holes can be reduced.
The original design scheme adopts a digital electronic detonator, and the cost is too high. Then, the local public bureau and the blasting equipment supplier are communicated repeatedly, and the non-electric millisecond detonators are used. The cost of excavating and blasting each square rock on the upper layer can be reduced by 8.1 yuan through blasting test analysis and comparison by using 21.84 yuan for each digital electronic detonator and 5.83 yuan for each non-electronic millisecond detonator. The economic benefits obtained are shown in Table 4.
TABLE 4 economic benefit analysis
| Serial number | Name of project | Number of | Univalent (yuan) | Price combination (Yuan) |
| 1 | Reduction of drilling | 12423.6m | 22.3 | 277046.28 |
| 2 | Saving explosive | 16708.89kg | 10.5 | 175443.35 |
| 3 | Saving detonator | 9469 Hair caring | 5.83 | 55204.27 |
| 4 | Detonator adjustment cost reduction | 55696.3m3 | 8.1 | 451140.03 |
| Total up to | 958833.93 |
From table 4, it can be seen that the total cost of 95.88 ten thousand yuan can be reduced by the blasting design scheme test and optimization and the excavation of the V-level surrounding rock tunnel segment.
Accelerating the project progress, controlling the residual V-grade surrounding rock of 654.5m on the outlet working face of the tunnel excavation construction period by 30 days after 4 months in 2021, and according to the original blasting design scheme, advancing to 1.2m daily and requiring 545.4 days for excavation supporting; according to the optimized scheme of the blasting test, the daily footage is 1.8m, and the total period of excavation and supporting is 363.6 days. Therefore, the construction period can be advanced by 181.8 days compared with the original scheme through the optimization of the blasting design test scheme.
In the Lingshan tunnel V-level surrounding rock single-cycle footage improvement blasting test, the single-cycle footage is successfully improved to 2.05 m. Because the design interval of the steel arch frames is 0.6m, in order to enable the single-circulation footage to be matched with the interval of the steel arch frames, the single-circulation footage in actual excavation is 1.8 m. In addition, under the limitation of the supply time of local blasting equipment (9: 00-21: 00 in the morning) and the limitation of the safe step distance of secondary lining concrete in the construction of the high-speed railway tunnel (the distance between the secondary lining and the tunnel face is less than 120m), one cycle of excavation per day cannot be realized in 5-8 months, and the average monthly footage is only about 45 m. To achieve an excavation schedule of at least one cycle per day, the supply time of the blasting equipment is adjusted to: 5:00 morning to 24:00 evening; meanwhile, the construction management of the internal secondary lining is enhanced, the excavation progress is not influenced by the problem of the safe step pitch of the secondary lining concrete, and the V-level surrounding rock excavation monthly footage of the export of the Lingshan tunnel is finally realized by more than 54 m: the footage for 9 months is 54.6m, the footage for 10 months is 61.8m, and the footage for 11 months is 57.6m, so that the construction period is shortened.
Although one embodiment of the present invention has been described in detail, the description is only for the purpose of illustrating the preferred embodiments of the present invention and should not be taken as limiting the scope of the invention. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.
Claims (10)
1. The blasting method for improving the V-level surrounding rock single-cycle footage of the high-speed rail tunnel is characterized by comprising the following steps of: comprises the following steps of (a) preparing a solution,
s1, excavating a section of the tunnel V-level surrounding rock, excavating an upper layer and a lower layer in part, wherein the upper part is advanced, the lower part is simultaneously followed, and the tunnel face of the upper part is 8-15 m ahead of the lower part;
excavating steps, namely excavating by changing a three-step method into a two-step method, and increasing the height of core soil to ensure the stability of the working face of an upper step; adopting two-side unidirectional cutting to ensure that complete core soil is left behind each stubble of cannon; improving the design single-cycle footage;
and S2, determining the number of the blast holes, arranging the blast holes at the upper part, and carrying out a blasting test, wherein the peripheral holes are subjected to smooth blasting.
2. The blasting method for improving the single-cycle footage of the V-level surrounding rock of the high-speed railway tunnel according to claim 1, wherein the blasting method comprises the following steps: the number of blast holes is as follows
The estimation is carried out in such a way that,
in the formula: f-the rock firmness coefficient; s-tunnel excavation section area, m 2。
3. The blasting method for improving the single-cycle footage of the V-level surrounding rock of the high-speed rail tunnel according to claim 1, wherein the blasting method comprises the following steps: in the step S1, in the step S,
the excavation height of the upper step is increased to more than 6 m;
the height of the core soil is increased to more than 3.8m, and the bottom width is more than 5 m;
adopting one-way cut holes on two sides of the upper step core soil, and arranging a plurality of cut holes;
under the protection of V-level surrounding rock advanced support and upper step core soil, the design single-cycle footage is improved to more than 1.8 m.
4. The blasting method for improving the single-cycle footage of the V-level surrounding rock of the high-speed rail tunnel according to claim 1, wherein the blasting method comprises the following steps: the dip angle of the cut holes is 60-80 degrees, the cut holes comprise a main cut hole, an auxiliary cut hole 1, an auxiliary cut hole 2 and an auxiliary cut hole 3 which are sequentially arranged from the position close to the core soil, the dip angle is sequentially increased, and the dosage of single holes is sequentially reduced.
5. The blasting method for improving the single-cycle footage of the V-level surrounding rock of the high-speed rail tunnel according to claim 1, wherein the blasting method comprises the following steps: the pitch of the main cut holes is smaller than that of the auxiliary cut holes 1, the pitch of the auxiliary cut holes 1 and the auxiliary cut holes 2 is not greater than that of the auxiliary cut holes 3, and the pitches of the auxiliary cut holes 1 and the auxiliary cut holes 2 are the same or different.
6. The blasting method for improving the single-cycle footage of the V-level surrounding rock of the high-speed rail tunnel according to claim 1, wherein the blasting method comprises the following steps: the blast hole also comprises an inner ring caving hole, an outer ring caving hole, a bottom hole and a peripheral light explosion hole, wherein the inner ring caving hole is positioned above the core soil, and the plurality of inner ring caving holes form an arc shape which is the same as that of the upper step; the outer ring burst holes are close to the peripheral light burst holes, the number of the outer ring burst holes is multiple, the outer ring burst holes and the inner ring burst holes are concentric and are arranged on the outer ring of the inner ring burst holes, and the outer ring burst holes on two sides are arranged on the outer ring of the cut hole; the bottom hole is arranged on the horizontal plane of the lower end of the upper step; and the peripheral light blasting holes adopt smooth blasting.
7. The blasting method for improving the single-cycle footage of the V-grade surrounding rock of the high-speed rail tunnel according to claim 6, wherein the blasting method comprises the following steps: peripheral light explosion holes are uniformly distributed on the outer arc surface of the upper step, the distance between the peripheral light explosion holes is the minimum of the distances between all blast holes, and the single-hole explosive quantity is the minimum.
8. The blasting method for improving the single-cycle footage of the V-grade surrounding rock of the high-speed railway tunnel according to any one of claims 1 to 7, wherein the blasting method comprises the following steps: in step S1, each cycle of excavation and blasting is carried out, advance support protection is set within 140 degrees of a top arch, and a small advanced guide pipe is a hot-rolled seamless steel pipe with the diameter of 42mm and the thickness of 3.5mm, the length of the small advanced guide pipe is 3.5m, and the distance between the small advanced guide pipe and the hot-rolled seamless steel pipe is 35 cm; the central soil is reserved in the middle of the face of each cycle.
9. The blasting method for improving the single-cycle footage of the V-grade surrounding rock of the high-speed railway tunnel according to any one of claims 1 to 7, wherein the blasting method comprises the following steps: the explosive for blasting comprises a cartridge with the diameter of phi 32mm, the weight of 300g, the length of 30cm and the density of 1.05-1.20 g/cm3The gap distance is more than or equal to 3 cm;
detonator: the inside of the hole is filled with MS 1-MS 11 sections of non-electric millisecond detonators, the outside of the hole is connected with MS1 sections of non-electric millisecond detonators, and the detonating adopts No. 8 common industrial electric detonators.
10. The blasting method for improving the single-cycle footage of the V-grade surrounding rock of the high-speed railway tunnel according to any one of claims 1 to 7, wherein: drilling a blast hole on a self-made drilling and blasting trolley, wherein the blast hole is drilled by a hand drill, and the diameter of the drilled hole is phi 42 mm; and (4) adopting a loader to load the slag of the dump truck.
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| CN104713431A (en) * | 2015-03-05 | 2015-06-17 | 中国水利水电第五工程局有限公司 | Smooth blasting method based on phi 32 mm cartridges |
| CN107060840A (en) * | 2017-05-07 | 2017-08-18 | 中铁十八局集团有限公司 | A kind of construction method of large cross-section tunnel V grades of country rock excavation supportings |
| KR20190080716A (en) * | 2017-12-28 | 2019-07-08 | 백종현 | Separated composite excavation method in plhbm |
| CN113465461A (en) * | 2021-08-02 | 2021-10-01 | 贵州华昱乾城科技服务有限公司 | Large-section tunnel blasting hole-reducing layout method |
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- 2022-03-31 CN CN202210328241.3A patent/CN114754639A/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104713431A (en) * | 2015-03-05 | 2015-06-17 | 中国水利水电第五工程局有限公司 | Smooth blasting method based on phi 32 mm cartridges |
| CN107060840A (en) * | 2017-05-07 | 2017-08-18 | 中铁十八局集团有限公司 | A kind of construction method of large cross-section tunnel V grades of country rock excavation supportings |
| KR20190080716A (en) * | 2017-12-28 | 2019-07-08 | 백종현 | Separated composite excavation method in plhbm |
| CN113465461A (en) * | 2021-08-02 | 2021-10-01 | 贵州华昱乾城科技服务有限公司 | Large-section tunnel blasting hole-reducing layout method |
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