CN109990673B - Method for excavating protective layer of karst landform downslope crack toe board - Google Patents
Method for excavating protective layer of karst landform downslope crack toe board Download PDFInfo
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- CN109990673B CN109990673B CN201810002926.2A CN201810002926A CN109990673B CN 109990673 B CN109990673 B CN 109990673B CN 201810002926 A CN201810002926 A CN 201810002926A CN 109990673 B CN109990673 B CN 109990673B
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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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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42D—BLASTING
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- F42D3/04—Particular applications of blasting techniques for rock blasting
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Abstract
The invention relates to a karst landform downslope crack toe board protection layer excavation method which is characterized in that the excavation method adopts a toe board building base surface bench blasting method and an upstream side slope dual-energy presplitting smooth surface blasting method to carry out blasting together, and combines a bench millisecond differential blasting method of a flexible cushion layer and a reserved protection layer, and specifically comprises the following steps: performing technical background matching; measuring and lofting; confirming the hole position of the blast hole; positioning a drilling machine; drilling by a drilling machine and filling a drilling record; rechecking and adjusting the drilling angle when the blast hole is drilled to about 40cm deep; controlling the depth of the blast hole, and reserving a 30-50cm protective layer; if special geological conditions are met, making relevant records, and considering whether to adjust blasting design; blasting construction; according to the blasting design, a flexible cushion layer is arranged in a blast hole, the blast hole is filled with powder, the hole is sealed, and the explosives in the hole are networked and blasted; and (6) excavating the protective layer. The method for excavating the karst landform downslope crack toe board protection layer saves cost, improves the mechanical utilization rate and the construction progress, and creates favorable conditions for subsequent construction.
Description
Technical Field
The invention belongs to the field of water conservancy and hydropower building construction, relates to a method for excavating toe boards of a concrete-faced rockfill dam, and particularly relates to a method for excavating a protective layer of a tailgating crack toe board and an upstream side slope of a karst landform.
Background
The research and the test of the primary blasting method of the bed rock protective layer have the history of only twenty years in China, the development of the method is quite slow, the method is not mature from the perspective of high speed and high efficiency of construction, and the method is still in the stage of continuous exploration and perfection, so the method is not widely applied to the rock foundation excavation construction of hydraulic buildings.
At the beginning of the fifty years, Burmani, Wagner, the academy of sciences, made pioneering studies on "space-charge blasting". Meanwhile, Swedish and Canadian scholars propose a peripheral blasting method, namely presplitting blasting and smooth blasting through tests, a smooth and flat excavation profile is obtained in rocks, and scholars in various countries begin to research the seam forming mechanism. A series of pre-splitting blasting tests are carried out in the Guzhou dam engineering in 1973, the slope is excavated by adopting the pre-splitting blasting in 1974, the adverse effect of blasting on a reserved area is effectively controlled, the shape of the excavated slope is ensured, overlarge over-excavation is avoided, the construction progress is accelerated, and the construction progress is rapidly popularized to the excavation construction of other large and medium hydropower engineering.
While the presplitting and smooth blasting technologies are continuously mature, the dam foundation excavation of the hydraulic building still adopts the traditional protective layer excavation method of a 'layer-by-layer peeling' type, namely, cobalt holes are drilled in the reserved protective layer by hand, shallow hole guns are used for carrying out layer-by-layer excavation, and a manual prying layer of 0.2-0.3 m is reserved. The excavation method has the advantages of large repeated base cleaning engineering quantity, long construction period occupation, high consumption and unsatisfactory quality. The majority of engineering technicians hope to improve the traditional protective layer excavation method urgently, accelerate the construction progress, and begin to try to apply the presplitting and smooth blasting technologies to the protective layer excavation.
When the presplitting and smooth blasting technologies are applied to excavate dam foundation protective layers, in order to further simplify construction procedures, accelerate construction progress and reduce excavation cost, a small-step millisecond blasting technology with a flexible cushion layer arranged at the bottom of a vertical blasting hole is introduced, 4 groups of protective layers (siltstones and sandy shales) are subjected to primary blasting tests by applying the technology at the construction place of Ministry of Japan and Yangtze river at the lock head of a Wan hydro junction ship lock in 1982, 4 groups of productivity tests are performed at bottom hole dam sections (medium-coarse-grained feldspar quartz sandstone) in 1985, a certain achievement is obtained, and the first-grade technological improvement of the original profit power department is obtained in 1986, the main results of this test were: the hand pneumatic drill is used for drilling holes and removing the blasting once, small bench sections are adopted, no coupling charging is carried out, millisecond difference detonation is carried out between holes (between rows), the hole depth is strictly controlled, and a flexible cushion layer is added at the bottom of the hole to slow down the destructive effect of blasting shock waves.
The method is a new idea in the existing dam foundation protective layer excavation, and a productive test is carried out in the second-stage flood discharge of the three gorges dam and the excavation of a building base surface of a factory dam section in 8-10 months in 1998, so that certain achievements are obtained, but the effect is not ideal, and further tests and researches are needed.
In most foreign countries, in order to quickly and economically excavate a rock foundation of a building, a reserved protective layer is small in thickness, the protective layer excavation process is simple, blasting is controlled once to excavate a foundation surface, and consolidation grouting reinforcement treatment is performed after new cracks and expanded cracks generated by blasting in the foundation are left to be covered with concrete. Some countries do not even have a clear base rock protective layer concept, for example, the existing construction specifications in Sweden do not clearly specify a protective layer excavation method, but adopt a method for carefully excavating a layer; the 70 s specifications allow a certain range of variation of the longitudinal wave velocity of the rock. Therefore, few foreign researches have been conducted on excavation methods of bedrock protective layers.
The rock-sandwiched hydro-junction and the water supply engineering in the North Qian province are in cloud noble plateaus and are distributed in wide karst landforms, and the limestone layer is large in thickness and wide in distribution. The toe boards of the dam are important seepage-proofing structures of the whole concrete face rock-fill dam, the geological conditions of the foundation surface of the toe board of the rock-sandwiched hydraulic junction are relatively poor, the change of the lithology and the geological conditions is large, most of the toe boards are bedding side slopes, rock weathering, joints, cracks and faults are complex and variable, and the excavation form size and the flatness of the foundation surface of the toe board directly influence the foundation quality, the construction progress and the construction cost. Therefore, how to control the flatness of the base surface of the toe board in the excavation process is a difficult problem. Blasting excavation is generally carried out by a blasting test aiming at rock conditions, and a blasting process with good excavation effect, moderate cost and high progress is preferably selected. The traditional technology has two types: the method comprises a presplitting and smooth blasting method and a protective layer reserving method, namely a protective layer-layer peeling protective layer excavating method. The disadvantages of the first method are: the dam foundation is only suitable for the dam foundation with relatively complete bedrock and better geological conditions, and is not suitable for the dam foundation with karst landform thin-layer joints, cracks and fault development. The disadvantages of the second method are: the repeated base cleaning engineering quantity is large, the occupied construction period is long, the consumption is high, and the quality is not ideal.
Disclosure of Invention
The invention provides a karst landform downslope crack toe board protective layer excavation method according to geological characteristics of the karst landform. According to the method, the flexible cushion layer blasting technology is organically combined with the reserved protective layer excavation, the toe board building base surface bench blasting and the upstream side slope dual-energy-gathering presplitting smooth blasting are blasted together, so that the explosion energy is basically attenuated under the action of the flexible cushion layer, and is attenuated again through the reserved protective layer, the building base surface is effectively prevented from being damaged by the explosion energy, and the dual-protection lower rock effect is achieved. Thereby guaranteed toe board and built the excavation roughness and the basement rock integrality of base surface.
The invention particularly provides an excavation method of a karst landform downslope fissure toe plate protection layer, wherein the excavation method adopts a toe plate foundation surface bench blasting method and an upstream side slope dual-energy presplitting smooth surface blasting method to carry out blasting together, and combines a bench millisecond differential blasting method of a flexible cushion layer and a reserved protection layer, and the method specifically comprises the following steps:
(1) technical background matching: intersecting the toe board building base surface excavation technical requirements, blasting design parameters and construction key points;
(2) measuring and lofting: setting out of toe boards and upstream slope blasting parts and determining blast hole points;
(3) confirming the hole positions of the blast holes: rechecking hole positions and hole depths according to blasting design, and judging whether the row spacing of the lofting single core to blast holes is qualified or not, wherein the deviation of the hole positions is less than 10 cm;
(4) positioning a drilling machine: adjusting the position of a drilling machine, measuring the angle of a hole drill and ensuring that the angle is correct;
(5) drilling by a drilling machine and filling a drilling record;
(6) rechecking and adjusting the drilling angle when the blast hole is drilled to about 40cm deep;
(7) controlling the hole depth of the blast hole, drilling the hole to the position 30-50cm away from the building base plane, and stopping drilling the hole to reserve a 30-50cm protective layer; if special geological conditions are met, making relevant records, and considering whether to adjust blasting design;
(8) blasting construction: rechecking the blasting design before loading the explosive; according to the blasting design, a flexible cushion layer is arranged in a blast hole, the blast hole is filled with powder, the hole is sealed, and the explosives in the hole are networked and blasted;
(9) excavating a protective layer: and (4) manually matching with a pickaxe machine and an electric hammer to excavate the protective layer to the design requirement.
In some preferred embodiments, the blastholes include a first primary blasthole located on the toe plate base, a second primary blasthole located adjacent the upstream slope, a buffer hole located adjacent the upstream slope, and a bi-poly energy pre-spalled finish hole located on the upstream slope; the buffer hole and the double-energy-gathering pre-splitting smooth surface hole are both provided with one row.
In some preferred embodiments, the first primary blasthole has one or more rows. The number of rows of the first main explosion hole arrangement may be set according to the size of the floor of the toe board, the degree of explosion, etc.
In other preferred embodiments, the second primary blasthole has one or more rows. The number of rows of the second main blast hole arrangement can be set according to the area size near the upstream slope and the blasting degree.
In some preferred embodiments, the first main explosion hole adopts a charge structure which charges continuously from the bottom of the hole to the top, and a flexible cushion layer is arranged at the bottom; the second main explosion hole adopts a charge structure for continuously charging charges from the bottom of the hole upwards, and the bottom of the second main explosion hole is free of a flexible cushion layer; the buffer holes adopt a structure of filling powder from the hole bottom to the upper part at intervals, and the bottom is provided with a flexible cushion layer; the double-energy-gathering pre-splitting smooth surface hole adopts a powder charging structure for continuously charging powder medicine in the double-energy-gathering tube, a phi 32 reinforced explosive roll is arranged in the high range of 1m at the bottom, and a flexible cushion layer is arranged at the bottom of the double-energy-gathering tube.
In some preferred embodiments, the flexible cushion layer is positioned between the reserved protective layer and the explosive loading area; before the explosive is filled in the blast hole, a flexible cushion layer is laid on the reserved protective layer at the bottom in the hole.
After the flexible cushion layer is arranged on the reserved protective layer, the upper portion rocks can be broken in the blasting process, and the damage to the lower portion bedrocks is reduced to the maximum extent. The first blasting shock wave is attenuated by the primary energy of the flexible cushion layer, the action of medium transfer blasting shock is reduced by using the advantage of flexible cushion layer blasting (the explosive cartridge is not in direct contact with the bottom of the hole), and the first blasting shock wave is attenuated again by the reserved protective layer; secondly, the blast hole and the flexible cushion layer have larger compressibility so as to reduce the blasting pressure. Thereby, the double protection function of the lower part rock is achieved through the two points.
In some preferred embodiments, the thickness of the flexible cushion layer is between 30 and 50 cm.
In some preferred embodiments, the compliant pad material is selected from cushioning materials. The flexible cushion layer mainly has the function of buffering, so that blasting impact is buffered and attenuated, and therefore, buffering materials such as sawdust and foam are selected.
In a more preferred embodiment, the flexible cushion material is selected from cushioning materials having a hollow structure. The cushion material with the hollow structure is used as the flexible cushion layer, and the cushion material has cushion performance, so that the blasting impact can be slowed down, and the energy attenuation is realized; hollow structure also can completely cut off the transmission of shock wave, more effective and quick messenger impact energy decay to, can guarantee subsequent toe board and build excavation roughness and the basement rock integrality of base face. Such as hollow bamboo tube made of moso bamboo, or beverage bottle made of waste mineral water bottle or cola, etc. In some embodiments, the flexible cushion material is selected from waste plastic bottles.
In some preferred embodiments, the filling explosive height is corrected in time according to the hole depth of the blast hole during blasting.
In some preferred embodiments, the technical intersection comprises a top-down bench cut; under-digging is strictly forbidden, and over-digging is reduced as much as possible; strictly controlling the flatness to be less than or equal to 15 cm; the building base surface can not have a reverse slope, an inverted suspension slope and a steep ridge sharp angle.
In some preferred embodiments, the technical background further comprises the following steps of explaining blasting design parameters, measuring, drilling, charging, blasting, excavating protective layers and the like.
In some preferred embodiments, hole sites are released according to a blasting design drawing, azimuth angles and hole inclinations of each row of blast holes are determined, and hole numbers are marked beside the hole sites by adopting spray painting; measuring the elevation of the hole opening of each hole; the technician calculates the actual hole depth for each hole as a function of the orifice elevation.
In some preferred embodiments, the drilling process tightly controls the hole depth.
Advantageous effects
Compared with the conventional presplitting blasting and reserved protective layer blasting excavation, the method for excavating the protective layer of the karst landform downslope cracked toe board saves cost by reserved protective layer flexible cushion layer blasting, improves the mechanical utilization rate and the construction progress, and creates favorable conditions for subsequent construction. Moreover, the toe board foundation surface bench blasting and the upstream side slope dual-energy-gathering presplitting smooth surface blasting are blasted together, and a bench millisecond differential blasting method of a flexible cushion layer and a reserved protective layer is combined, so that the flatness of the toe board foundation surface is improved, the overbreak is reduced, and the cost of backfilling concrete is saved; the integrity of the base surface is protected, and the anti-seepage capability of the toe board foundation is improved.
Drawings
FIG. 1 is a schematic plan view showing arrangement of blast hole sites and a detonation network in a flexible cushion layer, a reserved protective layer and an upstream slope blasting process according to the present invention;
FIG. 2 is a longitudinal sectional view (A-A sectional view) of the flexible cushion layer and the reserved protective layer of the present invention and the upstream slope blasting process of FIG. 1;
FIG. 3 is a cross-sectional view (B-B cross-sectional view) of the flexible cushion layer and the pre-protection layer of FIG. 1 and the upstream slope blasting process of the present invention;
FIG. 4 is a schematic view of a first primary charge configuration of the present invention
FIG. 5 is a schematic diagram of a second primary charge of the invention;
FIG. 6 is a schematic view of a buffer hole charge configuration of the present invention;
fig. 7 is a schematic diagram of a dual energy concentrating presplitting smooth-faced charge configuration of the present invention.
Detailed Description
The present invention will be further described with reference to the structures or terms used herein. In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is not excluded that the invention can also be implemented in other embodiments and that the structure of the invention can be varied without departing from the scope of use of the invention.
In the invention, aiming at the bedrock of karst landform, a toe board protective layer excavation method, namely an excavation method for reserved protective layer and flexible cushion layer blasting construction is adopted, the blasting method adopts toe board building base surface bench blasting and upstream side slope dual-energy presplitting smooth surface blasting to blast together, and combines a bench millisecond differential blasting method of a flexible cushion layer and a reserved protective layer, and the concrete construction steps are as follows:
1. technical background matching: intersecting the toe board building base surface excavation technical requirements, blasting design parameters and construction key points;
wherein, in the technical intersection, the ladder sections are required to be excavated from top to bottom; under-digging is strictly forbidden, and over-digging is reduced as much as possible; strictly controlling the flatness to be less than or equal to 15 cm; the foundation surface can not have a reverse slope, an inverted suspension slope, a steep ridge sharp corner, and the intersection of construction key points such as explanation of blasting design parameters, measurement, drilling, charging, blasting, protective layer excavation and the like.
The structure, size, hole array distance and position of the blast hole are set according to the process. In some embodiments, the blast hole 7 comprises a first main blast hole 9, a second main blast hole 10, a buffer hole 11 and a dual energy pre-splitting smooth surface hole 14, and the blast hole 7 is generally a vertical hole or an inclined hole. As shown in fig. 2 and 3, the hole diameter, the hole pitch, the hole depth and the arrangement of various holes designed in the excavation of one toe board protective layer are schematically illustrated. Wherein, fig. 2 is a longitudinal section view of the arrangement of the blast holes of fig. 1, a building base surface has a certain gradient, fig. 3 is a cross section view of the arrangement of the blast holes of fig. 1, a reserved protective layer 6 is arranged on the building base surface, a flexible cushion layer 2 can be designed on the reserved protective layer 6, a blast area 3 is arranged in a blast hole 7 on the flexible cushion layer, the blast area is filled with explosive, and then the blocking area 4 is formed by backfilling with stone chips.
2. In the invention, the designed blasting design is a stepped millisecond differential blasting method combining toe board building base plane stepped blasting and side slope dual-energy-gathering presplitting smooth blasting with a flexible cushion layer and a reserved protective layer. The specific structure of the blast hole is shown in fig. 1, fig. 2, fig. 3, fig. 4, fig. 5, fig. 6 and fig. 7.
3. Measuring and lofting: setting out the explosion part of the toe board and determining the position of a blast hole;
the measurement task of the toe plate base face excavation is responsible for by a special person of a measurement team, the lofting of the toe plate blasting part and the determination of the blast hole point position are tracked in the whole process, and the data are rechecked and calculated.
4. Confirming the hole positions of the blast holes: rechecking hole positions and hole depths according to blasting design, and judging whether the row spacing of the lofting single core to blast holes is qualified or not, wherein the deviation of the hole positions is less than 10 cm;
in some embodiments, the bore hole 7 is designed to have a bore diameter of: phi 90 mm; row spacing between holes: 2 m.times.2 m. As shown in fig. 2, in the schematic diagram of the arrangement of the blasting hole sites and the initiation network, the row spacing between the blast holes 7 is 2m, all the leads of the non-electric detonators 5 of the first main blasting hole 9 and the second main blasting hole 10 are networked, and the buffer hole 11 and the double-energy-gathering pre-splitting smooth surface hole 14 are connected with the exposed detonating cord 13 of each hole by the detonating cord and then connected with one non-electric detonator, and finally connected to the initiation point. And a row of second main blast holes 10 (one of blast holes 7) are respectively arranged on the inner side of the second row of first main blast holes 9 (one of blast holes 7), a row of buffer holes 11 (one of blast holes 7) are arranged on the inner side of the second row of second main blast holes 10 (one of blast holes 7), and a row of double-energy-gathering pre-splitting smooth surface holes 14 (one of blast holes 7) are arranged on the innermost side (slope pre-splitting and smooth blasting surface). In some embodiments, the hole depth is calculated by 0.5m in the normal direction of the underlying surface based on in-situ hole site measurements.
5. Positioning a drilling machine: adjusting the position of a drilling machine, measuring the angle of a hole drill and ensuring that the angle is correct;
in some embodiments, the drilling apparatus is a hydraulic drill.
6. Drilling by a drilling machine and filling a drilling record;
7. rechecking and adjusting the drilling angle when the blast hole is drilled to about 40cm deep;
and when the drill reaches about 40cm, the drilling angle is checked again, and the error is prevented from being overlarge through timely adjustment, so that the size and the perpendicularity of the blast hole are ensured.
8. Controlling the hole depth of the blast hole, and drilling to 30-50cm above the building base surface to serve as a reserved protective layer; if special geological conditions are met, making relevant records, and considering whether to adjust blasting design;
the drilling process strictly controls the hole depth and is executed according to a measurement lofting list.
9. Carrying out rechecking blasting design;
the blasting design is controlled according to the field inspection condition of the blast hole and the blasting test result, and the dosage is properly reduced when the blast hole is weak or broken.
According to the blasting design, a flexible cushion layer is arranged in a blast hole, the blast hole is filled with powder, the hole is sealed, and the explosives in the hole are networked and blasted;
in the invention, the designed blasting method is a stepped millisecond differential blasting method for adding a reserved protective layer on a flexible cushion layer. The specific process of adding the reserved protective layer on the flexible cushion layer and the blast hole structure, position and filling are shown in figures 1, 2, 3, 4, 5, 6 and 7. Specifically, the reserved protection layer 6 is arranged on the foundation surface 1, a toe board base reserved surface 8 is arranged on the reserved protection layer, and the blast hole 7 is drilled to the toe board base reserved surface 8. The bottom of a first main explosion hole 9 in the blast hole 7 is provided with a flexible cushion layer 2, an explosion area 3 is arranged above the flexible cushion layer 2, explosive is filled in the explosion area 3, an explosive charging structure for continuously charging from the bottom of the hole to the upper part is adopted, after the explosive charging is finished, a blocking area 4 is formed by backfilling with chips, and finally a non-electric detonator 5 is arranged above the hole 9, as shown in figure 4; the bottom of a second main explosion hole 10 in the blast hole 7 is not provided with a flexible cushion layer, the explosion area 3 adopts a charge structure for continuously charging from the bottom of the hole to the top, the blockage area 4 is formed by backfilling with stone chips after the charge is finished, and finally a non-electric detonator 5 is arranged above the hole 10, as shown in figure 5; the bottom of a buffer hole 11 in a blast hole 7 is provided with a flexible cushion layer 2, a structure of filling powder from the bottom of the hole to the top at intervals is adopted, as shown in figure 6, explosive sticks 12 and detonating cords 13 are bound on moso bamboo chips by plastic ropes to form intervals, one end of each detonating cord 13 is inserted into the explosive stick 12 at the bottom of the hole, the other end of each detonating cord is led out above the hole 11, and a blocking area 4 is formed by backfilling stone chips after the powder filling of a blasting area 3 is finished; the double-energy-gathering presplitting smooth surface hole 14 in the blast hole 7 adopts a charging structure that a double-energy-gathering tube is filled with powder 15 continuously, wherein a phi 32 reinforced explosive roll 18 is arranged in the height range of 1m at the bottom, meanwhile, a flexible cushion layer 2 is arranged at the bottom of the double-energy-gathering tube, as shown in figure 7, the reinforced explosive roll 18 and a detonating cord 13 are bound on the double-energy-gathering tube by transparent adhesive, one end of the detonating cord 13 is inserted into the double-energy-gathering tube at the bottom of the hole, the other end of the detonating cord is led out of the upper part of the hole 14, and after charging, a blocking area 4 is formed by backfilling with stone chips. A reserved protective layer 6 is arranged between the bottom of the blast hole 7 and the foundation surface 1, the thickness of the reserved protective layer 6 is usually 30-50cm, the flexible cushion layer 2 is firstly filled at the bottom when the first main blast hole 9, the slow-punching hole 11 and the dual-energy-gathering pre-splitting smooth surface hole 14 are filled according to specific geological and blasting design selection, and the flexible cushion layer 2 is made of buffer materials such as sawdust, foam or bamboo tubes or beverage bottles such as waste mineral water bottles or cola. If the flexible cushion layer 2 is too thick, the blasting impact is attenuated too much, the final blasting effect is influenced, and the workload of excavation is increased; if the compliant pad 2 is too thin, the shock wave damping is limited, which may cause damage to the bedrock and affect the integrity, and therefore the thickness of the compliant pad 2 is typically between 30-50 cm. The flexible cushion layer 2 can use 1-2 waste beverage bottles with the diameter of 64 mm and the length of 23 cm as the cushion layer. In the middle of the blast hole 7, there is a blasting area 3, and the blasting area 3 is used for loading explosive, such as a first main blast hole 9, a second main blast hole 10 for continuously loading 70 mm explosive cartridges, buffer holes 11 for intermittently loading 70 mm explosive cartridges, and pre-splitting holes 14 (continuously loading powdery explosive (pre-loaded in the dual-energy-gathering tube)). Then, a blocking area 4 is arranged above the blast holes 7 (the main blast holes 9, 10, the buffer holes 11 and the pre-splitting holes 14) and above the blasting area 3, the stone dust is placed in the blocking area 4 to block the blast holes 7, and the bottoms of the first main blast holes 9 and the second main blast holes 10 are connected with non-electric detonators 5 or bound with explosive by detonating cords to be connected into a whole (the buffer holes and the pre-splitting holes). And (3) monitoring the bottom bedding zone 2 of the blast hole 7 and the blasting operator and the quality inspector in the charging process in the whole process, and correcting the charging height in time according to the hole depth. The specific method comprises the following steps: before charging, waste mineral spring water bottles are sequentially placed near the blast hole opening, the blast hole depth is checked, then the waste mineral spring water bottles are placed into the blast hole 7 by hands, the mineral spring water bottles are pressed into the hole bottom by a bamboo stick, and then charging, plugging and networking are carried out. The powder charge both will reduce the influence of explosive blasting to building the basal plane, will guarantee blasting crushing effect simultaneously again, through experimental summary, bench blasting hole adopts the loaded constitution of continuous powder charge from the hole bottom upwards, and buffer hole 11 adopts interval loaded constitution, and two can presplitting smooth surface hole 14 adopt and adorn likepowder loaded constitution in succession.
The initiation network is one of the keys to ensuring the blasting effect, which must ensure that each cartridge can be initiated, and that initiation must be ensured in the design order (as shown in fig. 1, row 1 first main detonation hole → row 2 first main detonation hole → row 3 second main detonation hole → row 4 second main detonation hole → pre-split hole → buffer hole) and at the design interval. The blasting network adopts an interpore differential blasting network and is blasted by a non-electric detonator. The initiation network adopts the delay outside the hole, and the delay length is determined according to the number of the holes. The detonation sequence is sequentially detonated in sections along the direction with the smallest resistance line, and the maximum detonation explosive quantity of the section is controlled to be less than 100 kg.
The blasting control technology is adopted to control the dosage of the largest section of initiation, so that the excavation vibration wave speed is strictly controlled within a design allowable range, and the stability of the side slope is closely noticed.
In some embodiments, the compliant pad is between 30-50cm thick.
10. And (4) manually matching with a pickaxe machine and an electric hammer to excavate the protective layer to the design requirement.
After blasting and deslagging are finished, checking the underdigging condition of the toe board surface by using a measuring instrument, if the underdigging condition exists, crushing and clearing the underdigging part by using a head picking machine, then rechecking the elevation of the toe board building plane by using the measuring instrument, and repeating the steps until the elevation and the flatness of the toe board building plane meet the design requirements.
And (4) repairing and regulating by adopting an electric hammer if a reverse slope, an inverse suspension slope and a steep ridge sharp angle exist on the part of the toe board building base surface.
Finally, scum, mud, rust spots, calcium films, broken and loosened rock masses on the structural surface are manually removed, so that the flatness of the base surface of the toe board is ensured.
The specific embodiment is as follows: application of reserved protective layer flexible cushion layer blasting construction
The toe plate foundation face blasting construction process is relatively poor in geological condition aiming at the toe plate foundation face of the rock-sandwiched dam, the change of lithology and geological condition is large, most of toe plate foundation faces are bedding side slopes, rock weathering, joints, cracks and fault development are complex and changeable, the requirement on the excavation body size and flatness of the toe plate foundation face is high, construction convenience and economy are considered through multiple verification, and the reserved protective layer flexible cushion layer blasting construction process is selected.
The blasting construction process of the flexible cushion layer of the reserved protective layer of the toe board foundation surface of the rock-sandwiched dam is specifically characterized in that blasting construction parameters are determined through a blasting test before blasting excavation: the drilling equipment adopts a hydraulic drilling machine; the aperture is phi 90 mm; the row spacing between holes is 2m multiplied by 2 m; the hole depth is calculated by reserving 0.5m in the normal direction of the underlying surface according to the site hole position measurement calculation; the bottom flexible cushion layer is 0.4m, the hole bottom flexible cushion layer uses a moso bamboo pipe about 0.4m in earlier stage, several circulations are adjusted, and one hole uses 2 waste beverage bottles as cushion layer + hole bottom reserved 0.5m protective layer flexible cushion layer blasting excavation schemes. And various construction parameters are strictly controlled in the construction process, and finally, the excavation task of the floor of the toe board above the riverbed is finished with quality and quantity guarantee.
The application of the reserved protective layer flexible cushion layer blasting construction process ensures the flatness of the toe board after excavation.
(1) Through statistics, the flatness of the toe board foundation surface excavation is checked to be 40 groups, the maximum value is 21, the minimum value is 10, the average value is 13.78, the qualified rate is 35 groups, and the qualification rate is 87.5%.
(2) According to the technical requirements of excavation of dam and spillway foundations and slope support construction issued by design, 1 group of sound wave detection holes are arranged on each unit of a toe board, 3 holes (arranged in a triangular mode) are formed in each group, the hole distance is 2.1m, and the hole depth is 12 m. And comparing the sound wave result of the toe board foundation surface early exploration with the sound wave test condition after the excavation is finished. The acoustic test wave velocity during early exploration is about 4000m/s, 21 groups of 63 holes are tested by acoustic waves after blasting is finished, the average wave velocity is 4187m/s, the reduction rate of the acoustic waves after blasting is less than 10%, the standard requirement is met, and the rock surface has no obvious blasting cracks.
(3) The toe board has no underexcavation after excavation and specification maintenance, the surface flatness is less than 15cm, and local over excavation is more influenced by geological reasons such as faults, mud interlayers and the like. The integrity of the rock mass is not damaged by blasting, and the excavated surface has no obvious blasting cracks. The toe board excavation shape is controlled on the whole, the edges and corners are clear, and the building base surface is flat.
Through the analysis, the advancement of the blasting construction process of the reserved protective layer flexible cushion layer of the toe board foundation of the rock-sandwiched dam is fully reflected.
Claims (8)
1. A karst landform downslope crack toe board protection layer excavation method is characterized in that toe board building base surface bench blasting and upstream slope dual-energy presplitting smooth surface blasting are adopted in the excavation method to perform blasting together, and a bench millisecond differential blasting method of a flexible cushion layer and a reserved protection layer is combined, and the method specifically comprises the following steps:
(1) technical background matching: intersecting the toe board building base surface excavation technical requirements, blasting design parameters and construction key points;
(2) measuring and lofting: setting out of toe boards and upstream slope blasting parts and determining blast hole points;
(3) confirming the hole positions of the blast holes: rechecking hole positions and hole depths according to blasting design, and judging whether the row spacing of the lofting single core to blast holes is qualified or not, wherein the deviation of the hole positions is less than 10 cm;
(4) positioning a drilling machine: adjusting the position of a drilling machine, measuring the angle of a hole drill and ensuring that the angle is correct;
(5) drilling by a drilling machine and filling a drilling record;
(6) rechecking and adjusting the drilling angle when the blast hole is drilled to the depth of 40 cm;
(7) controlling the hole depth of the blast hole, drilling the hole to the position 30-50cm away from the building base plane, and stopping drilling the hole to reserve a 30-50cm protective layer; if special geological conditions are met, making relevant records, and considering whether to adjust blasting design;
(8) blasting construction: rechecking the blasting design before loading the explosive; according to the blasting design, a flexible cushion layer is arranged in a blast hole, the blast hole is filled with powder, the hole is sealed, and the explosives in the hole are networked and blasted;
(9) excavating a protective layer: manually matching with a pickaxe machine and an electric hammer to excavate a protective layer to meet the design requirement;
the blast hole comprises a first main blast hole positioned on the toe plate building base surface, a second main blast hole positioned near the upstream side slope, a buffer hole positioned near the upstream side slope and a dual-energy-gathering pre-splitting smooth surface hole positioned on the upstream side slope; the buffer hole and the double-energy-gathering pre-splitting smooth surface hole are both provided with one row.
2. The method for excavating the karst landform downslope crack toe board protective layer as claimed in claim 1, wherein the first main blasting hole adopts a charge structure which charges continuously from the bottom of the hole to the top, and a flexible cushion layer is arranged at the bottom; the second main explosion hole adopts a charge structure for continuously charging charges from the bottom of the hole upwards, and the bottom of the second main explosion hole is free of a flexible cushion layer; the buffer holes adopt a structure of filling powder from the hole bottom to the upper part at intervals, and the bottom is provided with a flexible cushion layer; the double-energy-gathering pre-splitting smooth surface hole adopts a powder charging structure for continuously charging powder medicine in the double-energy-gathering tube, a phi 32 reinforced explosive roll is arranged in the high range of 1m at the bottom, and a flexible cushion layer is arranged at the bottom of the double-energy-gathering tube.
3. The method for excavating the karst landform downslope fissure toe board protection layer according to claim 2, wherein the flexible cushion layer is positioned between the reserved protection layer and the explosive filling area; before the explosive is filled in the blast hole, a flexible cushion layer is laid on the reserved protective layer at the bottom in the hole.
4. The method for excavating the karst landform cis-slope fractured toe board protection layer according to claim 3, wherein the thickness of the flexible cushion layer is 30-50 cm.
5. The method for excavating the karst landform cis-slope fractured toe board protective layer according to claim 3, wherein the flexible cushion material is selected from a buffer material.
6. The method for excavating the karst landform cis-slope fractured toe board protection layer according to claim 5, wherein the flexible cushion material is selected from buffer materials with hollow structures.
7. The method for excavating the karst landform downslope fissure toe board protective layer according to claim 1, wherein the explosive filling height is corrected in time according to the blast hole depth in the blasting process.
8. The method for excavating the karst landform cis-slope fractured toe board protective layer according to claim 1, wherein the technical intersection comprises top-down bench excavation; under-digging is strictly forbidden, and over-digging is reduced as much as possible; strictly controlling the flatness to be less than or equal to 15 cm; the building base surface can not have a reverse slope, an inverted suspension slope and a steep ridge sharp angle.
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| CN113758388A (en) * | 2021-07-29 | 2021-12-07 | 乾县海螺水泥有限责任公司 | Bedding slope presplitting blasting method applying digital electronic detonator |
| CN114441347B (en) * | 2021-12-29 | 2024-02-23 | 陕西正通煤业有限责任公司 | Method for measuring crack development radius of top plate deep hole pre-splitting blast hole |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201016669Y (en) * | 2007-03-05 | 2008-02-06 | 中国水利水电第八工程局 | Special apparatus for double-cumulative presplitting and smooth blasting |
| CN201417115Y (en) * | 2009-05-20 | 2010-03-03 | 中国水利水电第八工程局有限公司 | Emulsion explosive loading device for double-energy gathering chutes |
| CN102691299A (en) * | 2012-06-19 | 2012-09-26 | 中国水利水电第七工程局有限公司 | High-geostress dam foundation excavation construction technology |
| CN106949797A (en) * | 2017-03-27 | 2017-07-14 | 武汉大学 | The moulding composite spherical energy-dissipating structure of impact for vertical holes explosion |
| CN107478114A (en) * | 2017-09-19 | 2017-12-15 | 中交公局厦门工程有限公司 | A kind of parallel slope buffered hole depth hole side slope pre split blasting construction method |
-
2018
- 2018-01-02 CN CN201810002926.2A patent/CN109990673B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201016669Y (en) * | 2007-03-05 | 2008-02-06 | 中国水利水电第八工程局 | Special apparatus for double-cumulative presplitting and smooth blasting |
| CN201417115Y (en) * | 2009-05-20 | 2010-03-03 | 中国水利水电第八工程局有限公司 | Emulsion explosive loading device for double-energy gathering chutes |
| CN102691299A (en) * | 2012-06-19 | 2012-09-26 | 中国水利水电第七工程局有限公司 | High-geostress dam foundation excavation construction technology |
| CN106949797A (en) * | 2017-03-27 | 2017-07-14 | 武汉大学 | The moulding composite spherical energy-dissipating structure of impact for vertical holes explosion |
| CN107478114A (en) * | 2017-09-19 | 2017-12-15 | 中交公局厦门工程有限公司 | A kind of parallel slope buffered hole depth hole side slope pre split blasting construction method |
Non-Patent Citations (2)
| Title |
|---|
| "双聚能预裂与光面爆破新技术评析";秦健飞;《水利水电施工》;20081231;第17-20页 * |
| "大花水水电站坝基开挖施工技术";叶靖等;《贵州水力发电》;20070430;第36-39页 * |
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