JP2020063660A - Underground pile breaking method - Google Patents

Abstract

To provide an underground pile breaking method that reduces the occurrence of vibration, noises, and dust significantly so that it can be used in city centers or the like.SOLUTION: The underground pile breaking method includes the steps for: piercing breaking substance loading holes in an underground pile, the pile head of which is exposed, from the pile head in the longitudinal direction of the underground pile; inserting, from the pile head into the breaking substance loading holes, breaking substances and cement tampers alternately in a manner of multiple layers in the longitudinal direction of the underground pile so that the breaking substances are arranged at regular intervals and cracks caused by letting off breaking substances on the pile head side do not reach the next breaking substance loading hole on the bottom side; and breaking the pile by lighting the multiply layered, inserted breaking substances in order from the pile head to the bottom of the underground pile.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for crushing underground piles that reduces the influence on the surrounding environment.

  In the following Patent Document 1, the conventional method for dismantling and removing cast-in-place reinforced concrete requires prior excavation work, and at a normal pile interval (about 5 to 8 m), a dismantling machine between piles after excavation. The invention focused on the fact that the work space is very narrow and the work beams are extremely limited due to excavation and the timber beams for excavation further restrict the work space. Has been done. Furthermore, the conventional dismantling method may generate noise for a long period of time and may cause environmental problems to the residents in the vicinity.

  In view of the above-mentioned conventional problems, in Patent Document 1, a deep underground obstacle is disassembled only by work from the ground, and a crushed piece after dismantling is easily carried out. Specifically, the following means have been proposed as a technical idea for providing the disassembling method.

  That is, as a method for disassembling a deep underground obstacle according to the document, an explosive loading hole that is constructed in a deep place in the ground and is vertical from the ground to the obstacle is punched, and then the explosive, detonator in the same hole in multiple stages from the ground, There is disclosed a method of inserting a tamping material, igniting and exploding, and then excavating and removing a fragment of an obstacle that is instantaneously fragmented by the explosion together with the surrounding soil.

  Then, according to the method proposed in the document, after confirming the head of the underground obstacle, a vertical explosive loading hole is bored in the center of the underground obstacle, and an explosive charge, a detonator in the borehole, By loading the tamping material, igniting and exploding, the obstacles are instantly crushed into small pieces by the energy of the explosion, so the crushed fragments of the underground obstacles can be easily excavated. It will be shipped.

  As described above, the above-ground structure via a plurality of piles installed on a hard ground (supporting ground) deep in the ground has conventionally been the mainstream in the case of building a high-rise building or the like in the center of the city. However, nowadays, a method of directly connecting an underground version (that is, a basement) of a ground structure from a hard support ground deep in the ground without using conventional underground piles will be adopted. It has become. This will enable effective use of deep underground spaces.

  In order to construct an underground version of a ground structure from a hard support ground deep underground, it is first necessary to remove and clean the underground piles of the old building to be demolished to expose the hard ground in the ground. The underground piles of the old building are generally made of reinforced concrete and are buried vertically vertically at relatively narrow intervals so that large heavy equipment cannot enter or work, so much effort is required to remove them. Requires.

JP 05-247939 A JP, 11-93559, A JP, 2005-10726, A JP, 2012-86926, A

  Patent document 1 describes "A vertical obstacle is formed in a deep hole in the ground, and a vertical explosive loading hole is drilled from the ground, and the same explosive, detonator, and tamping are loaded from the ground to ignite and explode." With this method, a large amount of noise and a large amount of vibration are generated, and it cannot be used in actual use in the city center.

  For example, a large noise causes complaints from offices, residents, passers-by, etc. living in a neighboring building, and a large vibration reaches a level (for example, seismic intensity 2 etc.) that stops an elevator in a neighboring building. The large noise and large vibration occur not only during the work of drilling a pile with a drilling machine such as a crawler drill but also when explosive powder explodes.

  Furthermore, it is feared that a large amount of dust will be released to the ground by the crushing work of underground piles made of reinforced concrete or the like. On the other hand, consideration and regulations for the surrounding environment at construction sites in the city center are becoming more and more severely restricted. In particular, in the city center, from the viewpoint of environmental preservation, severe restrictions are imposed on noise, vibration, etc. generated by construction work including explosion and crushing.

  The present invention has been made in view of the above problems, and proposes a method for crushing underground piles that further reduces the generation of vibration, noise, and dust so that it can be used in urban areas and the like. To aim.

  Underground pile crushing method of the present invention, in the underground pile in a state where the pile head is exposed, a step of drilling a crushing agent loading hole from the pile head along the length direction of the underground pile, and from the pile head, Inserting the crushing agent and the cement tamper into the crushing agent loading hole alternately in multiple steps along the length direction of the underground pile so that the crushing agent has a constant interval, and the crushing agent inserted in multiple steps And a step of sequentially igniting and crushing the medicine from the pile head toward the bottom of the underground pile at regular intervals within a range of 0.025 seconds to 0.5 seconds.

  The underground pile crushing method of the present invention is preferably such that the intervals of the crushing agents inserted in multiple stages are provided to such an extent that the crushing effect of the lower crushing agent is not hindered due to the crushing of the upper crushing agent. Is characterized by.

  The underground pile crushing method of the present invention, more preferably, between the step of inserting the crushing agent in multiple stages and the step of igniting and crushing, a step of placing a rubber sheet, an iron plate, and a bag on the pile head. Is further included.

  The underground pile crushing method of the present invention is more preferably a step of drilling a crushing agent loading hole from the pile head, and at the time of drilling, the arm portion extending from the pile head to the working space in the length direction of the underground pile is soundproof. It is characterized by being performed by a cured rock drill.

  The underground pile crushing method of the present invention is further preferably characterized in that the crushing agent is a vapor pressure crushing agent that crushes the underground pile by utilizing the water vapor pressure generated during thermal decomposition of the chemical.

  In the underground pile crushing method of the present invention, more preferably, the step of igniting and crushing the crushing agents inserted in multiple stages is such that each crushing agent is sequentially 0.25 seconds from the pile head toward the bottom of the underground pile. It is characterized by being ignited every time.

  The underground pile crushing method of the present invention, more preferably, the crushing agent utilizes the heat generated by the thermite reaction of the metal powder of copper oxide as an oxidizing agent and aluminum as a reducing agent to evaporate potassium alum as crystal water. It is characterized in that it generates a water vapor pressure, and the weight of the drug for one step is 0.5 kg to 1 kg.

  The underground pile crushing method of the present invention is more preferably characterized in that the distance between the crushing agents inserted in multiple stages is 450 mm to 500 mm.

  It is possible to propose a method of crushing underground piles that further reduces vibration, noise, and dust generation so that it can be used in urban areas.

It is a figure explaining one mode of an underground pile crushing method of the present invention in order of (a)-(g). It is a schematic diagram explaining the crushing design by 10 steps of crushing agents with respect to the underground pile of 1,600 mmφ pile length and 9150 mm length. It is a schematic diagram explaining the crushing design by a 13-step crushing agent with respect to the underground pile of diameter 1,500 mmφ of pile head and length 14030 mm. It is a schematic diagram explaining a comparative study of the crushing design with 7 steps of crushing agent for underground piles with a pile head diameter of 1500 mmφ and a length of 14000 mm. It is a diagram, and the right side of the drawing is a design drawing in which there is "consideration of staged", that is, the stages are sequentially blasted from the upper stage to the lower stage with each stage delayed by 0.25 seconds. It is a figure explaining (a) appearance of a cement tamper, (b) appearance of a gunsizer, (c) appearance of an ignition tool (igniter), and (d) installation and installation of them. It is a figure explaining the typical example of the rock drill which equipped the vertical arm part with the soundproofing and the prevention of scattering, and is a figure explaining the state where all the circumference of the outside is cured, and (b) is an operator. It is a figure explaining the state which has provided the visual recognition window in which the curing was absent on the side. It is a figure explaining the other example of curing of the arm part of a rock drill. (A) is a figure explaining the displacement speed with respect to the elapsed time of the test crushing 1st time (10 m) 55-100 type (25 milliseconds x 8 sets (namely, 8 steps)), and (b) is the test crushing 2nd time ( It is a figure explaining the displacement speed with respect to the elapsed time of 10m) 55-200 type (25 milliseconds x 5 sets (namely, 5 steps)), (c) is the 3rd (10m) test crushing type 55-100 type (250 mm). It is a figure explaining the displacement speed with respect to the elapsed time of seconds x 8 sets (namely, 8 steps). It is a figure explaining the gunsizer pattern of test number (1)-(3) corresponding to each test crush of (a)-(c) demonstrated in FIG. 8, and its preparatory work. It is a figure explaining the attachment of a gunsizer IC multistage igniter, and the method of extending a leg line.

  According to the underground pile crushing method of the embodiment, an underground pile (for example, a diameter of 1100 mmφ to 1800 mmφ) in which the pile head is exposed is provided with a crushing agent loading hole from the pile head along the length direction of the underground pile. From the pile head to the crushing agent loading hole, the crushing agent and the cement tamper are alternately placed, and the crushing agent is inserted in multiple stages along the length direction of the underground pile so that the crushing agent has a constant interval. , A step of igniting and crushing the crushing agents inserted in multiple stages sequentially from the pile head toward the bottom of the underground pile at regular time intervals in the range of 0.025 seconds to 0.5 seconds. It is characterized by having.

  As a result, the concrete portion of the reinforced concrete underground pile can be almost completely crushed to the size of another rubble that can be transported. Therefore, by cutting only the reinforcing bar portion with a construction cutter or the like, it becomes possible to remove and remove it together with the surrounding earth and sand using a shovel car or the like.

  Further, since the crushing agent is ignited sequentially from the pile head, the fracture surface of concrete is sequentially formed from the pile head. The crushing agent is sealed and isolated by a cement tamper between the crushing agents, so that the crushing effect of the crushing agent in the lower stage can be prevented from being hindered. Since crushing with a crushing agent utilizes a momentary expansion phenomenon of gas due to steam explosion or the like, it is preferable to ignite in a closed space, and when the escape route of gas is formed in advance, the crushing effect is It will be significantly reduced.

  In this respect, if a plurality of crushing agents formed in multiple stages are simultaneously ignited at the same time, the crushing effect is expected to be extremely high. That is, if each crushing agent arranged in multiple stages is simultaneously ignited in a state where each crusher is sealed in each crushing agent loading hole by each cement tamper, no gas escape area is formed in advance. . However, if all the crushing agents are ignited at the same time, if the amount of the crushing agent per stage is about 1 kg, then about 10 kg of the crushing agent will be ignited simultaneously in all 10 stages. Further, when the crushing agent is loaded in one step instead of in multiple steps, it is not necessary to fill the cement tamper in the first place, but even in this case, 10 kg of the crushing agent loaded in the one step is blasted at once.

  When a total of 10 kg of crushing agent is ignited and crushed at the same time, the buildings and the like located around it are vibrated to the extent of a seismic intensity of 2, and the noise is considerably loud. . If a vibration with a seismic intensity of about 2 occurs, the elevator of the neighboring building will be stopped, which will cause a significant hindrance to the work of the occupants. In addition, there is a great concern that this may be in conflict with various laws and regulations. Therefore, simultaneous crushing of all crushing agents having a multi-stage configuration is extremely difficult in reality.

  In this respect, like the invention of the present application, if the ignition is sequentially performed one step at a predetermined constant time within a range of 0.025 seconds to 0.5 seconds (most preferably 0.25 seconds) from the pile head, The generation of vibrations and noise is dispersed in time and can be relatively small. Within the range of 10 m, it is within the regulation range of the relevant law of 75 dB. According to the studies by the inventors, the time required for the peak value of vibration due to the crushing of underground piles to reach zero is about 0.5 seconds, within 0.5 seconds, and most preferably 0. Even if ignition occurs sequentially in 25 seconds, it will fall within the vibration range that can sufficiently meet various regulatory requirements.

  Furthermore, the reduction of the crushing effect can be minimized by the sequential ignition from the pile head. It is more preferable that the distance between the crushing agent and the crushing agent is such that a crack in the concrete does not reach the crushing agent directly below the crushing agent even if the crushing agent in the immediate upper stage is crushed. If the distance between the crushing agents is too small, when the crushing agent in the immediate upper stage crushes, the crack in the concrete will reach directly below, and it will be an escape route for gas, so the crushing effect of the crushing agent directly below may be reduced. Occurs.

  An IC igniter, which is a timed ignition device, may be used for ignition. In the IC igniter, the delay time from the reception of the ignition signal by the internal capacitor to the actual ignition can be arbitrarily selected. Therefore, even if the ignition signals are simultaneously transmitted to the crushing agents loaded in multiple stages, the upper stage It is possible to blast with a time difference from the bottom to the bottom.

  Drawing 1 is a figure explaining one mode of an underground pile crushing method of an embodiment in order of (a)-(g). In FIG. 1, (a) is a diagram for explaining a state in which a rock drill having a shatterproofing cure is used to punch a crushing agent loading hole in a pile head, and (b) is a diagram for explaining a crushing agent loading hole punched from the pile head. It is a figure which illustrates a mode that (c) loads a crushing medicine (gansizer) into a crushing agent loading hole, and (d) illustrates a mode of loading a cement tamper into a crushing agent loading hole. And (e) is a diagram for explaining how the crushed stone of No. 7 is loaded into the crushing agent loading hole, and (f) is a state in which the pile head on which the loading of crushing agent is completed in multiple stages is cured to avoid a gun phenomenon. FIG. 9 (g) is a diagram for explaining a state in which the ground pile is removed together with the surrounding sand and the like by a shovel car with respect to the ground pile that has been crushed. The steps of FIGS. 1 (b) to 1 (d) can be repeated a plurality of times depending on the number of stages of the crushing agent to be loaded. The step (e) may be omitted as appropriate, or the size of the crushed stone to be loaded may be changed.

  Further, the underground pile crushing method of the embodiment, preferably, the intervals of the crushing agents inserted in multiple stages are provided to such an extent that the crushing effect of the lower crushing agent is not hindered due to the crushing by the upper crushing agent. It is characterized by being.

  Here, the interval between the crushing agents inserted in multiple stages is such that the effect of crushing by the crushing agent in the upper stage is not hindered due to the crushing by the crushing agent in the upper stage, and it is typically caused by the crushing in the upper stage. It means that the crack in the underground pile does not reach the crushing agent directly below it.

  If the space between the crushing agents is not sufficient, or if the cement tamper filled between them is insufficiently filled, the underground pile created by crushing the crushing agent in the immediately upper stage. The crack reaches the crushing medicine directly below. In this case, the crack serves as an escape path for the gas, so that the crushing effect of the crushing agent directly below the crack is reduced. In this case, again, there is a concern that a separate drilling operation requires an additional crushing agent loading hole different from the current crushing agent loading hole to load and ignite the crushing agent, etc. A process delay occurs.

  In other words, from the viewpoint of only the crushing effect, each crushing agent arranged in multiple stages along the length direction (typically the central portion) of the underground pile along the length direction (depth direction) It is preferable to be ignited at the same time and to be crushed at once, which is the conventional wisdom in the blasting industry. However, in consideration of the surrounding environment at construction sites in the city center, and from the perspective of related regulations that are becoming stricter year by year, it is related to the limited sites in the city center (for example, scrap and build in a forest of office buildings in the vicinity. One shot crushing of underground piles due to simultaneous ignition at the site of one building is not realistic.

  In the present embodiment, the vibration and noise generated by sequentially igniting from the pile head have been successfully shifted by a slight time shift. Further, from the viewpoint of increasing the efficiency of work progress and crushing throughput, it is not preferable to set the time intervals too large, while making the time intervals too small causes vibrations and the like to increase. Therefore, in the present invention, from the research and study of vibration reduction at the time of crushing, the time interval is set to 0.025 seconds to 0.5 seconds (most preferably 0.25 seconds), and the ignition is sequentially performed by shifting by this time. Is.

  Further, if the ignition sequence is carried out in the reverse order of the present invention and the steps are sequentially carried out from the bottom of the underground pile, concrete crushing by the crushing agent in the lower stage is likely to proceed in the upward direction. Due to this, there is a high possibility that the crushing gas of the crushing agent in the immediately upper stage can escape, and there is a concern that the crushing effect will be reduced. This can be understood by carefully studying the environment in which underground piles are placed, where the pile heads are exposed to the atmosphere while the pile bottoms are driven into a rigid support ground.

  FIG. 2 is a schematic diagram illustrating a crushing design using 10-step crushing agent for an underground pile having a pile head diameter of 1600 mmφ and a length of 9150 mm. In the example shown in FIG. 2, the length of the crushing agent is 350 mm, and the crushing agent is loaded in 10 stages in the crushing agent loading hole of 75 mmφ at intervals of 450 mm. The loading amount of each stage is 0.5 kg. Then, the cells are blasted from the top to the bottom at 25 millisecond intervals, that is, from MS1 to MS10 in FIG. 2 in this order at 25 millisecond intervals.

  In addition, FIG. 3 is a schematic diagram illustrating a crushing design using 13 steps of crushing agent for an underground pile having a pile head diameter of 1500 mmφ and a length of 14030 mm. In the example shown in FIG. 3, the crushed medicines are loaded in 13 stages in the crushed medicine loading holes of 75 mmφ with the distance of 550 mm. The loading amount of each stage is 1.0 kg. Then, the blasting is sequentially performed at intervals of 25 milliseconds, most preferably in the order from the upper stage to the lower stage at 0.25 second intervals.

  Further, FIG. 4 is a schematic diagram for explaining a comparative study of a crushing design using 7 steps of crushing agents for an underground pile having a pile head diameter of 1500 mmφ and a length of 14000 mm. It is a design drawing for simultaneous blasting, and the right side of the drawing is a design drawing in which “stepping is considered”, that is, blasting is sequentially delayed from the upper stage to the lower stage by 0.25 seconds each. In the example shown in FIG. 4, the crushed medicines are loaded in seven stages in the crushed medicine loading holes of 65 mmφ or 75 mmφ, respectively, with the distance of 1000 mm left between them. The loading amount of each stage is 1.0 kg. Then, the blasting is sequentially performed at intervals of 25 milliseconds, most preferably in the order from the upper stage to the lower stage at intervals of 0.25 seconds.

  Further, in the underground pile crushing method of the embodiment, more preferably, between the step of inserting the crushing agent in multiple stages and the step of igniting and crushing, a rubber sheet, an iron plate and a glass bag are placed on the pile head. The method further comprises the step of:

  Here, the “bag” is a huge bag filled with the contents and has a function of weight. Scattering of dust and the like generated from ignition and crushing from the pile head and the soil around it by igniting and crushing, with rubber sheet, iron plate and glass bag preferably placed on the pile head in order. -The diffusion (that is, the gun phenomenon) can be reduced, and the diffusion of noise can be surely reduced. In addition, since it is possible to prevent crushed pieces of reinforced concrete underground piles, pebbles, and the like from scattering due to water vapor pressure, it is possible to ensure higher safety for the surrounding environment and workers. As the rubber sheet, for example, a black sheet having a thickness of 8 mm can be used. Further, as the iron plate, for example, a 22 mm thick 1.5 m × 1.5 m and 500 kg weight plate can be used.

  The following numerical formulas 1 to 3 explain the process and the result of the study on how to cure the pile head in order to avoid the gun phenomenon. Mathematical formula 1 explains the examination result of "Protection measures against gun phenomenon in concrete pile crushing by gunsizer", and Numerical formula 2 explains examination result of "Motion of protective material with weight 2t". Equation 3 explains the examination result of "the movement of the protective material when the gun phenomenon occurs".

  Further, in the underground pile crushing method of the embodiment, more preferably, the step of drilling a crushing agent loading hole from the pile head is an arm portion that is extended from the pile head to the working space in the length direction of the underground pile during drilling. Is performed with a rock drill that has been soundproofed and cured.

  Conventionally, rock drills have often been used when deeply mining a lateral tunnel. However, it has been made clear by the present inventors that the crushing agent loading hole having a diameter of several tens of mm to over 100 mm can also be used in the case of piercing a reinforced concrete underground pile at a deep depth. The drilling work causes a considerable amount of noise and, in some cases, dust containing small crushed pieces.

  For this reason, the arm portion of the rock drill, which is arranged to project upward from the pile head during the drilling operation, typically extends from the top of the arm portion to the height of the pile head (or the height of the exposed ground), It is preferable to carry out soundproofing so that the lowermost portion of the vertically arranged arm portion comes into contact with the ground over the entire height direction. For the soundproofing curing, it is more preferable to provide a visual inspection window by forming a lacking portion of the curing so that an operator of the rock drill can visually confirm an arbitrary predetermined position inside the arm. The crushing agent loading hole may be drilled from the pile head to the pile bottom, for example, about 10000 mm.

  FIG. 6 is a diagram illustrating a typical example of a rock drill in which soundproofing and shatterproofing curing is attached to a vertical arm portion, and FIG. 6A is a diagram illustrating a state in which the outer periphery is fully cured. FIG. 5B is a diagram illustrating a state in which a visual recognition window lacking curing is provided on the operator side. FIG. 7 is a diagram illustrating another example of curing the arm portion of the rock drill.

  Further, the underground pile crushing method of the embodiment is more preferably characterized in that the crushing agent is a vapor pressure crushing agent that crushes the underground pile by utilizing the water vapor pressure generated during thermal decomposition of the chemical.

  This makes it possible to withstand practical use in a relatively wide field from the city center including the ordinance-designated cities to the suburbs, and even to the mountains, without having to worry about so-called gunpowder crackdown laws. Further, since the crushing is performed dynamically by steam pressure, the crushing operation can be performed relatively safely and instantly in a short time.

  Further, in the method for crushing underground piles of the embodiment, more preferably, the step of igniting and crushing the crushing agents inserted in multiple stages is such that each crushing agent is sequentially discharged from the pile head toward the bottom of the underground pile. It is characterized by being ignited every 25 seconds.

  The research conducted by the present inventors has revealed that the vibration generated by crushing is reduced to zero in about 0.5 seconds from its peak. Therefore, most preferably, the crushing agent in the next lower stage is ignited at 0.25 second intervals corresponding to the time from the peak of noise to the half.

  Assuming that a peak of noise (or noise and vibration) caused by the ignited crushed drug occurs at the same time as ignition, the noise is halved 0.25 seconds later, so Even if the noise of the lower crushing agent continues to occur, the noise is not excessively loud due to the noise superposition. As a result, it becomes possible to sufficiently satisfy various regulations on the surrounding environment in the city center.

  In the underground pile crushing method of the embodiment, more preferably, the crushing agent utilizes the heat generated by the thermite reaction of the metal powder of copper oxide as an oxidizing agent and aluminum as a reducing agent to evaporate potassium alum as crystal water. It is characterized in that it generates a water vapor pressure, and the weight of the drug for one step is 0.5 kg to 1 kg.

  The present inventors belong to a crushing agent that uses the heat generated by the thermite reaction of metal powder of copper oxide as an oxidant and aluminum as a reducing agent to generate a vapor pressure of vaporized potassium alum as crystal water. It is marketed by a business company under the name of Gunsizer (registered trademark). FIG. 5 is a diagram for explaining (a) the appearance of a cement tamper, (b) the appearance of a gunsizer, (c) the appearance of an igniter (igniter), and (d) the installation thereof.

  Table 1 below describes the vapor pressure crushing chemical gunsizer. As a product description of the Gunsizer, (1) crushing agent, (2) igniter, and (3) IC stepped igniter are described in this order. The IC-stage firing igniter is an igniter capable of blasting the crushing agent loaded in each stage by delaying it for a predetermined time and shifting it.

  Gunsizer (registered trademark) of various model numbers is lined up according to the drug weight, size, etc., but if the underground pile is about 1100 mmφ to 1800 mmφ, a gun with a drug weight of 0.5 kg to 1 kg per step A sizer (registered trademark) can be used. That is, a 55-50 type Gunsizer (registered trademark) can be loaded, for example, from the center of the pile head of an underground pile having a length of 9150 mm and a diameter of 1600 mm in 10 steps at a pitch of 800 mm.

  Since the length of the 55-50 type Gunsizer (registered trademark) is 350 mm, the intervals of the gunsizer (registered trademark) are 450 mm apart. That is, the crushing agent loading holes each having a length of 450 mm, which is the distance between Gunsizer (registered trademark), can be filled with cement tamper and preferably No. 7 crushed stone. Then, by successively igniting them by shifting them preferably by 0.25 seconds from the upper stage side, it becomes possible to perform good crushing work while reducing vibration and noise. Table 2 describes variations of the Gunsizer. (Excerpt from Nippon Koki Co., Ltd. product website)

  The underground pile crushing method of the embodiment is further characterized in that the distance between the crushing agents inserted in multiple stages is 450 mm to 500 mm.

  By providing the crushing agent at an interval of about 450 mm to 500 mm, cracks generated by crushing in the upper stage do not reach the crushing agent directly below, and the crushing agent significantly functions effectively and smooth and efficient crushing work Can be carried out. In other words, by filling cement tamper or the like at intervals of about 450 mm to 500 mm, it is possible to protect the lower crushing agent and the like from the crushing of the immediately upper crushing agent. The crushing agent for one step is expected to crush the upper part of the crushing agent for the step. Further, this interval can be applied to many underground piles, and it is possible to achieve both cost reduction and smooth crushing work.

  Here, the reason why the vibration and noise are reduced even if the blasting is successively performed from the upper stage to the lower stage at 0.025 second (25 millisecond) intervals will be described in more detail. FIG. 8 is a diagram illustrating a vibration measurement value (separation distance 10 m) in the test crushing. FIG. 8A is a diagram for explaining the displacement speed with respect to the elapsed time of the first test crushing (10 m) 55-100 type (25 ms × 8 sets (that is, 8 steps)), and FIG. 8B is the test. Second crushing (10 m) 55-200 type (25 milliseconds × 5 sets (that is, 5 steps)) is a diagram for explaining the displacement speed with respect to the elapsed time, FIG. 8 (c) is the third crushing test (10 m) 55 It is a figure explaining the displacement speed with respect to the elapsed time of -100 type (250 milliseconds x 8 sets (namely, 8 steps)).

  Further, FIG. 9 is a diagram for explaining the gunsizer patterns of the test numbers (1) to (3) corresponding to the test crushing of (a) to (c) described in FIG. 8 and the preparation work thereof. In addition, FIG. 10 is a diagram illustrating a method of attaching the gunsizer IC staged igniter and extending the leg line.

  As is clear from the results of the blasting experiment when the time interval between each stepping shown in FIG. 8 is 0.025 seconds, sufficient reduction of vibration and noise can be expected. The theoretically best way to reduce vibration and noise is to blast the next stage after waiting for natural reduction of one stage of vibration, etc. (that is, blasting every 0.25 to 0.5 seconds). Easy to do. However, in reality, blasting every 0.025 seconds (minimum stage firing) gives the result as shown in FIG. It is proportional, but if the peak is shifted even a little (for example, 0.025 seconds), it will be suppressed by the vibration of about 1.5 times the one-step blast as shown in FIG. The reason for this is unknown at this point in time, but the present inventors presume that they may cancel each other out due to vibrations in opposite phases.

  The underground pile crushing method described above is not limited to the description exemplifying specific numerical values and the like in the embodiment, and a part of the main body is exposed while being deeply buried in the ground. It is widely applicable to the crushing work and the breaking work of the underground structure, and it is obvious to those skilled in the art and it is possible to appropriately change and arrange the materials, the process contents, the order and the procedure thereof within the scope of the present invention.

INDUSTRIAL APPLICABILITY The present invention is suitable for crushing underground structures embedded in the ground.

Claims (11)

In the underground pile in a state where the pile head is exposed, a step of drilling a crushing agent loading hole from the pile head along the length direction of the underground pile,
In the crushing agent loading hole, crushing agent and packing are alternately provided,
The crushing agent has a constant interval such that a crack caused by crushing the crushing agent on the pile head side does not reach the crushing agent loading hole on the bottom side in the immediate vicinity thereof,
A step of inserting in a plurality of stages along the length direction of the underground pile,
A step of sequentially igniting and crushing the crushing agents inserted in a plurality of stages from the pile head toward the bottom of the underground pile.
A method for crushing underground piles, which is characterized in that In the underground pile crushing method according to claim 1,
The intervals of the crushing agents inserted in the plurality of stages are set to such an extent that the effect of crushing by the crushing agent on the bottom side is not impeded due to crushing by the crushing agent on the pile head side. Medium pile crushing method. In the underground pile crushing method according to claim 1 or 2,
Between the step of inserting the crushing agent in a plurality of stages and the step of crushing by igniting,
The method further includes the step of placing a rubber sheet, an iron plate, and a bag on the pile head.
A method for crushing underground piles, which is characterized in that In the underground pile crushing method according to any one of claims 1 to 3,
The step of drilling a crushing agent loading hole from the pile head is
At the time of drilling, the arm portion extending from the pile head to the working space in the length direction of the underground pile is performed by a soundproof rock drill.
A method for crushing underground piles, which is characterized in that In the underground pile crushing method according to any one of claims 1 to 4,
The crushing agent is a vapor pressure crushing agent that crushes the underground pile by utilizing the water vapor pressure generated during thermal decomposition of the agent.
A method for crushing underground piles, which is characterized in that The underground pile crushing method according to any one of claims 1 to 5,
In the step of igniting and crushing the crushing agents inserted in the plurality of stages, each crushing agent is sequentially directed from the pile head toward the bottom of the underground pile in a time range of 0.025 seconds to 0.5 seconds. An underground pile crushing method characterized by being ignited. The underground pile crushing method according to any one of claims 1 to 6,
The crushing agent utilizes heat generated by the thermite reaction of metal powders of copper oxide as an oxidant and aluminum as a reducing agent, and generates steam pressure by evaporating potassium alum as crystal water. A method for crushing underground piles, characterized in that the weight of the agent is 0.5 kg to 1 kg. In the underground pile crushing method according to claim 7,
The distance between the crushing agents inserted in the plurality of stages is 450 mm to 500 mm.
A method for crushing underground piles, which is characterized in that In the underground pile crushing method according to any one of claims 1 to 8,
The filling includes cement tamper
A method for crushing underground piles, which is characterized in that In the underground pile crushing method according to claim 9,
The packing further includes crushed stone
A method for crushing underground piles, which is characterized in that In the underground pile crushing method according to any one of claims 1 to 10,
At least some or all of the vibrations due to the blasting of the adjacent crushing agents are in a relationship of canceling each other out of phase
A method for crushing underground piles, which is characterized in that