JP2020056268A - 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 is resistant to use in city centers.SOLUTION: The underground pile breaking method includes: a step for piercing a breaking substance loading hole and shock absorption hole in the pile head of an underground pile along the longitudinal direction of the underground pile while the pile head is exposed; a step for inserting, from the pile head into the breaking substance loading hole, breaking substances and cement tampers alternately so that breaking substances are separate from each other in regular intervals in a manner of multiple layers along the longitudinal direction of the underground pile; and a step for breaking the pile by lighting the multiply layered, inserted breaking substances in order from the pile head to the bottom of the underground pile every predetermined period that ranges 0.025 to 0.5 seconds.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an underground pile crushing method that reduces the influence on the surrounding environment.

  In the following Patent Document 1, a conventional excavation work is required in the conventional method of demolition and removal of cast-in-place reinforced concrete, and a demolition machine between excavated piles at a normal pile interval (about 5 m to 8 m). The invention that focuses on the fact that the work space is very small and that the work beam for excavation further restricts the work space due to the excavation is extremely inefficient. Have been. Furthermore, in the conventional disassembly method, noise was generated for a long period of time, and there were cases where environmental problems occurred to nearby residents.

  In view of the conventional problems described above, Patent Document 1 discloses a deep underground obstacle excellent in workability in which a deep underground obstacle is dismantled only by work from the ground, and a crushed piece after removal is easily carried out. Specifically, the following means have been proposed as technical ideas for providing a disassembly method.

  That is, as a method of dismantling a deep underground obstacle according to the literature, a hole for explosives built deep in the ground and drilled vertically from the ground to the obstacle, and then explosives, primers, There is disclosed a method of inserting a tamping material, igniting and exploding, and excavating and removing crushed pieces of obstacles crushed instantaneously by the explosion simultaneously with 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 drilled in the center of the underground obstacle, and during the drilling, the explosive, primer, Obstacles are instantly crushed into small lumps by the energy of the explosion by loading the tamping material, igniting, and exploding.Fragments of crushed underground obstacles can be easily excavated by excavation work It will be carried out.

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

  In order to build an underground version of an above-ground structure from solid support ground deep underground, it is first necessary to remove and clean the underground piles of the old building to be demolished, exposing the hard ground underground. The underground piles of the old building are generally made of reinforced concrete, etc., and are buried deep and vertically at relatively narrow intervals where large heavy equipment etc. cannot enter or work. Cost.

  Patent Document 2 below discloses a method of crushing an underground pile, in which a crushing agent loading hole is pierced from the pile head along the length direction of the underground pile in the underground pile with the pile head exposed. And inserting the crushing agent and the cement tamper alternately from the pile head into the crushing agent loading hole in multiple stages along the length direction of the underground pile so that the crushing agent is at a constant interval. And, the 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 intervals in the range of 0.025 seconds to 0.5 seconds, Is disclosed.

JP 05-247939 A JP-A-2017-125309

  Patent Literature 1 "A vertical explosive loading hole is drilled from above the ground into an obstacle built deep underground, and an explosive, a primer, and a tamping are loaded from above the ground to ignite and explode." Such a method generates loud noise and loud vibration, and cannot be put to practical use in the city center.

  For example, a loud noise may cause a complaint from an office, a resident, a pedestrian, or the like occupying a nearby building, and a loud vibration may reach a level that stops an elevator of the nearby building (for example, seismic intensity 2 or the like). The loud noise and the loud vibration are generated not only when the pile is drilled by a drill such as a crawler drill but also when the explosive explodes.

  Furthermore, there is a concern that a great deal of dust will be scattered to the ground due to the crushing work of the underground pile made of reinforced concrete or the like. On the other hand, considerations and regulations on the surrounding environment at construction sites and the like in the city center have been increasingly strictly restricted. In particular, in the city center, from the viewpoint of maintaining the environment, strict restrictions are imposed on noise, vibration, and the like generated by construction work including explosion crushing. Further, in the method disclosed in Patent Document 2, further improvement is expected in order to further reduce vibration and blasting sound to the surrounding environment and to further improve crushing efficiency.

  The present invention has been made in view of the above-described problems, and proposes a method of crushing an underground pile that further reduces the generation of vibration, noise, and dust so as to withstand use in a city center or the like. Aim. More preferably, it is an object of the present invention to propose a method of crushing an underground pile with improved crushing efficiency in consideration of the surrounding environment.

  The method for crushing an underground pile according to the present invention includes the steps of: drilling a crushing agent loading hole and a shock absorbing hole (discard hole) from the pile head along the length direction of the underground pile in the underground pile with the pile head exposed. And inserting the crushing agent and the cement tamper alternately from the pile head into the crushing agent loading hole in multiple stages along the length direction of the underground pile so that the crushing agent is at a constant interval. And, the 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 intervals in the range of 0.025 seconds to 0.5 seconds, It is characterized by having.

  In the method of crushing an underground pile according to the present invention, preferably, the shock absorbing hole has a slit shape at the center of the pile head, and the depth of the hole is in the length direction of the underground pile, the depth of the crushing agent loading hole. Or more.

  In the underground pile crushing method of the present invention, more preferably, the step of piercing the shock absorbing hole is such that a plurality of circular holes are continuously formed at predetermined intervals, whereby the gap between the holes collapses and a slit is formed. It is characterized in that it is a step of forming into a shape.

  The underground pile crushing method of the present invention is further preferably characterized in that the diameter of the circular hole is 8 to 12 cmφ, and the predetermined interval is 8 to 12 mm.

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

  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 loose bag on the pile head Is further provided.

  In the method of crushing an underground pile according to the present invention, more preferably, the step of piercing the crushing agent loading hole from the pile head includes a soundproof arm extending from the pile head to the working space in the length direction of the underground pile at the time of piercing. It is 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 an underground pile by using steam pressure generated during thermal decomposition of the drug.

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

  In the underground pile crushing method of the present invention, more preferably, the crushing agent uses the heat generated by thermite reaction of metal powder with copper oxide as an oxidizing agent and aluminum as a reducing agent to evaporate potassium alum as crystallization water. The pressure of the medicine for one stage is 0.5 kg to 1 kg.

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

  An underground pile crushing method capable of withstanding use in a city center or the like and further reducing the generation of vibration, noise, and dust can be proposed. More preferably, a method of crushing underground piles with improved crushing efficiency in consideration of the surrounding environment can be proposed, and a construction method that shortens the construction period in underground dismantling and is environmentally friendly can be realized.

It is a figure explaining one mode of the underground pile crushing method of the present invention in order of (a)-(g). It is a schematic diagram explaining the crushing design by a 10-stage crushing agent with respect to the underground pile with a pile head of 1600 mmφ and a length of 9150 mm. It is a schematic diagram explaining the crushing design by the 13-stage crushing agent with respect to an underground pile with a pile head diameter of 1500 mmφ and a length of 14030 mm. It is a schematic diagram explaining the comparative study of the crushing design with a 7-stage crushing agent for an underground pile with a pile head diameter of 1500 mmφ and a length of 14000 mm. In the drawing, the right side of the paper is a design diagram in which “stepping is considered”, that is, blasting is performed sequentially from the upper stage to the lower stage with a delay of 0.25 seconds at a time. It is a figure explaining (a) the appearance of a cement tamper, (b) the appearance of a gun sizer, and (c) description of the appearance of an ignition device (igniter), and (d) installation and installation thereof. It is a figure explaining the typical example of the rock drill which attached the soundproofing and the prevention of scattering to the vertical arm part, (a) is a figure explaining the state where all the outer periphery was cured, and (b) is an operator. It is a figure explaining the state where the visual recognition window with which curing was missing is provided in the side. It is a figure explaining other examples of curing of the arm part of a rock drill. (A) is a diagram for explaining the displacement speed with respect to the elapsed time of the first test crushing (10 m), Model 55-100 (25 ms × 8 sets (that is, 8 steps)), and (b) is the second test crushing ( 10m) is a diagram for explaining the displacement speed with respect to the elapsed time of the 55-200 type (25 milliseconds × 5 sets (that is, 5 steps)), wherein (c) is the third test crushing (10 m) type 55-100 (250 mm). FIG. 9 is a diagram illustrating a displacement speed with respect to an elapsed time of seconds × 8 sets (ie, 8 steps). FIG. 9 is a diagram illustrating a gun sizer pattern of test numbers (1) to (3) corresponding to each test crushing of (a) to (c) described in FIG. 8 and a preparation operation thereof. It is a figure explaining a method of attachment of a gun sizer IC stepped igniter, and extension of a leg line. It is a figure explaining the structure which provides an impact absorption hole (discard hole) in parallel with the crushing agent loading hole in the length direction of the underground pile. It is a figure explaining the formation method of a shock absorption hole, a formation result, etc. It is a figure explaining the variation of the insertion and arrangement pattern of a blasting agent. It is a table | surface which shows the example of the result of having measured the surrounding environment of the underground pile in the case of blasting by providing a shock absorption hole.

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

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

  In addition, since the crushing agent is ignited sequentially from the pile head, a concrete fracture surface is formed sequentially from the pile head. The crushing agent is sealed and isolated with a cement tamper between the crushing agents, so that the crushing effect of the lower crushing agent can be prevented from being hindered. Crushing with a crushing agent uses the instantaneous gas expansion phenomenon due to steam explosion, etc., so ignition in a closed space is preferable.If a gas escape route is formed in advance, the crushing effect will be reduced. It will be significantly reduced.

  In this respect, if a plurality of crushing agents formed in multiple stages are all 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 in which each crushing agent is sealed in the crushing agent loading hole by each cement tamper, a region where gas escapes in advance is not formed. . However, if all the crushing agents are ignited at the same time, if the amount of crushing agent per stage is assumed to be about 1 kg, about 10 kg of the crushing agents will be ignited simultaneously in all ten stages. In addition, when the crushing agent is loaded in one stage instead of in multiple stages, it is not necessary to fill the cement tamper in the first place, but even in this case, the 10 kg of the crushing agent loaded in the single stage is blasted at once.

  If a total of 10 kg of crushed medicine is ignited and crushed at the same time, vibrations corresponding to a seismic intensity of about 2 will be generated in buildings and the like located around it, and the noise will be considerably large. . If a vibration with a seismic intensity of about 2 occurs, the elevator of the neighboring building stops, which causes a remarkable hindrance to the work of the resident. In addition, there is a growing concern that this may be in conflict with various laws and regulations. For this reason, simultaneous crushing of all the crushing agents in a multi-stage configuration is extremely difficult in practice.

  In this regard, as in the invention of the present application, if the fire is sequentially fired one by one at predetermined intervals within a range of 0.025 seconds to 0.5 seconds (most preferably 0.25 seconds) from the pile head, The generation of vibration and noise can be dispersed over time and relatively small. Within the range of 10 m, it falls within the prescribed range of the related laws and regulations of 75 dB. According to the study of the inventor, the time required for the peak value of the vibration caused by the crushing of the underground pile to reach zero is about 0.5 seconds, about 0.5 seconds or less, and most preferably about 0.5 seconds or less. Even if ignition is performed sequentially in 25 seconds, the vibrations fall within a vibration range that can sufficiently satisfy various regulatory requirements.

  Furthermore, the reduction of the crushing effect can be minimized by sequential ignition from the pile head. It is further preferable that the interval between the crushing agents is such that even if the crushing agent in the nearest upper stage is crushed, the crack in the concrete does not reach the crushing agent immediately below. If the distance between the crushing agents is too small, if the crushing agent in the nearest upper stage crushes, cracks in the concrete will reach directly below, which will be a gas escape path, so the crushing effect of the crushing agent immediately below may be reduced. Occurs.

  For ignition, an IC igniter which is a timed ignition device may be used. In the IC igniter, the delay time from when the ignition signal is received by the built-in capacitor to when it actually ignites can be selected arbitrarily, so even if the ignition signal is transmitted simultaneously to each of the crushed drugs loaded in multiple stages, the upper stage It is possible to make a blast by providing a time difference sequentially 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 illustrating a state in which a crushed drug loading hole is drilled in a pile head using a rock drill that has been protected from scattering, and (b) illustrates a crushed drug loading hole drilled from the pile head. (C) is a diagram illustrating a state in which a crushing drug (gansizer) is loaded into a crushing agent loading hole, and (d) is a diagram illustrating a state in which a cement tamper is loaded into a crushing agent loading hole. (E) is a diagram for explaining how to load No. 7 crushed stone into the crushing agent loading hole, and (f) is a state in which the pile head in which crushing agent loading is completed in multiple stages is cured to avoid the gunshot phenomenon. (G) is a diagram illustrating a state in which the underground pile is removed with a shovel car together with surrounding soil and the like from the underground pile that has been crushed. The steps of FIGS. 1B to 1D can be repeated a plurality of times according to the number of stages of the crushed medicine to be loaded. Further, the step (e) may be appropriately omitted, or the size of the crushed stone to be loaded may be changed.

  In the underground pile crushing method of the embodiment, preferably, the interval between the crushing agents inserted in multiple stages is provided to such an extent that the effect of crushing by the lower crushing agent is not impaired due to the crushing by the upper crushing agent. It is characterized by being able to.

  Here, the interval between the crushed drugs inserted in multiple stages is such that the effect of the crushing by the lower crushing agent is not impaired due to the crushing by the upper crushing agent, typically caused by the upper crushing. This means that the cracks in the underground pile did not reach the crushing agent beneath 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 generated by the crushing of the crushing agent in the immediately upper stage Cracks reach the crushing agent just below. In this case, the cracks serve as escape paths for gas, so that the crushing effect of the crushing agent immediately below is reduced. In this case, again, there is a concern that a separate drilling operation may require an operation such as opening an additional crushing agent loading hole different from the current crushing agent loading hole and loading and igniting the crushing agent, A process delay occurs.

  In other words, from the pile head (typically the center) of the underground pile, along the length direction (depth direction), each of the crushing agents arranged in multiple stages is all from the viewpoint of the crushing effect alone. It is preferred that they be ignited at the same time and crushed at once, which has been the common sense in the blasting industry. However, in consideration of the surrounding environment at construction sites in the city center, and from the viewpoint of related regulations that are becoming stricter year by year, there are limited sites in the city center (for example, scrap-and-build related to the building of office buildings around. It is not realistic to crush one underground pile by simultaneous ignition at the site of the building.

  In the present embodiment, the vibration and noise generated by sequentially igniting from the pile head have been successfully reduced by slightly shifting the time. Also, from the viewpoint of increasing the efficiency of the construction progress and the crushing throughput, it is not preferable to make the time interval too large, while if the time interval is made too small, vibration and the like increase. Therefore, according to the present invention, the time interval is set to 0.025 seconds to 0.5 seconds (most preferably 0.25 seconds) from the research and examination of vibration reduction at the time of crushing, and the ignition is sequentially performed by shifting the time interval. It is.

  Also, if the ignition sequence was performed in the reverse order of the present invention and performed sequentially from the bottom of the underground pile, concrete crushing by the lower crushing agent would easily proceed in the upward direction. Therefore, there is a large possibility that a crush gas of the crushing agent at the immediately upper stage can escape, and the crushing effect may be reduced. This can be understood by carefully examining the placement environment of the underground piles, where the pile heads are exposed to the atmosphere while the pile bottoms are driven into hard supporting ground.

  FIG. 2 is a schematic diagram illustrating a crushing design using a 10-stage crushing agent for an underground pile having a pile head of 1600 mm in diameter and 9150 mm in length. In the example shown in FIG. 2, the length of the crushed drug is 350 mm, and the crushed drug is loaded into the crushed drug loading hole of 75 mmφ in 10 steps at intervals of 450 mm. The loading amount of each stage is 0.5 kg. Then, the blasting is performed at an interval of 25 milliseconds from the upper stage to the lower stage at an interval of 25 milliseconds, that is, from MS1 to MS10 in FIG.

  FIG. 3 is a schematic diagram for explaining a crushing design using a 13-stage 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 into the crushed medicine loading holes of 75 mmφ in 13 steps with an interval of 550 mm. The charge of each stage is 1.0 kg. Then, blasting is performed sequentially at an interval of 25 milliseconds, most preferably at an interval of 0.25 second from the upper stage to the lower stage.

  FIG. 4 is a schematic diagram for explaining a comparative study of a crushing design using a seven-stage crushing agent for an underground pile having a pile head of 1500 mm in diameter and a length of 14000 mm. It is a design drawing regarding simultaneous blasting of stages, and the drawing on the right side of the drawing is “with consideration of blasting”, that is, a blasting design in which the blasting is sequentially performed from the upper stage to the lower stage with a delay of 0.25 seconds for each stage. In the example shown in FIG. 4, the crushed medicine is loaded into the crushed medicine loading holes of 65 mmφ or 75 mmφ in seven steps, respectively, with an interval of 1000 mm. The charge of each stage is 1.0 kg. Then, blasting is performed sequentially at an interval of 25 milliseconds, most preferably at an interval of 0.25 second from the upper stage to the lower stage.

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

  Here, the loose bag is a bag that can be said to be a huge sandbag filled with contents, and has a weighting function. By igniting and crushing the pile head, preferably in a state where a rubber sheet, an iron plate, and a waste bag are placed in this order, scattering of dust and the like generated due to ignition and crushing from the pile head and surrounding soil and the like. -The diffusion (that is, the gun phenomenon) can be reduced, and the diffusion of noise can be surely reduced. In addition, since crushed pieces and pebbles of the reinforced concrete underground pile can be prevented from being scattered by the steam pressure, higher safety can be ensured for the surrounding environment and workers. For example, a black rubber sheet having a thickness of 8 mm can be used as the rubber sheet. Further, as the iron plate, for example, a 22 mm thick 1.5 m × 1.5 m, 500 kg weight can be used.

  The following equations 1 to 3 describe a process and a result of examining how to cure the pile head in order to avoid the gun phenomenon. Equation 1 describes the results of the study on "Protective measures against gun phenomena in crushing concrete piles with gunsizers", and Equation 2 describes the study results on "the movement of protective materials weighing 2 tons". Equation 3 describes the result of the examination of "movement of protective material when gun phenomenon occurs".

  Further, the underground pile crushing method of the embodiment, more preferably, the step of piercing the crushing agent loading hole from the pile head, the arm portion extending from the pile head to the working space in the length direction of the underground pile at the time of piercing. Is performed by a sound-cured rock drill.

  Conventionally, rock drills have often been used when, for example, mining a horizontal tunnel deeply. However, it has been revealed by the present inventor that a crushing agent loading hole having a diameter of about several tens of mm to more than 100 mm can also be used for drilling a deep reinforced concrete underground pile at a large depth. The drilling operation generates a considerable amount of noise and, in some cases, dust or the like containing small fragments.

  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 its top to the height of the pile head (or the height of the exposed ground), typically. It is preferable that the soundproofing be performed so that the lowermost portion of the arm portion is in contact with the ground over the entire height direction of the vertically arranged arm portion. In the soundproofing curing, it is further preferable to form a missing portion of the curing and provide a viewing window so that an arbitrary predetermined portion inside the arm can be visually confirmed by an operator of the rock drill. The crushing agent loading hole can be drilled from the pile head to the pile bottom, for example, over about 10,000 mm.

  FIGS. 6A and 6B are diagrams illustrating a typical example of a rock drill in which soundproofing and scattering prevention curing is mounted on a vertical arm portion. FIG. 6A is a diagram illustrating a state in which the outer periphery is entirely cured. b) is a diagram for explaining a state in which a viewing window with missing curing is provided on the operator side. FIG. 7 is a diagram illustrating another example of curing the arm portion of the rock drill.

  In addition, the underground pile crushing method of the embodiment is further preferably characterized in that the crushing agent is a steam pressure crushing agent that crushes the underground pile by using steam pressure generated at the time of thermal decomposition of the drug.

  As a result, there is no fear of violating so-called explosives-related laws and regulations, and it can be put to practical use in a relatively wide site from the city center including the ordinance-designated city to the suburbs to the mountainous area. In addition, since the crushing is dynamically performed by the steam pressure, the crushing operation can be performed relatively safely and instantaneously in a short time.

  Further, in the underground pile crushing method of the embodiment, more preferably, the step of igniting and crushing the crushed medicines inserted in multiple stages is performed by sequentially crushing each crushed medicine from the pile head toward the bottom of the underground pile. It is characterized by being ignited every 25 seconds.

  The present inventors have found that the vibration generated by the crushing is reduced from its peak to zero in about 0.5 seconds. For this reason, it is most preferable to ignite the next lower crushing agent at intervals of 0.25 seconds corresponding to the time from the peak of the noise to half.

  Assuming that a peak of noise (or noise and vibration) caused by the ignited crushed chemical occurs at the same time as the ignition, the noise is reduced by half after 0.25 seconds. Even if the noise of the lower crushing agent is generated continuously, the noise does not become excessively loud due to the superposition of the noise. As a result, various regulations on the surrounding environment in the city center can be sufficiently satisfied.

  In the underground pile crushing method of the embodiment, more preferably, the crushing agent utilizes the heat generated by the thermite reaction of metal powder with copper oxide as an oxidizing agent and aluminum as a reducing agent to evaporate potassium alum as crystallization water. The pressure of the medicine for one stage is 0.5 kg to 1 kg.

  A crushing agent that uses the heat generated by thermite reaction of metal powder between copper oxide as an oxidizing agent and aluminum as a reducing agent to generate steam pressure by evaporating potassium alum as water of crystallization is a business to which the present inventors belong. It is commercially available from the company under the name Gunsizer (registered trademark). FIG. 5 is a diagram for explaining (a) the appearance of a cement tamper, (b) the appearance of a gun sizer, (c) the appearance of a igniter (igniter), and (d) the mounting and installation thereof.

  Table 1 below describes the vapor pressure crushed drug gunsizer. The product description of the gun sizer is described in the order of (1) crushing agent, (2) igniter, and (3) IC igniter. The IC stage igniter is an igniter that can blast the crushed medicine loaded in each stage by delaying the crushed medicine by a predetermined time.

  Various types of Gunsizers (registered trademark) are available according to the drug weight and size, 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 stage is used. Sizer (registered trademark) can be used. That is, a 55-50 type Gunsizer (registered trademark) can be loaded, for example, in 10 stages at a pitch of 800 mm from the center of the pile head of an underground pile having a length of 9150 mm and a diameter of 1600 mmφ.

  Since the length of the 55-50 type Gunsizer (registered trademark) is 350 mm, the distance between the gunsizers (registered trademark) is 450 mm. That is, the crushing agent loading hole having a length of 450 mm, which is the interval between Gunsizers (registered trademark), can be filled with a cement tamper and preferably with a crushed stone No. 7. Then, by igniting sequentially, preferably by 0.25 seconds from the upper side, good crushing work can be performed while reducing vibration and noise. Table 2 illustrates variations of the gun sizer. (Excerpt from Nippon Koki Co., Ltd. product website)

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

  By setting the distance between the crushing agents at about 450 mm to 500 mm, the cracks generated by the crushing of the upper stage do not reach the crushing agent immediately below, the remarkable crushing agent functions effectively, and smooth and efficient crushing work Can be achieved. In other words, by filling the cement tamper or the like at intervals of about 450 mm to 500 mm, the lower crushing agent or the like can be protected from crushing of the crushing agent in the immediately upper stage. One stage of the crushing agent is expected to crush the upper part of the crushing agent of the stage. In addition, this interval can be applied to many underground piles, and both cost reduction and smooth crushing work can be achieved.

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

  FIG. 9 is a diagram for explaining the gun sizer 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. FIG. 10 is a diagram for explaining a method of attaching a gun sizer IC stepped igniter and extending a leg line.

  As is clear from the blasting test results when the time interval between each step shown in FIG. 8 is 0.025 seconds, a sufficient reduction in vibration and noise can be expected. In order to reduce vibration and noise, the method of blasting the next stage after waiting for natural reduction of vibration etc. for one stage (ie, sequentially blasting every 0.25 to 0.5 seconds) is the most theoretically understood Easy to do. However, in reality, the result as shown in FIG. 8 is obtained even for blasting every 0.025 seconds (minimum step firing), and when the peaks are the same, the vibration force or noise force is simply reduced to the amount of blasting agent. Although it is proportional, if the peak is shifted even a little (for example, 0.025 seconds), as shown in FIG. 8, the vibration can be reduced to about 1.5 times that of the single-stage blast. The reason for this is unknown at this time, but the present inventors speculate that they may cancel each other out due to anti-phase vibrations.

(Construction with shock-absorbing holes (discard holes))
FIG. 11 is a diagram illustrating a configuration in which a shock absorbing hole (discard hole) 2000 is provided in parallel with the crushing agent loading hole 2000 in the length direction of the underground pile 1000. As shown in FIG. 11, the shock absorbing holes 2000 are arranged in a rectangular shape at the center of the pile head of the underground pile 2000 in plan view, and the depth thereof is equal to or smaller than the crushing agent loading hole 2000. It is preferable to make it a little deeper.

  Since the shock absorbing hole 2000 is provided as a slit-shaped space (that is, a hollow state), it functions to absorb a shock when the blasting agent embedded in the surrounding pile blasts. If the shock absorbing hole 2000 is not provided, the vibration and shock of the blasting agent are considered to be gradually attenuated in the process of being transmitted mainly from the underground pile to the outside direction. Then, vibrations and impacts from the surroundings are directed toward this internal space. It is considered that shocks, vibrations, and the like transmitted from the surroundings in the shock absorbing hole 2000 weaken each other.

  FIG. 12A is a diagram illustrating a method of forming the shock absorbing hole 2000. Although it is difficult to directly drill a deep hole in a slit shape from the pile head of the underground pile, first, as shown in FIG. 12A, a plurality of drill holes 2500 are continuously formed at predetermined intervals t. Form. FIG. 12A shows an example in which four drill holes each having a diameter of 9 cm are continuously formed in a straight line. The predetermined interval t is between 8 and 12 mm, preferably 10 mm. As a result, due to vibration or impact in the process of forming the drill holes 2500, for example, a wall of t = 10 mm that forms between the drill holes 2500 collapses and is continuously connected, and finally has a slit shape. Strictly speaking, the diameter of the drill hole is also related to the diameter of the pile to be crushed. However, by setting the diameter in the range of approximately 8 cm to 12 cm, it is preferable from the viewpoint of work execution and the impact reduction effect is sufficiently obtained. Can be

  Here, if the predetermined interval t is too small, in the process of forming the drill hole 2500, the collapse of the wall between the holes becomes too easy, so that the drill hole 2500 should be drilled straight in the length direction of the underground pile. And bends towards the adjacent existing drill hole due to the collapsed wall. In this case, as a result, the slit-shaped shock absorbing holes 2000 cannot be formed. On the other hand, if the predetermined interval t is too large, the wall between the plurality of drill holes 2500 does not collapse and is not connected, and the slit does not have a slit shape. FIG. 12B is a diagram showing an example of the shock absorbing hole 2000 formed as described above.

  Further, as indicated by arrows in FIG. 12C, it is considered that the blasting shock and absorption tend to be in a structurally weak direction, and the shock and vibration directed to the shock absorbing hole 2000 are in the shock absorbing hole 2000. Therefore, the influence on the surrounding environment of the underground pile to be crushed can be extremely reduced. Further, since so-called abdominal muscles (rebars) are arranged near the circumference of the underground pile in plan view, it is possible to cancel and attenuate inward vibrations and the like reflected by the abdominal muscles in the shock absorbing hole 2000. it can. Here, the crushing drug loading holes 3000 can be arranged arbitrarily, but are illustrated as MS1 to MS8 in FIG. Further, the drill hole 2500 can be drilled by a drill having a hollow support column as shown in FIG.

  FIG. 13 is a view for explaining variations of the insertion / arrangement pattern of the blasting agent. In FIG. 13, the shock absorbing hole 2000 is not shown, but it can be formed as a slit in plan view that is deeply drilled in the length direction passing through the center of the underground pile. It is preferable that the blasting agent is not provided in the shock absorbing hole 2000 from the viewpoint of its functional characteristics, but it may be filled with, for example, groundwater.

  FIG. 14 is a table showing an example of the results of measuring the surrounding environment (vibration level) of the underground pile when the shock absorbing hole 2000 is provided and blasted. In the table of FIG. 14, SMB is an abbreviation for “Super Micro Blast”. In FIG. 14, if it is 75 dB or less, there is no problem at all, and if it is 100 dB or more, it is considered that practical use is difficult. However, it can be understood that almost satisfactory results are obtained. In the blasting process of the underground pile provided with the shock absorbing hole 2000, there was a concern that a large vibration was generated until the elevator of the surrounding building was stopped and transmitted to the surroundings, but such a concern could be eliminated. Become. The configuration in which the shock absorbing holes 2000 are provided is only required to pierce and form the shock absorbing holes 2000 before the blasting step of the blasting agent described above, so that the cost and cost are extremely simple and easy. It is preferable because there is no danger of increasing the construction period.

  The underground pile crushing method described above is not limited to the description that exemplifies specific numerical values and the like in the examples, and a part of the body is exposed while the main body is buried deep in the ground. The present invention can be widely applied to crushing and destruction work of underground structures, and it is possible for a person skilled in the art to change and arrange materials and process contents and their order and procedures as appropriate within the scope of the present invention.

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

1000 underground piles, 2000 shock-absorbing holes (disposal holes), 2500 drilling holes, 3000 crushing drug loading holes.

Claims (11)

Drilling a crushing agent loading hole and a shock absorbing hole from the pile head along the length direction of the underground pile in the underground pile with the pile head exposed,
A step of alternately inserting a crushing agent and a cement tamper from the pile head into the crushing agent loading hole in multiple stages along the length direction of the underground pile so that the crushing agent is at a constant interval. When,
The 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 intervals in the range of 0.025 seconds to 0.5 seconds. An underground pile crushing method, comprising: In the underground pile crushing method according to claim 1,
The underground, wherein the shock absorbing hole has a slit shape at the center of the pile head, and a depth thereof is equal to or greater than a depth of the crushing agent loading hole in a length direction of the underground pile. Pile crushing method. In the underground pile crushing method according to claim 2,
The step of drilling the shock absorbing hole is a step of forming a plurality of circular holes continuously at a predetermined interval and forming a slit shape by collapsing the holes. Underground pile crushing method. In the underground pile crushing method according to claim 3,
The underground pile crushing method, wherein the diameter of the circular hole is 8 to 12 cmφ and the predetermined interval is 8 to 12 mm. In the underground pile crushing method according to any one of claims 1 to 4,
The underground pile crushing method according to claim 1, wherein the intervals between the crushed drugs inserted in the multiple stages are provided to such an extent that the effect of crushing by the lower crushed drug is not impaired due to crushing by the upper crushed drug. In the underground pile crushing method according to any one of claims 1 to 5,
Between the step of inserting the crushing agent in multiple stages and the step of igniting and crushing,
An underground pile crushing method, further comprising a step of placing a rubber sheet, an iron plate, and a loose bag on the pile head. In the underground pile crushing method according to any one of claims 1 to 6,
Drilling a crushed drug loading hole from the pile head,
An underground pile crushing method, wherein an arm extending from the pile head to the working space in a length direction of the underground pile at the time of drilling is performed by a sound-proofed rock drill. In the underground pile crushing method according to any one of claims 1 to 7,
The underground pile crushing method according to claim 1, wherein the crushing agent is a steam pressure crushing agent that crushes the underground pile by using a water vapor pressure generated during thermal decomposition of a chemical. In the underground pile crushing method according to any one of claims 1 to 8,
The step of igniting and crushing the crushed medicines inserted in the multistage is characterized in that each crushed medicine is sequentially ignited every 0.25 seconds from the pile head toward the bottom of the underground pile. Underground pile crushing method. In the underground pile crushing method according to any one of claims 1 to 9,
The crushing agent uses heat generated by a thermite reaction of metal powder with copper oxide as an oxidizing agent and aluminum as a reducing agent, and generates steam pressure by evaporating potassium alum as crystallization water. Underground pile crushing method, wherein the weight of the drug is 0.5 kg to 1 kg. In the underground pile crushing method according to claim 10,
An underground pile crushing method, wherein an interval between the crushed drugs inserted in the multiple stages is 450 mm to 500 mm.