JP2020165146A - Pile head treatment method - Google Patents

Abstract

To provide a pile head treatment method capable of properly dividing an extra-banking portion into small pieces when a pile diameter of a cast-in-place concrete pile is large, when an extra-banking height is large, and the like.SOLUTION: A pile head treatment method includes: diagonally forming gunpowder charging holes 14, 15 for dividing obliquely from an outer peripheral face or an upper face of an extra-banking portion 6; charging a crushing agent 7 into the gunpowder charging holes 14, 15 for dividing; and dividing the extra-banking portion 6 into a plurality of crushed lumps by igniting the crushing agent 7. Thereby, the extra-banking portion can be properly divided and the divided crushed lumps can be efficiently removed.SELECTED DRAWING: Figure 2

Description

The present invention relates to a pile head treatment method for performing pile head treatment of cast-in-place concrete piles using a crushing agent such as a dynamic crushing agent.

Cast-in-place concrete piles are formed by building a reinforcing bar cage in a pile hole formed in the ground and then placing concrete in the pile hole.

At that time, by placing concrete in the pile hole, impurities such as soil and slime at the bottom emerge and settle and harden at the pile head, so the pile head part containing the impurities (hereinafter, surplus) A process of removing the part), that is, a pile head process is required.

Conventionally, in this type of pile head treatment, a method of manually scraping off the surplus portion by using a crusher such as a breaker to remove the generated concrete waste is common.

However, the pile head treatment method using a crusher requires a lot of time for the work, and there is a problem that the noise and vibration have a great influence on the surrounding environment.

In addition, as another pile head treatment method, there is also a pile head treatment method using a static crushing agent that divides the surplus portion into small pieces by the expansion action of the static crushing agent inserted into the sheath pipe or the like installed in the pile head in advance. Are known.

However, in the pile head treatment method using a static crushing agent, the state of installation of sheath pipes and concrete placement has a large effect, and it is difficult for the static crushing agent to act properly depending on the state, and the horizontal fracture surface is good. Since it is difficult to form, as a result, there is a tendency that the work of manually scraping off the surplus portion by using a crusher such as a breaker increases.

Therefore, in recent years, a plurality of charge holes are formed radially toward the center of the pile at a predetermined height of the pile head, a dynamic crushing agent is loaded in the charge holes, and the dynamic crushing agent is used for planning. A pile head treatment method has been proposed in which the surplus portion above the top is broken horizontally.

However, when the pile diameter is large or when it is difficult to approach heavy machinery, it is difficult to remove the surplus portion after horizontal fracture as it is, so the surplus portion after horizontal fracture is divided into small pieces. Need to be.

As a method of crushing the surplus part, a vertical pipe type horizontal fin (two flat steel layers) charge holder is placed inside the pile main bar on the outer circumference of the pile to make it sealed, and after casting cast-in-place concrete, A method is known in which a dynamic crushing agent is inserted into a charge holder and the surplus portion is broken horizontally and vertically by dynamic crushing by remote control (see, for example, Patent Documents 1 and 2).

In this construction method, the crushing force in the horizontal direction is ejected from between the horizontal fins, and the crushing force in the vertical direction is ejected from the gap between the two angle steels of the vertical pipe at a speed close to the speed of sound. It breaks in the vertical direction.

In addition, as a method of subdividing the surplus portion, a plurality of vertical holes drilled in the vertical direction from the upper surface of the surplus portion are provided radially at intervals in the radial direction, and the amount of charge is adjusted according to the pile diameter. A method has been proposed in which the crushing agent is ignited and divided into small pieces in the vertical direction after adjusting the above.

Further, as another method of subdividing the surplus portion 31 of the concrete pile 30, as shown in FIGS. 10 and 11, a predetermined height of the surplus portion 31 (a substantially intermediate height of the surplus portion 31). A plurality of lateral holes 32, 32 ... Directed in the radial direction are provided radially, and holes are drilled in the vertical direction from the upper surface of the surplus portion 30 at intervals in the radial direction so as not to interfere with the lateral holes 32, 32 ... The vertical holes 33, 33 ... Are provided radially, and the crushing agent 34 is loaded into the vertical holes 33, 33 ... And the horizontal holes 32, 32, respectively, and the crushing agent 34 is ignited to simultaneously provide the surplus portion 31 in the vertical and horizontal directions. A method of crushing is also conceivable. In the figure, reference numeral 35 is a charge hole for horizontal breaking, reference numeral 36 is a main bar, and reference numeral 37 is a band bar.

Japanese Unexamined Patent Publication No. 2016-151162 Japanese Unexamined Patent Publication No. 2013-124509

However, in the construction method using a vertical pipe type load holder with horizontal fins, the crushing force is relatively stable and it is possible to break in both horizontal and vertical directions with a single ignition, but the vertical before pile construction. It is necessary to attach a tube-type horizontal fin-equipped charge holder or the like, and there is a problem that it is difficult for the dynamic crushing agent to act properly if the charge holder or the like is not attached properly. Further, although the crushed pieces can be reduced by increasing the number of vertical tubes, there is a problem that the vertical tube type charge holder is expensive and the cost is high.

On the other hand, when a plurality of vertical holes drilled in the vertical direction from the upper surface of the surplus portion are provided radially at intervals in the radial direction, the pile diameter is large or the surplus is divided in the vertical direction. When the height of the pile is large, the crushed pieces are large, and even if heavy machinery can approach each other, it may not be easily transported.

In addition, in the method of crushing the surplus portion at the same time in the vertical and horizontal directions, when the vertical and horizontal legs are connected in series, the subsequent crushing may be hindered by cutting the other leg line due to the preceding crushing. was there.

In the method of crushing the surplus portion in the vertical and horizontal directions, a stepped electric detonator is used as the crushing agent to be loaded in each of the vertical and horizontal charge holes, and a time difference is provided in the crushing of each of the vertical and horizontal holes. However, in reality, there is a risk that the crushing will not proceed as expected, such as when the subsequent crushing part is affected by the preceding crushing.

Therefore, in view of such a conventional problem, the present invention allows the pile head to be accurately divided into small parts when the pile diameter of the cast-in-place concrete pile is large or the extra height is large. This was done for the purpose of providing a treatment method.

The feature of the invention according to claim 1 for solving the conventional problem as described above is that the surplus portion on the upper side from the planned top end of the columnar cast-in-place concrete pile is divided and a plurality of the surplus portions are provided. In the pile head treatment method of dividing and removing the pile head, a dividing charge hole is formed diagonally from the outer peripheral surface or the upper surface of the surplus portion, the dividing charge hole is loaded with a crushing agent, and the crushing is performed. The purpose is to divide the surplus portion into a plurality of crushed lumps by igniting the agent.

The feature of the invention according to claim 2 is that, in addition to the configuration of claim 1, the dividing charge holes inclined upward from the outer peripheral surface of the surplus portion to the central portion are spaced in the circumferential direction of the surplus portion. It is to form after.

The feature of the invention according to claim 3 is that, in addition to the configuration of claim 1 or 2, a downwardly inclined split charging hole extending from the outer peripheral surface of the surplus portion to the central portion is provided in the circumferential direction of the surplus portion. It is to be formed at intervals.

A feature of the invention according to claim 4 is that, in addition to the configuration of claim 3, the downwardly inclined dividing charge hole is arranged below the upwardly inclined dividing charge hole. is there.

The feature of the invention according to claim 5 is that, in addition to the configuration of any one of claims 1 to 4, the dividing charge hole is inclined downward from the center side of the upper surface of the surplus portion toward the outer peripheral surface side. Is to be formed at intervals in the circumferential direction.

The feature of the invention according to claim 6 is that, in addition to the configuration of any one of claims 1 to 5, a downwardly inclined partitioning charge hole extending from the outer edge side of the upper surface of the surplus portion to the central portion is peripheral. It is to be formed at intervals in the direction.

The feature of the invention according to claim 7 is, in addition to the configuration of any one of claims 1 to 6, a horizontal breaking charge in the horizontal direction from the outer peripheral surface to the central portion at the lower end portion of the surplus portion. By forming a hole, loading a crushing agent into the horizontal breaking charge hole, and igniting the crushing agent, the surplus portion is separated from the planned top end of the concrete pile, and then for the division. The purpose is to ignite the crushing agent loaded in the charge hole and divide the surplus portion into a plurality of crushed lumps.

In the pile head treatment method according to the present invention, by providing the configuration according to claim 1, the crushing force generated at each of the diagonally oriented charging holes for division is adjacent to another crushing force generating source. It also acts toward other matching charge holes for division, and the surplus portion is broken into each portion partitioned by the charge hole for division, and the surplus portion can be accurately divided into a plurality of crushed lumps. ..

Further, in the present invention, by providing the configuration according to claim 2, the crushing force propagates between the respective dividing charge holes formed at intervals in the circumferential direction, and between the respective dividing charge holes. A continuous planar fracture surface is formed, and a fracture surface that accurately divides the surplus portion into upper and lower parts can be formed.

Further, in the present invention, by providing the configuration according to claim 3, the crushing force propagates between the respective dividing charge holes formed at intervals in the circumferential direction, and between the respective dividing charge holes. A continuous planar fracture surface is formed, and a fracture surface that accurately divides the surplus portion into upper and lower parts can be formed. Further, since the drilling machine such as a drill can be turned downward, the worker can easily support the drilling machine and can easily perform the work from the outer circumference.

Furthermore, by providing the configuration according to claim 4, the crushing force propagates between the vertically arranged dividing charge holes, and the continuous planar shape is provided between the vertically arranged dividing charge holes. The fracture surface is formed, and the fracture surface that accurately divides the surplus portion in the circumferential direction can be formed.

Further, in the present invention, by providing the configurations of claims 5 to 6, the crushing force propagates between the respective dividing charge holes formed at intervals in the circumferential direction, and each dividing charge is propagated. A flat fracture surface is formed between the holes, and the surplus portion can be accurately divided into a plurality of crushed lumps. Further, since the drilling machine such as a drill can be turned downward from the upper surface of the surplus portion, the worker can easily support the drilling machine and can easily perform the work.

Further, in the present invention, by providing the configuration of claim 7, since the crushing agent loaded in each dividing charge hole is ignited after the horizontal break of the surplus portion, it is divided into small pieces without being affected by the horizontal break. Can work.

It is a top view which shows an example of the aspect of the pile head processing method which concerns on this invention. It is the front view of the same as above. It is a cross-sectional view taken along the line AA at the time of horizontal fracture as above. It is the cross-sectional view taken along the line AA at the time of the subdivision work of the same above. It is sectional drawing which shows the loading state of the above-mentioned crushing agent. It is a top view which shows another example of the aspect of the pile head processing method which concerns on this invention. It is a vertical sectional view of the same as above. It is a top view which shows still another example of the aspect of the pile head processing method which concerns on this invention. It is a vertical sectional view of the same as above. It is a top view which shows an example of the aspect of the conventional pile head processing method. It is a vertical sectional view of the same as above.

Next, an embodiment of the pile head treatment method according to the present invention will be described based on the examples shown in FIGS. 1 to 5. Reference numeral 1 in the drawing is a cast-in-place concrete pile (hereinafter referred to as a concrete pile).

In the concrete pile 1, a reinforcing bar cage 2 is built in a pile hole (not shown) formed in the ground, and a plurality of reinforcing bars (main bars) 3, 3 ... Are arranged at intervals in the circumferential direction, and then in the pile hole. It is constructed by placing concrete 4. Reference numeral 5 in the figure is a band bar constituting the reinforcing bar cage 2. In addition, in FIGS. 3 and 4, the description of the reinforcing bars 3, 3 ... And the band bar 5 is omitted for convenience of explanation.

At that time, since the tremie pipe is inserted into the bottom of the pile hole and the concrete 4 is launched from the bottom, impurities such as soil and slime at the bottom of the pile head of the concrete pile 1 are added to the concrete of the pile head. Since it is mixed, the pile head treatment is performed in order to remove the pile head portion (hereinafter, referred to as the surplus portion 6) containing the impurities.

The surplus portion 6 refers to a pile head portion above the planned top end 1a of the planned pile of the concrete pile 1.

In this pile head treatment method, a crushing agent 7 such as a dynamic crushing agent is used to divide the upper surplus portion 6 from the planned top end 1a of the columnar cast-in-place concrete pile 1 and to separate the surplus portion 6. It is designed to be divided into multiple crushed lumps and removed.

In order to separate the surplus portion 6 of the pile head from the planned top end 1a by using a crushing agent 7 such as a dynamic crushing agent, first, a hole such as a drill is drilled in the vicinity of the planned top end 1a of the pile head. A plurality of (6 in this embodiment) horizontal breaking charge holes 8, 8 ... Are drilled using a machine.

The horizontal breaking charge holes 8, 8 ... Are formed radially from the outer peripheral side of the pile toward the pile center side, and the horizontal breaking charge holes 8, 8 ... Are arranged at substantially equiangular intervals. There is.

Further, the total length L of the horizontal breaking charge holes 8, 8 ... Is about 90% of the pile radius, and the diameter of the horizontal breaking charge holes 8, 8 ... Is the diameter of the vinyl pipe 9 filled with the crushing agent 7. The inner diameter of the vinyl tube 9 is set to 60 ± 5% so that the ratio of the charge length L1 including the igniter 10 to the horizontal breaking charge holes 8, 8 ... length is 60 ± 5%. Set in consideration of bulk density, filling state, etc.

The tip (back end) of each of the horizontal breaking charge holes 8, 8 ... may be arranged slightly offset from the center of the pile so as not to interfere with each other.

As the crushing agent 7, various known dynamic crushing agents can be used, and for example, those containing cupric oxide, aluminum, magnesium sulfate heptahydrate as main components may be used, such as bromate. A medicine cylinder containing a gas generating agent as a main agent and an igniter may be integrated.

In addition, the standard amount of dynamic crushing agent is 256 g per 1 m ^{2 of} pile head cross-sectional area, and is in the range of 85% to 100% of the standard amount based on the pile diameter and the amount of main reinforcement of the pile. Adjust with.

Then, as shown in FIG. 4, the crushing agent 7 and the igniter 10 are filled in this order from the innermost part of the vinyl tube 9, and the vinyl tube 9 is inserted into the horizontal breaking charge holes 8, 8 ... The wire 10a is pulled out of the horizontal breaking charge holes 8, 8 ..., And then the filling 11 such as sand is filled in the horizontal breaking charge holes 8, 8 ... Both ends of the vinyl pipe 9 are fitted with plastic stoppers 12 and 12, and the outside thereof is sealed with a sealing material 13.

Further, when the loading operation is completed, the charge length L1 and the filling length L2 are measured, these measured values are recorded, and it is confirmed that they are within the appropriate value range.

Next, after evacuating the worker from around the pile and confirming the safety, the leg wire 10a drawn from the igniter 10 is connected to the blaster (not shown), and the crushing agent is remotely controlled by the blaster. 7 is ignited and the surplus portion 6 of the pile head is horizontally blasted.

The dynamic crushing agent induces a reduction reaction called a thermite reaction by ignition to generate high-temperature and high-pressure steam, and the concrete 4 is crushed by utilizing the expansion pressure of the generated steam, and the surplus portion 6 is piled up. It is broken horizontally from the head.

Next, in order to subdivide the surplus portion 6 with the dynamic crushing agent, first, the dividing charge holes 14, 14 ... Are formed diagonally from the outer peripheral surface or the upper surface of the surplus portion 6. The split charge holes 14, 14 ... May be formed together with the horizontal break charge holes 8, 8 ... When the holes are drilled, or may be formed after the horizontal break.

As shown in FIGS. 1 to 4, the dividing charge hole 14 is drilled diagonally upward from the outer peripheral surface of the surplus portion 6 using a drilling machine such as a drill, and is directed upward to the central portion. A plurality of inclined (six in this embodiment) dividing charge holes 14, 14 ... Are formed so as to be radially arranged at intervals in the circumferential direction of the surplus portion 6.

Further, a plurality of holes are drilled diagonally downward from the outer peripheral surface of the surplus portion 6 using a drill or the like, and a plurality of holes are inclined downward from the outer peripheral surface of the surplus portion 6 to the central portion (6 in this embodiment). The dividing charge holes 15, 15 ... Of the main) are formed so as to be arranged radially at intervals in the circumferential direction of the surplus portion 6.

The downwardly inclined dividing charge holes 15, 15 ... Are arranged below the upwardly inclined dividing charge holes 14, 14 ..., and the upwardly inclined dividing charge holes 14, 14 ... It is preferable to arrange the dividing charge holes 15, 15 ... Inclined downward so as to substantially overlap each other in the vertical direction.

Further, the upwardly inclined split charge holes 14, 14 ... And the downwardly inclined split charge holes 15, 15 ... Are drilled from the same position on the outer peripheral surface of the surplus portion 6 as in the present embodiment. Alternatively, the base end opening may be provided by shifting it up and down.

Then, as in the case of FIG. 4, the crushing agent 7 and the igniter 10 are filled in this order from the innermost part of the vinyl tube 9, and the vinyl tube 9 is inclined upward in the dividing charge holes 14, 14 ... And downward. After inserting into the dividing charge holes 15, 15 ... Inclined in the above direction, the leg line 10a is pulled out of the dividing charge holes 14, 15 and then the filling 11 such as sand is inclined upward for the division. Fill the inside of the charge holes 14, 14 ... And the downwardly inclined dividing charge holes 15, 15 ... Both ends of the vinyl pipe 9 are fitted with plastic stoppers 12 and 12, and the outside thereof is sealed with a sealing material 13.

Further, when the loading operation is completed, the charge length L1 and the filling length L2 are measured, these measured values are recorded, and it is confirmed that they are within the appropriate value range.

Next, after evacuating the worker from around the pile and confirming the safety, the leg wire 10a drawn from the igniter 10 is connected to the blaster (not shown), and the crushing agent is remotely controlled by the blaster. 7 is ignited, and the surplus portion 6 of the pile head is divided into a plurality of crushed lumps.

In the pile head treatment method configured in this way, the crushing force generated at each of the diagonally oriented dividing charge holes 14 and 15 at almost the same time is another crushing force generating source, which is another adjacent dividing charge hole. It also acts toward 14 and 15, and is formed at intervals from the center of the split charge holes 14 and 15, in the direction between the split charge holes 14 and 14, and in the direction between the split charge holes 15 and 15. The crushing force propagates up and down, and a flat fracture surface is formed between the dividing charge holes 14 and 14, between the dividing charge holes 15 and 15, and between the dividing charge holes 14 and 15, respectively. Each portion is divided by the dividing charge holes 14 and 15, that is, the portions are broken in the circumferential direction (6 divisions) and the vertical direction (3 divisions), and a plurality of surplus portions 6 are accurately formed (18 in this embodiment). It can be divided into crushed lumps.

The mode of the split charge hole is not limited to the mode shown in FIGS. 1 to 4, and for example, the split charge holes 14, 14 ... Inclined upward or the split charge holes 15 inclined downward. Only one of 15 ... may be provided.

Further, as an aspect of the dividing charge holes 14, 14 ..., For example, as shown in FIGS. 6 and 7, for division, which is inclined downward from the center side of the upper surface of the surplus portion 6 toward the outer peripheral surface side. The charge holes 16, 16 ... May be formed at intervals in the circumferential direction, and as shown in FIGS. 8 and 9, the surplus portion 6 is inclined downward from the outer edge side to the central portion of the upper surface. The divided charge holes 17, 17 ... May be formed at intervals in the circumferential direction. The same components as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted, and in FIGS. 6 to 9, for convenience of explanation, the reinforcing bars 3, 3 ... Is omitted.

By forming the dividing charge holes 16 and 17 in this way, the surplus portion 6 is formed into each portion partitioned by the dividing charge holes 16 and 17, that is, in the circumferential direction (6 divisions) and the vertical direction (6 divisions). It is divided into 12 crushed lumps (divided into 2).

In addition, the division charge holes may be combined with the modes of the division charge holes 14 to 17.

In the above-described embodiment, the crushing agent loaded in the horizontal breaking charge holes 8, 8 ... Is ignited to horizontally break the surplus portion 6 from the planned top end 1a, and then loaded into the split charge hole. An example of igniting a crushing agent and dividing it into a plurality of crushed lumps has been described, but even if the crushing agent loaded in the horizontal breaking charge hole and the crushing agent loaded in the dividing charge hole are ignited at the same time, Good.

1 Concrete pile 1a Planned top 2 Reinforcing bar cage 3 Reinforcing bar 4 Concrete 5 Reinforcing bar 6 Extra part 7 Crushing agent 8 Horizontal breaking charge hole 9 Vinyl pipe 10 Ignition tool 11 Filling 12 Plug 13 Sealing material 14 Dividing charge Hole 15 Divided charge hole 16 Divided charge hole 17 Divided charge hole

Claims (7)

In the pile head treatment method in which the surplus portion on the upper side from the planned top end of the columnar cast-in-place concrete pile is divided and the surplus portion is divided into a plurality of parts and removed.
A split charging hole is formed so as to be oblique from the outer peripheral surface or the upper surface of the surplus portion.
A pile head treatment method characterized by loading a crushing agent into the dividing charge hole and igniting the crushing agent to divide the surplus portion into a plurality of crushed lumps. The pile head treatment method according to claim 1, wherein the divided charge holes inclined upward from the outer peripheral surface of the surplus portion to the central portion are formed at intervals in the circumferential direction of the surplus portion. The pile head treatment method according to claim 1 or 2, wherein the dividing charge holes inclined downward from the outer peripheral surface of the surplus portion to the central portion are formed at intervals in the circumferential direction of the surplus portion. The pile head treatment method according to claim 3, wherein the downwardly inclined dividing charge hole is arranged below the upwardly inclined dividing charge hole. The pile head treatment according to any one of claims 1 to 4, wherein divisional charge holes inclined downward from the center side of the upper surface of the surplus portion toward the outer peripheral surface side are formed at intervals in the circumferential direction. Construction method. The pile head treatment method according to any one of claims 1 to 5, wherein the dividing charge holes inclined downward from the outer edge side of the upper surface of the surplus portion to the central portion are formed at intervals in the circumferential direction. By forming a horizontal breaking charge hole from the outer peripheral surface to the central part at the lower end of the surplus portion, loading the crushing agent into the horizontal breaking charge hole, and igniting the crushing agent. , The surplus portion is separated from the planned top of the concrete pile,
After that, the pile head treatment method according to any one of claims 1 to 6, wherein the crushing agent loaded in the dividing charge hole is ignited and the surplus portion is divided into a plurality of crushed lumps.

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