WO2015128944A1

WO2015128944A1 - Prefabricated pile construction method, program, memory medium, pile foundation, and prefabricated pile construction system

Info

Publication number: WO2015128944A1
Application number: PCT/JP2014/054542
Authority: WO
Inventors: 満丸後庵; 鈴木　良和
Original assignee: ジャパンパイル株式会社
Priority date: 2014-02-25
Filing date: 2014-02-25
Publication date: 2015-09-03
Also published as: JP6065155B2; JPWO2015129060A1; WO2015129060A1

Abstract

　This invention includes: setting steps (S13, S14) for setting a plurality of expansion ratios representing the proportion of the inside diameter of an expansion excavation unit (5) relative to the outside diameter design value obtained by adding a desired clearance value to the outer diameter of the tip part (10a) of a prefabricated pile (10); a design-support-force-measuring step (S16) for performing a load test with regards to one or more expansion ratios selected from the expansion ratios, and measuring the design support force for the prefabricated pile for the respective expansion ratio; a design-support-force-determining step (S17) for determining whether or not the product of the design support force and the number of prefabricated piles to be used is equal to or greater than the desired design load acting on a pile foundation formed by the prefabricated piles; an optimum-expansion-ratio-determining step (S18) for determining the smallest of the expansion ratios satisfying the criterion of the product being equal to or greater than the design load to be the optimum expansion ratio for the expansion excavation unit; and an expansion-excavation-unit-formation step (S19) for forming the expansion excavation unit on the basis of the optimum expansion ratio.

Description

Ready-made pile construction method, program, storage medium, pile foundation, and ready-made pile construction system

The present invention relates to a method for constructing a ready-made pile, a program, a storage medium, a pile foundation, and a construction system for a ready-made pile.

As foundation structures for buildings, etc., pile foundations made by burying prefabricated piles such as PHC piles, RC piles, PRC piles, steel piles, SC piles, and node piles in pile holes formed in the ground are often used. . An embedded pile method is known as a method for constructing a pile by building the ready-made pile. The embedded pile method has less noise and vibration than the driven pile method, and is often used particularly in urban areas. The embedded pile method includes a pre-boring method in which a ready-made pile is built in a hole excavated in advance by a drilling device such as an earth auger, and a ground auger is inserted into a hollow ready-made pile, and the ground below the tip of the ready-made pile is There is a medium digging method that builds a ready-made pile in the hole.

In the embedded pile method, first, a pile hole is excavated and an enlarged excavation part is formed at the bottom of the pile hole, and then a root-setting liquid such as cement milk is injected into the enlarged excavation part, and the tip of the ready-made pile is inserted into the inside. The tip support force is increased by inserting a portion to form a so-called rooted portion. As a construction method of a ready-made pile that forms an enlarged excavation part at the bottom of a pile hole and then forms a root-clamping part, Patent Document 1 includes a pre-boring method, and Patent Document 2 includes a medium-digging method. Each is disclosed.

JP 2008-106426 A JP 2006-342560 A

However, in the pre-boring method such as the pre-boring method and the digging method, the pre-made pile construction method adapts the ground strength and the bearing capacity of the pre-made pile in the environment where the ground strength is difficult to predict or the ground strength varies widely. There was a problem that it was difficult. In other words, if the ground strength is higher than expected when a load test of a ready-made pile is performed, an excessive tip support force can be obtained with respect to the design support force of the ready-made pile. It becomes a design. On the other hand, when the ground strength is lower than expected, only a tip support force that is too small relative to the design support force can be obtained. Therefore, it is necessary to redesign the pile hole including the enlarged excavation part.

In particular, when forming an enlarged excavation part that is larger than necessary when forming the root consolidation part, so-called over-specification occurs, and the injection amount of the root compaction liquid and the expansion excavation part for forming the root consolidation part are excavated. The amount of discharged soil is excessively increased, which is not preferable in terms of the cost of materials and the efficiency of construction work. In other words, in the process of constructing ready-made piles, the optimal design of the expansion ratio that shows the ratio of the inner diameter of the enlarged excavation part to the outer diameter of the tip part of the ready-made piles is not to be over-spec when forming the consolidation part. It becomes extremely important. In patent document 1 and patent document 2, although it refers to the construction method which forms an enlarged excavation part using excavation apparatuses, such as an earth auger, and then builds a ready-made pile and forms a solidification part, expansion No reference is made to obtaining the optimum value of the expansion ratio of the excavated part.

The present invention has been made in view of the above-mentioned problems, and when a pre-made pile is built in a pile hole having an enlarged excavation part on the bottom side, an economical design and construction of the pre-made pile according to the ground strength is possible. It aims at providing the construction method, program, storage medium, pile foundation, and construction system of a ready-made pile which set the expansion ratio efficiently.

One aspect of the present invention is a method for constructing a ready-made pile in which a ready-made pile is built in a pile hole in which an enlarged excavation part with an enlarged inner diameter is formed on the bottom side, and the outer diameter of the tip of the ready-made pile is desired. A setting step for setting a plurality of expansion ratios with different values based on predetermined data relating to the construction of the ready-made piles, and these, indicating the ratio of the inner diameter of the expanded excavation part to the outer diameter design value obtained by adding the clearance value Design bearing capacity measurement step of measuring a design bearing capacity of the ready-made pile at each of the one or more magnification ratios by carrying out a loading test for each of the cases of one or a plurality of magnification ratios selected from a plurality of magnification ratios And for each of the design support forces measured in the design support force measurement step, the product of the design support force and the number of the ready-made piles to be used acts on the pile foundation formed by the ready-made piles. Design of A design support force determination step for determining whether or not the load is greater than or equal to a load, and the expansion excavation unit that sets a minimum expansion ratio among the expansion ratios that satisfy the condition that the product is greater than or equal to the design load in the design support force determination step An optimum enlargement ratio determining step for determining an optimum enlargement ratio for forming the enlargement excavation portion and an enlargement excavation portion forming step for forming the enlargement excavation portion based on the optimum enlargement ratio are included.

According to one aspect of the present invention, it is possible to efficiently set an optimum expansion ratio that enables an economical design of a ready-made pile matched to the ground strength. Thereby, the overspec at the time of forming an expanded excavation part can be reduced. Specifically, a loading test is performed in the design bearing capacity measurement process to obtain the design bearing capacity, and the design bearing capacity determination process and the optimum magnification ratio determination process are performed based on the design bearing capacity, and the minimum magnification ratio is determined. By setting it as the optimal expansion ratio, the design bearing capacity can be determined without changing the specifications of the ready-made pile specifications (pile type, pile diameter D, pile length L, material strength, etc.) that were initially set. In addition, since the optimum enlargement ratio can be set with as few loading tests as possible, it is possible to reduce the labor and test period of the loading test. Thereby, economic efficiency can further be improved. Furthermore, since the ready-made pile is constructed by an embedding method such as a pre-boring method or a medium digging method, it does not stop at a high level and can be reliably constructed at a design depth position.

At this time, according to one aspect of the present invention, in the setting step, a design value enlargement ratio set based on at least the predetermined data, an enlargement ratio that is smaller than the design value enlargement ratio, and the design value enlargement ratio An enlargement ratio having a larger value may be set.

Thus, the validity of the design value magnification ratio set in the setting process including the magnification ratio smaller than the design value magnification ratio and the large magnification ratio can be further examined. In addition, if construction is carried out at an enlargement ratio smaller than the design value enlargement ratio, not only will the construction efficiency be improved, but the amount of excavation and the use of curable materials can be reduced, and the specifications of construction equipment can be reduced. be able to. Furthermore, if construction is performed at an enlargement ratio that is larger than the design value enlargement ratio, the amount of excavation and the amount of curable material used for hardening the tip are increased, but safer design and construction are possible.

Further, in one aspect of the present invention, in the setting step, an enlarged excavation section length that is an axial length of the enlarged excavation section may be set for each of the plurality of enlargement ratio cases.

In this way, the optimal enlargement ratio and the length of the expanded excavation section are determined after examining the appropriateness of the expansion ratio and the axial length of the expanded excavation section, so that a more suitable size of the expanded excavation section is secured. be able to.

Moreover, in one aspect of the present invention, in the design support force determination step, a product of the design support force measured based on the design value enlargement ratio from the design value enlargement ratio and the number of the ready-made piles, It is determined whether or not the desired design load acting on the pile foundation formed by the ready-made piles is greater than or equal to the desired design load in the design support force determination step. Further, a predictive design for determining whether or not a predicted design support force estimated based on at least the design support force measured in the design support force measurement step is greater than or equal to the design support force set in the setting step. A supporting force determination step may be included.

In this way, it is possible to reliably set a more suitable optimum enlargement ratio after further examining the validity of the design value enlargement ratio set in the setting step.

In one aspect of the present invention, in the design support force determination step, the product of the design support force measured based on the enlargement ratio and the number of the ready-made piles in order from the smallest of the plurality of enlargement ratios. However, it is good also as determining whether it is more than the said desired design load which acts on the said pile foundation formed with the said ready-made pile.

In this way, it is possible to more efficiently and reliably set the optimum enlargement ratio that does not result in over-spec.

Moreover, in one aspect of the present invention, the ready-made pile may be a nodal pile provided with a convex portion on the outer peripheral surface of the tip portion.

In this way, it is possible to improve the integrity with the root hardening part. In addition, it is possible to reduce over specs and high stops especially when constructing joint piles.

Moreover, the other aspect of this invention is a program for making a computer perform the construction method of the ready-made pile in any one mentioned above.

According to another aspect of the present invention, the optimal expansion ratio of the expanded excavation portion formed on the bottom side of the pile hole can be set in accordance with such a program in as few loading tests as possible.

Moreover, the other aspect of this invention is the storage medium which memorize | stored the program for making a computer perform the construction method of the ready-made pile described in any of the above-mentioned so that a computer could read.

According to the other aspect of the present invention, the optimum expansion ratio of the expanded excavation part formed on the bottom side of the pile hole can be set in the loading test as few times as possible according to the program stored in the storage medium. .

Moreover, the other aspect of this invention is the pile foundation formed with the ready-made pile built in the ground by the construction method of the ready-made pile described in any one of the above-mentioned.

According to another aspect of the present invention, since it is possible to reduce over-spec and high stop when building ready-made piles on the ground, the cost when constructing a pile foundation made of such ready-made piles is reduced, and construction work efficiency is reduced. Can be improved.

Further, another aspect of the present invention is a ready-made pile construction system in which a ready-made pile is built in a pile hole in which an enlarged excavation part having an enlarged inner diameter is formed on the bottom side, and at least a predetermined related to the construction of the ready-made pile. The storage unit for storing the data, and calculation processing by a computer based on at least the predetermined data, the outer diameter design value obtained by adding a desired clearance value to the outer diameter of the tip of the ready-made pile A calculation unit for obtaining an enlargement ratio indicating a ratio of an inner diameter of the enlarged excavation part, and a setting that is included in the calculation part and sets a plurality of enlargement ratios with different values based on at least predetermined data relating to the construction of the ready-made pile And the product of the design support force and the number of the ready-made piles to be used for each of the design support forces measured at least by the design support force measuring device. A determination unit that determines whether or not the design load is greater than or equal to a desired design load acting on the pile foundation that is formed, and is included in the calculation unit, and at least satisfies the condition that the product is greater than or equal to the design load in the determination unit A determination unit that determines a minimum expansion ratio among the expansion ratios as an optimal expansion ratio for forming the expansion excavation unit, and one or a plurality selected from the plurality of expansion ratios set in the setting unit A design bearing force measuring device for carrying out a loading test for each of the cases with an enlargement ratio and measuring the design support force of the ready-made pile at the one or more enlargement ratios, and capable of expanding in the outer diameter direction on the tip side A movable excavation section, and a drilling device that forms the expansion excavation section based on the optimum expansion ratio when excavating the pile hole.

According to another aspect of the present invention, the optimum enlargement ratio of the enlarged excavation part formed on the bottom side of the pile hole can be set in as few loading tests as possible. Specs and high stops can be reduced efficiently.

At this time, in another aspect of the present invention, the storage unit includes, as the predetermined data, at least soil soil data in which the ready-made pile is built, measurement data of the load test described above, and past construction of the ready-made pile. The result data may be stored as a database.

By setting the optimal expansion ratio based on the predetermined data relating to the construction of such ready-made piles, it is possible to form an expanded excavation section based on the optimal expansion ratio more suitable for actual ground.

As described above, according to the present invention, when a ready-made pile is built in a pile hole in which an enlarged excavation part with an enlarged inner diameter is formed on the bottom side, an economical design and construction of a ready-made pile according to the ground strength is performed. It is possible to provide a method for constructing ready-made piles and the like that efficiently set an enlargement ratio that enables the construction. Moreover, according to this invention, since a ready-made pile is constructed | assembled by embedding methods, such as a pre-boring method and a medium digging method, it can construct reliably in a design depth position, without stopping at high. Furthermore, according to this invention, when building a ready-made pile in a pile hole, the optimal expansion ratio of the expansion excavation part formed in the bottom part side of a pile hole can be set by the load test as few times as possible.

It is a schematic block diagram which shows a part of pile foundation formed with the ready-made pile built with the construction method of the ready-made pile which concerns on one Embodiment of this invention. It is a block diagram which shows the whole structure of the construction system of the ready-made pile which concerns on one Embodiment of this invention. It is a flowchart which shows the outline of the construction method of the ready-made pile which concerns on one Embodiment of this invention. It is a graph which shows the relationship between the calculated value of the design support force of the ready-made pile in the construction method of the ready-made pile which concerns on one Embodiment of this invention, and the measured value of a design support force. It is a flowchart which shows the detail of the construction method of the ready-made pile which concerns on one Embodiment of this invention. It is a flowchart which shows the detail of the modification of the construction method of the ready-made pile which concerns on one Embodiment of this invention. It is a flowchart which shows the detail of the construction method of the ready-made pile which concerns on other one Embodiment of this invention. It is a flowchart which shows the detail of the modification of the construction method of the ready-made pile which concerns on other one Embodiment of this invention.

Hereinafter, preferred embodiments of the present invention will be described in detail. The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are essential as means for solving the present invention. Not necessarily.

(First embodiment)
First, the outline of the structure of the ready-made pile built by the construction method of the ready-made pile which concerns on one Embodiment of this invention, and the pile foundation formed with the said ready-made pile is demonstrated, using drawing. Drawing 1 is a schematic structure figure showing a part of pile foundation formed with a ready-made pile built with a construction method of a ready-made pile concerning one embodiment of the present invention. In addition, FIG. 1 is a figure which shows the structure of the tip solidification part of the ready-made pile especially constructed by the pre-boring method among the construction methods of the ready-made pile concerning this embodiment.

As shown in FIG. 1, the pile foundation 1 is formed by a ready-made pile 10 built in a pile hole 3 excavated at a predetermined position of the ground GN. That is, a plurality of pile holes 3 are excavated at a predetermined position of the ground GN, and ready-made piles 10 are respectively built in the respective pile holes 3, and the pile foundation 1 is formed by these ready-made piles 10. In this embodiment, as the ready-made pile 10, a node pile in which a plurality of convex portions 12 are provided on the outer peripheral surface 10b of the distal end portion 10a is built. In addition, in the construction method which concerns on this embodiment, the ready-made pile 10 used as construction object is not limited to a node pile, It is applicable also to other ready-made piles 10 such as a straight pile.

Moreover, in order to ensure the tip support force, a root-setting part 14 is provided on the tip side of the ready-made pile 10. The root consolidation part 14 injects cement milk as a hardening material into the bottom side of the pile hole 3 and then agitates and mixes with the excavated soil to form a soil cement. The tip 10a of the ready-made pile 10 is placed in the soil cement layer. It is formed by sinking and solidifying and integrating the soil cement. In the present embodiment, the root consolidation portion 14 has an enlarged bulb shape in which the outer diameter is larger than the inner diameter of the upper portion of the pile hole 3 in order to ensure a larger tip support force. In order to form such an enlarged bulb-shaped root consolidation part 14, an enlarged excavation part 5 having an enlarged inner diameter is formed on the bottom side of the pile hole 3.

In the present embodiment, as shown in FIG. 1, the outer diameter De of the tip rooting portion 14 is substantially the same as the inner diameter De of the enlarged excavation portion 5. Then, the axial length Ld of the tip rooting portion 14 is shorter than the extended excavation portion length Lω which is the axial length of the enlarged excavation portion 5. Specifically, the axial length of the expanded excavation section length Lω is 2 m or more and 50% or less of the pile length of the ready-made pile 10 to be built in the pile hole 3, and the axial length of the tip consolidation part 14 Ld is a larger value of either 2 m or the outer diameter De of the tip root fixing portion 14. The length Ld of the root hardening part 14 may be substantially the same as the expanded excavation part length Lω.

Moreover, in order to ensure the desired tip supporting force of the ready-made pile 10, in order to form the outer diameter De of the root-solidified portion 14 with respect to the outer diameter Don of the tip portion 10a of the ready-made pile 10, that is, to form the root-solidified portion 14. It is necessary to adjust the enlargement ratio ω indicating the ratio of the inner diameter De of the enlarged excavation part 5 to be excavated. The expansion ratio ω is set to a design value based on predetermined data relating to the construction of the ready-made pile 10 such as a preliminary geological survey result, statistical data, and past construction data performed before the construction of the ready-made pile 10. However, when excavating the pile hole 3 at the actual construction site, the geological structure and soil quality of the ground GN may differ from the previous survey results, and when the ready-made pile 10 is constructed with the set value of the expansion ratio ω as it is , May cause over-spec or high-stop.

In this way, it is possible to adapt the ground strength and the bearing capacity of ready-made piles in an environment where the geological structure and soil quality of the ground GN are different from the previous survey results, or in an environment where the ground strength is difficult to predict or where the ground strength varies widely. difficult. That is, when the ready-made pile 10 is constructed, the geological condition of the ground GN is determined, and the appropriate depth L of the pile hole 3, the enlargement ratio ω of the enlarged excavation part 5, and the enlarged excavation part length Lω are optimized. There is a need.

In particular, the enlargement ratio ω of the enlarged excavation portion 5 is a value that determines the outer diameter De of the root consolidation portion 14, and when the error between the design value and the actual measurement value is large, so-called over-spec is obtained, and the material, etc. This is not preferable in terms of cost and construction work efficiency. That is, in order to secure the desired tip support force of the ready-made pile 10, the length Ld of the root-solidifying portion 14 can be adjusted as appropriate by adjusting the amount of cement milk that becomes a hardening agent.

However, since the outer diameter De of the root consolidation part 14 is directly determined by the inner diameter De of the excavation part 5, it is difficult to adjust the enlarged excavation part 5 after excavation. In other words, it is extremely important to obtain the optimum value of the enlargement ratio ω of the enlarged excavation part 5 in order to ensure the desired tip support force of the ready-made pile 10 without over-spec. Further, in order to obtain the optimum value of the enlargement ratio ω, it is important to efficiently obtain the optimum value based on the result of the loading test on the ground GN that is the actual site.

For this reason, in this embodiment, the construction method of the ready-made pile 10 by the construction system 100 (refer FIG. 2) demonstrated below is implemented, the optimal value of expansion ratio (omega) is calculated | required more efficiently and reliably, and an overspec is carried out. It is reduced. In addition, it is possible to suppress over-spec and high stop when building the ready-made pile 10 on the ground GN, to reduce the cost when constructing the pile foundation 1 made of the ready-made pile 10 and to improve the construction work efficiency. I have to.

Further, in the present embodiment, the expansion ratio ω of the root consolidation portion 14, that is, the expansion ratio ω of the expansion excavation portion 5, is set to a desired value for the inner diameter De of the expansion excavation portion 5 and the outer diameter Don of the convex portion 12 of the ready-made pile 10. The outer diameter design value Ds (Ds = Don + x) obtained by adding the clearance value x is defined by the following equation (1).
ω = De / Ds (1)

In the present embodiment, the enlargement ratio ω is set in the range of 1.0 to 2.0, for example, but the upper limit value of the enlargement ratio ω is not limited to 2.0. Further, in the present embodiment, in order to obtain a more suitable enlargement ratio ω of the enlarged excavation part 5 in consideration of design errors of the ready-made pile 10, the pile hole 3, and the enlarged excavation part 5, the above formula (1) For the denominator, not the value of the outer diameter Don of the tip 10a of the ready-made pile 10, but the outer diameter design value Ds obtained by adding the desired clearance value x as an adjustment value to the outer diameter Don is used.

The clearance value x is appropriately determined on the basis of N data indicating the strength of the ground on which the ready-made pile 10 is constructed, past construction data, soil data, and other predetermined data relating to construction. For example, when the outer diameter Don of the tip portion 10a of the ready-made pile 10 is 1.0 m, the clearance value x is 0.05 m to 0.1 m. The clearance value x may be 0 depending on the N value or the like. The clearance value is 0.2 m at the maximum. Furthermore, in this embodiment, as shown in FIG. 1, since the joint pile is used as the ready-made pile 10, the outer diameter of the convex portion 12 is used as the outer diameter Don of the ready-made pile 10. When the pile 10 is a straight pile, the outer diameter of the shaft portion of the straight pile is used.

Next, the configuration of the ready-made pile construction system according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a block diagram showing the overall configuration of a ready-made pile construction system according to an embodiment of the present invention.

As shown in FIG. 2, the construction system 100 of the ready-made pile 10 according to the present embodiment accesses a database server having a database in which the computer 101 owned by the user stores predetermined data related to the construction of the ready-made pile 10. While performing the search process, the optimum value of the enlargement ratio ω of the enlarged excavation section 5 is obtained. In the present specification, “user” refers to a person who designs or constructs the ready-made pile 10. The “computer” refers to an information terminal device including an arithmetic device capable of various arithmetic processes such as a super computer, a general-purpose computer, an office computer, a control computer, a personal computer, and a portable information terminal.

The construction system 100 according to the present embodiment is used when the ready-made pile 10 is built in the pile hole 3 in which the enlarged excavation portion 5 having an enlarged inner diameter is formed on the bottom side, and the computer 101, the design support force measuring device 128, And a drilling device 130. The construction system 100 calculates the optimum enlargement ratio ω with the computer 101 based on the measurement data of the design support force measuring device 128 and the like, and has the enlarged excavation unit 5 with the excavator 130 based on the enlargement ratio ω. The pile hole 3 is excavated. In addition, the structure of the construction system 100 is not limited to FIG. 2, A various deformation | transformation implementation, such as abbreviate | omitting a part of the component or adding another component, is possible.

As shown in FIG. 2, the computer 101 includes a storage unit 102, a CPU (Central Processing Unit) 110, an input unit 120, an output unit 122, a communication unit 124, a ROM (Read Only Memory) 108, and a RAM (Random access Memory) 106. , And a storage medium 104, and these components are electrically connected to each other via a system bus 125. Therefore, the CPU 110 accesses the storage unit 102, ROM 108, RAM 106, and storage medium 104, grasps the operation state of the input unit 120, outputs data to the output unit 122, and transmits / receives various information to / from the Internet 126 via the communication unit 124. Etc.

The storage unit 102 is a data server having a function of storing at least predetermined data related to the construction of the ready-made pile 10. In the present embodiment, the storage unit 102 includes, as the predetermined data, at least soil data of the ground GN in which the ready-made pile 10 is built, pile materials, construction specifications, and measurement data obtained by performing a load test using the design support force measuring device 128. And the past construction results data of the ready-made pile 10 are stored as a database.

Based on the predetermined data relating to the construction of such ready-made piles, by setting the optimum expansion ratio ω of the expanded excavation part 5, it becomes more geological data including the geological structure information, soil information, etc. in the actual ground GN The enlarged excavation section 5 can be formed with a suitable optimum enlargement ratio ω based on the above. In addition, by accumulating these data in the storage unit 102, when the ready-made pile 10 is built in another construction site, the expansion ratio of the expanded excavation unit 5 is utilized using the accumulated data stored in the storage unit 102. The optimum values of ω and the expanded excavation length Lω can be obtained with higher accuracy.

The CPU 110 has a function of controlling the operation of each component included in the construction system 100 in accordance with data received via the communication unit 124 and various programs stored in the ROM 108 and the storage medium 104. In addition, the CPU 110 has a function of appropriately storing necessary data and the like in the RAM 106 that temporarily stores these various processes.

In the present embodiment, the CPU 110 performs arithmetic processing by a computer based on predetermined data relating to the construction of the ready-made pile 10 and performs various arithmetic processes necessary for obtaining the expansion ratio ω of the expanded excavation section 5. Function as. That is, the CPU 110 performs calculation processing by the computer 101 based on at least the predetermined data, and adds the desired clearance value x to the outer diameter Don of the tip portion 10a of the ready-made pile 10 with respect to the outer diameter design value Ds. It has a function of obtaining an enlargement ratio ω indicating the ratio of the inner diameter De of the enlarged excavation part 5.

In the present embodiment, the CPU 110 includes a setting unit 112, a determination unit 114, and a determination unit 116. In the present specification, “predetermined data” related to the construction of the ready-made pile 10 is at least soil data of the ground GN in which the ready-made pile 10 is built, measurement data of a loading test by the design bearing capacity measuring device 128, And various data such as past construction performance data of the ready-made pile 10. That is, the “predetermined data” means that in the process of constructing the ready-made pile 10, when excavating the pile hole 3 having the enlarged excavation part 5, the optimum expansion ratio ω and the enlarged excavation part length Lω of the enlarged excavation part 5 It refers to various data necessary to determine the values ωopt and Lωopt, and is also used to determine the pile type.

In the process of constructing the ready-made pile 10 in the construction system 100, the setting unit 112 is based on predetermined data relating to the construction of the ready-made pile 10, and the design load (column load) P of the ready-made pile 10 and the design support force of the pile. R, the expansion ratio ω of the expanded excavation section 5, the function of calculating various data that requires setting such as the expanded excavation section length Lω. In the present embodiment, the setting unit 112 has a function of setting a plurality of expansion ratios ω of the expanded excavation unit 5 with different values based on at least predetermined data relating to the construction of the ready-made pile 10. Moreover, in this embodiment, it has a function which sets multiple expansion excavation part length Lomega corresponding to expansion ratio (omega).

The determination unit 114 has a function of determining the validity of various data set based on predetermined data related to the construction of the ready-made pile 10 in the process of constructing the ready-made pile 10 with the construction system 100. In the present embodiment, the determination unit 114 determines that the product of at least the design support force R measured by the design support force measuring device 128 and the design support force R and the number of ready-made piles 10 to be used is the ready-made pile. 10 has a function of determining whether or not a desired design load (column load) P that is applied to the pile foundation 1 formed by 10 or more.

The determination unit 116 has a function of determining optimum values of various data set based on predetermined data relating to the construction of the ready-made pile 10 based on the determination result in the determination unit 114. In the present embodiment, the determination unit 116 is the smallest among the enlargement ratios ω that satisfy the condition that the product of the design support force R and the number J of the ready-made piles 10 is at least the design load (column load) P in the determination unit 114. Has the function of determining the optimum enlargement ratio ωopt for forming the enlarged excavation part 5. Moreover, in this embodiment, it has the function to determine also the optimal expansion excavation part length Lωopt corresponding to the optimal expansion ratio ωopt.

The input unit 120 has a function of inputting various data such as predetermined data related to the construction of the ready-made pile 10, and for example, a mouse, a keyboard, a touch panel, or the like is used. In the present embodiment, the input unit 120 performs, for example, character input when operating the setting unit 112, the determination unit 114, and the determination unit 116 and input of measurement data of the design support force measuring device 128. Further, in the present embodiment, the input unit 120 is necessary when obtaining the optimum values ωopt and Lωopt of the enlarged excavation part 5 and the enlarged excavation part length Lω based on at least predetermined data relating to the construction of the ready-made pile 10. It is also used when inputting various data. That is, the input unit 120 is used when inputting various data stored in the storage unit 102 or when inputting various data for obtaining the optimum values ωopt and Lωopt of the enlargement ratio ω and the enlarged excavation part length Lω. .

The output unit 122 has a function of outputting a calculation result by the CPU 110, information of the storage unit 102 serving as a database, and the like. For example, a display monitor or the like is used as the output unit 122. In the present embodiment, the output unit 122 performs screen display when the setting unit 112, the determination unit 114, and the determination unit 116 are operated, for example.

The storage medium 104 is a medium readable by the computer 101 and has a function of storing programs, data, and the like. The function of the storage medium 104 can be realized by various memories such as an optical disk (CD, DVD), HDD, or USB. In the storage medium 104, a program for realizing the function of each component of the construction system 100 according to the present embodiment is stored so as to be readable by the computer 101. For this reason, according to the said program, each process in the construction method of the ready-made pile 10 which concerns on this embodiment comes to be performed by implement | achieving the function of each component of the said construction system 100. FIG. In addition, the detail of the construction method of the ready-made pile 10 which concerns on this embodiment performed by the said program is mentioned later.

The design bearing capacity measuring device 128 performs a loading test after constructing a test pile 10 '(hereinafter referred to as a test pile 10') in a test pile hole 3 'formed in the ground GN in which the ready-made pile 10 is built. And has the function of measuring the ultimate bearing capacity of the test pile 10 '. In the present embodiment, the design support force measuring device 128 performs a loading test for each case of one or a plurality of magnification ratios ω selected from the plurality of magnification ratios ω set by the setting unit 112, and The ultimate bearing capacity of the ready-made pile 10 at one or a plurality of enlargement ratios ω is measured.

Specifically, the design support force measuring device 128 performs a loading test of the test pile 10 ′ corresponding to the case of one or a plurality of enlargement ratios ω selected from the plurality of enlargement ratios ω set by the setting unit 112. Implement and measure the ultimate bearing capacity of the test pile 10 '. Further, the design bearing capacity measuring device 128 is a ground for constructing the ready-made pile 10 when the test pile hole 3 'is drilled before the ready-made pile 10 is constructed in the process of measuring the ultimate bearing capacity of the test pile 10'. It is also used to check GN geological data and N value. The design support force measuring device 128 may be referred to as a loading test device.

The excavator 130 has a function of excavating a pile hole 3 having a desired diameter and depth in the ground GN. As the excavator 130, an earth auger or the like provided with a excavating rod 131 provided with a screw-like excavating blade 132 around it and a movable excavating portion 134 that can be expanded in the outer diameter direction on the distal end side of the excavating rod 131 is used. The In this embodiment, when excavating the pile hole 3 with the excavator 130, the optimum enlargement ratio ωopt of the enlarged excavation unit 5 determined by the determination unit 116 of the CPU 110 and the optimum enlarged excavation part length Lωopt of the enlarged excavation unit 5 are used. Thus, the enlarged excavation part 5 is formed.

As described above, according to the construction system 100 of the present embodiment, the optimum enlargement ratio ωopt of the enlarged excavation part 5 formed on the bottom side of the pile hole 3 can be set by the loading test as few times as possible. For this reason, in the process of constructing the ready-made pile 10, the overspec and high stop at the time of forming the expansion excavation part 5 can be reduced efficiently and economically. Also, after setting a plurality of enlargement ratios ω, do not unnecessarily increase the number of loading tests performed when determining the optimum value ωopt from among these enlargement ratios ω, that is, with fewer loading tests. The optimum value ωopt can be determined. For this reason, the labor, time, and cost cost in constructing the ready-made pile 10 can be reduced by reducing the number of loading tests that require a large burden both in terms of time and cost. Economical ready-made pile 10 can be designed and constructed.

Next, the outline of the construction method of the ready-made pile which concerns on one Embodiment of this invention is demonstrated, using drawing. FIG. 3 is a flowchart showing an outline of a method for constructing a ready-made pile according to an embodiment of the present invention.

As shown in FIG. 3, the construction method of the ready-made pile 10 which concerns on this embodiment is the construction method of the ready-made pile 10 which builds the ready-made pile 10 in the pile hole 3 in which the expanded excavation part 5 which expanded the internal diameter was formed in the bottom part side. In the process, the main focus is on obtaining a more suitable optimum enlargement ratio ωopt of the enlarged excavation section 5 based on the measurement result of the loading test in particular.

First, a design load (column load) P is set (step S10). The design load (column load) P is set based on the weight of the building built on the pile foundation 1, the upper load, and the like. Next, the design support force R and the pile number J of the ready-made pile 10 are set (step S11). The design support force R and the number J of piles of the ready-made pile 10 are set so as to satisfy the following conditional expression (2).
Number of piles J x Design capacity of pile R ≥ Margin M x Design load (column load) P ... (2)

The design support force R of the pile is calculated from the following equation (3), for example.
Design bearing capacity R = 1 / μ × {αNaAp + (β · Ns · Ls + γ · q _u · Lc) · Φ} (3)
In the above formula (3), μ is the safety factor, α is the pile tip bearing capacity coefficient, Na is the average value of the N value at the tip of the pile, Ap is the pile tip area, β is the pile circumference in sandy and gravelly ground. Coefficient of surface friction, Ns is the average value of N of sandy ground around the pile, Ls is the total length of the ground around the pile that touches the sandy and gravelly ground, and γ is in the clayey ground The coefficient of frictional force around the pile surface, q _u is the average uniaxial compressive strength of the clay ground out of the ground around the pile, Lc is the total length of the ground around the pile that touches the clay ground, and Φ is the pile Indicates the circumference. In addition, the design support force R of the pile calculated from the above formula (3) is hereinafter referred to as a calculated value of the design support force R.

In addition, the calculated value of pile design bearing capacity R and the number of piles J are approximately the same as the design load (column load) P, and the optimum combination of the calculated value of design bearing capacity R per pile and the number of piles J Set as follows. Basically, the calculated value of design bearing capacity R of piles and the number of piles J are set so as to reduce the number of piles J, but the most effective (economic) number of piles J for each column in comparison with the cost etc. And set the calculated value of design bearing capacity R of pile. The margin M indicating the margin is determined by design conditions and the like, but is usually a value of 1 or more, and generally a value of about 1.1 is used, but is limited to M = 1.1. Is not to be done.

Below, an example of each value constituting the right side of Equation (3) is shown. In addition, the value shown below is an example and is not limited to this value.

The safety factor μ is a value determined as appropriate based on design conditions and the like, and is 2, 2.5, or 3, for example.

The pile tip bearing capacity coefficient α is calculated from, for example, the following formula (4) in the case of sandy ground and gravelly ground.
α = 240ω ^1.5 + 90ω …… (4)
Here, ω is an enlargement ratio.

Moreover, in the case of a clayey ground, it calculates from the formula (5) shown below, for example.
α = 210ω ^1.25 + 90ω …… (5)

The average value Na of the N values at the pile tip is calculated from the following formula (6) when the pile tip ground is sandy ground or gravelly ground.
Na = (Nu + 3N _L ) / 4 (6)
However, Na is 3 or more, and Na> 60 when Na> 60. Here, Nu is an average value of the N value from the tip of the pile to the position of 2 m upward, and _NL is an average value of the N value from the tip of the pile to the position of (De + Don) downward.

On the other hand, the average value Na of the pile tip is calculated from the following formula (7) when the pile tip ground is clayey ground.
Na = (Nu + 2N _L ) / 3 (7)
However, when Na> 58.3, Na is set to 58.3.

The pile tip area Ap is calculated from Ap = π · (Don / 2) ² .

The pile peripheral friction coefficient β in sandy / gravel ground is β = 5-8 in the straight part of the pile. Moreover, it is a value which satisfy | fills (beta) = 9.5 (omega) and (beta) * Ns = (30 + 5.5Ns) * (omega) in the node part of a pile.

Of the ground around the pile, the average value Ns of sandy ground is 1 or more, and Ns> 30 when Ns> 30. On the other hand, of the ground around the pile, the total length Ls in contact with the sandy / gravel ground is calculated excluding the distance from the tip of the pile to a position of 2 m.

The pile peripheral surface frictional force coefficient γ in the clayey ground is β = 0.7 to 9.0 in the straight portion of the pile. Further, a value satisfying γ = 1.0ω and _{γ · q u = (20 +} 0.5q u) · ω in the section portion of the pile.

Of the ground around the pile, the average value q _u of the uniaxial compressive strength of the clay-based ground is 10 kN / m ² or more, and when q _u > 200 kN / m ² , q _u is 200 kN / m ² . Of the ground around the pile, the total length Lc in contact with the clay-based ground is calculated by excluding the distance from the tip of the pile to a position of 2 m.

周 Pile circumference Φ is calculated as Φ = π · D. Here, D is a pile diameter (m). In the case of joint piles, the diameter is the node diameter.

In addition, the safety factor μ, the pile tip bearing force coefficient α, the pile peripheral surface friction force coefficient β, γ, etc. in the equation (3) are appropriately set according to the field conditions such as geology.

After step S11 is finished, next, in order to determine the calculated value of the expansion ratio ω of the expanded excavation part 5, various data relating to the ready-made pile 10 are examined and adjusted (step S12). In this process S12, as various data concerning the ready-made pile 10 to be examined, the pile length L, the pile diameter D (node diameter Don in this embodiment), the PHC pile, and the RC pile are specifically constructed. , PRC piles, steel piles, SC piles, node piles, and other types of piles, enlargement ratio ω of the enlarged excavation part 5 for forming the tip consolidation part 14, and an enlarged excavation part length Lω. As shown in Equation (1) described above, in this embodiment, the expansion ratio ω is relative to the outer diameter design value Ds obtained by adding the desired clearance value x to the outer diameter Don of the tip portion 10a of the ready-made pile 10. The ratio of the internal diameter De of the expansion excavation part 5 is shown.

Generally, when the pile length L is increased, the pile diameter D is increased, the enlargement ratio ω is increased, and the expanded excavation section length Lω is increased, the supporting force of the ready-made pile 10 is increased. When the supporting force of the ready-made pile 10 is increased, it is necessary to increase the material strength by increasing the concrete strength of the ready-made pile 10 or increasing the plate thickness of the steel pipe. Also, construction equipment such as a hydraulic expansion device is required during construction. For this reason, the specifications of construction equipment increase and the cost increases.

In addition, although this embodiment demonstrated the case where process S12 was implemented after process S11, you may implement process S11 and process S12 simultaneously. That is, the pile length L, the pile diameter D, the pile type, the enlargement ratio ω, and the enlarged excavation length Lω may be set at the same time as the number of piles J and the calculated design support force R of the piles are set.

The design value expansion ratio ωd and the expanded excavation section length Lωd are set based on various data relating to the ready-made pile 10 adjusted in step S12 (setting step S13). After that, enlargement ratio ωc (ωc <ωd) that prioritizes cost by reducing the enlargement ratio relative to the design value enlargement ratio ωd, and enlargement that emphasizes safety by increasing the enlargement ratio relative to the design value enlargement ratio ωd The ratio ωs (ωs> ωd) is set (setting step S14). In the present embodiment, in step S14, the expanded excavation section length Lωc (Lωc <Lωd) in which the expanded excavation section length is shortened and the cost is prioritized with respect to the expanded excavation section length Lωd and the expanded excavation section length Lωd is expanded. The extended excavation section length Lωs (Lωs> Lωd) that places importance on safety is set.

In addition, the design value expansion ratio ωd and the expanded excavation section length Lωd of the expanded excavation section 5 are set based on data based on the ground columnar diagram created by the ground survey, construction results, past accumulated data, and the like. Further, the enlargement ratio ωc giving priority to cost and the enlargement ratio ωs giving priority to safety are calculated and set from the following expressions (8) and (9), respectively.
ωc = ωd−σ (8)
ωs = ωd + σ (9)
Here, σ is a deviation, for example, 0.1 to 0.3. The said deviation is set based on the data by the ground columnar figure created by the ground survey, construction results, past accumulated data, and the like.

In the present embodiment, in the setting steps S13 and S14, a plurality of enlargement ratios ω of the enlarged excavation part 5 are set with different values based on predetermined data relating to the construction of the ready-made pile 10. Specifically, the design value expansion ratio ωd set based on at least predetermined data, the cost priority expansion ratio ωc that is smaller than the design value expansion ratio ωd, and the safety priority that is greater than the design value expansion ratio ωd Set the magnification ratio ωs. Further, for each case of the expansion ratios ωd, ωc, and ωs, the expanded excavation section lengths Lωd, Lωc, and Lωs are set, respectively.

In the present embodiment, the enlargement ratio ω and the enlarged excavation part Lω are each set in three ways. However, in order to examine the validity of the design values of the enlargement ratio ω and the enlarged excavation part length Lω, at least two kinds are set. It is sufficient if the above is set, and when the validity of the design value is further examined, four or more patterns may be provided. In this embodiment, the expansion ratio ω and the expanded excavation length Lω are each set in three ways. However, since it is necessary to examine at least the validity of the expansion ratio ω, only a plurality of expansion ratios ω are provided. It may be.

As described above, in the present embodiment, in the setting steps S13 and S14, the design value magnification ratio ωd, the magnification ratio ωc smaller than the design value magnification ratio ωd, and the magnification ratio ωs larger than the design value magnification ratio ωd are set. ing. For this reason, even if there is a difference between the design value enlargement ratio ωd obtained by calculation in advance and the enlargement ratio ω obtained based on the actual measurement value measured in the loading test, the validity of the design value enlargement ratio ωd is confirmed. The final optimum enlargement ratio ωopt can be determined after further examination. In addition, by obtaining the expanded excavation lengths Lωd, Lωc, and Lωs corresponding to the respective cases of the respective expansion ratios ωd, ωc, and ωs, the validity of the design values including the expanded excavation length Lω is scrutinized and finally The size of the enlarged excavation part 5 can be ensured.

When the setting steps S13 and S14 are completed, the test pile 10 'is then constructed (test pile construction step S15). The construction of the test pile 10 ′ is performed in the vicinity of the ground GN where the ready-made pile 10 is actually built. In the test pile construction process S15, there are cases where the test piles 10 'corresponding to the respective enlargement ratios ωd, ωc, and ωs are all enforced and separately as necessary. Details of the test pile construction step S15 will be described later.

Next, a loading test is performed for each of the cases having one or more enlargement ratios selected from the plurality of enlargement ratios ωd, ωc, and ωs, and the design support of the ready-made pile 10 at the one or more enlargement ratios ω is performed. Each of the forces R is measured (design support force measurement step S16). In this embodiment, in order to closely examine the validity of the design value, the enlargement ratio ω and the enlarged excavation part Lω are set in three ways, respectively. The cost is also heavy. For this reason, in the construction method of the ready-made pile 10 which concerns on this embodiment, in order to suppress a loading test by the minimum number of times required, the procedure which performs a loading test is elaborated. The details of the design support force measurement step S16 will be described later.

When the design support force measurement step S16 is completed, the design support force R is measured for each Rωi (Rωi is at least one of Rωd, Rωc, and Rωs) measured in the design support force measurement step S16. The product of the supporting force Rωi and the number of ready-made piles 10 to be used is obtained. Then, it is determined whether or not the product is greater than or equal to a desired design load (column load) P acting on the pile foundation 1 formed by the ready-made pile 10 (design support force determination step S17). In the present embodiment, it is determined whether or not the design support force Rωi satisfies the following conditional expression (10) for the case of the enlargement ratio ω for which the loading test has been performed.
Number of piles J x design bearing force Rωi ≥ margin M x design load (column load) P ... (10)

Next, in the design support force determination step S17, an expansion ratio that satisfies the condition that the product of the design support force Rωi and the number of ready-made piles 10 to be used is equal to or greater than the product of the margin M and the design load (column load) P Among ωd, ωc, and ωs, the minimum expansion ratio ωi is determined as the optimal expansion ratio ωopt for forming the expanded excavation portion 5 (optimal expansion ratio determination step S18). In the present embodiment, in the optimum enlargement ratio determination step S18, optimum values ωopt and Lωopt of the enlarged excavation section length Lω corresponding to the enlargement ratio ω and the enlargement ratio ω are determined. Then, in the process of excavating the pile hole 3, the enlarged excavation part 5 is formed based on the optimum enlargement ratio ωopt and the optimum enlarged excavation part length Lωopt (enlarged excavation part forming step S19). After that, various processes for building and constructing the ready-made pile 10 in the excavated pile hole 3 are performed.

Thus, in the construction method of the present embodiment, the optimum enlargement ratio ωopt of the enlarged excavation part 5 formed on the bottom side of the pile hole 3 can be set with as few loading tests as possible. And the overspec at the time of forming the expanded excavation part 5 can be reduced, reducing cost. Moreover, in the construction method of this embodiment, since the high stop of the ready-made pile 10 can be prevented reliably, it can construct reliably in a design depth position. Furthermore, the pile support capacity can be set according to the type of pile, pile diameter, pile length, expansion ratio of the tip consolidation part, enlarged excavation part length of the tip consolidation part, etc. according to the ground strength. The optimal and economical design and construction can be performed.

In addition, in setting process S14, it can also set by the method (A) thru | or (C) described below as a method of setting expansion ratio (omega) c and (omega) s based on the predetermined data etc. which concern on construction of a ready-made pile. .

(Setting by method (A))
Based on the ultimate bearing capacity of the pile, the following procedure is used. This procedure will be described with reference to Table 1 below.

First, as shown in Table 1, the design value expansion ratio ωd (ωd = 1.3 in Table 1), the expanded excavation section length Lωd, as shown in Table 1, by the cost comparison of the pile setting as described above based on the geological conditions, load conditions, etc. (Lωd = 10 m), safety factor μ _d (μ _d = 2.5) and design support force Rωd (calculated value) (Rωd = 3600 kN) are set. At this time, the safety factor μ is set based on the magnification with respect to the design support force to be confirmed in the loading test, past performance data, and the like. In the case of Table 1, it is assumed that 2.5 times the design support force is confirmed in the loading test.

Next, the set design support force Rωd (calculated value) and the safety factor μ _d (= 2.5) are substituted into the following equation (11) to calculate the ultimate support force Ru _d (Ru _d = 9000 kN). To do.
Ru _d = Rωd (calculated value) × μ _d (11)

Next, safety factors μ _c and μ _s (μ _c = 2 and μ _s = 3) corresponding to the cases of the enlargement ratios ωc and ωs are set. Note that the safety factors μ _c = 2 and μ _s = 3 are applied only when setting the enlargement ratios ωc and ωs, and other specifications of the pile, such as the design bearing force R (calculated value), etc. It does not apply when setting. That is, other specifications of the pile are calculated with a safety factor μ = 2.5.

Subsequently, the design support force Rωd (calculated value) and the safety factors μ _c and μ _s calculated above are substituted into the following expressions (12) and (13), respectively, and the ultimate support forces Ru _c and Ru are obtained. _{_{s (Ru c = 7200kN, Ru}} s = 10800kN) is calculated.
Ru _c = Rωd (calculated value) × μ _c (12)
Ru _s = Rωd (calculated value) × μ _s (13)

The pile of specifications (pile diameter, pile length, etc.) without changing the expansion ratio .omega.c satisfying ultimate bearing capacity _{_{Ru c (Ru c = 7200kN)}} (ωc = 1.1) and enlargement Division Lωc (Lωc = 8m ) Is calculated.

Further, similarly to the ultimate support force Ru _c , the enlargement ratio ωs (ωs = 1.5) and the enlarged excavation section length Lωs (Lωs = 9 m) satisfying the ultimate support force Ru _s (R _s = 10800 kN) are calculated.

(Setting by method (B))
It is set based on the relationship between the design support force R (calculated value) of the pile calculated from the above-described equation (3) and the design support force R of the pile measured by the loading test. In addition, the design support force R of the pile measured by the loading test is hereinafter referred to as the design support force R (measured value).

FIG. 4 is a diagram showing the relationship between the design support force R (calculated value) and the design support force R (measured value) of the pile. 4 is a straight line when the design support force R (calculated value) and the design support force R (measured value) have a one-to-one relationship (in the legend in the figure, Rac = Rat). It is.

As shown in FIG. 4, the design support force R (measured value) of the pile is greater than the design support force R (calculated value). A correlation is confirmed between the design support force R (measured value) and the design support force R (calculated value). In the present embodiment, an average value (a dotted line in FIG. 4) of a ratio (measured value / calculated value) of each design support force R (measured value) to a plurality of design support forces R (calculated values) is, for example, about 1. It has doubled.

Investigate and set the expansion ratio ωc that gives priority to cost over the average value and average value -1.06σ. For example, when the average value of 1.2 is adopted, when the calculated value of the ultimate support force based on the design value enlargement ratio ωd is 6000 kN, the ultimate support force becomes 5000 kN by dividing 6000 kN by the value 1.2. Set the ratio ωc.

Also, the enlargement ratio ωs is set from the same value or the lowest value depending on the actual performance that is below the design support R (measured value). For example, the ratio (measured value / calculated value) of the data of the design support force R (measured value) below the design support force R (calculated value) to the design support force R (calculated value) is 0.95. If the calculated value of the ultimate bearing force Rud based on the design value magnification ratio ωd is 6000 kN, for example, by dividing the calculated value 6000 kN of the ultimate bearing force Rud by 0.95, An enlargement ratio ωs is set to 6320 kN.

(Setting by method (c))
Set based on past tip support force data using a ground column diagram or the like. That is, when the tip bearing capacity of a pile can be evaluated based on the data of the past loading test, it sets based on the data.

Next, the details of the method for constructing a pre-made pile by the pre-made pile construction system of this embodiment will be described with reference to the drawings. FIG. 5 is a flowchart showing details of a method for constructing a ready-made pile according to an embodiment of the present invention. In FIG. 5, in particular, after passing through the setting steps S13 and S14 of the enlargement ratio ω, setting up the test pile, measuring the design support force, determining the appropriateness of the design support force, and determining the optimum enlargement ratio A simple flow will be described.

As shown in FIG. 5, first, the test pile 10 'is constructed in the vicinity of the ground GN where the ready-made pile 10 is actually built (test pile construction step S15). In the present embodiment, all the test piles 10 'corresponding to the respective enlargement ratios ωd, ωc, and ωs are executed.

Next, among the test piles 10 ′ corresponding to the respective expansion ratios ωd, ωc, and ωs, a loading test is performed on the test pile 10 ′ corresponding to the design value expansion ratio ωd (step S16-1). That is, in this embodiment, in order to give the highest priority to the validity of the design value enlargement ratio ωd, a loading test is performed from the case of the design value enlargement ratio ωd, and the design support force corresponding to the design value enlargement ratio ωd Rωd is measured.

After measuring the design support force Rωd, the process proceeds to the design support force determination step S17-1, and the product of the design support force Rωd measured based on the design value expansion ratio ωd and the number J of ready-made piles 10 is It is determined whether or not the desired design load (column load) P acting on the pile foundation 1 formed by the ready-made pile 10 and the margin M are greater than or equal to each other. That is, it is examined whether or not the conditional expression (10) described above is satisfied.

If the product of the design support force Rωd and the number of ready-made piles 10 is equal to or greater than the product of the margin M and the design load (column load) P in the design support force determination step S17-1, then the design support force The predicted design support force Rωc ′ is estimated based on the design support force Rωd measured in the measurement step S16-1 (predicted design support force estimation step S17-1a). The predicted design bearing force Rωc ′ was measured by the ultimate bearing force Ru _d (calculated value) and Ru _c (calculated value) calculated for each case of the set design value magnification ratio ωd and magnification ratio ωc, respectively, and a load test. It is estimated from the ratio with the ultimate support force Ru _d (measured value) calculated based on the design support force Rωd (measured value).

Specifically, it estimates using the formula (14) shown below.
Rωc ′ = Ru _d (measured value) / (Ru _d (calculated value) / Ru _c (calculated value)) (14)

When the influence of the enlargement ratio ω is 2/3 of the ultimate support force, it is estimated using the following formula (15).
Rωc ′ = {Ru _d (measured value) −Ru _d (calculated value)} × 2/3 + R _c (calculated value) (15)

In this way, it is possible to reliably set a more suitable optimum enlargement ratio ωopt after further examining the validity of the design value enlargement ratio ωd set in the setting step S13.

The method for estimating the predicted design support force Rωc ′ from the above-described equation (14) or equation (15) will be specifically described with reference to Table 1 and Table 2 described above.

As shown in Table 1, the safety factor μd in the case of the enlargement ratio ωd = 1.3 is set to 2.5, and the safety factor μc in the case of the enlargement ratio ωc = 1.1 is set to 2. Subsequently, the respective enlargement ratios ωd and ωc and the safety factors μd and μc are substituted into the above-described equations (11) and (12), respectively, and the ultimate bearing forces Ru _d (calculated values) and Ru _c (calculated values) are obtained. calculate. (Specifically, the ultimate bearing force Ru _d (calculated value) = 9000 kN, the ultimate bearing force Ru _c (calculated value) = 7200 kN)

Next, as shown in Table 2, the ultimate support force Ru _d (measured value) = 11500 kN is calculated based on the design support force R (measured value) measured by the loading test. Then, the predicted design support force Rωc ′ is calculated by substituting the calculated ultimate support force Ru _d (calculated value), Ru _c (calculated value) and the ultimate support force Ru _d (measured value) into the above-described equation (14). To do. In this way, the predicted design support force Rωc ′ is estimated and obtained based on the design support force Rωd measured in the design support force measurement step S16-1.

That is, in the predicted design support force estimation step S17-1a, the design support force Rωd (calculated value) is compared with the actual design support force Rωd (measured value), and the correction value of the design support force Rωd (calculated value) is calculated. The difference which shows the shift | offset | difference degree with the said calculated value used as a candidate is grasped. Then, the predicted design support force Rωc ′ is estimated by correcting the design support force Rωc (calculated value) by the difference.

As shown in FIG. 5, after estimating the predicted design support force Rωc ′, it is examined whether or not the condition that the predicted design support force Rωc ′ is greater than the design support force Rωd (calculated value) is satisfied (predicted design support). Force determination step S17-1b).

If the predicted design support force Rωc ′ is larger than the design support force Rωd (calculated value) in the predicted design support force determination step 17-1b, then a loading test is performed for the case of the cost priority expansion ratio ωc (step S16). -2). In this loading test, the design support force Rωc (measured value) corresponding to the cost priority enlargement ratio ωc is measured.

Next, it is determined whether or not the product of the number of piles J and the design support force Rωc (measured value) is equal to or greater than the product of the margin M and the design load (column load) P (step S17-2). In step S17-2, when the product of the number of piles J and the design support force Rωc (measured value) satisfies a condition equal to or greater than the product of the margin M and the design load (column load) P, the cost priority enlargement ratio ωc Is determined as the optimum enlargement ratio ωopt (step S18-1). In step S18-1, the optimum enlargement ratio ωopt is determined, and at the same time, the enlarged excavation length Lωc determined in step S14 corresponding to the enlargement ratio ωc is decided as the optimum enlargement portion length Lωopt.

Then, the process proceeds to step S19, and the pile construction is performed based on the case of the optimum enlargement ratio ωopt and the optimum enlarged excavation section length Lωopt determined in step S18-1. Thereby, construction cost can be reduced rather than implementing this pile construction based on the case of design value expansion ratio omegad.

On the other hand, if the product of the number of piles J and the design support force Rωc (measured value) is smaller than the product of the margin M and the design load (column load) P as a result of the examination in step S17-2, the design value The expansion ratio ωd is determined to be the optimal expansion ratio ωopt, and the expanded excavation section length Lωd corresponding to the design value expansion ratio ωd is determined to be the optimal expansion section length Lωopt (step 18-2). And it transfers to process S19 and implements this pile construction based on the case of optimal expansion ratio omegaopt and optimal expansion excavation part length Lomegaopt.

Further, as a result of the examination in the predicted design support force determination step S17-1b, when the predicted design support force Rωc ′ is smaller than the design support force Rωd (calculated value), the design value enlargement ratio ωd is determined as the optimum enlargement ratio ωopt. Then, the extended excavation section length Lωd corresponding to the design value expansion ratio ωd is determined as the optimum expansion section length Lωopt (step 18-2). And it transfers to process S19 and implements this pile construction based on the case of optimal expansion ratio omegaopt and optimal expansion excavation part length Lomegaopt.

Therefore, in this case, it is not necessary to carry out the loading test for the case of the enlargement ratio ωc giving priority to cost. Since the loading test requires a lot of time and cost, it is preferable to perform the loading test as few times as possible. For this reason, it is desirable to avoid performing the loading test in step S16-2 when the predicted design supporting force determination step S17-1b shifts to step S18-2. Specifically, the product of the number of piles J and the design support force Rωc (measured value) is the product of the margin M and the design load (column load) P in step S17-2 despite the execution of step S16-2. In the end, it is desirable to avoid the formation of an enlarged excavation part with the design value enlargement ratio ωd in Steps S18-2 and S19, that is, the waste of the loading test at the enlargement ratio ωc.

As described above, in the present embodiment, by estimating the predicted design support force Rωc ′, in step S17-2, the product of the number of piles J and the design support force Rωc (measured value) becomes the margin M and the design load (column The probability that it is equal to or higher than the product of the load (P) can be remarkably improved. As a result, it is possible to omit a loading test for a case with a wasteful enlargement ratio ωc, so that it is possible to shorten the construction period and further reduce the cost.

In addition to this, in the present embodiment, in order to form the enlarged excavation portion 5 that does not become over-spec based on the calculated value of the design support force R based on the enlargement ratio ω and the measurement result of the actual measurement value, the enlargement ratio ω Are set as the set value expansion ratio ωd, the cost priority expansion ratio ωc, and the safety priority expansion ratio ωs. Then, based on the actual loading test result, a more suitable optimum enlargement ratio ωopt is set. In such a case, a suitable optimum enlargement ratio ωopt is determined after further examination of the appropriateness of the design value enlargement ratio ωd, which is the median value of the enlargement ratio ω. It is possible to set an optimal enlargement ratio ωopt suitable for.

On the other hand, if it is determined in step S17-1 that the product of the design support force Rωd (measured value) and the number of ready-made piles 10 is smaller than the product of the margin M and the design load (column load) P, A loading test is performed on the case with the priority enlargement ratio ωs, and the design bearing force Rωs of the ready-made pile 10 is measured (step S16-3). Thereafter, it is examined whether or not the product of the number of piles J and the design support force Rωs (measured value) is greater than or equal to the product of the margin M and the design load (column load) P. That is, in the case of the design support force Rωs (measured value), it is examined whether or not the conditional expression (2) is satisfied (step S17-3).

In step S17-3, when the product of the number of piles J and the design support force Rωs (measured value) is equal to or greater than the product of the margin M and the design load (column load) P, the safety priority priority enlargement ratio ωs is optimized. The enlargement ratio ωopt is determined (step S18-3). In step S18-3, the optimum enlargement ratio ωopt is determined, and at the same time, the enlarged excavation part length Lωs determined in step S14 corresponding to the enlargement ratio ωs is decided as the optimum enlargement part length Lωopt. Thereafter, the process proceeds to step S19, and the main pile construction is performed based on the case of the optimum enlargement ratio ωopt and the optimum enlarged excavation section length Lωopt determined in step S18-3.

On the other hand, if it is determined in step S17-3 that the product of the number of piles J and the design support force Rωs (measured value) is smaller than the product of the margin M and the design load (column load) P, a new design The support force R is set, and a new pile number J is calculated (step S17-3a). For example, with the setting of a new design support force R, the number of piles is increased by one as a new pile number J (= J + 1). The cost is compared among the design value enlargement ratio ωd and the enlargement ratio ωs to determine the cheaper one as the optimum enlargement ratio ωopt, and at the same time, the enlarged excavation section length Lωd determined in step S14 corresponding to the enlargement ratio ωopt, Any one of Lωs is determined as the optimum enlarged portion length Lωopt (step 18-4). Thereafter, the process proceeds to step S19, and the main pile construction is performed based on the case of the optimum enlargement ratio ωopt and the optimum enlarged excavation section length Lωopt determined in step S18-4.

As described above, in the present embodiment, the validity of the design value magnification ratio ωd, which is the median value of the magnification ratios ω set in a plurality of ways, is further examined according to the flow described above, and then the actual loading test result is obtained. A suitable optimal enlargement ratio ωopt is determined. For this reason, it is possible to set a suitable optimum enlargement ratio ωopt more reliably while completing the optimum loading test as many times as necessary, thereby reducing over-spec when forming the enlarged excavation part 5 in a shorter time and at a lower cost. can do. Moreover, since the high stop of the ready-made pile 10 can be prevented reliably, it can construct reliably in a design depth position. Furthermore, in this embodiment, since the number of times of performing the loading test can be surely kept within two times, it is easy to assemble a work process in the process of constructing the ready-made pile 10.

In this embodiment, in the test pile construction step S15, all the test piles 10 'corresponding to the respective enlargement ratios ωd, ωc, and ωs are performed, but may be performed separately as necessary. If it does in this way, construction of test pile 10 'can also be completed by minimum necessary. FIG. 6 is a flowchart showing details of a modification of the method for constructing a ready-made pile according to an embodiment of the present invention.

As shown in FIG. 6, in the modification of the present embodiment, first, in the vicinity of the ground GN in which the ready-made pile 10 is actually built, the test pile 10 ′ corresponding to the ready-made pile 10 in the case of the design value expansion ratio ωd. (Test pile construction process S15-1). Next, a loading test of the test pile 10 ′ corresponding to the design value expansion ratio ωd is performed (step S16-1), and the design support force Rωd is measured.

In the loading test in step S16-1, when the design support force Rωd is measured, the design support force determination step S17-1 to the predicted design support force determination step S17-1b are performed as described above.

When the predicted design support force Rωc ′ is larger than the design support force Rωd (calculated value) in the predicted design support force determination step 17-1b, next, the test pile 10 ′ is tested in the case of the cost priority expansion ratio ωc. Construction is performed (step S15-2).

Then, as described above, steps S16-2 to S18-1 are performed. Thereafter, the process proceeds to step S19, and the main pile construction is performed based on the case of the optimum enlargement ratio ωopt and the optimum enlarged excavation section length Lωopt determined in step S18-1.

On the other hand, if the predicted design support force Rωc ′ is equal to or less than the design support force Rωd (calculated value) in the predicted design support force determination step S17-1b, step 18-2 is performed as described above. Then, it transfers to process S19 and implements this pile construction.

If it is determined in step S17-1 that the product of the design support force Rωd and the number J of ready-made piles 10 is smaller than the product of the margin M and the design load (column load) P, then the design support force continues. The predicted design support force Rωs ′ is estimated based on the design support force Rωd measured in the measurement step S16-1 (predicted design support force estimation step S17-1c). Note that the method for estimating the predicted design support force Rωs ′ in the predicted design support force estimation step S17-1c is the same as that described above, and a description thereof will be omitted.

After that, test construction is performed for the case of the expansion ratio ωs giving priority to safety (step S15-3). Then, as described above, Step S16-3 to Step S18-3 or Step 18-4 are performed. Thereafter, the process proceeds to step S19, and the main pile construction is performed based on the case of the optimum enlargement ratio ωopt and the optimum enlarged excavation section length Lωopt determined in step S18-3 or step 18-4.

As described above, in the modification of the present embodiment, the construction of the test pile 10 ′ corresponding to each of the expansion ratios ωd, ωc, and ωs is not performed from the beginning, and the necessary minimum value including the design value expansion ratio ωd is included. Only the test construction is performed, and the loading test of the test pile 10 ′ corresponding to the enlargement ratio ω subjected to the test construction is performed. For this reason, it is not necessary to excavate the test hole 3 'more than necessary, and wasteful excavation work can be reduced.

In the modification of the present embodiment, the validity of the design value magnification ratio ωd, which is the median value of the magnification ratios ω set in a plurality of ways, is further examined according to the flow described above, and then based on the actual loading test results. A suitable optimum enlargement ratio ωopt is determined. For this reason, it is possible to set a suitable optimum enlargement ratio ωopt more reliably while performing the optimum loading test with the minimum necessary number of times.

(Second Embodiment)
Next, the details of the construction method of the ready-made pile according to the second embodiment of the present invention will be described using the drawings. FIG. 7 is a flowchart showing details of a method for constructing a ready-made pile according to another embodiment of the present invention. In FIG. 7, in particular, after setting steps S13 and S14 for the enlargement ratio ω, setting of the test pile, measurement of the design support force R, determination of the validity of the design support force R, and determination of the optimum enlargement ratio ωopt are performed. A detailed flow up to this point will be described.

As shown in FIG. 7, in this embodiment, in order to set the optimum enlargement ratio ωopt that does not become over-specification more efficiently and reliably, the design support force in order from the smallest of the plurality of enlargement ratios ωd, ωc, and ωs. R is determined. That is, the loading test is performed from the test pile 10 'corresponding to the cost-prioritized expansion ratio ωc among the expansion ratios ωd, ωc, and ωs set in the setting steps S13 and S14 (see FIG. 3).

First, construction of the test pile 10 ′ corresponding to the ready-made pile 10 is performed in the vicinity of the ground GN where the ready-made pile 10 is actually built (test pile construction step S25). In the present embodiment, all the test piles 10 'corresponding to the respective enlargement ratios ωd, ωc, and ωs are executed.

Next, among the test piles 10 ′ corresponding to the respective expansion ratios ωd, ωc, and ωs, a loading test is performed on the test pile 10 ′ corresponding to the cost priority expansion ratio ωc (step S26-1). In other words, in the present embodiment, in order to give the highest priority to the validity of the cost-priority expansion ratio ωc having a small value, a loading test is performed from the case of the expansion ratio ωc, and the design support corresponding to the expansion ratio ωc is supported. Measure force Rωc.

After the design support force Rωc is measured, the process proceeds to the design support force determination step S27-1, and the design support force Rωc (hereinafter referred to as the design support force Rωc (measured value)) measured based on the design value enlargement ratio ωc. ) And the number J of ready-made piles 10 is determined as to whether or not the product of the margin M and the design load (column load) P is equal to or greater.

In the design support force determination step S27-1, if the product of the design support force Rωc (measured value) and the number J of ready-made piles 10 is equal to or greater than the product of the margin M and the design load (column load) P, The expansion ratio ωc giving priority to cost is determined as the optimal expansion ratio ωopt, and at the same time, the expanded excavation section length Lωc determined in step S14 corresponding to the expansion ratio ωc is determined as the optimal expansion section length Lωopt (step S28-1).

Then, the process proceeds to step S19, and the pile construction is performed based on the case of the optimum enlargement ratio ωopt and the optimum enlarged excavation section length Lωopt determined in step S28-1. Thereby, construction cost can be reduced rather than implementing this pile construction based on the case of expansion ratio ωd.

On the other hand, if it is determined in step S27-1 that the product of the design support force Rωc (measured value) and the number of ready-made piles 10 is smaller than the product of the margin M and the design load (column load) P, A loading test is performed on the case with the design value expansion ratio ωd, and the design support force Rωd of the ready-made pile 10 is measured (step S26-2).

Thereafter, it is examined whether or not the product of the number of piles J and the design support force Rωd (measured value) is greater than or equal to the product of the margin M and the design load (column load) P (step S27-2). That is, in the case of the design support force Rωd, it is examined whether or not the conditional expression (2) described above is satisfied.

In step S27-2, when the product of the number of piles J and the design support force Rωd (measured value) is greater than or equal to the product of the margin M and the design load (column load) P, the design value enlargement ratio ωd is optimized. The expansion ratio ωopt is determined, and at the same time, the expanded excavation section length Lωd determined in step S14 corresponding to the expansion ratio ωd is determined as the optimal expansion section length Lωopt (step S28-2). In step S28-2, when the enlargement ratio ωd is determined to be the optimum enlargement value ωopt, the process proceeds to step S19. Based on the case of the optimum enlargement ratio ωopt and the optimum enlarged excavation section length Lωopt determined in step S28-2. Implement this pile construction.

On the other hand, if it is determined in step S27-2 that the product of the design support force Rωd (measured value) and the number J of ready-made piles 10 is smaller than the product of the margin M and the design load (column load) P, A loading test is performed on the case with the safety expansion ratio ωs, and the design bearing force Rωs of the ready-made pile 10 is measured (step S26-3).

Thereafter, it is examined whether or not the product of the number of piles J and the design support force Rωs (measured value) is greater than or equal to the product of the margin M and the design load (column load) P (step S27-3). That is, in the case of the design support force Rωs (measured value), it is examined whether or not the conditional expression (2) is satisfied.

In step S27-3, when the product of the number of piles J and the design support force Rωs (measured value) is equal to or greater than the product of the margin M and the design load (column load) P, the enlargement ratio ωs is set to the optimum enlargement ratio. At the same time, the enlarged excavation section length Lωs determined in step S14 corresponding to the enlargement ratio ωs is determined as the optimum enlargement section length Lωopt (step S28-3). In step S28-3, when the enlargement ratio ωs is determined to be the optimum enlargement value ωopt, the process proceeds to step S19. Based on the case of the optimum enlargement ratio ωopt and the optimum enlarged excavation section length Lωopt determined in step S28-3. Implement this pile construction.

On the other hand, when the product of the number of piles J and the design support force Rωs (measured value) is smaller than the product of the margin M and the design load (column load) P in step S27-3, a new design support force R And a new pile number J is calculated (step S27-3a). For example, with the setting of the new design support force R, the new pile number J is set to (J + 1), and the pile number is increased by one. Then, the cost is compared among the enlargement ratios ωd and ωs, and the cheaper one is determined as the optimum enlargement ratio ωopt, and at the same time, one of the enlarged excavation section lengths Lωd and Lωs determined in step S14 corresponding to the enlargement ratio ωopt. Is determined as the optimum enlarged portion length Lωopt (step S28-4). Thereafter, the process proceeds to step S19, and the main pile construction is performed based on the case of the optimum enlargement ratio ωopt and the optimum enlarged excavation section length Lωopt determined in step S28-4.

Thus, in this embodiment, since the loading test is performed from the test pile 10 'corresponding to the cost-priority expansion ratio ωc, it is possible to set the optimum value ωopt of the expansion ratio ω that does not become over-specification more efficiently. it can. Further, since the loading test is performed from the test pile 10 ′ corresponding to the cost-prioritized enlargement ratio ωc, when the optimum enlargement ratio ωopt is set to a smaller value of the enlargement ratio ω, it corresponds to the enlargement ratio ω. It is possible to minimize the number of times the loading test of the design support force R is performed. In other words, when the cost priority enlargement ratio ωc is determined to be the optimum enlargement ratio ωopt, the load test can be performed only once, so the optimum value ωopt of the enlargement ratio ω that does not become over-specification is set more efficiently. can do.

In this embodiment, in the test pile construction step S25, all the test piles 10 'corresponding to the respective enlargement ratios ωd, ωc, and ωs are performed, but may be performed separately as necessary. If it does in this way, construction of test pile 10 'can also be completed by minimum necessary. FIG. 8 is a flowchart showing details of a modification of the method for constructing a ready-made pile according to another embodiment of the present invention.

As shown in FIG. 8, in the modification of the present embodiment, in order to more efficiently and surely set the optimum expansion ratio ωopt that does not become overspec, first, in the vicinity of the ground GN that actually builds the ready-made pile 10, For the case of the enlargement ratio ωc, the test pile 10 ′ corresponding to the ready-made pile 10 is constructed (test pile construction step S25-1).

Next, as described above, step S26-1 is performed, and then step S28-1 is performed after step S27-1.

On the other hand, if it is determined in step S27-1 that the product of the design support force Rωc (measured value) and the number J of ready-made piles 10 is smaller than the product of the margin M and the design load (column load) P, The predicted design support force Rωd ′ is estimated based on the design support force Rωc (measured value) measured in S27-1 (predicted design support force estimation step S27-1a). Note that the method for estimating the predicted design support force Rωd ′ in the predicted design support force estimation step S27-1a is the same as described above, and thus the description thereof is omitted.

Thereafter, for the case of the design value expansion ratio ωd, the test pile 10 ′ corresponding to the ready-made pile 10 is constructed (test pile construction step S25-2).

Next, as described above, step S26-2 is performed, and then step S28-2 is performed through step S27-2. And it transfers to process S19 and implements this pile construction based on the case of the optimal expansion ratio omegaopt determined by process S28-2, and the optimal expansion excavation part length Lomegaopt.

On the other hand, when it is determined in step S27-2 that the product of the design support force Rωd (measured value) and the number J of ready-made piles 10 is smaller than the product of the margin M and the design load (column load) P, The predicted design support force Rωs ′ is estimated based on the design support force Rωd (measured value) measured in step S26-2 (predicted design support force estimation step S27-2a). Note that the method for estimating the predicted design support force Rωs ′ in the predicted design support force estimation step S27-2a is the same as described above, and thus the description thereof is omitted.

Thereafter, the test pile 10 ′ corresponding to the ready-made pile 10 is installed in the case of the expansion ratio ωs (test pile construction step S25-3).

Next, as described above, step S26-3 is performed, and then step S28-3 is performed via step S27-3. And it transfers to process S19 and implements this pile construction based on the case of the optimal expansion ratio omegaopt determined by process S28-3 and the optimal expansion excavation part length Lomegaopt.

On the other hand, when it is determined in step S27-3 that the product of the design support force Rωs (measured value) and the number J of ready-made piles 10 is smaller than the product of the margin M and the design load (column load) P, As described above, step S27-3a and step S28-4 are performed.

Then, the process proceeds to step S19, and the pile construction is performed based on the case of the optimum enlargement ratio ωopt and the optimum enlarged excavation section length Lωopt determined in step S28-4.

As described above, in this embodiment, since the loading test is performed from the test pile 10 'corresponding to the cost-priority expansion ratio ωc with a small expansion ratio ω, the optimum value ωopt of the expansion ratio ω that does not become over-specification more efficiently. Can be set. Further, since the loading test is performed from the test pile 10 ′ corresponding to the cost-prioritized enlargement ratio ωc, when the optimum enlargement ratio ωopt is set to a smaller value of the enlargement ratio ω, it corresponds to the enlargement ratio ω. It is possible to minimize the number of times the loading test of the design support force R is performed.

Although each embodiment of the present invention has been described in detail as described above, it is easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. It will be possible. Therefore, all such modifications are included in the scope of the present invention.

For example, a term described together with a different term having a broader meaning or the same meaning at least once in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings. Moreover, the structure of the construction system of a ready-made pile and the operation | movement of the construction method of a ready-made pile are not limited to what was demonstrated in each embodiment of this invention, A various deformation | transformation implementation is possible.

1 pile foundation, 3 pile hole, 5 enlarged excavation part, 10 ready-made pile, 10 'test pile, 10a tip part, 10b outer peripheral surface, 12 convex part, 14 consolidation part, 100 (prepared pile) construction system, 101 computer , 102 storage unit, 104 storage medium, 106 RAM, 108 ROM, 110 CPU (calculation unit), 112 setting unit, 114 determination unit, 116 determination unit, 120 input unit, 122 output unit, 124 communication unit, 125 system bus, 126 Internet, 128 Design support force measurement device, 130 Excavation device, 131 Excavation rod, 132 Excavation blade, 134 Movable excavation part, S13, S14 Setting process, S16 Design support force measurement process, S17 Design support force determination process, S17-1b Preliminary design support capacity judgment process, S18 optimum enlargement ratio determination process S19 expansion drilling portion forming step

Claims

It is a construction method of a ready-made pile in which a ready-made pile is built in a pile hole in which an expanded excavation part with an enlarged inner diameter is formed on the bottom side,
Based on the predetermined data relating to the construction of the ready-made pile, an expansion ratio indicating the ratio of the inner diameter of the enlarged excavation part to the outer diameter design value obtained by adding a desired clearance value to the outer diameter of the tip of the ready-made pile Setting process to set multiple values with different values,
Design bearing force measurement for carrying out a loading test for each of the cases of one or more magnification ratios selected from the plurality of magnification ratios and measuring the design bearing force of the ready-made piles at the one or more magnification ratios, respectively. Process,
For each of the design support forces measured in the design support force measurement step, a desired design in which the product of the design support force and the number of the ready-made piles used acts on the pile foundation formed by the ready-made piles. A design support force determination step for determining whether or not the load is greater than or equal to,
An optimum enlargement ratio determining step of determining a minimum enlargement ratio among the enlargement ratios satisfying a condition that the product is equal to or greater than the design load in the design support force determination step as an optimum enlargement ratio for forming the enlarged excavation portion; ,
An expanded excavation portion forming step for forming the expanded excavation portion based on the optimum expansion ratio.
In the setting step, a design value enlargement ratio set based on at least the predetermined data, an enlargement ratio having a value smaller than the design value enlargement ratio, and an enlargement ratio having a value larger than the design value enlargement ratio are set. The construction method of the ready-made pile of Claim 1 characterized by the above-mentioned.
3. The ready-made pile construction method according to claim 2, wherein in the setting step, an enlarged excavation section length that is an axial length of the enlarged excavation section is set for each of the plurality of enlargement ratio cases. .
In the design support force determination step, a product of the design support force and the number of the ready-made piles measured based on the design value enlargement ratio from the design value enlargement ratio is formed by the ready-made piles. Determining whether or not it is greater than or equal to the desired design load acting on the foundation;
When the product is greater than or equal to the desired design load in the design support force determination step, the predicted design support force estimated based on at least the design support force measured in the design support force measurement step, and the The construction method of the ready-made pile of Claim 2 including the prediction design support force determination process which determines whether the product with the said number of ready-made piles is more than the said desired design load.
In the design support force determination step, a product of the design support force and the number of the ready-made piles measured based on the enlargement ratio in order from the plurality of the enlargement ratios is formed by the ready-made piles. It determines about whether it is more than the said desired design load which acts on the said pile foundation, The construction method of the ready-made pile of Claim 2 characterized by the above-mentioned.
The said ready-made pile is a node pile in which a convex part is provided in the outer peripheral surface of a front-end | tip part, The construction method of the ready-made pile of any one of Claim 1 thru | or 5 characterized by the above-mentioned.
The program for making a computer perform the construction method of the ready-made pile of any one of Claims 1 thru | or 6.
A storage medium storing a computer-readable program for causing a computer to execute the ready-made pile construction method according to any one of claims 1 to 6.
A pile foundation formed by a ready-made pile built in the ground by the ready-made pile construction method according to any one of claims 1 to 6.
A construction system for a ready-made pile that builds a ready-made pile into a pile hole in which an enlarged excavation part with an enlarged inner diameter is formed on the bottom side,
A storage unit for storing at least predetermined data relating to the construction of the ready-made pile;
The ratio of the inner diameter of the expanded excavation portion to the outer diameter design value obtained by calculating with a computer based on at least the predetermined data and adding a desired clearance value to the outer diameter of the tip portion of the ready-made pile. An arithmetic unit for obtaining an enlargement ratio;
A setting unit that is included in the calculation unit and sets a plurality of the enlargement ratios with different values based on at least the predetermined data relating to the construction of the ready-made pile,
The number of the ready-made piles to be used with the design support force that is included in the calculation unit and is measured by a loading test of a case having one or more enlargement ratios selected from the plurality of enlargement ratios set by the setting unit And a determination unit that determines whether or not the product is greater than or equal to a desired design load acting on a pile foundation formed by the ready-made pile,
The minimum enlargement ratio among the enlargement ratios that are included in the arithmetic unit and satisfy the condition that the product is equal to or greater than the design load at least by the determination unit is determined as an optimum enlargement ratio for forming the enlarged excavation part. A decision unit;
An installation system for a ready-made pile characterized by comprising:
The storage unit stores, as the predetermined data, at least the soil data of the ground where the ready-made pile is built, the measurement data of the load test described above, and the past construction performance data of the ready-made pile in a database. The construction system of the ready-made pile of Claim 10.