JP4101616B2 - Pile indentation test method and beam - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pile indentation test method for confirming the bearing capacity of a support pile embedded in a construction ground of a detached house, a reinforced concrete structure, or the like, and a beam used in the test apparatus.
[0002]
[Prior art]
Conventionally, as an indentation test method for piles, a reaction force pile is driven into four locations around the test pile, a beam is passed above the test pile, and a jack is placed between the test pile and the beam to obtain an indentation reaction force. A test method is known (for example, refer to Patent Document 1).
[0003]
[Patent Document 1]
JP 57-100210 A (page 2-3, FIG. 1-2)
[0004]
[Problems to be solved by the invention]
However, in this method, a heavy machine for driving reaction force piles is prepared separately from the heavy machine for driving support piles, or the reaction force piles are placed at least on both sides of the test pile for balancing. It had to be buried in two places, and it took time and effort to bury them.
[0005]
Then, the subject of this invention is providing the indentation test method of the pile which eliminates the said conventional trouble, saves the effort of obtaining the indentation reaction force, and can be performed simply.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the pile indentation test method according to the invention of claim 1 is a method of pressing a beam body between a test pile and a beam body by fixing the beam body over the test pile to be measured. This is a pile indentation test method in which a jack is disposed and a pressing force is applied downward to the test pile by the pressurizing jack and the amount of settlement of the test pile is measured. A fixed pile is buried at a predetermined distance from the pile, one end of the beam body is connected and fixed to the pile head of the fixed pile, and the other end of the beam body is straddled with the heavy machinery, and from the test pile At a predetermined distance, the beam body is fixed in contact with the bottom surface of the heavy machine, and if the load from the heavy machine cannot be obtained sufficiently against the pressing force by the pressure jack at the time of the fixation, from the test pile The predetermined distance to the fixed position of the heavy machinery is the distance from the test pile to the fixed position of the fixed pile. While adjusting the length to be longer than the distance, if the supporting force of the fixed pile is weak against the pressing force of the pressure jack and the pulling reaction force cannot be expected, the predetermined distance from the test pile to the fixed position of the fixed pile is tested. It adjusts so that it may become longer than the predetermined distance from a pile to the fixed position of a heavy machine .
[0009]
A beam body for indentation testing of a pile according to the invention of claim 2 includes a lower stage portion of the beam body fixed to the heavy machine according to claim 1, and a test pile and a fixed pile of the test pile and the fixed pile through the step portion from the lower stage portion of the beam body. And an upper stage portion of the beam body that is passed upward.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show an embodiment of a pile indentation test apparatus using the pile indentation test method according to the present invention. The present invention is used for a pile indentation test defined in JGS1811 (Geotechnical Society Standard).
[0011]
The indentation test device 1a of the present pile includes an input unit for inputting a load applied to the test pile 60, a load application time, and a settling amount of the test pile, and records and adds these for each load applied to the test pile 60. A recording device 76 for displaying the amount of settlement of the test pile 60 after the grant time has passed, a heavy machine 7 capable of placing the test pile 60, an auger 80 for excavation as a fixed pile rotated and buried by the heavy machine 7, and the test pile 60 And a pressing jack 64 for applying a pressing force to the upper side of the test pile 60 via a pile head pedestal 85, and the pressing jack 64 is mounted on the beam body. 50 is fixed to the lower side.
[0012]
As the heavy machine 7, a self-propelled pile driving machine is used in which a support pile made of a steel pipe or the like is rotated and embedded by rotating the motor. The columnar frame 3 is formed in a column shape by a long steel pipe having a large diameter, and is erected on the main body portion 8 of the heavy machine 7 so as to be perpendicular to the ground 55 leveled horizontally. On the side surface of the columnar frame 3, an elevating rail 3 a for the elevating unit 5 is provided. The lifting rail 3a is provided with a motor 6 for rotating and embedding a support pile formed as a lifting unit 5 so as to be lifted and lowered by a winch equipped with a heavy machine 7 with a drive shaft 6a facing downward. As the motor 6, an electric motor capable of forward and reverse rotation is used.
[0013]
The excavation auger 80 is rotationally embedded to the required depth H1 at a distance L1 from the test pile 60 by the motor 6 of the heavy machine 7. As the test pile 60, a support pile that optimally satisfies the application condition of the indentation test is selected from the plurality of support piles that are rotationally embedded up to the support layer 56 by the heavy machine 7 on the building site. In addition, the SMD ("super mini drill", the same hereafter) pile which provides a spiral blade at the front-end | tip of a steel pipe is used for the support pile.
[0014]
The beam body 50 is formed of, for example, a long H steel material, one end of which is connected to the pile head of the excavating auger 80 via a connecting member such as a pin joint, passes over the test pile 60, and the heavy machinery 7 and the test. It is adjusted to be substantially horizontal by the support of the beam pedestal 51 installed on the ground 55 between the pile 60 and the other end is provided so as to abut against the bottom surface 8 a of the heavy machine 7. In addition, a hydraulic jack having a pressurizing capacity of 30 tons at the maximum is used for the pressurizing jack 64, and the press jack 64 is small and small enough to be loaded on a wagon car. Further, a jack pump 68 for driving a jack having a function of converting a loaded load amount into an electrical signal and outputting it is connected to the pressurizing jack 64.
[0015]
The pile head pedestal 85 is composed of a pedestal portion 85 a disposed between the test pile 60 and the pressurizing jack 64, and a receiving portion 85 b for disposing the gauge 74. The pedestal portion 85a is formed in a cap shape in which a wall body is erected on the entire circumference of a circular thick steel plate. The cradle portion 85b is made of a steel material having an L-shaped cross section, and protrudes from the wall of the pedestal portion 85a so that one plane thereof and the upper surface of the pedestal portion 85a are flush with each other.
[0016]
The gauge 74 includes a cylindrical gauge main body 74a and a small-diameter movable rod 74b protruding from the gauge main body 74a so that the axis coincides with the axis, and the axis of the gauge main body 74a matches the burying direction of the test pile 60. The movable bar 74b is fixed to the gauge base 87 disposed on the ground via the adjustment arm 88 so that the movable bar 74b comes into contact with the receiving portion 85b. Further, the gauge 74 is configured to be able to output by converting the amount of subsidence of the test pile 60 from the amount of expansion / contraction of the movable rod 74b relative to the gauge body 74a, that is, the amount of movement of the pile head pedestal 85, into an electrical signal.
[0017]
The loaded load data, the load time data output from the jack pump 68 after being converted into an electrical signal, and the settlement amount data of the test pile 60 output from the gauge 74 are input to the recording device 76 and recorded.
[0018]
Next, the pile indentation test method performed by the apparatus 1a having the above configuration will be described together with the procedure thereof.
(1) The support pile is buried by the heavy machine 7. And after embedding completion, the support pile used as a measuring object is selected as the test pile 60. FIG. The excavator auger 80 as a fixed pile is embedded up to the required depth H1 at a distance L1 from the test pile 60 by the same heavy machine 7 (FIG. 1).
(2) Further, the beam body 50 lifted by the lifting unit 5 of the heavy machine 7 is lowered above the test pile 60 and the excavation auger 80, and one end is connected to the pile head of the excavation auger 80 by, for example, pin joining. It fixes and supports between the other end and the test pile 60 with the beam base 51 (FIG. 2).
[0019]
(3) The other end of the beam body 50 is straddled by the heavy machine 7, the support height is adjusted by the beam body base 51, and the beam body 50 is placed on the bottom surface 8 a of the heavy machine 7 at a distance L 2 from the test pile 60. Abut and fix. At this time, the distance L2 is longer than the distance L1, and the pressing position of the test pile 60 in the beam body 50 is provided closer to the excavation auger 80.
(4) The pressurizing jack 64 is disposed on the top of the pile head of the test pile 60 via the pile head pedestal 85, and the upper end of the pressurizing jack 64 is brought into contact with the lower flat portion of the beam body 50.
(5) A gauge 74 for measuring the amount of movement of the pile head pedestal 85 that moves along with the settlement of the test pile 60 is installed on the cradle 85b (FIG. 3).
[0020]
(6) The pressurizing jack 64 is actuated by the jack pump 68, and the pressing force composed of the pulling reaction force of the buried excavating auger 80 is applied to the test pile 60 vertically downward.
(7) The load applied to the test pile 60, the load application time, and the amount of settlement of the test pile 60 are respectively input and recorded in the recording device 76, and the test at the time when the load application time has elapsed for each load applied to the test pile 60. The amount of settlement of the pile 60 is displayed in a graph by the display unit. From the test result of this device 1a, for example, based on the judgment criteria that pass when the amount of settlement is 1% or less of the nominal diameter of the test pile 60, the support force of the support pile is confirmed, the load-displacement relationship and the limit Support force can be calculated. Note that a printer device may be connected to the recording device 76 to print out the loaded load, the load application time, and the settlement amount.
[0021]
Therefore, according to the pile indentation test method of this embodiment, as shown in FIG. 4, when the fixed position of the test pile 60 is used as the fulcrum of the beam body 50, as shown in FIG. The distance L1) × (the pulling reaction force F1 of the excavating auger 80) and (the distance L2 from the test pile 60) × (the load F2 due to the weight of the heavy machinery 7) are equal to each other. Even if there is not enough, a pressing force F larger than the load F2 can be applied to the test pile 60. Therefore, in comparison with the necessity of embedding at least two reaction force piles on both sides of the test pile 60 in the past, a desired pressing force F is obtained with the effort of embedding one excavation auger 80. This makes it possible to save the labor of burial work.
[0022]
Also, as the distance L 2 is longer than the distance L 1, the pressing position of the test pile 60 in Haritai 50, since there is provided in a fixed position near the drilling auger 80, the load is sufficiently obtained from heavy machinery 7 Even if it is not possible, it is possible to maintain a balance with respect to the large pulling reaction force of the excavating auger 80, and a large pressing force can be applied to the test pile 60 even with a small heavy machine.
[0023]
Here, by adjusting the pressing position of the test pile 60 against the beam body 50, the maximum pressing force Fmax of (the pulling reaction force F1max immediately before the excavating auger is pulled out) + (the load F2 due to the heavy weight of the heavy machinery) is set to the test pile. 60 can be applied.
[0024]
Moreover, using the heavy machine 7 which can drive a support pile, not only the rotary auger 80 which is a fixed pile is rotationally embedded, but also the beam body 50 is lifted using the elevating part 5 and placed at a predetermined position. it can. Therefore, the work required for a series of different procedures in the pile indentation test can be performed with one heavy machine 7, and the construction cost can be reduced and a test can be easily performed without using a plurality of heavy machines.
[0025]
5-7 is a side view which shows one embodiment of the beam body 52 which concerns on this invention, and shows the indentation test apparatus 1b of a pile which uses this. This apparatus 1b is configured by replacing the beam body 50 and the beam body 52 according to the present invention in the apparatus 1a of FIG. The beam body 52 includes a beam body lower step portion 52a fixed to the main body bottom surface 8a of the heavy machine 7 and a beam body passed over the test pile 60 and the excavation auger 80 from the beam body lower step portion 52a via the step portion 52b. It is comprised from the upper stage part 52c. In the stepped portion 52b, the upper surface of the end of the beam lower step 52a and the lower surface of the end of the upper beam step 52c are connected by an adhesive means such as welding.
[0026]
A pile indentation test method performed by the apparatus 1b using the beam body 52 having the above configuration will be described together with the procedure thereof. Since the procedure other than the procedure related to the beam body 52 is the same as that of the apparatus 1a, a description thereof will be omitted.
(1) The test pile 60 and the excavation auger 80 are embedded by the heavy machine 7 at an interval of a distance L1 (FIG. 5, intermediate procedure omitted).
(2) The beam body 52 is lifted by the lifting / lowering unit 5 of the heavy machinery, and is arranged so that the beam body upper step portion 52c is passed above the test pile 60 and the excavation auger 80. Then, the outer end portion of the beam upper stage portion 52c is connected and fixed to the pile head of the excavating auger 80 by pin joining, and the beam lower step portion 52a is placed on the ground (FIG. 6).
[0027]
(3) After the beam body lower step portion 52a is straddled by the heavy machine 7, the beam body 52 is again lifted by the elevating unit 5, and the beam body lower step portion 52a is placed at the distance L2 from the test pile 60. It is pressed against the bottom surface 8a and fixed (FIG. 7).
(4) A pressing force composed of a pulling reaction force of the buried excavating auger 80 is applied to the test pile 60 vertically downward (the procedure is omitted in the middle).
(5) The load applied to the test pile 60, the load application time, and the amount of settlement of the test pile 60 are input and recorded in the recording device 76, and the test when the load application time elapses for each load applied to the test pile 60. The amount of settlement of the pile 60 is displayed in a graph by the display unit.
[0028]
Therefore, according to this beam body 52, the beam body lower step portion 52a is provided with the step portion 52b so that the beam body upper step portion 52c is passed over the test pile 60 and the excavation auger 80. Even if the height of the bottom surface 8a of the main body is low, it can be carried out without adding other work not related to the test procedure as long as at least the vehicle height corresponding to the beam height can be secured. Therefore, the selection range of the heavy machinery 7 is further expanded as compared with the case where the beam body 50 is used, and the pile pushing test can be performed more easily.
[0029]
The present invention is not limited to the above-described embodiment, and as illustrated below, the shape, configuration, and procedure of each part can be changed as appropriate without departing from the spirit of the present invention. It is.
(1) Excavation augers 80 as fixed piles are not limited to one, such as when the pulling reaction force per one is not sufficiently obtained due to soft ground, etc. good.
(2) The fixed position of the test pile 60 in the beam bodies 50 and 52 can be provided not only near the fixed position of the excavating auger 80 as a fixed pile but also near the fixed position of the heavy machinery 7. For example, this is effective when the supporting force of the fixed pile is weak due to soft ground or the like, and the pulling reaction force cannot be expected.
[0030]
(3) The pile head of the test pile 60 is not limited to the pile head pedestal 85, and a pile band composed of a steel band and a cradle projecting radially from four locations of the band is configured. The pile band may be fastened by bolting the band. In this case, the gauge 74 is installed on the cradle.
(4) The connecting member is not limited to pin joining, but may be a member in which a beam is inserted into an annular body provided on a pile head of an excavating auger. (5) The motor 6 is not limited to an electric motor but may be a hydraulic motor or the like. good.
(6) The support pile as the test pile 60 is not limited to the SMD pile, but may be other feathered piles or ready-made piles such as RC piles.
(7) The fixed pile is not limited to the auger 80 for excavation, and may be any pile that can obtain a sufficient pulling reaction force, and may be replaced with an SMD pile used as a support pile.
[0031]
【The invention's effect】
As described in detail above, according to the first aspect of the invention, it is possible to apply a large pressing force to the test pile with a heavy machine having a small weight by utilizing the principle of the lever by the beam. Therefore, it is possible to easily perform the indentation test of the pile without the trouble of burying work such as providing a plurality of reaction force piles and beams around the conventional test pile. Further, the pulling reaction force of the fixed pile can be used as a pressing force, and a larger pressing force can be applied to the test pile.
[0034]
According to the invention of claim 2 , even when the height of the bottom surface of the main body of the heavy machinery is low, as long as at least the vehicle height corresponding to the beam height can be secured, other work unrelated to the test procedure is not added. Can be implemented. Therefore, the pile indentation test can be performed more easily.
[Brief description of the drawings]
FIG. 1 is a process explanatory diagram of a pile indentation test apparatus using a pile indentation test method according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram of another process by the apparatus of FIG. 1;
FIG. 3 is an explanatory diagram of another process by the apparatus of FIG. 1;
FIG. 4 is an operation explanatory diagram at a fixed position of a beam body.
FIG. 5 is a process explanatory diagram of a pile indentation test apparatus using a pile indentation test method according to an embodiment of the present invention.
FIG. 6 is an explanatory view of another process by the apparatus of FIG. 5;
FIG. 7 is an explanatory diagram of another process by the apparatus of FIG. 5;
[Explanation of symbols]
1a, 1b ··· Pile indentation test equipment, 3 ··· Columnar frame, 5 · · Elevator, 6 · · Motor, 6a · · Drive shaft, 7 · · Heavy machinery, 50, 52 · · Beam, 52a · · Beam lower step, 52b ... Step, 52c ... Beam upper, 55 ... Ground, 60 ... Test pile, 64 ... Pressure jack, 68 ... Jack pump, 74 ... Gauge, 76 ... · Recording device, 80 · · Excavator auger as fixed pile, 85 · · Pile head pedestal, 85a · · Pedestal portion, 85b · · Receiving portion.

Claims (2)

Fix the beam body over the test pile to be measured and fix it, arrange a pressure jack between the test pile and the beam body, and apply a pressing force downward to the test pile with the pressure jack, A pile indentation test method for measuring the settlement amount of the test pile,
A fixed pile is buried at a predetermined distance from the test pile with a heavy machine capable of driving the test pile,
Connect and fix one end of the beam to the pile head of the fixed pile ,
The other end of the beam body is straddled with the heavy machinery, and at a position a predetermined distance from the test pile, the beam body is fixed to the bottom surface of the heavy machinery,
During the fixing,
When the load from the heavy machinery is not sufficiently obtained for the pressing force by the pressurizing jack,
While adjusting the predetermined distance from the test pile to the fixed position of the heavy machinery to be longer than the predetermined distance from the test pile to the fixed position of the fixed pile,
When the supporting force of the fixed pile is weak with respect to the pressing force by the pressurizing jack and the pulling reaction force cannot be expected,
Adjust so that the predetermined distance from the test pile to the fixed position of the fixed pile is longer than the predetermined distance from the test pile to the fixed position of the heavy machinery,
Pile indentation test method characterized by the above. A beam body lower step portion fixed to the heavy machine according to claim 1 , and a beam body upper step portion passed from the lower step portion of the beam body to the test pile and the fixed pile via the step portion. A beam for indentation testing of piles.

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