WO2019186660A1 - Procédé d'estimation de capacité de charge ponctuelle d'un pieu à enfoncement rotatif, système de gestion de capacité de charge ponctuelle, procédé de gestion de construction, et programme - Google Patents

Procédé d'estimation de capacité de charge ponctuelle d'un pieu à enfoncement rotatif, système de gestion de capacité de charge ponctuelle, procédé de gestion de construction, et programme Download PDF

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Publication number
WO2019186660A1
WO2019186660A1 PCT/JP2018/012209 JP2018012209W WO2019186660A1 WO 2019186660 A1 WO2019186660 A1 WO 2019186660A1 JP 2018012209 W JP2018012209 W JP 2018012209W WO 2019186660 A1 WO2019186660 A1 WO 2019186660A1
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Prior art keywords
support force
rotary press
tip support
pile
tip
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PCT/JP2018/012209
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English (en)
Japanese (ja)
Inventor
吉郎 石濱
悦孝 柳
裕貴 日下
将一 田邊
和秀 戸田
妙中　真治
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日本製鉄株式会社
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Priority to JP2020510206A priority Critical patent/JP6856171B2/ja
Priority to PCT/JP2018/012209 priority patent/WO2019186660A1/fr
Publication of WO2019186660A1 publication Critical patent/WO2019186660A1/fr

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    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/22—Piles
    • E02D5/24—Prefabricated piles
    • E02D5/28—Prefabricated piles made of steel or other metals
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/22—Piles
    • E02D5/56—Screw piles
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D7/00—Methods or apparatus for placing sheet pile bulkheads, piles, mouldpipes, or other moulds
    • E02D7/22—Placing by screwing down

Definitions

  • the present invention relates to a tip support force estimation method, tip support force management system, construction management method, and program for a rotary press-fit pile.
  • a method using a dynamic penetration test is known as a method for confirming the bearing capacity of a pile tip ground of a steel pipe pile under construction.
  • Such a dynamic penetration test is performed by measuring a penetration amount and a rebound amount of a steel pipe pile by dropping a hammer with a predetermined weight from a predetermined height with respect to the steel pipe pile reaching a predetermined depth.
  • the ultimate bearing capacity is estimated by the pile driving method.
  • a predetermined support force can be expected when an estimated support force exceeding the design support force is calculated.
  • the construction method in which the bearing capacity is confirmed by the dynamic penetration test described above there is a demerit that in addition to generating noise and vibration, the construction method that does not use a hammer for construction requires preparation of the hammer. It was.
  • tip blade is, for example in patent document Are listed.
  • the blade needs to be attached to the tip, but there are problems such as the need for the processing cost and the installation cost of the blade. Therefore, a rotary press-fit method using a rotary press-fit pile having high environmental performance is sometimes used because blades are unnecessary, processing costs are low, and noise and vibration are relatively small.
  • the conventional rotary press-fit method has the following problems.
  • the rotary press-fit method has features such as low noise, low vibration and space saving, and is an ideal method peculiar to steel pipe piles because it is constructed by applying pressure input and torque directly to the pile body itself.
  • a loading test is performed each time to confirm the bearing capacity performance. There was a problem that it was necessary.
  • the tip support force is estimated from torque and friction force according to the roughness of the tip.
  • the clogging condition of the tip sediment and the composition of the clogged soil are the control of construction. It is difficult to assume the roughness of the tip from the results of previous ground surveys, and it is difficult to estimate the tip support force.
  • the rotary press-in method does not have a clear management method at the time of stopping, and therefore, there is only a method based on the management of the penetration length. And the ground at the point where the pile is placed may be separated from the place where the preliminary survey was performed, and the ground condition is not necessarily the same as the survey result.
  • the support layer is at a depth shallower than the survey results, it is necessary to spend time on hard ground that is difficult to press-fit in order to secure the penetration depth even though sufficient support force has already been obtained. To secure more than necessary.
  • An object of the present invention is to provide a tip support force estimation method, a tip support force management system, a construction management method, and a program that can be rotated.
  • the outline of the present invention is as follows.
  • the first aspect of the present invention is that the tip of the rotary press-fit pile that estimates the tip support force of the rotary press-fit pile at the time of construction in which the rotary press-fit pile made of a steel pipe pile with the pile tip released is put into the ground.
  • a support force estimation method using an input step of inputting a pressure input Qin and a support force estimation index H measured at the time of construction, the pressure input Qin and the support force estimation index H, Based on the tip support force estimation formula expressed by the formula (1) formulated from the correlation between the pressure input Qin, the tip support force Ru, and the support force estimation index H in the rotary press pile, An estimation step of estimating the tip support force Ru.
  • the supporting force estimation index H may be 0.5D ⁇ ⁇ / w.
  • the corrected pressure input Qin ′ which is the influence of the peripheral friction of the rotary press-fit pile, is measured and obtained by the following formula (3a)
  • the tip support force Ru may be estimated based on a corrected tip support force estimation formula obtained by correcting the tip support force estimation formula using a correction coefficient ⁇ .
  • the bearing capacity estimation index H is It may be T / 0.5D.
  • the measured value of the corrected rotational torque Ts which is the influence of the peripheral friction of the rotary press-fit pile, and the following formula (3b-1):
  • the tip support force Ru is estimated based on the corrected tip support force estimation formula obtained by correcting the tip support force estimation formula by using the correction coefficient ⁇ 1 obtained and the correction coefficient ⁇ 2 obtained by the following equation (3b-2). Also good.
  • the tip support force of the rotary press-fit pile is calculated using the method of estimating the tip support force of the rotary press-fit pile according to any one of (1) to (7) above.
  • a tip support force management system for managing wherein the tip support force Ru is calculated based on a storage unit storing the tip support force estimation formula and the tip support force estimation formula stored in the storage unit. And an arithmetic processing unit.
  • whether or not to continue the penetration of the rotary press-fit pile according to the calculated tip support force Ru is determined in the arithmetic processing unit. Good.
  • the storage unit stores a design tip support force Ra necessary for the rotary press-fit pile to be constructed, and the arithmetic processing unit calculates the calculated It may be determined whether the tip support force Ru is greater than or equal to the designed tip support force Ra.
  • the tip supporting force management system according to any one of (8) to (10) may further include a display unit that displays a result processed by the arithmetic processing unit.
  • the third aspect of the present invention manages the construction of the rotary press-fit pile using the method for estimating the tip bearing capacity of the rotary press-fit pile according to any one of (1) to (7) above.
  • the construction management method further includes a step of determining whether or not to continue the penetration of the rotary press-fit pile according to the estimated tip support force Ru. (13)
  • the tip support force Ru calculated by the tip support force estimation formula is greater than or equal to the design tip support force Ra required for the rotary press-fit pile to be constructed.
  • the penetration of the rotary press-fit pile may be stopped and the penetration of the rotary press-fit pile may be continued when the design tip support force Ra is smaller.
  • the correction pressure input Qin ′ or the correction rotation which is an influence of the peripheral friction of the rotary press-fitting pile
  • the tip support force Ru may be calculated based on a corrected tip support force estimation formula corrected by the coefficient ⁇ 2.
  • a fourth aspect of the present invention is a program for causing a computer to execute the tip pressing force estimating method for a rotary press-fit pile according to any one of the above (1) to (7).
  • a fifth aspect of the present invention is a program that causes a computer to execute the construction management method according to any one of (12) to (14).
  • the present invention by accurately estimating the tip support force of the rotary press-fitting pile in the rotary press-fitting method, it becomes possible to cope with the unevenness of the support layer, and the construction quality can be improved.
  • index H ( 0.5Dx (theta) / w).
  • index H ( T / 0.5D). It is a figure which shows an example of formulation of a tip support force estimation formula. It is a flowchart which shows the step by the construction management method of the rotation press-fit pile which uses the tip supporting force estimation method.
  • FIG. 1 is a schematic view showing a state in which a rotary press-fit pile 1 made of a steel pipe pile with a free end 1a is press-fitted into the ground.
  • the rotary press-fit pile 1 has a predetermined rotational pitch p by applying a pressure input Qin (kN) in the axial direction while applying a rotational torque T (kN ⁇ mm) in the axial direction. Is pressed into the ground.
  • the pressure input Qin is a load that is applied from the pile head toward the tip of the pile by gripping the pile portion that is exposed to the ground portion with the construction machine during construction.
  • Rotation pitch p is made dimensionless by using the radius of the pile that is 1/2 of the outer diameter D (mm) of the rotation speed ⁇ (rad / min) with respect to the penetration speed w (mm / min) of the rotary press-fit pile.
  • the penetration speed w is a speed at which the rotary press-in pile 1 is inserted into the ground per minute
  • the rotary speed ⁇ is an angle at which the rotary press-in pile 1 rotates per minute.
  • the tip support force Ru is a support force exerted in the vicinity of the tip of the pile.
  • the tip support force Ru is exhibited not only in the tip portion 1a of the rotary press-fit pile 1, but also in the range A from the tip portion 1a of the rotary press-fit pile 1 to about 1 to 5 times the pile outer diameter D. It is the resistance toward the pile tip direction from the pile head 1b of the pile shaft.
  • Rotational press-fit pile 1 is rotationally press-fitted into the ground by applying rotational torque T and press input Qin by a pile rotary press-in machine 2 as shown in FIGS.
  • the rotary press-fit pile 1 may be a steel pipe pile with a bit in which a drilling bit for excavation is provided at the distal end portion 1a, or a bit-free steel pipe pile in which a drilling bit for excavation is not provided in the distal end portion 1a.
  • the excavation bit has a structure for improving workability, unlike a blade attached to obtain a supporting force.
  • the outside protrusion length from the steel pipe pile outer surface of the excavation bit is 20 mm or less.
  • a friction cutter having an axial length of about 300 mm may be provided at the tip of the steel pipe pile.
  • the friction cutter has a double pipe structure, and protrudes from the outer surface of the steel pipe pile at 20 mm or less.
  • the inner protruding length of the excavation bit is also preferably 20 mm or less.
  • a self-propelled presser main body 24 provided with a leader 24A and a drive motor 25 for rotating a grip portion 24B provided on the leader 24A are provided.
  • the three-point pile driving machine 2A can be used.
  • the stationary presser main body 26 provided with a gripping portion 26A and a thrust jack 26B, and a drive motor 27 for rotating the gripping portion 26A.
  • the all-around swivel press-fitting machine 2B (2) may be used.
  • the pile driving depth is configured to be measured by a general measuring device such as a stroke sensor or an encoder provided in the leader.
  • the present inventors diligently studied a method for accurately estimating the tip support force Ru of the rotary press-fit pile constructed in this way.
  • the pressure input Qin and the component factor (rotational speed / penetration speed or rotational torque) of the bearing capacity estimation index H are measured during construction to rotationally press-fit the rotary press-fit pile into the ground.
  • the tip support force estimation formula expressed by the following formula (1) formulated from the correlation between the input Qin, the tip support force Ru, and the support force estimation index H, the tip support force Ru of the rotary press-fit pile is calculated. We found that estimation is effective.
  • the tip supporting force estimation method according to the present embodiment estimates the tip supporting force of the rotary press-fitted pile based on the rotational speed ⁇ and the penetration speed w at the time of construction for rotary press-fitting the rotary press-fitted pile into the ground. It has a process and an estimation process. That is, in the tip supporting force estimation method according to the present embodiment, when the outer diameter of the rotary press-fit pile is D (mm), the rotational speed is ⁇ (rad / min), and the penetration speed is w (mm / min). The value (rotation pitch) indicated by 0.5D ⁇ ⁇ / w is defined as the support force estimation index H.
  • the pressure input Qin obtained in the input step and the support force estimation index H are used, and the pressure input Qin, the tip support force Ru, and the support force estimation index H in the rotary press-fit pile are calculated.
  • the tip support force Ru of the rotary press-fit pile 1 is estimated based on the tip support force estimation formula expressed by the following formula (1a) formulated from the correlation.
  • A1 is the gradient when the approximate line of the plot point of the test result with the X axis as the natural logarithm of the bearing capacity estimation index H and the Y axis as Qin / Ru is expressed by the following equation (2a).
  • B1 is the Y intercept when the approximate line of the plot point of the test result with the X axis as the natural logarithm of the bearing capacity estimation index H and the Y axis as Qin / Ru is expressed by the following equation (2a).
  • a logarithmic approximation line by a least square method may be used as the approximation line of the plot points.
  • the tip support force estimation formula expressed by the above formula (1a) is a formula formulated by a construction test and a loading test as described later.
  • the press input Qin, the penetration speed w, and the rotation speed ⁇ are continuously measured by a measurement unit provided in the pile rotation press-fitting device 2.
  • measurement information of the pressure input Qin, the penetration speed w, and the rotational speed ⁇ is continuously or intermittently measured during the construction for rotationally press-fitting the rotary press-fit pile 1.
  • the tip support force Ru can be calculated from the measured measurement information based on the tip support force estimation formula expressed by the above-described formula (1a). That is, by using the tip support force estimation formula formulated based on the fact that there is a high correlation among the pressure input Qin, the rotation speed ⁇ , the penetration speed w, and the tip support force Ru during construction, It is possible to estimate the tip support force Ru of the rotary press-fit pile constructed by rotary press-fit with high accuracy.
  • the rotary press-fit pile can be stopped in a state where a sufficient tip support force Ru can be exhibited. Therefore, as in the case of controlling the stop depending on the depth to the support layer, it is possible to prevent an excessive or insufficient penetration length with respect to the support layer, and it is possible to cope with the unevenness of the support layer.
  • a rotary press-fitting pile 1 is rotationally press-fitted into the actual ground or artificially created ground, and the preset depth at which the rotary press-in construction is stopped (stop depth Z0).
  • the penetration is made while maintaining the rotational speed ⁇ at a constant value.
  • the pressure input Qin is controlled so as to be a substantially constant value, although there is some ups and downs due to changes in ground resistance.
  • the stop depth Z0 is a depth at which the tip support force designed based on the pile outer diameter D and the ground conditions used in the construction test can be obtained.
  • a section having a length of about 0.1 times the pile outer diameter D is set as an immediately preceding section K from the stop depth Z0, and the tip 1a of the rotary press-fit pile 1 reaches this section K.
  • the loading test the rotary press-fit pile for testing is stopped at a predetermined depth, and then loaded with a load from the vertical direction. And the stress distribution of the pile of a plurality of cross sections is measured in the depth direction, and the peripheral friction force and the tip support force Ru are separated and measured.
  • the loading test is, for example, “pile indentation test”, “pile rapid loading test”, “pile loading test” shown in “Pile vertical loading test method / comment 2002” published by the Geotechnical Society. It may be carried out according to the “impact loading test”.
  • Table 1 shows the presence or absence of excavation bits, pile outer diameter (mm), support layer ground type (sand layer / gravel layer), pressure input Qin (kN), rotational speed ⁇ (rad) for tests 1 to 25 as specific examples. / Min), penetration speed w (mm / min), rotational pitch 0.5D ⁇ ⁇ / w ( ⁇ ), tip support force Ru (kN), and Qin / Ru ( ⁇ ).
  • a bit-free steel pipe pile without a drilling bit was used.
  • Tests 15 to 25 a steel pipe pile with a bit in which four excavation bits were evenly provided in the circumferential direction at the tip portion was used.
  • equation (1a-1) which is a tip support force estimation equation corresponding to equation (1), is derived.
  • a sufficient safety factor is taken into consideration with respect to the design formula of the tip support force Ru, and therefore variation is allowed even in the stop management formula. Therefore, it is appropriate to use the expression (1a-1) obtained from the approximate expression of all data.
  • the maximum value of the Qin / Ru point is parallel to the approximate line of the equation (2a-1).
  • the formula (2a-1 ′) which is an approximate line indicating the upper limit to be included, may be calculated, and the formula (1a-1 ′) obtained based on this may be used as the tip support force estimation formula.
  • the above-mentioned tip bearing capacity estimation formula is an estimation formula derived based on the plot points of tests 1 to 25, but is derived using only the test results according to the presence or absence of the bit of the press-fit steel pipe pile to be actually constructed.
  • the accuracy of estimation can be increased. That is, when estimating the bearing capacity of a steel pipe pile with a bit, as shown in FIG. 7A, the equation (2a-1-1) is obtained in the same manner as the equation (2a-1) for the test with a bit. The equation (1a-1-1) obtained based on this may be used as the supporting force estimation equation.
  • the test without a bit is similar to the above equation (2a-1) (2a-1-2) An approximate line of the equation may be obtained, and the equation (1a-1-2) obtained based on the approximate line may be used as the supporting force estimation equation.
  • the approximated line (2a-1 ') which is an approximated line translated from the approximated line (2a-1) based on the least square method of the plot, is derived and is the tip bearing force estimation expression (1a).
  • -1 ′) equation was obtained.
  • the approximate line may be obtained by using an approximation method other than the least square method.
  • the approximate line represented by the above equation (2a-1 ′) may not be obtained by parallel translation with the slope of the approximate line obtained by the least square method being strictly constant. It may be a straight line or a curve enveloping.
  • the range in which the penetration speed w is changed is a range from the maximum speed determined from the machine capability to almost zero.
  • the correction coefficient ⁇ expressed by the expression (3a) is obtained by removing the correction pressure input Qin ′ that is the influence of the pile peripheral surface from the pressure input Qin at the time of construction. Then, a more precise tip support force Ru can be estimated by the corrected tip support force estimation formula (1a-1 *) using the correction coefficient ⁇ .
  • the pressure input Qin at the time of construction and the corrected pressure input Qin ′ are values that continuously change in accordance with the change in the penetration speed w, that is, a function of the penetration speed w.
  • the corrected pressure input Qin ′ As the corrected pressure input Qin ′ to be removed from the pressure input Qin, a value corresponding to the penetration speed w during construction of the support layer is used. Therefore, when the tip support force is estimated by the expression (1a *), the correction coefficient ⁇ is a value that is sequentially calculated according to the change in the penetration speed w when the support layer is applied.
  • the tip support force estimation method according to the present embodiment is for estimating the tip support force of the rotary press-fit pile based on the rotational torque T during construction for rotary press-fitting the rotary press-fit pile into the ground.
  • T rotational torque
  • D pile outer diameter
  • the estimated index is H.
  • the press input Qin and the rotational torque T that is a constituent factor of the bearing force estimation index H are measured and input to the computer.
  • the pressure input Qin obtained in the input step and the support force estimation index H are used, and the pressure input Qin, the tip support force Ru, and the support force estimation index H in the rotary press-fit pile are calculated.
  • the tip support force estimation formula expressed by the following formula (1b) formulated from the correlation the tip support force Ru of the rotary press-fit pile is estimated.
  • A2 is the gradient when the approximate line of the plot point of the test result with the X axis as the natural logarithm of the bearing capacity estimation index H and the Y axis as Qin / Ru is expressed by the following equation (2b).
  • B2 is the Y intercept when the approximate line of the plot points of the test result with the X axis as the natural logarithm of the bearing capacity estimation index H and the Y axis as Qin / Ru is expressed by the equation (2b).
  • a logarithmic approximation line by a least square method may be used as the approximation line of the plot points.
  • the tip support force estimation formula expressed by the above formula (1b) is a formula formulated by a construction test and a loading test as described later.
  • the press input Qin and the rotation torque T are continuously measured by a measuring unit provided in the pile rotation press-fitting device 2.
  • the measurement information of the pressure input Qin and the rotational torque T is measured continuously or intermittently during construction for rotationally press-fitting the rotary press-fit pile, and the measured measurement is performed.
  • the tip support force Ru can be calculated from the information based on the tip support force estimation formula expressed by the above-described formula (1b). That is, by using the tip support force estimation formula formulated based on the fact that there is a high correlation among the pressure input Qin at the time of construction, the rotational torque T, and the tip support force Ru, rotational press-fitting is easy and accurate. It is possible to estimate the tip support force Ru of the rotary press-fitted pile constructed by.
  • the rotary press-fit pile can be stopped in a state where a sufficient tip support force Ru can be exhibited. Therefore, as in the case of controlling the stop depending on the depth to the support layer, it is possible to prevent an excessive or insufficient penetration length with respect to the support layer, and it is possible to cope with the unevenness of the support layer.
  • a rotary press-fitting pile 1 is rotationally press-fitted into the actual ground or artificially created ground, and the preset depth at which the rotary press-in construction is stopped (stop depth Z0).
  • the pressure input Qin is controlled so as to be a substantially constant value, although there is some ups and downs due to changes in ground resistance.
  • the stop depth Z0 is a depth at which the tip support force designed based on the pile outer diameter D and the ground conditions used in the construction test can be obtained.
  • the rotational torque T is measured when the tip 1a of the rotary press-fit pile 1 arrives at this section K, with a section about 0.1 times the outer diameter D of the pile as the section K just before stopping, from the stopping depth Z0. The average value is adopted.
  • the loading test the rotary press-fit pile for testing is stopped at a predetermined depth, and then loaded with a load from the vertical direction. And the stress distribution of the pile of a plurality of cross sections is measured in the depth direction, and the peripheral friction force and the tip support force Ru are separated and measured.
  • the loading test is, for example, “pile indentation test”, “pile rapid loading test”, “pile loading test” shown in “Pile vertical loading test method / comment 2002” published by the Geotechnical Society. It may be carried out according to the “impact loading test”.
  • Table 2 shows the presence or absence of excavation bits, pile outer diameter (mm), support layer ground type (sand layer / gravel layer), pressure input Qin (kN), rotational torque T (kN) for tests 1 to 24 as specific examples. Mm), T / 0.5D (kN), tip support force Ru (kN), and Qin / Ru ( ⁇ ).
  • Mm T / 0.5D
  • kN tip support force
  • Qin / Ru ⁇
  • equation (1b-1) which is a tip support force estimation equation corresponding to equation (1), is derived.
  • a sufficient safety factor is taken into consideration with respect to the design formula of the tip support force Ru, and therefore variation is allowed even in the stop management formula. Therefore, it is appropriate to use the expression (1b-1) obtained from the approximate expression of all data.
  • the formula (1b-1) is the tip support force estimation formula from the data of the pressure input Qin and the rotational torque T measured every moment from the pile rotary presser 2 during construction. Can be used to estimate the tip support force Ru.
  • the maximum value of the Qin / Ru point is parallel to the approximate line of equation (2b-1).
  • the formula (2b-1 ′) which is an approximate line indicating the upper limit to be included, may be calculated, and the formula (1b-1 ′) obtained based on this may be used as the tip support force estimation formula.
  • the tip support force estimation formula (1b) is derived by deriving the formula (2b-1 ′), which is an approximated line translated from the formula (2b-1), which is an approximate line based on the least square method of the plot. -1 ′) equation was obtained.
  • the approximate line may be obtained by using an approximation method other than the least square method.
  • the approximate line represented by the above equation (2b-1 ′) may not be obtained by parallel translation with the slope of the approximate line obtained by the least square method being strictly constant.
  • the target plot point It may be a straight line or a curve enveloping.
  • the correction rotational torque Ts and the correction pressure input Qin ′ which are resistance forces in the pushing direction caused by Specifically, the correction coefficient ⁇ 1 expressed by the equation (3b-1) is obtained by removing the corrected rotational torque Ts that is the influence of the pile peripheral surface from the rotational torque T at the time of construction. Further, a correction coefficient ⁇ 2 expressed by the equation (3b-2) is obtained by removing the corrected pressure input Qin ′ from the pressure input Qin at the time of construction. Then, a more precise tip support force Ru can be estimated by using the corrected tip support force estimation formula (1b *) using the correction coefficients ⁇ 1 and ⁇ 2.
  • the third embodiment of the present invention is a tip support force management system (hereinafter referred to as a tip support force management system according to this embodiment) that manages the tip support force of the rotary press-fit pile using the tip support force estimation method described above. And includes a measurement unit, a storage unit, and an arithmetic processing unit.
  • the tip support force management system 10 is a pile rotary press-fit that press-fits the rotary press-fit pile 1 into the ground by moving up and down the gripping part that holds the rotary press-fit pile 1 as described above.
  • the machine 2 is used.
  • This system 10 inputs the measured values (pressure input Qin, penetration speed w, rotational speed ⁇ , rotational torque T) acquired by the pile rotary presser 2 to the computer 3 and supports the tip by the arithmetic processing unit 31 in the computer 3.
  • the force Ru is calculated and estimated.
  • the measured value measured by the pile rotary presser 2 is connected to a computer 3 having an arithmetic processing unit 31 so that it can communicate wirelessly or by wire.
  • the computer 3 includes the arithmetic processing unit 31 and a storage unit 32.
  • the computer 3 may include a display unit 4 that displays the estimated value of the tip support force Ru calculated by the arithmetic processing unit 31.
  • the storage unit 32 incorporates a tip support force estimation formula and a predetermined design tip support force Ra.
  • the measurement values measured by the measurement units 21 and 22 are time series data measured continuously or intermittently in the penetration process of the rotary press-fit pile 1, and these time series data are stored in the storage unit 32. .
  • the pressure input Qin obtained by penetrating a plurality of rotary press-fitting piles into the ground at a plurality of locations before construction, and the tip A tip supporting force estimation formula obtained in advance from the correlation between the supporting force Ru and the supporting force estimation index H may be used.
  • the arithmetic processing unit 31 uses the tip support force estimation formula stored in the storage unit 32 and based on the measurement values (data in the storage unit) input from the measurement units 21 and 22 of the pile rotary press-fitting machine 2. A calculation process for calculating the tip support force Ru is executed. Further, the arithmetic processing unit 31 performs processing for comparing the calculated tip support force Ru with the design tip support force Ra. It is preferable that the processing result (determination result of the estimated tip support force Ru and the design tip support force Ra) is output by the display unit 4 so as to be visible.
  • the design tip support force Ra is the set value of the tip support force required for the rotary press-fit pile to be constructed.
  • the required safety factor A margin may be set accordingly.
  • the penetration of the rotary press-fit pile 1 is stopped based on the tip support force Ru estimated by the tip support force management system 10. That is, in this Embodiment, the construction management of the rotary press-in pile 1 which press-fits the rotary press-in pile 1 with the pile rotary press-in machine 2 using the tip support force management system 10 can be performed.
  • further penetration may be made to ensure a slight margin in order to further improve safety.
  • the pile rotary press machine 2 press-fits the ground while applying rotational force and pressure input to the rotary press-fit pile 1, and, as shown in FIG. 4, press input Qin and support force estimation index (penetration speed w and rotation)
  • press input Qin and support force estimation index penetration speed w and rotation
  • the speed ⁇ or the rotational torque T) is measured by the pressure input measuring unit 21 and the index measuring unit 22, respectively.
  • the pressure input measuring unit 21 for measuring the pressure input Qin a pressure input value for press-fitting the rotary press-fitting pile 1 into the ground G using a hydraulic sensor for detecting the hydraulic pressure of a drive motor provided in the leader of the pile rotary press-fitting machine 2
  • the structure which measures as is adopted For example, it is measured and recorded every time the rotary press pile 1 rotates continuously or about 1/4 rotation or 1/8 rotation in the circumferential direction.
  • the index measurement unit 22 includes, for example, a configuration for measuring a stroke per unit time (penetration speed w) of a gripping part that grips the rotary press-in pile 1 and the rotary press-in pile 1.
  • a configuration in which the rotational speed is measured using an encoder or the like from the rotating portion of the gripping portion to be gripped can be employed.
  • the rotational torque T as a support force estimation parameter
  • adopted is employ
  • the fourth embodiment of the present invention is a construction management method for managing the construction of a rotary press-fit pile using the above-described tip support force estimation method (hereinafter, sometimes referred to as a construction management method according to this embodiment). Yes, it has a measurement process, a calculation process, and a determination process.
  • step S1 the rotary press-fitting machine 2 (2A, 2B) shown in FIGS. 2 and 3 is used to start rotary press-fitting with respect to the ground while applying rotational force and pressure input to the rotary press-fitted pile 1.
  • step S2 in the press input measurement part 21 and index measurement part 22 which are shown in FIG. 4 of the pile rotary press machine 2 during rotary press-fitting, it is a constituent factor of the press input Qin and the supporting force estimation index H, respectively.
  • the penetration speed w and the rotational speed ⁇ or the rotational torque T are measured. The measurement is performed continuously or at a predetermined time pitch.
  • step S3 the tip support force Ru is calculated based on the measured data using the tip support force estimation formula stored in the storage unit 32 in advance.
  • step S ⁇ b> 4 the arithmetic processing unit 31 determines whether or not the calculated tip support force Ru is greater than or equal to the design tip support force Ra stored in advance in the storage unit 32. If the calculated tip support force Ru is greater than or equal to the design tip support force Ra (Ru ⁇ Ra, Step S4: YES), the process proceeds to Step S5. On the other hand, when the calculated tip support force Ru is smaller than the design tip support force Ra (Ru ⁇ Ra, step S4: NO), the process returns to step S2 and continues with the rotary press-fitting operation and each data (pressure input Qin, penetration speed).
  • step S4 if there is a hard thin layer that is not suitable for the support layer in the ground or an obstacle with high hardness, Ru ⁇ Ra may be temporarily satisfied. In such a case, it is not appropriate to stop the press-fitting work.
  • the amount of pile sinking is about 10% of the pile diameter, so it is stable in the section where the length of 10% or more of the pile diameter is penetrated. Then, when it is confirmed that the relationship of Ru ⁇ Ra is obtained, the process may proceed to step S5.
  • the numerical value of the tip support force Ru calculated by the arithmetic processing unit 31, the result of step S4 (the comparison result of the tip support force Ru and the design tip support force Ra), and the like are output via the display unit 4 so as to be visible. It is preferable.
  • step S4 by confirming that the calculated tip support force Ru is greater than or equal to the design support force Ra, a sufficient tip support force is ensured, and the rotary press-fit pile 1 is fixed.
  • step S5 the penetration by the rotary press-fitting of the rotary press-fit pile 1 is stopped and stopped, and the construction is completed.
  • the stop of the rotary press-in pile 1 is to stop the penetration due to the rotary press-in, and after stopping the rotation, stop applying the press input at the time of construction and apply the press input at the time of construction.
  • the rotation may stop after stopping.
  • step S6 the rotary press-fit pile 1 is once lifted at the upper part of the support layer, and in step S7, the correction pressure input Qin ′ related to the influence of the circumferential friction or the correction The rotational torque Ts is measured.
  • step S8 the pressure input Qin when penetrating the support layer and the support force estimation index H (rotational speed ⁇ and penetrating speed w or rotational torque Ts) are measured.
  • step S9 the arithmetic processing unit 31 uses the measured penetration speed w and the corrected pressure input Qin ′, or the measured rotational torque T, pressure input Qin, corrected rotational torque Ts, and corrected pressure input Qin ′.
  • correction coefficients ( ⁇ , ⁇ 1, ⁇ 2 described above) are obtained from the relational expressions stored in the storage unit 32 in advance.
  • the arithmetic processing unit 31 calculates the tip support force Ru based on the measured data using the corrected tip support force estimation formula.
  • step S10 the arithmetic processing unit 31 determines whether or not the calculated tip support force Ru is greater than the value of the design tip support force Ra stored in the storage unit 32 in advance. If the calculated tip support force Ru is greater than or equal to the design tip support force Ra (Ru ⁇ Ra, step S10: YES), the process proceeds to step S5. On the other hand, when the calculated tip support force Ru is smaller than the design tip support force Ra (Ru ⁇ Ra, Step S10: NO), the process returns to Step S8 and continues with each of the data (pressure input Qin, penetration speed) along with the rotary press-in operation. w, rotation speed ⁇ , and rotation torque T) are measured, and the penetration of the rotary press-in pile 1 by rotary press-in is continued.
  • step S10 by confirming that the calculated tip support force Ru is greater than or equal to the design support force Ra, a sufficient tip support force is ensured, and the rotary press-fit pile 1 is fixed.
  • step S5 the penetration by the rotary press-fitting of the rotary press-fit pile 1 is stopped and stopped, and the construction is completed.
  • the tip support force Ru calculated by the tip support force estimation formula formulated in the arithmetic processing unit 31 of the computer 3 is equal to or greater than the design tip support force Ra. Whether or not it is greater than the design tip support force Ra required for the rotary press-fit pile 1 to be constructed, the penetration of the rotary press-fit pile 1 is stopped, and if it is less than the design tip support force Ra, the rotary press-fit pile 1
  • the construction can be managed so that the penetration of
  • the pressure input Qin and the supporting force estimation index H Measurement information of (rotational speed ⁇ and penetration speed w or rotational torque Ts) is measured continuously or intermittently, and the tip support force Ru is calculated from the measured measurement information based on the tip support force estimation formula.
  • the support force estimation index H rotational speed ⁇ and penetration speed w or rotational torque Ts
  • the tip support force Ru of the rotary press-fit pile 1 constructed by rotary press-fitting can be estimated easily and accurately, so that the rotary press-fit pile 1 of the rotary press-fit pile 1 can be estimated according to the estimated tip support force Ru. It can be determined whether or not to continue the penetration.
  • the rotary press-fit pile 1 can be stopped in a state where a sufficient tip support force Ru can be exhibited. Therefore, it is possible to prevent excessive or insufficient penetration length to the support layer, as in the case of controlling the stop by the depth to the support layer, it is possible to cope with the unevenness of the support layer, and to improve the construction quality Can do.
  • the above-described method for estimating the tip bearing force or the construction management method of the rotary press-fit pile is realized by a computer comprising a CPU, a memory, and an interface executing a computer program, and the above-described steps S3 to S4 or S9 to S10 are performed. It is realized by the cooperation of various hardware resources of the computer and the computer program. Further, the computer program described above may be provided by being stored in a non-temporary tangible recording medium that can be read by a computer.
  • Example 1 As a test example, a steel pipe having an outer diameter of 800 mm was applied under the condition that the intermediate layer was 10 m, and a loading test was performed. 12 to 15 show the results as graphs. In these graphs, the vertical axis represents the penetration ratio into the support layer (the penetration amount L (mm) into the support layer divided by the pile outer diameter D (mm)).
  • FIG. 12 is a graph showing the relationship between the penetration ratio L / D and the pressure input Qin (kN).
  • FIG. 13 is a graph showing the relationship between the penetration ratio L / D and the rotational speed ⁇ (rad / min).
  • FIG. 14 is a graph showing the relationship between the penetration ratio L / D and the penetration speed w (mm / min).
  • FIG. 12 is a graph showing the penetration ratio into the support layer (the penetration amount L (mm) into the support layer divided by the pile outer diameter D (mm)).
  • FIG. 12 is a graph showing the relationship between the penetration ratio L / D and the pressure input Qin
  • the tip support force Ru actually obtained from the loading test is in good agreement with the tip support force estimated from the tip support force estimation formula E1. Furthermore, when the tip support force estimation formula E2 is used, it can be confirmed that the tip support force can be sufficiently estimated on the safe side. Therefore, it was confirmed that the estimated value of the tip support force Ru according to the present invention is effective.
  • Example 2 As a test example, a steel pipe having an outer diameter of 800 mm was applied under the condition that the intermediate layer was 10 m, and a loading test was performed. 16 to 18 show the results as graphs. In these graphs, the vertical axis represents the penetration ratio into the support layer (the penetration amount L (mm) into the support layer divided by the pile outer diameter D (mm)).
  • FIG. 16 is a graph showing the relationship between the penetration ratio L / D and the pressure input Qin (kN).
  • FIG. 17 is a graph showing the relationship between the penetration ratio L / D and the rotational torque T (kN ⁇ m).
  • the tip support force Ru actually obtained from the loading test is in good agreement with the tip support force estimated from the tip support force estimation formula E3. Furthermore, when the tip support force estimation formula E4 is used, it can be confirmed that the tip support force can be sufficiently estimated on the safe side. Therefore, it was confirmed that the estimated value of the tip support force Ru according to the present invention is effective.
  • the present invention is limited to the above embodiment. It can be changed as appropriate without departing from the scope of the invention.
  • a screw auger or a hammaglab to drain the earth and sand in the steel pipe of the rotary press-fit pile, or in the steel pipe by discharging the water by piping in the steel pipe
  • An auxiliary method such as a method of loosening the earth and sand or a method of applying vibration using a vibro hammer or the like may be used.
  • the present invention by accurately estimating the tip support force of the rotary press-fitting pile in the rotary press-fitting method, it becomes possible to cope with the unevenness of the support layer, and the construction quality can be improved.

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  • Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Paleontology (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Piles And Underground Anchors (AREA)
  • Placing Or Removing Of Piles Or Sheet Piles, Or Accessories Thereof (AREA)

Abstract

L'invention concerne un procédé d'estimation de la capacité de charge ponctuelle d'un pieu à enfoncement rotatif par estimation de la capacité de charge ponctuelle d'un pieu à enfoncement rotatif composé d'un pieu tubulaire en acier, une extrémité de pointe du pieu étant laissée ouverte, au moment de la construction pour enfoncer en rotation le pieu à enfoncement rotatif dans le sol. Ledit procédé d'estimation de la capacité de charge ponctuelle du pieu à enfoncement rotatif comprend : une étape pour entrer une pression d'enfoncement Qin mesurée au moment de la construction et un indice d'estimation de capacité de charge H ; et une étape d'estimation pour estimer, à l'aide de la pression d'enfoncement Qin et de l'indice d'estimation de capacité de charge H, une capacité de charge ponctuelle Ru du pieu à enfoncement rotatif sur la base d'une formule d'estimation de capacité de charge ponctuelle exprimée par la formule (1), qui est formulée à partir de la corrélation de la pression d'enfoncement Qin du pieu à enfoncement rotatif, la capacité de charge ponctuelle Ru, et l'indice d'estimation de capacité charge H. A : gradient lorsqu'une ligne approximative de points tracés d'un résultat d'essai est exprimée par la formule (2), l'axe X représentant le logarithme naturel de l'indice d'estimation de capacité de charge H, et l'axe Y étant Qin/Ru ; et B : tranche Y lorsqu'une ligne approximative de points tracés d'un résultat d'essai est exprimée par la formule (2), l'axe X représentant le logarithme naturel de l'indice d'estimation de capacité de charge H, et l'axe Y étant Qin/Ru.
PCT/JP2018/012209 2018-03-26 2018-03-26 Procédé d'estimation de capacité de charge ponctuelle d'un pieu à enfoncement rotatif, système de gestion de capacité de charge ponctuelle, procédé de gestion de construction, et programme WO2019186660A1 (fr)

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JP2020510206A JP6856171B2 (ja) 2018-03-26 2018-03-26 回転圧入杭の先端支持力推定方法、先端支持力管理システム、施工管理方法、及びプログラム
PCT/JP2018/012209 WO2019186660A1 (fr) 2018-03-26 2018-03-26 Procédé d'estimation de capacité de charge ponctuelle d'un pieu à enfoncement rotatif, système de gestion de capacité de charge ponctuelle, procédé de gestion de construction, et programme

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06346443A (ja) * 1993-06-07 1994-12-20 Kawasaki Steel Corp 基礎用鋼管杭の打設方法
JPH09279561A (ja) * 1996-04-18 1997-10-28 Shimizu Corp 杭の載荷試験方法および構造物の建設方法
JP2000080650A (ja) * 1998-03-10 2000-03-21 Nippon Steel Corp 回転圧入杭の施工管理方法
JP2000080649A (ja) * 1997-10-30 2000-03-21 Nippon Steel Corp 回転圧入杭の施工管理方法と回転圧入杭
JP2002021076A (ja) * 2000-07-05 2002-01-23 Nippon Steel Corp 回転圧入杭の施工管理システムおよび施工管理方法
JP2015017493A (ja) * 2013-06-14 2015-01-29 株式会社技研製作所 回転圧入杭の先端抵抗推定方法及び推定システム

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6574341B2 (ja) * 2015-06-12 2019-09-11 株式会社技研製作所 先端抵抗力度推定システム、圧入施工システム、及び先端抵抗力度推定方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06346443A (ja) * 1993-06-07 1994-12-20 Kawasaki Steel Corp 基礎用鋼管杭の打設方法
JPH09279561A (ja) * 1996-04-18 1997-10-28 Shimizu Corp 杭の載荷試験方法および構造物の建設方法
JP2000080649A (ja) * 1997-10-30 2000-03-21 Nippon Steel Corp 回転圧入杭の施工管理方法と回転圧入杭
JP2000080650A (ja) * 1998-03-10 2000-03-21 Nippon Steel Corp 回転圧入杭の施工管理方法
JP2002021076A (ja) * 2000-07-05 2002-01-23 Nippon Steel Corp 回転圧入杭の施工管理システムおよび施工管理方法
JP2015017493A (ja) * 2013-06-14 2015-01-29 株式会社技研製作所 回転圧入杭の先端抵抗推定方法及び推定システム

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