Load-displacement relationship estimation method and press-in construction system

Abstract

To provide a load displacement relationship estimation method that can improve estimation accuracy of a load displacement relationship, and a press-in construction system.SOLUTION: A load displacement relationship estimation method includes a design calculation process for calculating design load displacement relationship by using known information about the ground, a simplified horizontal loading test process to penetrate piles into the ground and apply a horizontal load to the piles, to measure horizontal load values and horizontal displacement values, to obtain simplified load-displacement relationship, and an estimation process to calculate a correction coefficient based on the design load displacement relationship and the simplified load displacement relationship, and obtain the estimated load displacement relationship based on the design load displacement relationship and the correction coefficient.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a load-displacement relationship estimation method and a press-in construction system. [Background technology]

[0002] Patent document 1 discloses a method of using a beam-spring model as an example of a method for estimating the load-displacement relationship, which is the relationship between the magnitude of the horizontal load applied to a pile and the magnitude of the horizontal displacement occurring in the pile, based on known information about the ground (for example, various ground conditions obtained from a ground survey). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-83637 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, it is known that the conventional estimation method using a mathematical model such as a beam-spring model tends to overestimate the horizontal displacement. This is thought to be because the conventional estimation method has low estimation accuracy of the load-displacement relationship, and an excessive safety margin must be taken in constructing the mathematical model in order to ensure the safety of construction. The present inventors have considered that the reason for the decrease in estimation accuracy in the conventional estimation method is that the influence of the process of penetrating the pile into the ground is not properly taken into account.

[0005] In addition, the ground is generally often uneven in the horizontal direction. However, from a practical point of view, there are limitations on the locations and number of times that ground investigations can be performed. Therefore, it is not always possible to perform ground investigations at the locations where piles are actually penetrated, and there are many cases where the ground conditions used as input conditions in the mathematical model as described above do not match the ground conditions at the pile penetration position. In addition, there is a possibility that the ground investigation cannot be performed sufficiently, and the ground conditions used as input conditions are insufficient. The present inventors have considered that the inaccuracy of the input conditions as described above is also a factor in the deterioration of the estimation accuracy.

[0006] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a load-displacement relationship estimation method and a press-in construction system that can improve the estimation accuracy of the load-displacement relationship. [Means for solving the problem]

[0007] In order to solve the above problems, a load-displacement relationship estimation method according to one aspect of the present invention is a load-displacement relationship estimation method for obtaining an estimated load-displacement relationship, which is an estimated value of a load-displacement relationship, when a load-displacement relationship is a relationship between a horizontal load value, which is the magnitude of a horizontal load applied to a pile penetrated into the ground, and a horizontal displacement value, which is the magnitude of a horizontal displacement occurring at a representative measurement point provided on the pile, and for calculating the design load-displacement relationship using known information about the ground, when a design load-displacement relationship is a relationship between a horizontal load design value, which is a design value of the horizontal load value, and a horizontal displacement design value, which is a design value of the horizontal displacement value, The method includes a design calculation process, a simplified horizontal load test process of penetrating the pile into the ground and applying a horizontal load to the pile, measuring the horizontal load value and the horizontal displacement value, and obtaining a simplified load-displacement relationship which is the relationship between the horizontal load measurement value which is the measurement value of the horizontal load value and the horizontal displacement measurement value which is the measurement value of the horizontal displacement value, and an estimation process of calculating a correction coefficient which is a value for correcting the difference between the design load-displacement relationship and the load-displacement relationship based on the design load-displacement relationship and the simplified load-displacement relationship, and obtaining the estimated load-displacement relationship based on the design load-displacement relationship and the correction coefficient.

[0008] According to the above aspect of the present invention, it is possible to estimate the load-displacement relationship that reflects both the ground conditions at the pile penetration position and the influence of the pile penetration process. Therefore, the load-displacement relationship can be estimated with high accuracy regardless of the pile penetration method (percussion, vibration, drilling, press-in, etc.). Furthermore, even when there is little information about the ground due to insufficient investigation, etc., and the reliability of the design load-displacement relationship is low, it is possible to suppress a decrease in the estimation accuracy.

[0009] In addition, in the simplified horizontal load test step, a plurality of the horizontal load measurement values ​​and a plurality of the horizontal displacement measurement values ​​may be obtained, and in the estimation step, the correction coefficient may be calculated for each of the plurality of the horizontal load measurement values.

[0010] In this case, there is room to select a correction factor that seems appropriate from among multiple correction factors. Also, when the pile is used as a structure, it is possible to obtain an estimated result that is more in line with the actual conditions of use by selecting a correction factor based on the assumed horizontal load that may be applied to the pile.

[0011] In addition, the horizontal displacement design value is δ des , the horizontal displacement measurement value corresponding to the horizontal displacement design value is expressed as δ meas , where the correction coefficient is α, α=δ meas / δ des may be also possible.

[0012] The horizontal displacement design value is δ des , the horizontal displacement estimate value, which is the estimated value of the horizontal displacement value corresponding to the horizontal displacement design value, is δ est , the correction coefficient is α, then δ est = δ des ×α.

[0013] Furthermore, a pressing-in construction system according to one embodiment of the present invention is a pressing-in construction system that executes any one of the load-displacement relationship estimation methods described above, and includes a pressing-in device capable of performing pressing-in construction to press the pile into the ground, and a computer communicatively connected to the pressing-in device, and the computer executes at least the design calculation process and the estimation process. Effect of the Invention

[0014] According to the above aspects of the present invention, it is possible to provide a load-displacement relationship estimation method and a press-in construction system that can improve the estimation accuracy of the load-displacement relationship. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram showing an example of press-in construction using the press-in construction system according to the present embodiment. [Diagram 2] FIG. 1 is a block diagram showing a configuration of a press-in construction system according to an embodiment of the present invention. [Figure 3A] FIG. 11 is a diagram specifically illustrating data of a load-displacement relationship. [Figure 3B] FIG. 11 is a diagram specifically illustrating data contained in an estimated load-displacement relationship. [Figure 3C] FIG. 11 is a diagram specifically illustrating data of a design load-displacement relationship. [Figure 3D] FIG. 13 is a diagram specifically illustrating data of a simplified load-displacement relationship. [Figure 4] 3 is a flowchart showing a load-displacement relationship estimation method according to the present embodiment. [Figure 5A] FIG. 1 is a two-dimensional plot of a design load-displacement relationship and a simplified load-displacement relationship in a press-in construction system according to an embodiment. [Figure 5B] FIG. 1 is a two-dimensional plot of a design load-displacement relationship, an estimated load-displacement relationship, and a load-displacement relationship in a press-in construction system according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] (Press-in construction system) Hereinafter, the press-in construction system of this embodiment will be described with reference to the drawings. As shown in FIG. 1, the press-in construction system S includes a press-in device 1, a pile 2 to be pressed into ground 4 by the press-in device 1, and a computer 3 connected to the press-in device 1 so as to be able to communicate with it via wired or wireless communication.

[0017] Although the pile 2 in this embodiment is a steel sheet pile with a C-shaped cross section, other types of piles 2 may be adopted. For example, the pile 2 may be a steel pipe pile with an O-shaped cross section. The material of the pile 2 does not have to be steel, and may be, for example, concrete. In this specification, the pile 2 that has been pressed into the ground 4 is particularly called a "completed pile 2A", and the pile 2 before or during pressing is particularly called a "pressed pile 2B". In this embodiment, pressing is adopted as an example of a method for penetrating the pile 2 into the ground 4, but a penetration method other than pressing, such as impact, vibration, or drilling, may be adopted.

[0018] The press-fitting device 1 includes a press-fitting machine body 10, a power unit, a reaction stand, a radio control, a laser sight, etc. (not shown). The press-fitting machine body 10 includes a chuck 10a, a chuck frame 10b, a leader mast 10c, a slide frame 10d, and a clamp unit 10e.

[0019] In this embodiment, the direction in which the pile 2 is inserted is referred to as the up-down direction. The direction perpendicular to the up-down direction is referred to as the horizontal direction. The position in the up-down direction is simply referred to as the height. In the horizontal direction, the direction in which the chuck 10a and the leader mast 10c are aligned is referred to as the front-rear direction (travel direction). The direction perpendicular to both the up-down direction and the front-rear direction is referred to as the left-right direction.

[0020] The chuck 10a is a part that grips the pile 2. The chuck frame 10b is a part that moves the chuck 10a up and down to move the press-in pile 2B up and down. The leader mast 10c is a part that guides the up and down movement of the press-in pile 2B and positions the press-in pile 2B in the left and right direction. The slide frame 10d is a part that positions the press-in pile 2B in the front and rear direction. The clamp section 10e is a part that fixes the press-in machine main body 10 to the ground 4. By the action of each part of the press-in machine main body 10 described above, the completed pile 2A that is aligned in the up and down direction can be installed at a desired position in the ground 4.

[0021] 2, the press-in construction system S of this embodiment includes a horizontal load measuring means 11, a horizontal displacement measuring means 12, and a horizontal loading means (not shown) of the press-in device 1, and a design calculation unit 31 and an estimation unit 32 of the computer 3. The press-in construction system S is a system that estimates the load-displacement relationship D0 of the ground 4 around the pile 2 by the computer 3 that acquires information from the horizontal load measuring means 11 and the horizontal displacement measuring means 12 of the press-in device 1.

[0022] The load-displacement relationship D0 is the relationship between the magnitude of the horizontal load applied to the completed pile 2A (horizontal load value D01a) and the magnitude of the horizontal displacement of the completed pile 2A caused by the horizontal load (horizontal displacement value D01b). In this embodiment, the horizontal displacement refers to the horizontal component of the deviation of the representative measurement point 2a provided on the completed pile 2A from the reference position. The position (height) of the representative measurement point 2a on the completed pile 2A can be arbitrarily set by the user (see FIG. 1). FIG. 3A is a block diagram showing the details of the load-displacement relationship D0. The load-displacement relationship D0 has a plurality of horizontal load values ​​D01a and a plurality of horizontal displacement values ​​D01b. As described above, the horizontal displacement value D01b is a value obtained according to the horizontal load value D01a. In other words, the horizontal displacement value D01b is an output value of a function that uses the horizontal load value D01a as an input value. That is, each horizontal load value D01a has a corresponding horizontal displacement value D01b, and conversely, each horizontal displacement value D01b has a corresponding horizontal load value D01a. A pair of corresponding horizontal load values ​​D01a and D01b is called a load-displacement value pair D01. The load-displacement relationship D0 can be regarded as an array including a plurality of load-displacement value pairs D01.

[0023] Knowing the load-displacement relationship D0 in the ground 4 is particularly important when the completed pile 2A is used as a structure such as a building foundation or a breakwater on the ground 4. This is because the load-displacement relationship D0 is an important index for accurately knowing the horizontal strength of the structure. Furthermore, even when a structure is constructed on the ground 4 separately from the completed pile 2A, the load-displacement relationship D0 is often used to evaluate the behavior of the structure. Therefore, it is important to accurately estimate the load-displacement relationship D0.

[0024] The press-in construction system S is a system that estimates the load-displacement relationship D0 of the ground 4 around the pile 2, and more specifically, is a system that obtains an estimated load-displacement relationship D5 (see FIG. 3B) that is an estimated value of the load-displacement relationship D0. In other words, the purpose of the press-in construction system S is to obtain an estimated load-displacement relationship D5 that is close to the load-displacement relationship D0. As shown in FIG. 3B, the estimated load-displacement relationship D5 can be considered as an array including a plurality of estimated load-displacement value sets D51. Each estimated load-displacement value set D51 has a horizontal load estimated value D51a and a horizontal displacement estimated value D51b that correspond to each other.

[0025] The horizontal loading means is any means capable of applying a horizontal load to the completed pile 2A. The horizontal loading means may be built into or attached to the press-fitting machine body 10, or may be provided separately from the press-fitting machine body 10. In particular, a configuration in which the horizontal loading means is built into or attached to the press-fitting machine body 10 is preferable because it has the effect of eliminating the need to separately prepare a reaction pile or the like required for applying a horizontal load. As the horizontal loading means, for example, a configuration in which the leader mast 10c is rotated to apply a force along the left-right direction to the chuck 10a gripping the completed pile 2A may be adopted. A configuration in which the grip of the completed pile 2A by the chuck 10a is released, the chuck 10a and the completed pile 2A are tied together with a strong string or the like, and the chuck 10a is rotated may be adopted. A configuration in which the chuck 10a gripping the pile 2 is moved in the forward and backward directions by the slide frame 10d may also be adopted. In other words, the details of the configuration are arbitrary as long as it is possible to apply a horizontal load to the completed pile 2A.

[0026] The horizontal load measuring means 11 is some means capable of measuring the magnitude of the horizontal load applied by the horizontal loading means. The horizontal load measuring means 11 may be built in or attached to the press-in machine body 10, or may be provided separately from the press-in machine body 10. For example, a configuration in which a hydraulic sensor or the like is provided in addition to the horizontal loading means can be adopted as the horizontal load measuring means 11. The horizontal displacement measuring means 12 is some means capable of measuring the horizontal displacement of the completed pile 2A. The horizontal displacement measuring means 12 may be built in or attached to the press-in machine body 10, or may be provided separately from the press-in machine body 10. For example, a measuring instrument such as a load cell or a total station can be adopted as the horizontal displacement measuring means 12. The details of the horizontal load measuring means 11 and the horizontal displacement measuring means 12 are also arbitrary as long as they are configured to measure the horizontal displacement or horizontal load.

[0027] The design calculation unit 31 is a part that calculates a design load-displacement relationship D1, which is a design value of the load-displacement relationship D0, based on known information (ground conditions) about the ground 4 obtained in advance by a ground investigation or the like. As shown in Fig. 3C, the design load-displacement relationship D1 can be regarded as an array including a plurality of design load-displacement value pairs D11. Each design load-displacement value pair D11 has a horizontal load design value D11a and a horizontal displacement design value D11b that correspond to each other.

[0028] The estimation unit 32 is a part that calculates an estimated load-displacement relationship D5 (see FIG. 3B) based on the design load-displacement relationship D1 and the simplified load-displacement relationship D3. The estimation unit 32 is also a part that calculates a correction coefficient C that is a value for correcting the difference between the design load-displacement relationship D1 and the load-displacement relationship D0.

[0029] (Load-displacement relationship estimation method) Next, a description will be given of an example of a load-displacement relationship estimation method using the press-in construction system S configured as above. As shown in Fig. 4, the load-displacement relationship estimation method of this embodiment includes a design calculation process S1, a simple horizontal load test process S3, and an estimation process S5.

[0030] Before entering the design calculation process S1, a ground survey or the like is carried out to obtain ground conditions related to the ground 4. The survey may be carried out by the person who executes the load-displacement relationship estimation method of the present embodiment, or may be carried out in advance by another person. Examples of the obtained ground conditions include the so-called N value.

[0031] Next, a design calculation process S1 is performed to calculate a design load-displacement relationship D1, which is a design value of the load-displacement relationship D0, based on known information (ground conditions) about the ground 4. The design calculation process S1 is mainly performed by the design calculation unit 31. An example of the design calculation process S1 will be described below.

[0032] First, a plurality of horizontal load design values ​​D11a are prepared arbitrarily by the user. Next, a mathematical model such as a beam-spring model or a finite element method is constructed based on known information (ground conditions) on the ground 4. In this embodiment, a beam-spring model is used, and a spring constant, a yield point, etc. are set for each of the plurality of springs. Next, for each of the plurality of horizontal load design values ​​D11a, a horizontal displacement design value D11b is calculated based on the constructed beam-spring model. Next, the corresponding horizontal load design value D11a and the horizontal displacement design value D11b are linked to obtain a design load-displacement value set D11. Finally, the design load-displacement relationship D1 is obtained in the form of an array including a plurality of design load-displacement value sets D11. Note that the horizontal displacement design value D11b may be prepared arbitrarily first, and the horizontal load design value D11a may be calculated based on the beam-spring model. In addition, the design load-displacement relationship D1, the design load-displacement value set D11, the horizontal load design value D11a, and the horizontal displacement design value D11b may be stored in the design calculation unit 31 or in the estimation unit 32. Alternatively, they may be stored in a memory (not shown) inside the computer 3.

[0033] Next, a simple horizontal load test process S3 is performed. The simple horizontal load test process S3 is a process for obtaining a simple load-displacement relationship D3. The simple horizontal load test process S3 includes a penetration process S3A, a horizontal loading process S3C, and a data shaping process S3E. In the penetration process S3A, the pile 2 (press-in pile 2B) is penetrated into the ground 4 by the press-in device 1. In the horizontal loading process S3C, a horizontal load is applied to the pile 2 (completed pile 2A) by the horizontal loading means, and the horizontal load value D01a is measured by the horizontal load measuring means 11 and the horizontal displacement value D01b is measured by the horizontal displacement measuring means 12. The actual measurement value of the horizontal load value D01a obtained by the horizontal load measuring means 11 is referred to as a horizontal load measurement value D31a (hereinafter, see FIG. 3D). The actual measurement value of the horizontal displacement value D01b obtained by the horizontal displacement measuring means 12 is referred to as a horizontal displacement measurement value D31b. The horizontal load measurement value D31a and the horizontal displacement measurement value D31b are time-series data that are measured continuously or intermittently. The horizontal load measurement value D31a and the horizontal displacement measurement value D31b that are measured simultaneously correspond to each other.

[0034] In the data shaping step S3E, as shown in FIG. 3D, each horizontal load measurement value D31a and each horizontal displacement measurement value D31b are linked as a simplified load-displacement value set D31 based on the above-mentioned correspondence relationship. In addition, a simplified load-displacement relationship D3 is obtained as an array including a plurality of simplified load-displacement value sets D31. As described above, the simplified horizontal load test step S3 is a step of obtaining a simplified load-displacement relationship D3, which is a relationship between the horizontal load measurement value D31a and the horizontal displacement measurement value D31b. The data shaping step S3E may be performed by the horizontal load measuring means 11, the horizontal displacement measuring means 12, the estimation unit 32, or a data shaping unit (not shown) provided inside the press-fitting device 1 or the computer 3. In addition, the simplified load-displacement relationship D3, the simplified load-displacement value set D31, the horizontal load measurement value D31a, and the horizontal displacement measurement value D31b may be stored in the horizontal load measuring means 11, the horizontal displacement measuring means 12, or the estimation unit 32, or may be stored in the data shaping unit or memory described above.

[0035] Incidentally, for example, when the completed pile 2A is used as a structure, a horizontal load strong enough to cause large plastic deformation of the ground 4 should not be applied to the completed pile 2A. This is because it leads to a decrease in the ability of the ground 4 to hold the structure. Therefore, the horizontal loading step S3C is often performed in a range where large plastic deformation does not occur in the ground 4. Therefore, the simplified load-displacement relationship D3 obtained in the simplified horizontal loading test step S3 often does not include the simplified load-displacement value set D31 (horizontal load measurement value D31a) corresponding to a state where the ground 4 causes large plastic deformation. In other words, it is difficult to know the horizontal displacement value D01b that occurs when a strong horizontal load (large horizontal load value D01a) is suddenly applied to the completed pile 2A (structure) from only the simplified load-displacement value set D31.

[0036] On the other hand, since the design calculation process S1 is based on a mathematical model, the design load-displacement relationship D1 may include a design load-displacement value set D11 (horizontal load design value D11a) corresponding to a state in which the ground 4 undergoes large plastic deformation. However, since the design load-displacement relationship D1 is calculated using information obtained by ground investigation, it is difficult to consider the influence of the process of penetrating the press-in pile 2B into the ground 4. In addition, as described above, the investigation is not necessarily performed at the penetration position of the completed pile 2A, so that the input conditions of the mathematical model used in the design calculation process S1 may differ from the input conditions that should actually be used (ground conditions at the penetration position). For the above reasons, the design load-displacement relationship D1 calculated in the design calculation process S1 is not necessarily accurate.

[0037] Therefore, in the load-displacement relationship estimation method of this embodiment, an estimated load-displacement relationship D5 is calculated based on the design load-displacement relationship D1 and the simplified load-displacement relationship D3 in the estimation step S5 described below. By combining the simplified load-displacement relationship D3, which is accurate but has a limited range of data, with the design load-displacement relationship D1, which has a sufficient range of data but lacks accuracy, it is expected that an estimated load-displacement relationship D5, which is accurate and has a sufficient range of data, can be obtained.

[0038] The estimation process S5 is mainly performed by the estimation unit 32. The estimation process S5 includes a correction coefficient calculation process S5A and an estimated load-displacement relationship calculation process S5C. The correction coefficient calculation process S5A is a process in which a correction coefficient C is calculated based on the design load-displacement relationship D1 obtained in the design calculation process S1 and the simplified load-displacement relationship D3 obtained in the simplified horizontal load test process S3. The estimated load-displacement relationship calculation process S5C is a process in which an estimated load-displacement relationship D5 is calculated based on the design load-displacement relationship D1 obtained in the design calculation process S1 and the correction coefficient C obtained in the correction coefficient calculation process S5A.

[0039] An example of the correction coefficient calculation step S5A is shown below. First, the simplified load-displacement value set D31 is arbitrarily selected by the user from the simplified load-displacement relationship D3. Next, the horizontal load measurement value D31a included in the selected simplified load-displacement value set D31 is referenced, and the design load-displacement value set D11 having the horizontal load design value D11a having the same value as the horizontal load measurement value D31a is selected. That is, the simplified load-displacement value set D31 and the corresponding design load-displacement value set D11 are selected one by one. If there is no horizontal load design value D11a having the same value as the horizontal load measurement value D31a, the design calculation step S1 may be redone based on a new horizontal load design value D11a, and the design load-displacement relationship D1 may be calculated again. Alternatively, the simplified load-displacement relationship D3 may be complemented (the simplified load-displacement value set D31 may be added) based on a statistical method or the like. Alternatively, the design calculation step S1 and the simplified horizontal load test step S3 may be performed in advance so that the horizontal load design value D11a and the horizontal load measurement value D31a are consistent with each other. Alternatively, the design load-displacement value set D11 may be selected first, and then the simplified load-displacement value set D31 corresponding to the design load-displacement value set D11 may be selected. Next, the ratio between the horizontal displacement design value D11b included in the selected design load-displacement value set D11 and the horizontal displacement measurement value D31b included in the selected simplified load-displacement value set D31 is calculated, and the value of the ratio is set as the correction coefficient C. In other words, the selected horizontal displacement design value D11b is multiplied by δ des , the horizontal displacement measurement value D31b corresponding to the horizontal displacement design value D11b is expressed as δ meas When the correction coefficient C is α, the following formula (1) holds.

[0040]

number

[0041] An example of the estimated load-displacement relationship calculation step S5C is shown below. First, each of the multiple horizontal load design values ​​D11a included in the design load-displacement relationship D1 is copied and set as a horizontal load estimated value D51a. Next, each of the multiple horizontal displacement design values ​​D11b included in the design load-displacement relationship D1 is multiplied by a correction coefficient C, and the obtained value is set as a horizontal displacement estimated value D51b. That is, each of the multiple horizontal load design values ​​D11a is multiplied by F i des , each of the multiple horizontal displacement design values ​​D11b is δ i clac , each of the multiple horizontal load estimates D51a is F i est , each of the multiple horizontal displacement estimates D51b is δ i est Then, the following formulas (2) and (3) are established: Here, N is the number of design load-displacement value pairs D11 included in the design load-displacement relationship D1.

[0042]

number

[0043]

number

[0044] In the above example, a single simplified load-displacement value set D31 (horizontal load measurement value D31a) is selected when calculating the correction coefficient C, but multiple simplified load-displacement value sets D31 may be selected. In this case, multiple correction coefficients C may be calculated. More specifically, a correction coefficient C may be calculated for each of the selected multiple horizontal load measurement values ​​D31a, and multiple estimated load-displacement relationships D5 may also be calculated accordingly. In other words, each of the multiple horizontal displacement measurement values ​​D31b selected to calculate the correction coefficient C from the multiple horizontal displacement design values ​​D11b may be calculated as δj meas , and the corresponding horizontal displacement design value D11b is δ j des , each of the multiple correction coefficients C is α j , the horizontal displacement estimate D51b calculated based on each correction coefficient C is expressed as δ i j、est Then, the following formulas (4) and (5) are established. Note that M is the number of calculated correction coefficients C (the number of estimated load-displacement relationships D5) and can take a value between 1 and N.

[0045]

number

[0046]

number

[0047] When multiple correction coefficients C and estimated load-displacement relationships D5 are calculated as described above, there is room to select an appropriate correction coefficient C and estimated load-displacement relationship D5 from the multiple correction coefficients C according to the condition of the ground 4. Furthermore, when the pile 2 (completed pile 2A) is used as a structure, an estimated load-displacement relationship D5 that is more suited to the actual use conditions can be obtained by selecting the correction coefficient C in consideration of the horizontal load value D01a that can be applied to the completed pile 2A.

[0048] As described above, the load-displacement relationship estimation method of this embodiment can calculate a single or multiple estimated load-displacement relationships D5 (and correction coefficients C) through the design calculation process S1, the simplified horizontal load test process S3, and the estimation process S5. Note that the above-mentioned calculation method is an example, and may be modified as appropriate.

[0049] Next, the operation of the press-in construction system S configured as above and the load-displacement relationship estimation method using the press-in construction system S will be described.

[0050] In the conventional estimation method using a mathematical model such as a beam-spring model, the estimated value of the horizontal displacement value D01b was overestimated. This is thought to be because the estimation accuracy of the load-displacement relationship D0 in the conventional estimation method is low, and an excessive safety margin must be taken in constructing a mathematical model to ensure the safety of construction. The inventors of the present application have considered that the reason for the decrease in estimation accuracy in the conventional estimation method is that the influence of the process of penetrating the pile 2 (press-in pile 2B) into the ground 4 is not properly taken into consideration. For example, when the press-in pile 2B penetrates the ground 4, the soil displaced by the press-in pile 2B is compressed around the press-in pile 2B. For this reason, it is expected that the ground around the completed pile 2A will harden and the horizontal displacement value D01b will become smaller.

[0051] In addition, the ground 4 is generally often uneven in the horizontal direction. However, from a practical point of view, there are limitations on the points and the number of times that a ground investigation can be performed. Therefore, a ground investigation cannot always be performed at the point where the press-in pile 2B is actually penetrated, and there is a possibility that the ground conditions used as input conditions in the mathematical model as described above do not match the ground conditions at the penetration position of the press-in pile 2B. In addition, there is a possibility that the ground investigation cannot be performed sufficiently, and the ground conditions used as input conditions are insufficient. The present inventors have considered that the inaccuracy of the input conditions as described above is also a factor in the deterioration of the estimation accuracy.

[0052] In contrast, in the load-displacement relationship estimation method of the present embodiment, in addition to obtaining the design load-displacement relationship D1 using the mathematical model, the horizontal load measurement value D31a and the horizontal displacement measurement value D31b (simplified load-displacement relationship D3) are measured using the completed pile 2A. Then, a correction coefficient C is calculated based on the design load-displacement relationship D1 and the simplified load-displacement relationship D3, and the correction coefficient C is incorporated into the calculation of the estimated load-displacement relationship D5. This makes it possible to obtain the estimated load-displacement relationship D5 taking into account the influence of the process of penetrating the press-in pile 2B into the ground 4. In addition, since the calculation result (design load-displacement relationship D1) by the mathematical model is corrected by the correction coefficient C, it is possible to prevent the actual load-displacement relationship D0 and the estimated load-displacement relationship D5 from deviating from each other even when the reliability of the input conditions of the mathematical model is low. As described above, by using the load-displacement relationship estimation method of the present embodiment, an estimated value of the load-displacement relationship D0 (estimated load-displacement relationship D5) can be obtained with higher accuracy than the conventional estimation method.

[0053] In particular, when the completed pile 2A is used as a structure such as a foundation for a building or a breakwater, it can be confirmed whether the completed pile 2A can exert the desired strength in the ground 4 based on the obtained estimated load-displacement relationship D5. For example, when the horizontal displacement estimated value D51b is greater than the desired value, it is considered that the strength of the completed pile 2A is insufficient and that the design (shape, press-in depth, etc.) of the completed pile 2A needs to be reviewed. On the other hand, when the horizontal displacement estimated value D51b is less than the desired value, it is considered that the strength of the completed pile 2A is excessive. Here, when the completed pile 2A can be redesigned and reconstructed, an appropriate redesign can be performed by reflecting the above-mentioned confirmation results. This makes it possible to suppress an increase in construction costs due to the excessive strength of the completed pile 2A while ensuring the strength of the completed pile 2A.

[0054] As described above, the load-displacement relationship estimation method of the present embodiment is a method for obtaining an estimated load-displacement relationship D5, which is an estimated value of the load-displacement relationship D0, when the load-displacement relationship D0 is the relationship between the horizontal load value D01a, which is the magnitude of the horizontal load applied to the pile 2 penetrated into the ground 4, and the horizontal displacement value D01b, which is the magnitude of the horizontal displacement generated at the representative measurement point 2a provided on the pile 2. When the design load-displacement relationship D1 is the relationship between the horizontal load design value D11a, which is the design value of the horizontal load value D01a, and the horizontal displacement design value D11b, which is the design value of the horizontal displacement value D01b, the design load-displacement relationship D1 is calculated using known information about the ground 4. The method includes a design calculation process S1, a simplified horizontal loading test process S3 in which the pile 2 is penetrated into the ground 4 while applying a horizontal load to the pile 2, and the horizontal load value D01a and horizontal displacement value D01b are measured to obtain a simplified load-displacement relationship D3 which is the relationship between a horizontal load measurement value D31a which is the measurement value of the horizontal load value D01a, and a horizontal displacement measurement value D31b which is the measurement value of the horizontal displacement value D01b, and an estimation process S5 in which a correction coefficient C which is a value for correcting the difference between the design load-displacement relationship D1 and the load-displacement relationship D0 is calculated based on the design load-displacement relationship D1 and the simplified load-displacement relationship D3, and an estimated load-displacement relationship D5 is obtained based on the design load-displacement relationship D1 and the correction coefficient C.

[0055] Further, the pressing-in construction system S of this embodiment is a pressing-in construction system that executes the above-mentioned load-displacement relationship estimation method, and includes a pressing-in device 1 capable of performing pressing construction to press a pile 2 into the ground 4, and a computer 3 communicatively connected to the pressing-in device 1, and the computer 3 executes at least the design calculation process S1 and the estimation process S5.

[0056] With these configurations, it is possible to obtain an estimated load-displacement relationship D5 that reflects both the ground conditions at the penetration position of the pile 2 and the effects of the penetration process of the pile 2. Therefore, it is possible to obtain a highly accurate estimated load-displacement relationship D5 regardless of the penetration method of the pile 2 (percussion, vibration, drilling, press-in, etc.). Furthermore, even when there is little known information about the ground 4 due to insufficient investigation, etc., and the reliability of the design load-displacement relationship D1 is low, it is possible to suppress a decrease in the estimation accuracy.

[0057] In addition, in the simplified horizontal load test step S3, a plurality of horizontal load measurement values ​​D31a and a plurality of horizontal displacement measurement values ​​D31b are obtained, and in the estimation step S5, the correction coefficient C may be calculated for each of the plurality of horizontal load measurement values. In this case, there is room to select a correction coefficient that is considered appropriate.

[0058] In addition, the horizontal displacement design value D11b is δ des , the horizontal displacement measurement value D31b corresponding to the horizontal displacement design value D11b is expressed as δ meas , where the correction coefficient C is α, then α=δ meas / δ des It is.

[0059] In addition, the horizontal displacement design value D11b is δ des , the horizontal displacement estimated value D51b, which is the estimated value of the horizontal displacement value D01b corresponding to the horizontal displacement design value D11b, is expressed as δ est , the correction coefficient C is α, and then δ est = δ des ×α. EXAMPLES

[0060] The above embodiment will be described below using specific examples, but the present invention is not limited to the following examples.

[0061] Using the press-in construction system S and the load-displacement relationship estimation method according to the above embodiment, an estimated load-displacement relationship D5 in a certain ground was calculated. Note that multiple correction coefficients C were calculated, and multiple estimated load-displacement relationships D5 were also calculated accordingly.

[0062] FIG. 5A is a two-dimensional plot of the design load-displacement relationship D1 and the simplified load-displacement relationship D3. The correction coefficients 1 to 6 represent the correction coefficients C calculated multiple times. FIG. 5B is a two-dimensional plot of the design load-displacement relationship D1, multiple estimated load-displacement relationships D5, and the load-displacement relationship D0. The estimated load-displacement relationships 1 to 6 are the estimated load-displacement relationships D5 corresponding to the correction coefficients 1 to 6, respectively. The scale of the design load-displacement relationship D1 is different between FIG. 5A and FIG. 5B, but this is because the height of the representative measurement point 2a described above is different between FIG. 5A and FIG. 5B. The load-displacement relationship D0 is a measured value. In order to measure the load-displacement relationship D0, an experiment was conducted by exceptionally allowing a strong horizontal load that caused the ground to undergo large plastic deformation.

[0063] 5B, the estimated load-displacement relationship D5 (estimated load-displacement relationships 1 to 6) have a higher estimation accuracy of the load-displacement relationship D0 than the design load-displacement relationship D1. In this way, by calculating the correction coefficient C based on the design load-displacement relationship D1 and the simplified load-displacement relationship D3, and calculating the estimated load-displacement relationship D5 based on the design load-displacement relationship D1 and the correction coefficient C, the estimation accuracy of the load-displacement relationship D0 can be improved.

[0064] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0065] For example, in the above embodiment, the estimated load-displacement relationship D5 is obtained by correcting the design load-displacement relationship D1 using the correction coefficient C, but a mathematical model such as a beam-spring model may be corrected using the simplified load-displacement relationship D3. Also, the design load-displacement relationship D1 may be calculated again based on the corrected mathematical model.

[0066] In the above embodiment, the estimated load-displacement relationship D5 is obtained for the completed pile 2A, but the estimated load-displacement relationship D5 may be obtained for the pressed-in pile 2B during pressing. More specifically, the estimated load-displacement relationship D5 may be obtained for each pressing depth of the pressed-in pile 2B. This configuration is effective when the completed pile 2A is used as a structure under conditions where a sufficient ground investigation cannot be performed (the reliability of the design load-displacement relationship D1 is low), such as emergency construction immediately after a disaster. By adopting this configuration, the pressing depth of the pressed-in pile 2B required to ensure that the ground 4 has a sufficient force to support the completed pile 2A can be determined while the pressing construction is proceeding.

[0067] Moreover, the horizontal load measuring means 11 , the horizontal displacement measuring means 12 , and the horizontal loading means may be provided separately from the press-fitting device 1 .

[0068] In addition, within the scope of the spirit of the present invention, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, and the above-described embodiments and variations may be combined as appropriate. [Explanation of symbols]

[0069] S…Press-in construction system 1…Press-in device 2…Pile 3…Computer 4…Ground D0…Load-displacement relationship D01a…Horizontal load value D01b…Horizontal displacement value D1…Design load-displacement relationship D11a…Horizontal load design value D11b…Horizontal displacement design value D3…Simplified load-displacement relationship D31a…Horizontal load measurement value D31b…Horizontal displacement measurement value D5…Estimated load-displacement relationship D51a…Horizontal load estimation value D51b…Horizontal displacement estimation value C…Correction coefficient S1…Design calculation process S3…Simplified horizontal load test process S5…Estimation process

Claims

1. A load-displacement relationship estimation method for obtaining an estimated load-displacement relationship, which is an estimated value of a load-displacement relationship, when a relationship between a horizontal load value, which is the magnitude of a horizontal load applied to a pile penetrated into the ground, and a horizontal displacement value, which is the magnitude of a horizontal displacement occurring at a representative measurement point provided on the pile, is defined as a load-displacement relationship, a design calculation process for calculating a design load-displacement relationship between a horizontal load design value, which is a design value of the horizontal load value, and a horizontal displacement design value, which is a design value of the horizontal displacement value, using known information about the ground; A simplified horizontal load test process in which the pile is penetrated into the ground and a horizontal load is applied to the pile, the horizontal load value and the horizontal displacement value are measured, and a simplified load-displacement relationship is obtained, which is a relationship between a horizontal load measurement value, which is a measurement value of the horizontal load value, and a horizontal displacement measurement value, which is a measurement value of the horizontal displacement value; an estimation step of calculating a correction coefficient, which is a value for correcting a difference between the design load-displacement relationship and the load-displacement relationship, based on the design load-displacement relationship and the simplified load-displacement relationship, and obtaining the estimated load-displacement relationship based on the design load-displacement relationship and the correction coefficient, The design load-displacement relationship includes both the horizontal displacement design value corresponding to a non-plastic deformation range, which is a range of the horizontal load value in which the ground does not plastically deform, and the horizontal displacement design value corresponding to a plastic deformation range, which is a range of the horizontal load value in which the ground plastically deforms, In the simple horizontal load test step, a horizontal load is applied to the pile in the non-plastic deformation range, The estimation step includes calculating the correction coefficient based on the horizontal displacement design value and the horizontal displacement measurement value in the non-plastic deformation range, and obtaining a horizontal displacement estimation value that is an estimation value of the horizontal displacement value in the plastic deformation range based on the correction coefficient and the horizontal displacement design value in the plastic deformation range. When the design horizontal displacement value in the non-plastic deformation range is δ des1 , the measured horizontal displacement value corresponding to the same horizontal load value as the design horizontal displacement value is δ meas , and the correction coefficient is α, α=δ meas / δ des1 ; The load-displacement relationship estimating method, wherein δ est =δ des2 ×α is satisfied, where δ des2 is the design horizontal displacement value in the plastic deformation range, and δ est is the estimated horizontal displacement value corresponding to the same horizontal load value as the design horizontal displacement value.

2. In the simplified horizontal load test step, a plurality of horizontal load measurements and a plurality of horizontal displacement measurements are obtained, The load-displacement relationship estimating method according to claim 1 , wherein in the estimating step, the correction coefficient is calculated for each of the plurality of horizontal load measurement values.

3. A press-in construction system for executing the load-displacement relationship estimation method according to claim 1 or 2, A press-in device capable of performing press-in construction to press the pile into the ground; A computer communicatively connected to the press-fitting device; A horizontal loading means for applying a horizontal load to the pile; A horizontal load measuring means for measuring the horizontal load value; a horizontal displacement measuring means for measuring the horizontal displacement value, The computer executes at least the design calculation step and the estimation step.

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