Estimation device and estimation method

Abstract

To reproduce a liquefaction strength curve, and simultaneously and more accurately reproduce characteristics indicating a shear strain development process than a liquefaction parameter estimated from only the liquefaction strength curve.SOLUTION: An estimation device 10 sets characteristics indicating a liquefaction strength curve and a shear strain development process as targets of a reproduction object using a liquefaction parameter, sets an initial value for the liquefaction parameter, and estimates the liquefaction parameter so that each error of the characteristics indicating the liquefaction strength curve and the shear strain development process estimated from the liquefaction parameter, and the characteristics indicating the liquefaction strength curve and the shear strain development process set as the targets is equal to or less than an allowable error.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an estimation device and an estimation method, and more particularly, to an estimation device and an estimation method for estimating liquefaction parameters capable of reproducing a target liquefaction strength curve and characteristics representing the development process of shear strain.

Background Art

[0002] Patent Document 1 discloses an estimation device that estimates a liquefaction strength curve according to the type of selected sandy soil using a liquefaction strength curve estimation processing program.

[0003] Patent Document 2 discloses an estimation device that generates a relationship between an increment of normalized cumulative dissipated energy obtained by dividing the cumulative dissipated energy of a specimen by the effective confinement pressure of the specimen at the start of the n-th repeated loading, and a cyclic stress ratio of the repeated loading obtained by dividing the shear stress of the repeated loading by the effective confinement pressure at the n-th time, generates a relationship between the normalized cumulative dissipated energy obtained by dividing the cumulative dissipated energy by the effective confinement pressure at the n-th time and the excess pore water pressure ratio obtained by dividing the excess pore water pressure by the initial effective confinement pressure, and estimates a liquefaction strength curve based on the relationship between the increment of the normalized cumulative dissipated energy and the cyclic stress ratio and the relationship between the normalized cumulative dissipated energy and the excess pore water pressure ratio.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] When repeated forces act on the ground, a design that takes into account the reduction in ground strength due to liquefaction is required. Therefore, when analyzing the state of the ground using analytical software that can consider ground liquefaction, it may be necessary to estimate liquefaction parameters by the analytical software that can reproduce the target liquefaction strength curve obtained from indoor soil tests or the like.

[0006] On the other hand, the liquefaction strength curve shows the number of repeated loadings when the shear strain of the ground reaches a specified magnitude. That is, the liquefaction strength curve does not include information on the development process of the shear strain representing the state of the shear strain until the shear strain of the ground reaches the specified magnitude and after the shear strain of the ground exceeds the specified magnitude.

[0007] Therefore, even if liquefaction parameters that can faithfully reproduce the liquefaction strength curve are obtained by a conventional estimation device, the characteristics representing the development process of the shear strain obtained from the liquefaction parameters may be significantly different from the actual characteristics.

[0008] The present invention has been made in view of the above facts, and an object of the present invention is to provide an estimation device and an estimation method for estimating liquefaction parameters that can reproduce the liquefaction strength curve and, at the same time, can more accurately reproduce the characteristics representing the development process of the shear strain than the liquefaction parameters estimated only from the liquefaction strength curve.

Means for Solving the Problems

[0009] To achieve the above object, the estimation device of the present invention includes a processor, and the processor Target defines the liquefaction strength curve and the characteristics representing the development process of the shear strain, and Set at the same time, Used for the analysis of the liquefaction characteristics of the ground represented by the characteristics representing the liquefaction strength curve and the development process of the shear strain sets the liquefaction parameters As the initial value, the liquefaction parameter estimated by setting only the liquefaction strength curve as the target so that each error between the liquefaction strength curve estimated from the liquefaction parameters and the characteristics representing the development process of the shear strain, and the liquefaction strength curve and the characteristics representing the development process of the shear strain set as the target are within a predetermined range.By repeatedly correcting, the liquefaction parameter corresponding to the liquefaction characteristics of the ground represented by the characteristics representing the target liquefaction strength curve and the development process of the shear strain It is estimated. Thus, according to the estimation device of the present invention, not only the liquefaction strength curve but also the characteristics representing the development process of shear strain are set as the targets to be reproduced using the liquefaction parameters for the estimation device. Therefore, while reproducing the liquefaction strength curve, it is possible to accurately reproduce the characteristics representing the development process of shear strain more accurately than the liquefaction parameters estimated only from the liquefaction strength curve.

[0010] In addition, the present invention sets the characteristics representing the relationship between shear stress and shear strain, the characteristics representing the relationship between shear strain and the number of repeated loadings, the characteristics representing the relationship between the excess pore water pressure ratio and the number of repeated loadings, or the effective stress path as the characteristics representing the development process of the shear strain. Thus, according to the estimation device of the present invention, as the characteristics representing the development process of shear strain, any one or more of a plurality of characteristics can be set as the target to be reproduced using the liquefaction parameters. Therefore, even when the characteristics representing the development process of a specific type of shear strain cannot be obtained, it is possible to estimate the liquefaction parameters using the characteristics representing the development process of other available types of shear strain.

Effect of the Invention

[0012] According to the present invention, there is an effect that it is possible to estimate the liquefaction parameters that can accurately reproduce the characteristics representing the development process of shear strain more accurately than the liquefaction parameters estimated only from the liquefaction strength curve while reproducing the liquefaction strength curve.

Brief Description of the Drawings

[0013]

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Mode for Carrying Out the Invention

[0014] Hereinafter, this embodiment will be described with reference to the drawings. Note that the same components and the same processing are given the same reference numerals throughout the drawings, and duplicate explanations are omitted.

[0015] FIG. 1 is a diagram showing a functional configuration example of the estimation device 10 according to this embodiment. The estimation device 10 is a device that estimates liquefaction parameters for reproducing characteristics representing the development process of the liquefaction strength curve and shear strain.

[0016] Here, the "liquefaction strength curve" is a characteristic of the ground obtained by performing repeated undrained triaxial tests on specimens collected from the ground, and is expressed as the change in the repeated stress ratio (hereinafter referred to as the "stress ratio") with respect to the number of repeated loadings.

[0017] Further, the "characteristics representing the development process of shear strain" refer to the characteristics representing the temporal change in physical properties that occur when shear strain is generated in a substance. Therefore, the characteristics representing the development process of shear strain include, for example, the characteristics representing the relationship between shear stress and shear strain, the characteristics representing the relationship between shear strain and the number of repeated loadings, the characteristics representing the relationship between the excess pore water pressure ratio and the number of repeated loadings, and the effective stress path. However, these characteristics are only examples of the characteristics representing the development process of shear strain.

[0018] Further, the "liquefaction parameter" is a parameter used for analyzing the liquefaction characteristics of the ground, and specifically, it is a parameter for controlling the progress of liquefaction. For example, in the 2D cocktail glass model element parameter determination support program (FLIPCSIM (registered trademark)) provided by the FLIP Consortium, the liquefaction characteristics of the ground are analyzed using the liquefaction parameters of S1, W1, P1, P2, and C1.

[0019] Here, S1 is a liquefaction parameter that defines the final state of liquefaction and defines the lower limit value of the liquefaction front parameter S0 that represents the degree of progress of liquefaction. W1 is a liquefaction parameter that defines the overall behavior of liquefaction, and specifically, it defines the liquefaction strength. P1 is a liquefaction parameter that defines the behavior in the first half of liquefaction, and specifically, it defines the rising characteristics of the excess pore water pressure in the first half. P2 is a liquefaction parameter that defines the behavior in the second half of liquefaction, and specifically, it defines the rising characteristics of the excess pore water pressure in the second half. C1 is a liquefaction parameter related to the lower limit value of the shear stress ratio for liquefaction.

[0020] An estimation device 10 for estimating such liquefaction parameters includes each functional unit of a reception unit 12, an estimation unit 14, and a display unit 16, and a parameter DB 18.

[0021] The reception unit 12 receives various instructions from the user, and the liquefaction strength curve and the characteristics representing the development process of shear strain that are set as the target of reproduction using the liquefaction parameters. Further, the reception unit 12 receives the initial values of the liquefaction parameters from the user.

[0022] The estimating unit 14 estimates the liquefaction parameters while updating the liquefaction parameters so that the respective errors between the liquefaction strength curve estimated from the liquefaction parameters and the characteristics representing the development process of the shear strain, and the characteristics representing the liquefaction strength curve and the development process of the shear strain received by the receiving unit 12 fall within a predetermined range. The estimated liquefaction parameters are stored in a parameter DB (Database).

[0023] Note that the estimating device 10 does not necessarily need to include a parameter DB. For example, a parameter DB may be constructed in an external device connected by a communication line (not shown) such as the Internet. In the following description, it is assumed that a parameter DB is constructed in the estimating device 10.

[0024] The display unit 16 displays the estimated liquefaction parameters on the screen. Note that the estimating device 10 may notify the user of the liquefaction parameters in another form instead of, or in addition to, displaying the liquefaction parameters on the screen. Specifically, the estimating device 10 may transmit the liquefaction parameters to an external device connected by a communication line, or the estimating device 10 may print the liquefaction parameters on paper using an image forming device such as a printer.

[0025] The estimating device 10 shown in FIG. 1 is configured using, for example, a computer 20. FIG. 2 is a diagram showing a main part configuration example of the electrical system in the estimating device 10 configured using the computer 20.

[0026] The computer 20 includes a CPU (Central Processing Unit) 21 that undertakes the processing of each functional unit related to the estimation device 10 shown in FIG. 1, and a ROM (Read Only Memory) 22 that stores an estimation program for causing the computer 20 to function as the estimation device 10. Further, the computer 20 includes a RAM (Random Access Memory) 23 used as a temporary working area for the CPU 21, a non-volatile memory 24, and an input / output interface (I / O) 25. The CPU 21, ROM 22, RAM 23, non-volatile memory 24, and I / O 25 are respectively connected via a bus 26.

[0027] The non-volatile memory 24 is an example of a storage device that maintains stored data even when the power supplied to the non-volatile memory 24 is cut off. For example, a semiconductor memory is used, but a hard disk may also be used. In the non-volatile memory 24, for example, a parameter DB 18 is constructed. The non-volatile memory 24 does not necessarily have to be built into the computer 20 and may be a portable storage medium detachable from the computer 20, such as a USB (Universal Serial Bus) memory or a memory card.

[0028] Connected to the I / O 25 are, for example, an input unit 27 and a display unit 28.

[0029] The input unit 27 is a unit that receives an instruction from the user and notifies the CPU 21. For example, buttons, a touch panel, a keyboard, a mouse, etc. are used.

[0030] The display unit 28 is a device that visually notifies the user of the information processed by the CPU 21. For example, the estimated liquefaction parameters are displayed. For the display unit 28, for example, a liquid crystal display or an organic EL (Electro Luminescence) display is used.

[0031] Note that the units connected to the I / O 25 of the computer 20 are not limited to the units shown in FIG. 2. For example, when connecting the estimation device 10 to a communication line, a communication unit is connected to the I / O 25. The communication unit includes a communication protocol for performing data communication with an external device connected to the communication line.

[0032] Next, the operation of the estimation device 10 will be described in detail.

[0033] FIG. 3 is a flowchart showing an example of the flow of the estimation process executed by the CPU 21 of the estimation device 10 when receiving an estimation instruction of the liquefaction parameter from the user.

[0034] The estimation program that defines the estimation process is stored in advance, for example, in the ROM 22 of the estimation device 10. The CPU 21 of the estimation device 10 reads the estimation program stored in the ROM 22 and executes the estimation process.

[0035] Note that the estimation device 10 is assumed to have received in advance from the user the liquefaction strength curve that is the target of reproduction using the liquefaction parameter and the characteristics representing the development process of the shear strain, and stores them in the RAM 23. For convenience of explanation, the liquefaction strength curve that is the target of reproduction using the liquefaction parameter and the characteristics representing the development process of the shear strain may be expressed as the "target liquefaction strength curve" and the "characteristics representing the development process of the target shear strain", respectively.

[0036] First, in step S10 of FIG. 3, the CPU 21 acquires the liquefaction strength curve from the RAM 23 and sets it as the target liquefaction strength curve.

[0037] FIG. 4 is a diagram showing an example of the target liquefaction strength curve. In FIG. 4, the horizontal axis represents the number of repeated loading cycles, and the vertical axis represents the stress ratio.

[0038] In step S20, the CPU 21 acquires the characteristics representing the development process of the shear strain from the RAM 23 and sets them as the characteristics representing the development process of the target shear strain. In the present embodiment, as an example, the characteristics representing the relationship between the shear strain and the number of repeated loadings are used as the characteristics representing the development process of the target shear strain. However, it goes without saying that characteristics representing other types of development processes of the shear strain may be set as the characteristics representing the development process of the target shear strain.

[0039] FIG. 5 is a diagram showing an example of the characteristics representing the relationship between the target shear strain and the number of repeated loadings. In FIG. 5, the horizontal axis represents the number of repeated loadings, and the vertical axis represents the shear strain. In the example shown in FIG. 5, the relationships between the respective shear strains and the number of repeated loadings for stress ratios of 0.15, 0.2, 0.4, 0.6, and 0.8 are shown.

[0040] In step S30 of FIG. 3, the CPU 21 sets the initial value of the liquefaction parameter. The CPU 21 may set the value specified by the user as the initial value of the liquefaction parameter, or may set the value generated according to a rule predetermined by the CPU 21 as the initial value of the liquefaction parameter. When setting the value generated by the CPU 21 as the initial value of the liquefaction parameter, the CPU 21 sets, for example, a randomly generated value or a value preset in the non-volatile memory 24 as the initial value of the liquefaction parameter.

[0041] Thereafter, using a known identification method, the liquefaction parameter is estimated so that the respective errors between the liquefaction strength curve estimated from the liquefaction parameter and the characteristics representing the development process of the shear strain, and the target liquefaction strength curve and the characteristics representing the development process of the target shear strain fall within a predetermined range. In the present embodiment, as an example, the MIEC (Modal Iterative Error Correction) method is used to estimate the liquefaction parameter. However, the liquefaction parameter may be estimated using the nonlinear least squares method, the Newton method, or the steepest descent method.

[0042] In step S40, the CPU 21 generates an N-dimensional (N is a natural number) candidate parameter vector with the initial values of each of the liquefaction parameters set in step S30 as elements. In the present embodiment, since the liquefaction characteristics of the ground are analyzed using the liquefaction parameters of S1, W1, P1, P2, and C1, a 5-dimensional candidate parameter vector is generated.

[0043] In step S50, the CPU 21 executes a known element analysis using the candidate parameter vector, and reproduces the liquefaction strength curve and the characteristics representing the development process of shear strain from the candidate parameter vector. The liquefaction strength curve reproduced from the candidate parameter vector and the characteristics representing the development process of shear strain are respectively referred to as the "reproduced liquefaction strength curve" and the "characteristics representing the development process of reproduced shear strain".

[0044] Then, the CPU 21 calculates an error vector representing the difference between the reproduced liquefaction strength curve and the characteristics representing the development process of reproduced shear strain, and the target liquefaction strength curve and the characteristics representing the development process of target shear strain.

[0045] In step S60, the CPU 21 determines whether the magnitude of the error vector falls within a predetermined range. Note that the magnitude of the error vector is called "error", and the predetermined range set for the magnitude of the error vector is called "allowable error".

[0046] When the obtained error is less than or equal to the allowable error, the characteristics representing the target liquefaction strength curve and the development process of the target shear strain can be reproduced within the allowable error by using the elements of the current candidate parameter vector. Therefore, the CPU 21 stores each element of the current candidate parameter vector in the non-volatile memory 24 as the estimation result of the liquefaction parameter, and ends the estimation process shown in FIG. 3.

[0047] On the other hand, if it is determined in the determination process of step S60 that the obtained error exceeds the allowable error, the process proceeds to step S70.

[0048] In step S70, the CPU 21 executes parameter correction processing to update the candidate parameter vector so that the error becomes smaller than the current error, and then proceeds to step S50. That is, the CPU 21 repeatedly updates the candidate parameter vector until the error becomes equal to or less than the allowable error.

[0049] Next, the details of the parameter correction processing in step S70 will be described. FIG. 6 is a flowchart showing an example of the flow of the parameter correction processing.

[0050] In step S100, the CPU 21 calculates the partial derivative matrix (Jacobian matrix) of the error vector. For calculating the partial derivative matrix, either analytical differentiation or numerical differentiation may be used.

[0051] In step S110, the CPU 21 performs singular value decomposition of the partial derivative matrix calculated in step S100.

[0052] In step S120, the CPU 21 extracts the low-order modes from the result of the singular value decomposition in step S110. For selecting the low-order modes, there are, for example, a method of selecting from a preset threshold value for the singular values, a method of selecting up to a preset number of modes, a method using the norm ratio of the current input / output vectors, that is, the norm ratio of the error vector and the candidate parameter vector, and a method of selecting the low-order modes by combining these selection methods. The CPU 21 selects the low-order modes according to the selection method instructed by the user.

[0053] In step S130, the CPU 21 generates a partial inverse matrix of the partial derivative matrix using the submatrix corresponding to the low-order modes extracted in step S120.

[0054] In step S140, the CPU 21 multiplies the error vector by the partial inverse matrix of the partial derivative matrix generated in step S130 to generate a correction parameter vector.

[0055] In step S150, the CPU 21 adds the correction parameter vector generated in step S140 to the candidate parameter vector to update the candidate parameter vector, and ends the parameter correction process.

[0056] In this way, in the parameter correction process, since the error can be efficiently reduced by constructing a partial inverse matrix of the partial derivative matrix using the low-order mode, the convergence of the error can be improved.

[0057] Note that in step S60 of FIG. 3, when the error becomes equal to or less than the allowable error, the estimation process is ended. However, the CPU 21 may measure the number of repetitions of the parameter correction process for each estimation process, and end the estimation process when the number of repetitions of the parameter correction process reaches the specified number specified by the user. Further, the CPU 21 may end the estimation process when the error becomes equal to or less than the allowable error, or when the number of repetitions of the parameter correction process reaches the specified number.

[0058] Furthermore, when setting the initial value of the liquefaction parameter in the estimation device 10 in step S30 of FIG. 3, the liquefaction parameter estimated by setting only the target liquefaction strength curve may be set as the initial value of the liquefaction parameter.

[0059] Specifically, for example, the liquefaction parameter estimated by a conventional estimation device that estimates the liquefaction parameter by setting only the target liquefaction strength curve may be set in the estimation device 10 as the initial value of the liquefaction parameter.

[0060] <Estimation result of liquefaction parameter> FIG. 7 is a diagram showing an example of the estimation result of the liquefaction parameters obtained by executing the estimation process shown in FIG. 3. To evaluate the estimation result of the liquefaction parameters by the estimation process shown in FIG. 3, in FIG. 7, the liquefaction strength curves reproduced from the previously prepared liquefaction parameters (also referred to as “correct values”) and the characteristics representing the relationship between the shear strain and the number of repeated loading cycles are set in the estimation device 10 as the characteristics representing the target liquefaction strength curve and the development process of the target shear strain. The liquefaction parameters (also referred to as “estimated values”) estimated by the estimation device 10 are compared with the correct values.

[0061] In the correct value column of the estimation result shown in FIG. 7, the correct values are described for each type of liquefaction parameter, and in the estimation result column, the estimated values are described for each type of liquefaction parameter. The value in parentheses in the estimation result column is the ratio of the estimated value to the correct value, and the closer it is to 1, the higher the evaluation of the estimated value.

[0062] Furthermore, for comparison, in the column of the estimation result by the prior art in FIG. 7, the estimation results estimated by a conventional estimation device that estimates the liquefaction parameters by setting only the liquefaction strength curve reproduced from the same correct value as the target are shown for each liquefaction parameter. The value in parentheses in the column of the estimation result by the prior art also represents the ratio of the estimated value to the correct value, similar to the estimation result column.

[0063] It can be seen from the estimation result in FIG. 7 that the average of the deviation amounts of each liquefaction parameter estimated by the estimation device 10 from the correct value is smaller than the average of the deviation amounts of each liquefaction parameter estimated by the conventional estimation device from the correct value.

[0064] Also, FIG. 8 is a diagram showing a graph 30 of the target liquefaction strength curve (described as “target”), a graph 31 of the liquefaction strength curve reproduced from the liquefaction parameters estimated by the estimation device 10 according to the present embodiment (described as “embodiment”), and a graph 32 of the liquefaction strength curve reproduced from the liquefaction parameters estimated by the conventional estimation device (described as “prior art”).

[0065] As can be seen from FIG. 8, the liquefaction strength curve reproduced using the liquefaction parameters estimated by the estimation device 10 more accurately reproduces the target liquefaction strength curve than the liquefaction strength curve reproduced using the liquefaction parameters estimated by the conventional estimation device.

[0066] FIG. 9 is a diagram showing, for each stress ratio, an example of characteristics representing the relationship between the shear strain reproduced from the estimation result and the number of repeated loadings.

[0067] FIG. 9(A) shows a graph 33 of characteristics representing the relationship between the target shear strain and the number of repeated loadings at a stress ratio of 0.80 (described as "target"), a graph 34 of characteristics representing the relationship between the shear strain reproduced from the liquefaction parameters estimated by the estimation device 10 according to the present embodiment (described as "embodiment"), and a graph 35 of characteristics representing the relationship between the shear strain reproduced from the liquefaction parameters estimated by the conventional estimation device (described as "prior art").

[0068] FIG. 9(B) shows a graph 36 of characteristics representing the relationship between the target shear strain and the number of repeated loadings at a stress ratio of 0.20 (described as "target"), a graph 37 of characteristics representing the relationship between the shear strain reproduced from the liquefaction parameters estimated by the estimation device 10 according to the present embodiment (described as "embodiment"), and a graph 38 of characteristics representing the relationship between the shear strain reproduced from the liquefaction parameters estimated by the conventional estimation device (described as "prior art").

[0069] As can be seen from FIG. 9, the characteristics representing the relationship between the shear strain reproduced using the liquefaction parameters estimated by the estimation device 10 and the number of repeated loadings more accurately reproduce the characteristics representing the relationship between the target shear strain and the number of repeated loadings than the characteristics representing the relationship between the shear strain reproduced using the liquefaction parameters estimated by the conventional estimation device and the number of repeated loadings.

[0070] Furthermore, from the results of FIGS. 8 and 9, it can be considered that the conventional estimation device reproduces the liquefaction strength curve, although its reproduction accuracy is inferior to that of the estimation device 10. On the other hand, it is hard to say that the characteristics representing the relationship between the shear strain and the number of repeated loadings are reproduced. In contrast, in the case of the estimation device 10, both the liquefaction strength curve and the characteristics representing the relationship between the shear strain and the number of repeated loadings are reproduced so as to overlap with the target.

[0071] FIG. 10 is a diagram showing an example of the characteristics representing the relationship between the shear stress reproduced from the estimation result and the shear strain.

[0072] FIG. 10(A) is a graph 39 (described as "target") showing the characteristics representing the relationship between the shear stress and the shear strain at a stress ratio of 0.80 reproduced from the correct value, and a graph 40 (described as "embodiment") showing the characteristics representing the relationship between the shear stress and the shear strain at a stress ratio of 0.80 reproduced from the liquefaction parameters estimated by the estimation device 10 according to the present embodiment.

[0073] FIG. 10(B) is a diagram showing the graph 39 (described as "target") shown in FIG. 10(A) and a graph 41 (described as "prior art") showing the characteristics representing the relationship between the shear stress and the shear strain at a stress ratio of 0.80 reproduced from the liquefaction parameters estimated by the conventional estimation device.

[0074] From FIG. 10, it can be seen that the characteristics representing the relationship between the shear stress and the shear strain reproduced using the liquefaction parameters estimated by the estimation device 10 reproduce the characteristics representing the relationship between the shear stress and the shear strain reproduced from the correct value with higher accuracy than the characteristics representing the relationship between the shear stress and the shear strain reproduced using the liquefaction parameters estimated by the conventional estimation device.

[0075] As described in step S20 of the estimation process in FIG. 3, in the present embodiment, the characteristic representing the relationship between the shear strain and the number of repeated loadings is set as the characteristic representing the development process of the target shear strain. However, the characteristic representing the relationship between the shear stress and the shear strain is not set in the estimation device 10 as the target for reproduction using the liquefaction parameters. Nevertheless, the estimation device 10 estimates the liquefaction parameters that reproduce the characteristic representing the relationship between the shear stress and the shear strain with higher accuracy than the conventional estimation device.

[0076] The same evaluation is also recognized for the characteristic representing the relationship between the excess pore water pressure ratio, which is not set in the estimation device 10 as the target for reproduction using the liquefaction parameters, and the number of repeated loadings, and for the reproduction of the effective stress path. Further, the same evaluation is recognized even when the combination of the type of the characteristic representing the development process of the target shear strain and the type of the characteristic representing the development process of the shear strain reproduced from the liquefaction parameters estimated by the estimation device 10 is changed.

[0077] That is, in the estimation device 10 according to the present embodiment, if any one type of the characteristics representing the development process of the shear strain is set as the characteristic representing the development process of the target shear strain, the characteristics representing the development process of other types of shear strain, which are not set as the target for reproduction using the liquefaction parameters, can also be reproduced with higher accuracy than the conventional estimation device.

[0078] In step S20 of the estimation process shown in FIG. 3, the characteristic representing the development process of the shear strain is acquired and only the characteristic representing the development process of the target shear strain is set. However, for example, in addition to the characteristic representing the development process of the target shear strain, the characteristic representing the relationship between the shear stress and the shear strain may also be set as the target. By setting a plurality of characteristics representing the development process of the target shear strain in this way, the characteristics representing the development process of the shear strain may be reproduced with higher accuracy than when one characteristic representing the development process of the target shear strain is set.

[0079] The invention related to the estimation device 10 has been described above using the embodiments. However, the present invention is not limited to the scope described in the embodiments. Various changes or improvements can be made to the embodiments without departing from the gist of the present invention, and the forms with such changes or improvements are also included in the technical scope of the present invention. For example, the processing order of the estimation processing shown in FIG. 3 and the parameter correction processing shown in FIG. 6 may be changed without departing from the gist of the present invention.

[0080] In the embodiment, as an example, the form of realizing the estimation processing and the parameter correction processing by software has been described. However, these processes may be implemented in, for example, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a PLD (Programmable Logic Device) and processed by hardware. In this case, the processing speed can be increased compared with the case where the estimation processing and the parameter correction processing are realized by software.

[0081] Thus, the CPU 21 may be replaced with a dedicated processor specialized for specific processing such as an ASIC, an FPGA, a PLD, a GPU (Graphics Processing Unit), and an FPU (Floating Point Unit).

[0082] Also, the operation of the CPU 21 in the estimation device 10 may be realized not only in a form realized by one CPU 21 but also in a form realized by a plurality of CPUs 21. Furthermore, the operation of the CPU 21 in the estimation device 10 may be realized by the cooperation of the CPUs 21 in the respective computers 20 existing at physically separated positions using cloud computing.

[0083] In the above-described embodiment, the form in which the estimation program is installed in the ROM 22 has been described, but the present invention is not limited thereto. The estimation program can also be provided in a form recorded on a storage medium readable by the computer 20. For example, the estimation program may be provided in a form recorded on an optical disk such as a CD (Compact Disc)-ROM or a DVD (Digital Versatile Disc)-ROM. Further, the display program according to the present invention may be provided in a form recorded on a portable semiconductor memory such as a USB memory or a memory card.

[0084] Furthermore, the estimation device 10 may download the estimation program from an external device connected to the communication line via the communication unit.

Explanation of Reference Numerals

[0085] 10 Estimation device 12 Reception unit 14 Estimation unit 16 Display unit 18 Parameter DB 20 Computer 21 CPU 22 ROM 23 RAM 24 Non-volatile memory 25 I / O 26 Bus 27 Input unit 28 Display unit 30 - 41 Graph

Claims

1. Comprising a processor, The processor is configured to: Set a target liquefaction strength curve and characteristics representing the development process of shear strain, and set, as an initial value of a liquefaction parameter used for analyzing the liquefaction characteristics of the ground represented by the liquefaction strength curve and the characteristics representing the development process of the shear strain, the liquefaction parameter estimated by setting only the liquefaction strength curve as the target, By repeatedly correcting the liquefaction parameter so that each error between the characteristics representing the liquefaction strength curve and the development process of the shear strain estimated from the liquefaction parameter and the characteristics representing the liquefaction strength curve and the development process of the shear strain set as the target falls within a predetermined range, estimate the liquefaction parameter corresponding to the liquefaction characteristics of the ground represented by the target liquefaction strength curve and the characteristics representing the development process of the shear strain Estimation device.

2. Characteristics representing the relationship between shear stress and shear strain, characteristics representing the relationship between shear strain and the number of repeated loadings, characteristics representing the relationship between the excess pore water pressure ratio and the number of repeated loadings, or an effective stress path is set as the characteristics representing the development process of the shear strain The estimation device according to claim 1.

3. Using a computer, Set a target liquefaction strength curve and characteristics representing the development process of shear strain, and as an initial value of a liquefaction parameter used for analyzing the liquefaction characteristics of the ground represented by the liquefaction strength curve and the characteristics representing the development process of the shear strain, set the liquefaction parameter estimated by setting only the liquefaction strength curve as the target, and By repeatedly correcting the liquefaction parameter so that each error between the characteristics representing the liquefaction strength curve and the development process of the shear strain estimated from the liquefaction parameter and the characteristics representing the liquefaction strength curve and the development process of the shear strain set as the target falls within a predetermined range, execute the step of estimating the liquefaction parameter corresponding to the liquefaction characteristics of the ground represented by the target liquefaction strength curve and the characteristics representing the development process of the shear strain Estimation method.

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