Analysis system, analysis method and analysis program

Abstract

To provide an analysis system, an analysis method and an analysis program for supporting structural calculation of a structure using a pile in a composite ground including ground improvement etc.SOLUTION: An analysis device 20 includes a storage unit for storing a ground model of an initial ground before ground improvement and a composite ground after the ground improvement, with respect to a pile, and a control unit connected to a user device. A control unit 21 calculates a first characteristic value of the initial ground stored in the storage unit, and a second characteristic value of the composite ground, by a first analysis method, compares the first characteristic value with the second characteristic value, and calculates a characteristic value increase rate. The control unit 21 calculates a second horizontal resistance index of a ground spring of the composite ground obtained by multiplying a first horizontal resistance index of the ground spring of the initial ground by the characteristic value increase rate, and outputs the second horizontal resistance index so as to perform structural calculation of a structure by a second analysis method using the second horizontal resistance index.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an analysis system, an analysis method, and an analysis program for supporting structural calculations of structures. [Background technology]

[0002] When constructing a structure, a response analysis of the structure to earthquake motion is performed (see, for example, Patent Document 1). The technology described in this document calculates earthquake motion at multiple levels of the ground surface through a ground response analysis using earthquake motion at multiple levels of the engineering bedrock. Furthermore, the measured seismic intensity of the earthquake motion at the ground surface is calculated. Then, an earthquake response analysis of the building to the earthquake motion at multiple levels of the ground surface is performed.

[0003] Technologies for suppressing ground liquefaction are also being considered (see, for example, Patent Document 2). In the technology described in this document, ground that is likely to liquefy is surrounded by wall-shaped ground improvement bodies, which constrain the ground and suppress shear deformation of the ground. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-153191 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-051852 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional design pile stress evaluation models (pile group frame model, beam-spring model), the horizontal resistance of the ground is modeled as the ground spring around the pile. The evaluation method for the ground spring around the pile only targets the original ground, and does not target composite ground including ground improvement. Therefore, the pile stress is not evaluated accurately. [Means for solving the problem]

[0006] An analysis system for solving the above problem includes a control unit connected to a memory unit that stores ground models of the initial ground before ground improvement and the composite ground after ground improvement, and the control unit calculates a first characteristic value of the initial ground and a second characteristic value of the composite ground stored in the memory unit using a first analysis method, compares the first characteristic value with the second characteristic value to calculate a characteristic value increase rate, calculates a second horizontal resistance index of the ground spring of the composite ground by multiplying a first horizontal resistance index of the ground spring of the initial ground by the characteristic value increase rate, and outputs the second horizontal resistance index to perform structural calculations of a structure using a second analysis method using the second horizontal resistance index. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to assist in structural calculations of structures using piles in composite ground, including ground improvement work. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram of an analysis system according to an embodiment. [Figure 2] FIG. 2 is an explanatory diagram of a hardware configuration of the embodiment. [Figure 3] FIG. 2 is an explanatory diagram of a processing procedure according to an embodiment. [Figure 4] FIG. 2 is an explanatory diagram of a ground spring according to an embodiment. [Figure 5] 1A and 1B are explanatory diagrams of a three-dimensional FEM model of an initial ground according to an embodiment, in which (a) is a perspective view and (b) is a top view. [Figure 6] 1A and 1B are explanatory diagrams of a three-dimensional FEM model of a composite ground according to an embodiment, in which (a) is a perspective view and (b) is a top view. [Figure 7] FIG. 10 is an explanatory diagram of pile head load relative to standardized pile head displacement in the embodiment. [Figure 8] FIG. 10 is an explanatory diagram of the horizontal ground reaction coefficient with respect to the standardized pile head displacement in the embodiment. [Figure 9] FIG. 10 is an explanatory diagram of the characteristic value increase rate with respect to the standardized pile head displacement due to ground improvement in the embodiment. [Figure 10] FIG. 10 is an explanatory diagram of an increase in horizontal ground reaction force against horizontal pile displacement due to ground improvement according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of an analysis system, an analysis method, and an analysis program will be described below with reference to Figures 1 to 10. In this embodiment, the analysis system will be described as one that predicts the influence on the ground spring around piles in lattice-pattern ground improvement work performed to construct a structure (building) on ​​liquefied ground. As shown in FIG. 1, this embodiment uses a user device 10 and an analysis device 20 connected via a network.

[0010] (Hardware configuration description) 2, the hardware configuration of the information processing device H10 that constitutes the user device 10 and the analysis device 20 will be described. The information processing device H10 includes a communication device H11, an input device H12, a display device H13, a storage device H14, and a processor H15. Note that this hardware configuration is an example, and it can also be realized by other hardware.

[0011] The communication device H11 is an interface that establishes a communication path with another device and executes data transmission and reception, and is, for example, a network interface or a wireless interface.

[0012] The input device H12 is a device that accepts input of various information, such as a mouse, a keyboard, etc. The display device H13 is a display or the like that displays various information. The storage device H14 is a storage device that stores data and various programs for executing various functions of the user device 10 and the analysis device 20. Examples of the storage device H14 include a ROM, a RAM, and a hard disk.

[0013] The processor H15 uses programs and data stored in the storage device H14 to control each process in the user device 10 and the analysis device 20. Examples of the processor H15 include a CPU and an MPU. The processor H15 loads programs stored in a ROM or the like into a RAM and executes various processes for each process.

[0014] The processor H15 is not limited to a processor that performs all of its processing using software. For example, the processor H15 may include a dedicated hardware circuit (e.g., an application-specific integrated circuit (ASIC)) that performs hardware processing for at least some of the processing it performs. That is, the processor H15 may be configured with the following:

[0015] [1] One or more processors that operate according to a computer program (software). [2] One or more dedicated hardware circuits that perform at least some of the various processes; or [3] Circuits containing combinations of these The processor includes a CPU and memory, such as RAM and ROM, that stores program code or instructions configured to cause the CPU to perform processes. Memory, i.e., computer-readable media, includes any available media that can be accessed by a general-purpose or special-purpose computer.

[0016] (System Configuration) Next, each function of the analysis system will be explained using FIG. The user device 10 is a computer terminal used by a user who performs analysis.

[0017] The analysis device 20 is a computer system that performs analysis and includes a control unit 21, a seismic performance evaluation information storage unit 22, and an FEM information storage unit . The control unit 21 performs the processes described below (processes including a management stage, an FEM analysis stage, an earthquake resistance performance evaluation stage, etc.) By executing programs for each process for this purpose, the control unit 21 functions as a management unit 211, an FEM analysis unit 212, an earthquake resistance performance evaluation unit 213, etc.

[0018] The management unit 211 acquires three-dimensional models of the building and ground from the user device 10. Furthermore, the management unit 211 controls the FEM analysis unit 212 and the seismic performance evaluation unit 213 to perform earthquake motion analysis.

[0019] The FEM analysis unit 212 executes a process of evaluating the horizontal subgrade reaction coefficient using a three-dimensional finite element method as a first analysis method. The earthquake-resistant performance evaluation unit 213 executes a process of performing earthquake-resistant performance evaluation as a second analysis method using a pile stress evaluation model using ground springs.

[0020] The seismic performance evaluation information storage unit 22 stores a pile stress evaluation model for performing seismic performance evaluation. The pile stress evaluation model is a model in which a pile perimeter ground spring is arranged around the pile. The pile stress evaluation model stores information on the diameter, length, and type of pile, as well as the soil quality, characteristic values, and strength of the ground. Here, the characteristic values ​​of the ground include at least one of stiffness value, nonlinear characteristics, etc.

[0021] 4, in the pile stress evaluation model 300, a ground spring 302 is arranged relative to a pile 301. At the end of the pile 301, a ground roller 303 is arranged. The FEM information storage unit 23 stores a three-dimensional FEM model for performing three-dimensional FEM analysis. The three-dimensional FEM model includes information on the ground and piles. In this embodiment, an initial ground model of only the ground before ground improvement and a composite ground model after ground improvement are used. Since the three-dimensional FEM model is symmetrical, it is analyzed using a shape divided into two halves (1 / 2 model).

[0022] Figure 5 is an explanatory diagram of a 3D FEM model M10 of the initial ground before ground improvement, where Figure 5(a) is a perspective view and Figure 5(b) is a top view. Multiple ground layer elements M12 are arranged on the ground surface M11. Furthermore, multiple pile elements M13 are arranged to reach the bearing layer. Information about soil quality, characteristic values, and strength is set in the stratum element M12. For the pile element M13, information regarding diameter, length, and type is set.

[0023] Figure 6 is an explanatory diagram of a 3D FEM model M20 of the composite ground after ground improvement, where Figure 6(a) is a perspective view and Figure 6(b) is a top view. As with the 3D FEM model M10, multiple stratum elements M12 are arranged relative to the ground surface M11. Furthermore, as with the 3D FEM model M10, multiple pile elements M13 are arranged reaching the bearing layer. Then, in the 3D FEM model M20, ground improvement elements M25 are arranged in the area to be improved. In this embodiment, lattice-shaped ground improvement elements M25 are arranged around the pile elements M13.

[0024] Information about the arrangement, characteristic values, and strength is set in the soil improvement elements M25. In this embodiment, it is assumed that the soil improvement elements M25 are arranged in a grid-like manner surrounding the pile elements M13 near the ground surface M11.

[0025] (Analysis processing) Next, the analysis process of earthquake motion will be explained using FIG. First, the control unit 21 of the analysis device 20 executes a process for setting a calculation target (step S11). Specifically, an initial ground model before ground improvement and a 3D FEM model are specified as calculation targets in the user device 10. In this case, the management unit 211 of the control unit 21 acquires the initial ground model and the 3D FEM model specified in the user device 10 and records them in the seismic performance evaluation information storage unit 22 and the FEM information storage unit 23, respectively.

[0026] Next, the control unit 21 of the analysis device 20 executes a process of calculating the subgrade reaction coefficient of the initial ground (step S12). Specifically, the FEM analysis unit 212 of the control unit 21 performs a three-dimensional FEM analysis by inputting a predetermined earthquake motion into the initial ground model recorded in the FEM information storage unit 23. As shown in Figure 7, curve C11 is obtained as the analysis result (first characteristic value) of pile head load with respect to pile head displacement / pile diameter.

[0027] Then, the FEM analysis unit 212 acquires the first coefficient of horizontal subgrade reaction in the initial ground model. Here, the coefficient of horizontal subgrade reaction kh is calculated for pile head displacement / pile diameter using the following formula (1).

[0028]

number

[0029] y1: Pile head displacement H: Pile cap load (pile cap horizontal force) EI: Bending rigidity of pile (elastic modulus of pile E · moment of inertia of pile I) kh: Coefficient of horizontal subgrade reaction (soil spring) B: Pile diameter In Figure 8, the white circles indicate the horizontal subgrade reaction coefficient (first subgrade reaction coefficient) of the initial ground before ground improvement.

[0030] Next, the control unit 21 of the analysis device 20 executes a setting process for a composite ground model (step S13). Specifically, in the user device 10, a composite ground model is created in which a ground improvement area is set for the initial ground model. In this case, the management unit 211 of the control unit 21 acquires the composite ground model created in the user device 10 and records it in the FEM information storage unit 23.

[0031] Next, the control unit 21 of the analysis device 20 executes a process of calculating the subgrade reaction coefficient of the composite ground (step S14). Specifically, the FEM analysis unit 212 of the control unit 21 performs a three-dimensional FEM analysis by inputting a predetermined earthquake motion into the composite ground model recorded in the FEM information storage unit 23.

[0032] As shown in Figure 7, curve C12 is obtained as the analysis result (second characteristic value) of pile head load against pile head displacement / pile diameter. As shown, for the same pile head load, the displacement of the composite ground is smaller than that of the initial ground.

[0033] Then, the FEM analysis unit 212 acquires the second coefficient of horizontal subgrade reaction in the composite ground model. Here, too, the coefficient of horizontal subgrade reaction kh is calculated for pile head displacement / pile diameter using the above-mentioned [Equation 1]. In Figure 8, the horizontal subgrade reaction coefficient (second subgrade reaction coefficient) of the composite ground is shown by the black circle.

[0034] Next, the control unit 21 of the analysis device 20 executes a process for calculating the characteristic value increase rate due to the ground improvement (step S15). Specifically, the management unit 211 of the control unit 21 compares the first subgrade reaction coefficient with the second subgrade reaction coefficient. Then, the management unit 211 calculates the characteristic value increase rate of the ground spring by dividing the second subgrade reaction coefficient by the first subgrade reaction coefficient.

[0035] Figure 9 shows the rate of increase in characteristic values ​​due to ground improvement versus pile head displacement / pile diameter. Then, when pile head displacement = 0.01 (m), the rate of increase in the reference horizontal subgrade reaction coefficient kh0 and the rate of increase in the ultimate subgrade reaction coefficient py are determined. Here, the rate of increase R1 (1.1 times) for the reference horizontal subgrade reaction coefficient kh0 and the rate of increase R2 (1.2 times) for the ultimate subgrade reaction coefficient py are determined. Here, the reference horizontal subgrade reaction coefficient kh0 is an index representing the horizontal resistance that the ground exerts on the foundation, and the ultimate subgrade reaction coefficient py is an index representing the maximum horizontal resistance that the ground exerts on the foundation.

[0036] Next, the control unit 21 of the analysis device 20 executes an update process for the pile stress evaluation model (step S16). Specifically, the management unit 211 of the control unit 21 multiplies the first horizontal resistance index of the initial ground by an increase rate to update the reference horizontal subgrade reaction coefficient and the ultimate subgrade reaction coefficient (plastic horizontal subgrade reaction coefficient) as the second horizontal resistance index of the ground spring. As shown in Figure 10, curve C31 of the horizontal subgrade reaction force against the horizontal pile displacement is updated to curve C32 using an increase rate. In this case, the reference horizontal subgrade reaction coefficient on curve C32 increases from value P11 to value P12 using an increase rate R1. Also, the ultimate subgrade reaction coefficient increases from value P21 to value P22 using an increase rate R2.

[0037] Next, the control unit 21 of the analysis device 20 executes a structural analysis process for the building (step S17). Specifically, the seismic performance evaluation unit 213 of the control unit 21 performs seismic performance evaluation using the updated horizontal resistance indexes of the ground spring (standard horizontal subgrade reaction coefficient, ultimate subgrade reaction coefficient). Here, the standard horizontal subgrade reaction coefficient is used to evaluate the building's response to normal earthquake motion (design earthquake motion). Specifically, the mass of each story of the building and the standard horizontal subgrade reaction coefficient are used to calculate horizontal force, and it is examined whether the structural members of the building can withstand that force. In addition, the ultimate subgrade reaction coefficient is used to evaluate the building's response to a large-scale earthquake. In this case, if necessary, the pile diameter, etc. is redesigned to achieve the required horizontal resistance, taking into account ground improvement.

[0038] (Action of this embodiment) By taking into account ground improvement, the ground spring acting on the piles used in structural calculations is strengthened.

[0039] (Effects of this embodiment) (1) In this embodiment, the control unit 21 of the analysis device 20 executes a process for calculating the subgrade reaction coefficient of the initial ground (step S12), thereby making it possible to calculate the subgrade reaction coefficient before ground improvement. (2) In this embodiment, the control unit 21 of the analysis device 20 executes a process for setting a composite ground model (step S13), thereby making it possible to identify an area where three-dimensional ground improvement work is to be carried out.

[0040] (3) In this embodiment, the control unit 21 of the analysis device 20 executes a process for calculating the subgrade reaction coefficient of the composite ground (step S14), thereby making it possible to calculate the subgrade reaction coefficient after ground improvement.

[0041] (4) In this embodiment, the control unit 21 of the analysis device 20 executes a process for calculating the characteristic value increase rate due to ground improvement (step S15) and a process for updating the pile stress evaluation model (step S16). This allows the effects of ground improvement to be reflected in the analysis model. Furthermore, piles can be designed with ground improvement in mind. For example, if the pile rigidity is insufficient, a PHC pile wrapped in a steel pipe can be used, but this may increase the cost of the PHC pile. Therefore, piles that take ground improvement into consideration can economically improve the rigidity.

[0042] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility. In the above embodiment, the control unit 21 of the analysis device 20 functions as the management unit 211, the FEM analysis unit 212, the seismic performance evaluation unit 213, etc. Then, the control unit 21 executes the structural analysis processing of the building (step S17). The hardware configuration is not limited to this. For example, the FEM analysis unit 212 and the seismic performance evaluation unit 213 may be provided in different devices. In this case, the control unit 21 of the analysis device 20 outputs a pile stress evaluation model updated in consideration of ground improvement. Then, this pile stress evaluation model may be used to perform the structural analysis processing of the building in another device.

[0043] In the above embodiment, grid-like ground improvement is assumed for liquefied ground. However, the ground improvement method is not limited to this. Surface improvement methods, columnar improvement methods, etc. may also be applied.

[0044] In the above embodiment, it is assumed that a building is to be constructed on liquefied ground, but the present invention can also be applied to cases where ground improvement work is carried out on soft ground and a structure is to be constructed. In the above embodiment, the control unit 21 of the analysis device 20 executes a structural analysis process for the building (step S17). Here, seismic performance evaluation is performed. The seismic performance evaluation of the structure is not limited to an evaluation method using static horizontal loading. For example, time history response analysis, response spectrum analysis, etc. may also be used.

[0045] Next, the technical ideas that can be understood from the above-described embodiment and other examples will be described below. (a) The analysis system according to any one of claims 1 to 3, characterized in that the control unit performs seismic performance evaluation as the second analysis method.

[0046] (b) The analysis system according to any one of (a) above, characterized in that a ground model in which ground improvement has been performed in a grid pattern around the piles is used as the composite ground. [Explanation of symbols]

[0047] 10...user device, 20...analysis device, 21...control unit, 211...management unit, 212...FEM analysis unit, 213...seismic performance evaluation unit, 22...seismic performance evaluation information storage unit, 23...FEM information storage unit.

Claims

1. An analysis system having a control unit connected to a memory unit that stores a ground model of an initial ground before ground improvement and a composite ground after ground improvement for a pile, The control unit Calculating a first characteristic value of the initial ground and a second characteristic value of the composite ground recorded in the memory unit by a first analysis method; comparing the first characteristic value with the second characteristic value to calculate a characteristic value increase rate; Calculating a second horizontal resistance index of the ground spring of the composite ground by multiplying the first horizontal resistance index of the ground spring of the initial ground by the characteristic value increase rate; An analysis system that outputs the second horizontal resistance index in order to perform structural calculations of a structure by a second analysis method using the second horizontal resistance index.

2. The analysis system described in claim 1, characterized in that the control unit uses the finite element method as the first analysis method to calculate the horizontal subgrade reaction coefficient of the initial ground as the first characteristic value, and calculates the horizontal subgrade reaction coefficient of the composite ground as the second characteristic value.

3. The analysis system according to claim 2, characterized in that the control unit further calculates the ultimate subgrade reaction coefficient of the initial ground as the first characteristic value and the ultimate subgrade reaction coefficient of the composite ground as the second characteristic value.

4. A method for analyzing piles using an analysis system equipped with a control unit connected to a memory unit that stores ground models of the initial ground before ground improvement and the composite ground after ground improvement, The control unit Calculating a first characteristic value of the initial ground and a second characteristic value of the composite ground recorded in the memory unit by a first analysis method; comparing the first characteristic value with the second characteristic value to calculate a characteristic value increase rate; Calculating a second horizontal resistance index of the ground spring of the composite ground by multiplying the first horizontal resistance index of the ground spring of the initial ground by the characteristic value increase rate; An analysis method comprising: outputting the second horizontal resistance index in order to perform structural calculations of a structure by a second analysis method using the second horizontal resistance index.

5. A program for performing analysis on piles using an analysis system equipped with a control unit connected to a memory unit that stores ground models of the initial ground before ground improvement and the composite ground after ground improvement, The control unit Calculating a first characteristic value of the initial ground and a second characteristic value of the composite ground recorded in the memory unit by a first analysis method; comparing the first characteristic value with the second characteristic value to calculate a characteristic value increase rate; Calculating a second horizontal resistance index of the ground spring of the composite ground by multiplying the first horizontal resistance index of the ground spring of the initial ground by the characteristic value increase rate; An analysis program characterized by functioning as a means for outputting the second horizontal resistance index in order to perform structural calculations of a structure by a second analysis method using the second horizontal resistance index.

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