JP2003294850A - Ground response-analyzing method and system, program for making computer to execute the ground response- analyzing method, and record medium with recorded program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To analyze a ground response to an earthquake regarding the depth direction of the ground. <P>SOLUTION: The analysis program is executed on a computer. The analysis program 12 determines oscillatory waves (ground input waves) that occur in the ground for each section in a mesh-like map that is divided in the mesh shape (S104), and calculates the distribution of the ground response (acceleration, velocity, relative displacement, distortion, and the like) in a depth direction in each division based on the determined oscillatory waves (S110). Additionally, from the calculation result of the ground response, ground deformation judgment processing such as liquefaction judgment (S116), sideward amount-of-flow judgment (S118), and amount-of-ground-subsidence judgment (S120), and damage scale judgment processing (S124, S126) regarding an underground structure are made. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground response analysis method and a ground response analysis system for analyzing response characteristics of ground to an earthquake.

[0002]

2. Description of the Related Art Conventionally, for example, JP-A-8-32904
A simulated prediction device for earthquake damage disclosed in Japanese Patent No. 3 is known. This simulated prediction device is equipped with means to set the epicenter and the magnitude of the earthquake at any position on the map, and the set epicenter and magnitude of the earthquake, and the epicenter and each section of the mesh map. The acceleration response of each section to the earthquake is calculated on the basis of the distance of 1 and the geological data existing between them. Then, based on the calculated acceleration response, the degree of damage to the building structure existing in each section is predicted and calculated.

[0003]

By the way, underground,
Various structures such as subway stations, sewer facilities, and underground structures of buildings have been constructed, and it is important to predict earthquake damage for these underground structures. Then, in order to predict the earthquake damage of underground structures, it is necessary to analyze the ground response not only in the ground surface but also in the depth direction of the underground.

However, in the above-mentioned conventional simulated predicting device, the acceleration response calculated for each section is the response on the ground surface. For this reason, although the above-mentioned conventional simulation prediction device is suitable for performing earthquake damage prediction for a building structure on the ground, it is difficult to apply it to earthquake damage prediction for an underground structure.

The present invention has been made in view of the above points, and an object thereof is to provide a ground response analysis method and a ground response analysis system capable of analyzing the ground response to an earthquake in the depth direction of the ground. And

[0006]

In order to achieve the above object, the present invention is a method for analyzing ground response to an earthquake, in which a vibration wave input to a base is divided into a plurality of pieces by a computer. A vibration wave determination step is determined for each section of the map, a response analysis step for calculating the ground response in each section as a distribution in the depth direction based on the determined vibration wave, and the calculated ground response is displayed. And displaying step.

According to the present invention, the base vibration wave is determined for each section of the map divided into a plurality of sections, and the ground response in each section is calculated as a distribution in the depth direction based on the vibration wave. Therefore, the ground response to the earthquake can be analyzed in the depth direction of the ground.

Further, in the ground response analysis method of the present invention, a step of displaying the map divided into the plurality on the screen by a computer and a step of accepting designation of an analysis target area on the displayed map are further executed. However, in the response analysis step, the ground response may be calculated for a section within the designated analysis target area. By doing so, the user can easily specify the analysis target area on the map.

Further, in the ground response analysis method of the present invention, a step of acquiring geological data regarding the geology of the ground by a computer, the calculated ground response, and the acquired ground data based on the ground liquefaction, The step of predicting and evaluating the ground damage related to at least one of the ground subsidence amount and the lateral flow amount may be further executed. By doing this, it becomes possible to predict and evaluate the ground deformation that occurs during an earthquake.

Further, in the ground response analysis method of the present invention, the step of acquiring structure data relating to an underground structure by a computer, and the ground response based on the calculated ground response and the acquired structure data The step of predicting and evaluating the damage level of the structure may be further executed. By doing this, it becomes possible to predict and evaluate the damage level of the underground structure that occurs during an earthquake.

Further, the displaying step includes a step of displaying the calculation result of the ground response at a designated depth of each section on the map in a color, a density, or a pattern according to the value. Good. In this way, the user can grasp the ground response analysis result in a visually easy-to-understand manner.

Further, the displaying step may include a step of displaying a distribution of the ground response in a depth direction in a designated section. By doing so, the user can confirm the distribution of the ground response in the desired section in the depth direction.

The ground response may include at least one of acceleration, velocity, relative displacement, shear stress and strain.

A ground response analysis system can be constructed by a computer that executes the ground response analysis method of the present invention.

[0015]

1 is a block diagram of a ground response analysis system 10 which is an embodiment of the present invention. When the assumed earthquake is designated, the ground response analysis system 10 of the present embodiment calculates the distribution of the response in the depth direction of the ground in each section of the mesh-shaped map according to the specified earthquake, and further calculates the calculation result. Based on this, prediction and evaluation of ground deformation and damage to underground structures are performed.

The ground response analysis system 10 is composed of, for example, a computer such as a personal computer or a PDA terminal, and the function of the ground response analysis system 10 is realized by executing a predetermined analysis program 12 on the computer. It As shown in FIG. 1, the ground response analysis system 10 includes a program execution unit 14 including a CPU of a computer, a storage unit 16 such as a hard disk device, and a display unit 18 such as a display device. The analysis program 12 is, for example, C
The storage unit 1 included in the computer 12 by being downloaded from an external server via a medium such as a D-ROM or a DVD-ROM, or via a network.
Installed in 6.

The ground response analysis system 10 includes a map database 20, a geological database 22, a topographic database 24, a structure database 26, and an earthquake database 2.
A database of 8 etc. is provided. These databases 20 to 28 may be built on the storage unit 16 or may be provided on an external database server accessible via the network.

In the map database 20, for example, a predetermined distance interval (for example, 50
Map data for displaying a mesh map divided in a grid pattern at 0 m intervals) is recorded, so that it is possible to perform enlargement / reduction around an arbitrary position with this mesh map displayed. Has become.

The geological database 22 records geological data indicating the properties of the ground in each section of the mesh map. Specifically, as geological data, ground type (types of diluvium, alluvium, soft layer, etc.), soil layer composition (layer thickness, type of soil, depth of groundwater level, etc.), soil characteristics of each soil layer. (N value,
Data such as unit volume weight γt and effective unit volume weight γ't) are recorded.

The terrain database 24 records terrain data relating to the altitude of each section of the mesh map and the slope of the ground surface.

The structure database 26 includes structures including underground structure names, plane position information, depth information (top depth, bottom depth), structure type, foundation type, design age, construction age, etc. Data is recorded.

The seismic database 28 stores seismic waves representing seismic waveforms of various earthquakes that occurred in the past, epicenter position (longitude, latitude, depth), magnitude of earthquake (magnitude),
Earthquake data including date and time of occurrence is recorded.

In the present embodiment, the analysis program 12
Refers to the databases 20 to 28 as appropriate,
Performs processing such as ground response analysis and earthquake damage assessment for earthquakes. FIG. 2 is a flowchart of the processing executed by the analysis program 12, and FIG.
It is a figure which represents typically the processing procedure of the ground response analysis by 2. The outline of the processing by the analysis program 12 is as follows.
In the ground response analysis, first, an acceleration input wave (hereinafter, referred to as a foundation input wave) to the foundation 70 in each section 50a of the mesh map 50 is determined (S102, S104).
Then, for each section 50a in the selected area,
The ground response distribution in the depth direction (vertical direction) is calculated using, for example, the well-known program "SHAKE" (S1).
08, S110). This program "SHAKE"
It is a ground response analysis program for the Heisei layer, which was developed by the University of California and is open to the public. It is capable of performing seismic response analysis of multiple layers based on the one-dimensional waveform theory. As analysis results, transfer functions such as acceleration, stress, strain, etc. in each layer of the ground, response waveforms, etc. are output. By calculating the ground response distribution in the depth direction for each mesh section by the program "SHAKE", the ground response to the earthquake is obtained as a three-dimensional distribution including the depth direction. The ground response thus obtained is displayed on the screen in various modes (S
112). The calculation of the ground response distribution is "SHAKE"
However, the program may be performed by another program having the same function.

Further, using the obtained ground response, processing such as liquefaction determination, ground subsidence amount determination, lateral flow amount determination, etc. (S
114 to S118) and the damage level determination processing (S120, S122) for the underground structure.

Details of the processing by the analysis program 12 will be described below with reference to the flow chart shown in FIG. 2 and various display screens shown in FIGS.

When the analysis program 12 is started, first, the initial menu screen shown in FIG. 4 is displayed (S10).
0). The initial menu screen includes menu items such as “ground response analysis system”, “ground simple damage evaluation system”, and “structure simple damage evaluation system”.

When the "ground response analysis system" menu is selected on the initial menu screen, a seismic motion selection screen for designating an expected earthquake is displayed (S102).
On this seismic motion selection screen, you can select the method of specifying the expected earthquake from one of the menus "Specify seismic data", "Specify hypocenter", and "Specify excess probability".
A board input wave determination process is performed according to each menu (S104).

The "designate seismic wave data" menu is a menu for designating past seismic waves as assumed earthquakes, and the user can designate an assumed earthquake from the earthquake data recorded in the earthquake database 28. Then, the seismic wave represented by the designated seismic data is used as the base input wave in each section.

The "source designation" menu is a menu for the user to designate the source, and the user calculates the source position (latitude, longitude, depth), the magnitude of the earthquake (magnitude), and the input wave of the foundation. Specify the area where Then, based on the designated epicenter position and magnitude, for example, using the distance attenuation formula represented by the following formula, the base wave input wave in each section in the designated area is calculated.

Acceleration = C · 10A · M · (distance from epicenter + 30m) -1.218 where M is the magnitude of the epicenter, and C and A are constants determined according to the type of ground including the epicenter. In case of the ground (Ko layer) C = 987.4, A = 0.21
6, in the case of two types of ground (alluvium) C = 232.5, A =
0.313, in the case of three types of ground (soft layer) C = 403.
8, A = 0.265.

The "excess probability designation" menu is a menu for designating an assumed earthquake as "earthquake motion occurring with a probability of Y% or more in the next X years", and the user can designate the X and Y values. . From the specified X and Y values,
The base wave input of each mesh section is calculated based on the statistical distribution of past earthquakes.

When the board input wave is determined in this way, a processing menu screen as shown in FIG. 5 is then displayed.
When the "area selection" button is clicked on this screen, the area selection screen (FIG. 6) for selecting the target area for ground response analysis is displayed (S108). Figure 6
As shown in, on the area selection screen, a target area for ground response analysis can be selected on the mesh map.

When the "OK" button is clicked on the processing menu screen of FIG. 5 after the target area is selected on the area selection screen, the depth by the program "SHAKE" is determined for each section in the selected area. The ground response analysis in the direction is performed (S110). That is, first, referring to the geological database 22, for each section, soil layer composition (layer thickness, soil type), soil characteristics of each soil layer (initial damping constant h0, unit volume weight γt, initial shear wave velocity Vs). ,
Geological data such as strain-dependent curve G / G0) is acquired. Then, based on these geological data and the determined basement input wave, the ground response at each depth of the ground surface and the underground is calculated. Specifically, the ground response includes: -response acceleration history and maximum response acceleration-response speed history and maximum response speed-relative response displacement history and maximum relative response displacement-effective strain value and maximum strain value-maximum shear stress A predetermined step size (eg 1
m)).

When the above ground response analysis processing is completed, a screen for specifying the type of ground response to be displayed (maximum acceleration distribution, maximum velocity distribution, maximum stress distribution, or maximum strain distribution) and the depth of the formation to be displayed. In accordance with these designations, as shown in FIG. 7, for example, as shown in FIG. 7, a color corresponding to the ground response value (maximum acceleration in the example of the same figure) of each section (or the ground response value is displayed). Pattern and density)
The analysis result screen displayed by is displayed (S112). That is, since the ground response at each depth is calculated for each section in the ground response analysis processing, the specified ground response at the specified depth for each section is displayed in a color according to the value. You can do it. With such a display, the user can visually understand the ground response analysis result in an easily understandable manner.

On the analysis result screen, the type of ground response to be displayed can be appropriately changed to maximum acceleration distribution, maximum velocity distribution, maximum stress distribution, or maximum strain distribution. Further, as shown in FIG. 8, the scale of the mesh map can be changed to display the analysis result of a wide area.

Further, by selecting any mesh on the analysis result screen, the ground response distribution in the depth direction of the mesh is displayed, or the ground response waveform at the specified depth of the mesh is displayed. It can also be done. For example, FIG. 9 is a screen displaying the distribution in the depth direction regarding the maximum strain, the maximum shear stress, the maximum acceleration, and the maximum relative displacement for a certain section, and FIG.
0 is a screen displaying a relative displacement waveform at a certain depth level of a certain section.

The ground response calculated as described above is recorded in the storage unit 16 or the like, and based on the recorded ground response calculation result, predictive evaluation calculation of ground damage and underground structure damage as described below is performed. Be done.

When the "Simple soil damage evaluation system" menu is selected on the initial menu screen shown in FIG. 5, each determination process of liquefaction determination, ground subsidence amount determination, and lateral flow amount determination is performed. .

First, on the analysis result screen as shown in FIG. 7, the section to be processed is selected by the user (S
114). Then, liquefaction determination processing is performed on the selected section (S116). In this liquefaction determination process, for example, “Road Bridge Specification / Dialog V Seismic Design”
The liquefaction determination process is performed according to the liquefaction determination guideline described in (Japan Road Association, 1997). That is, the maximum shear stress of each soil layer calculated by the ground response analysis, the soil layer composition (soil layer thickness, soil type, groundwater depth) recorded in the geological database 22, and soil parameters of each soil layer. Based on (N value, unit volume weight γt, effective unit volume weight γ't), liquefaction resistivity (F
L value) and liquefaction index (PL value) for each mesh
Is calculated and displayed on the screen.

Next, the lateral flow amount determination processing is executed (S118). In this lateral flow amount determination processing, for example,
"Railway Structure Design Standard / Commentary Seismic Design"
The lateral flow rate is determined according to the lateral flow rate determination guidelines described in Railway Technical Research Institute, Maruzen, 1999). That is, it was determined to be a liquefied layer in the above liquefaction determination processing (that is, the FL value is less than or equal to a predetermined reference value).
Layer thickness of soil layer, corrected N value calculated in liquefaction determination process, soil composition (soil layer thickness) recorded in geological database 22,
The lateral flow rate in each section is calculated and displayed based on the deformation rate of the seawall top, the height of the seawall, the distance from the seawall, and the representative value of the ground surface gradient recorded in the topographic database 28 for each section. To be done. As the lateral flow rate, two types of lateral flow rates, that is, the ground behind the shoreline and the sloping ground, are calculated. In addition, the deformation rate of the top of the seawall, the height of the seawall,
An input screen for the user to input the distance from the seawall is displayed, and the value input on this screen is used.

Next, the ground subsidence amount determination processing is executed (S120). In this ground subsidence amount determination processing, for example,
The amount of ground subsidence is calculated in accordance with the guidelines for determining the amount of subsidence described in "Guidelines and explanations for seismic resistance of sewer facilities" (issued by the Japan Sewer Association, 1997). That is, the ground subsidence amount in each section is calculated based on the layer thickness of the soil layer determined to be the liquefaction layer in the liquefaction determination process described above.

The results of the liquefaction determination, the lateral flow rate determination, and the ground subsidence amount determination described above are displayed in the same manner as the display screen of the ground response analysis result. By performing the color-coded display according to the corresponding color, the user can easily understand the ground damage determination result visually.

Further, when the "structure simple damage evaluation system" menu is selected on the initial menu screen, the earthquake damage evaluation process for the underground structure is performed. First,
The user selects an underground structure to be evaluated (S122). The selection of the underground structure is performed, for example, by clicking on the underground structure displayed on the mesh map. Then, the earthquake damage evaluation process is performed on the selected underground structure. First, the damage evaluation index Dm is calculated for the underground structure based on the ground response analysis result described above (S124).

For example, when the underground structure is the box culvert shown in FIG. 11 or the pile foundation shown in FIG. 12, the height H of the structure, the relative displacement di of the ground at the top of the structure, and the bottom of the structure The relative displacement amount dj of the ground is the structure database 26
The damage evaluation index Dm is calculated by the damage evaluation formula: Dm = (di-dj) / H 2 using these values.

Then, according to the calculated value of the damage evaluation index Dm, the scale of damage is judged as shown in the following table,
The determination result is displayed on the screen (S126).

[Table 1]

In the above example, the case where the underground structure is a box culvert or a pile foundation is shown, but the damage evaluation formula is provided for each type of structure, and even if it is the same type, the construction year Different damage evaluation formulas are provided for each.

As described above, according to this embodiment, the acceleration, velocity,
Ground response such as relative displacement, shear stress, and strain can be calculated in the depth direction of the ground. Therefore, by using the ground response in such a depth direction, it is possible to appropriately perform predictive evaluation of damage to an underground structure or ground due to an earthquake.

Further, since the analysis target area can be selected and the analysis result / evaluation result can be displayed in each section on the mesh-shaped map, it is possible to provide a user interface that is easy for the user to use.

In the above embodiment, calculation processing such as ground response analysis and processing such as screen display and user input are performed on the same computer, but the present invention is not limited to this.
The ground response analysis system may be configured by a host computer and a terminal computer, and may be executed on the host computer, and the calculation result may be displayed or only the user input may be performed on the terminal computer. In this case, for example, the host computer may be configured as a server on the Internet, and the ground response analysis service may be provided to the terminal accessing via the Internet.

[0050]

According to the present invention, the ground response to an earthquake can be analyzed in the depth direction of the ground.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a ground response analysis system that is an embodiment of the present invention.

FIG. 2 is a flowchart of processing executed by an analysis program.

FIG. 3 is a diagram schematically showing a processing procedure of ground response analysis by an analysis program.

FIG. 4 is a diagram showing an initial menu screen.

FIG. 5 is a diagram showing a processing menu screen.

FIG. 6 is a diagram showing an area selection screen.

FIG. 7 is a diagram showing an example of an analysis result screen.

FIG. 8 is a diagram showing an analysis result screen displaying a wide area analysis result with a reduced scale.

FIG. 9 is a diagram showing a screen on which distributions in the depth direction of maximum strain, maximum shear stress, maximum acceleration, and maximum relative displacement are displayed for a certain section.

FIG. 10 is a diagram showing a screen displaying a relative displacement waveform at a certain depth level of a certain section.

FIG. 11 is a diagram showing a box culvert as an example of an underground structure.

FIG. 12 is a diagram showing a pile foundation as an example of an underground structure.

[Explanation of symbols]

10 Ground response analysis system 12 Analysis program 14 Program execution section 16 Memory 20 map database 22 Geological database 24 Topographic database 26 Structure database 28 Earthquake database

Claims (10)

[Claims] 1. A method of analyzing a ground response to an earthquake, comprising a vibration wave determining step of determining a vibration wave input to a foundation by a computer for each section of a map divided into a plurality of sections. A method of performing a response analysis step of calculating a ground response in each section as a distribution in a depth direction based on an oscillating wave, and a display step of displaying the calculated ground response. 2. The ground response analysis method according to claim 1, further comprising: a computer displaying the map divided into a plurality of parts on a screen; and a step of accepting designation of an analysis target area on the displayed map. The method further characterized in that in the response analysis step, the ground response is calculated for a section within the designated analysis target area. 3. The ground response analysis method according to claim 1 or 2, wherein a step of acquiring geological data related to the geology of the ground by a computer, based on the calculated ground response and the acquired geological data, And a step of predicting and evaluating ground damage related to at least one of ground liquefaction, ground subsidence amount, and lateral flow amount. 4. The ground response analysis method according to claim 1, wherein the computer acquires structural data relating to the underground structure, the calculated ground response and the acquired data. Predicting and evaluating the damage level of the underground structure based on the structure data. 5. The ground response analysis method according to claim 1, wherein the displaying step displays a calculation result of the ground response at a designated depth of each section according to its value. Displaying on the map in different colors, densities, or patterns. 6. The ground response analysis method according to claim 1, wherein the displaying step includes a step of displaying a distribution of the ground response in a depth direction in a designated section. A method characterized by the following. 7. The ground response analysis method according to claim 1, wherein the ground response is acceleration,
A method comprising: velocity, relative displacement, shear stress, and / or strain. 8. A ground response analysis system including a computer that executes the ground response analysis method according to claim 1. 9. A program for causing a computer to execute the ground response analysis method according to any one of claims 1 to 7. 10. A recording medium on which the program according to claim 9 is recorded.