A method for determining the seismic response of an engineering site under the action of a seismic rupture

Abstract

The present application relates to the technical field of earthquake engineering, and provides a method for determining the seismic response of an engineering site under the action of a seismogenic fault, comprising the following steps: S1, determining the bedrock surface of the engineering site; S2, establishing the scale range of the engineering site; S3, selecting near-fault ground motion records and site categories for inputting seismic waves; S4, outputting the site response under the input of ground motion; and S5, outputting the site response under the input of dislocation. 地表 The dislocation input of the finite element software site earthquake is used to obtain the surface displacement deformation characteristics and select the maximum displacement value D 位移 The present application provides a method for selecting near-fault ground motion records considering dislocation in a consistent manner for the site classification of the input mode of the calculation and analysis of the seismogenic fault engineering site, respectively strips the seismic input of the acceleration time history and the bedrock dislocation amount input, and is closer to the actual earthquake disaster, so as to provide reasonable design parameters for the seismic design of the engineering structure and the design of the anti-fracture capacity.

Description

Technical Field

[0001] This invention relates to the field of earthquake engineering technology, and in particular to a method for determining the seismic response of an engineering site under seismogenic faulting. Background Technology

[0002] For specific engineering sites in tectonic regions adjacent to active faults that generate surface deformation zones, designers need to comprehensively consider factors such as peak ground acceleration (PGA) and acceleration response spectrum, and surface deformation to meet site requirements. Traditionally, determining the effective spatial range of a site considering the seismogenic fault relies heavily on engineers' experience, lacking quantitative criteria based on key parameters. When a site is close to an active fault, engineering structures traversing the fault zone face severe risks from the coupling effect of large coseismic deformation caused by fault displacement and strong near-field ground motion. To ensure the seismic safety of such major projects, designers must use inputs that reflect both bedrock dislocation induced by fault displacement and ground motion inputs that include near-field strong ground motion elements and conform to site characteristics for seismic parameter design. However, limited by existing strong ground motion observation data, measured ground motion records possessing both fault dislocation characteristics and near-field strong ground motion parameters are extremely scarce.

[0003] This practical dilemma urgently requires the establishment of a comprehensive engineering site geometry range that takes into account the source mechanism, propagation path, and site conditions. It also necessitates the systematic development of methods for selecting seismic motion inputs and determining responses that meet the needs of engineering applications, thereby providing a reliable basis for structural engineering in seismic design. Summary of the Invention

[0004] To overcome or alleviate one or more of the above-mentioned technical problems, the purpose of this invention is to provide a method for determining the ground motion response of an engineering site under seismic faulting. This method comprehensively considers the characteristics of fault activity, geological conditions of the engineering site, ground motion pulses, and displacement inputs to determine the ground motion response of the engineering site, providing reasonable design parameters for the seismic design and fracture resistance design of engineering structures.

[0005] This invention provides the following technical solution:

[0006] A method for determining the seismic response of an engineering site under seismogenic faulting includes the following steps:

[0007] S1. Determine the bedrock surface of the engineering site.

[0008] Drilling is carried out within the engineering site to determine its site type; shear wave velocity is measured and the bedrock depth Z is determined in combination with the displacement of the soil and rock mass;

[0009] S2. Establish the dimensional range of the engineering site.

[0010] By collecting and organizing data on fault activity characteristics, seismic activity, geological conditions, and tectonic stress fields in the site area, a source mechanism model, a propagation medium model, and a site condition model are established. Boundary loads and displacements are calculated, and the horizontal boundary L of the engineering site is determined.

[0011] S3. Selection of seismic wave input

[0012] Based on data from domestic and international strong-motion seismic stations, the distribution map of active faults at the location, the bedrock depth Z, and the horizontal boundary L, near-fault ground motion records with a magnitude Ms greater than 6.5 within 2 kilometers of the active fault are selected, and their site categories are assigned. Then, for each strong-motion record, at least three near-fault seismic acceleration time histories of the same site category are selected. These acceleration time histories are normalized and then converted into acceleration time histories A1(t) and displacement time histories S0(t) with zero displacement integrals. Next, based on the seismic fortification intensity of the engineering site, the acceleration time histories at the bedrock surface A2(t) are calculated. For the displacement time histories S0(t), the maximum surface displacement D is extracted. 地表 ;

[0013] S4, Site response output under seismic input

[0014] For the acceleration time history record A2(t) at the bedrock surface location obtained in step S3, it is used as the input ground motion for seismic response analysis in finite element software. A soil layer calculation model for the engineering site is established, and the ground acceleration time history A2(t) is calculated. After being converted into a site response spectrum, it is then calibrated as the design response spectrum Sa(t). The Sa(t) diagram serves as the basis for the seismic design of the engineering structure.

[0015] S5, Field Response Output under Dislocation Input

[0016] For the maximum surface displacement value D obtained in step S3 地表 The relationship between surface dislocations and bedrock dislocations based on fault dip angles at different engineering sites is shown in the following formula:

[0017] (1)

[0018] Where β is the fault dip angle, and D 基岩 The maximum displacement value of the bedrock surface is used as the dislocation input for the site seismic analysis in the finite element software. Based on the project site area, a soil layer calculation model is established for the site. The surface displacement and deformation characteristics are calculated, and the maximum displacement value D is selected. 位移 It is directly used as the design displacement of the engineering site for seismic design analysis.

[0019] Preferably, the specific steps for determining the bedrock surface depth Z in step S1 are as follows:

[0020] At least two boreholes must be drilled within the engineering site to determine its site type. If active faults exist within the site, at least six joint boreholes with a spacing of no more than 10 meters must be drilled near the active fault locations to determine the site type. A ground-excited wave velocity meter must be placed in at least two corresponding boreholes to obtain the shear wave velocity V at different depths. se The average value was taken; referring to the geological data near the site, the soil and rock layers of the joint boreholes were divided according to the comprehensive standard columnar section of the soil and rock layers; the bedrock location was determined according to the shear wave velocity of at least 800 m / s for Class I0 and I1 sites, where the bedrock location is a depth, and the bedrock location was determined considering that the soil and rock mass displacement between adjacent boreholes of the joint boreholes was no greater than 2 m, and the maximum depth of the two was selected as the bedrock depth Z; the bedrock location was determined according to the shear wave velocity of at least 500 m / s for Class II, III, and IV sites, and the bedrock location was determined considering that the soil and rock mass displacement D between adjacent boreholes of the joint boreholes was no greater than 1 m, and the maximum depth of the two was selected as the bedrock depth Z; shear wave velocity V se A ground-excited wave velocity meter was placed in at least two corresponding boreholes to obtain wave velocities at different depths and take the average value. The soil and rock layer division of the joint boreholes was based on geological data near the site and on a comprehensive standard columnar section of soil and rock layers.

[0021] Preferably, the method for determining the value of the horizontal boundary L of the engineering site in step S2 is as follows:

[0022] Using the near-fault ground motion prediction method based on the kinematic source model, the slip time history is obtained to calculate the load P and displacement U at each node. The horizontal location with almost no motion or force, i.e., where the load P and displacement U are 0, is selected as the candidate boundary of the engineering site and denoted as L. p L u Simultaneously, it is considered that the value of the horizontal boundary L is not less than 10 times the location of the bedrock at the site, i.e., L z The horizontal boundary is determined by selecting the maximum value among the three as the horizontal boundary L of the engineering site.

[0023] Preferably, the acceleration time history record A1(t) with zero displacement integral in step S3 is obtained by filtering and baseline correction from 0.1Hz to 50Hz and handling displacement drift on the basis of the original acceleration time history record A0(t). The initial ground motion acceleration time history A0(t) is baseline calibrated and filtered by seismic wave processing software. The baseline calibration adopts constant baseline calibration, and the filtering adopts Butterworth function to filter from 0.1Hz to 50Hz. For the displacement time history record S0(t), it is obtained by directly performing a second integration on the basis of the original acceleration time history record A0(t).

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) Based on the reasonable quantification of the source mechanism, soil layer information parameters, bedrock displacement, etc., this invention gives the range of geometric dimensions (L×Z) of the engineering site considering the seismogenic fault, avoiding the fuzzy processing methods of previous human experience, and laying the foundation for the calculation and analysis of the engineering site;

[0026] (2) The present invention provides a method for selecting near-fault ground motion records that consider displacement and are consistent with the site classification in the calculation and analysis of the seismogenic fault engineering site, and separately separates the ground motion input of acceleration time history and the bedrock dislocation input. Compared with the previous method that only considered ground motion input or bedrock dislocation input, this method is significantly different and closer to the actual earthquake damage.

[0027] (3) For different types of engineering structures, this invention can comprehensively analyze the response of engineering structures on seismic fault sites by using both the site soil response results (design response spectrum) under seismic input and the site soil response results (surface dislocation, displacement) under bedrock dislocation. Compared with the prior art, this invention provides a more comprehensive and practical dynamic response of engineering structures in active fault-prone areas, providing technical support for their seismic design and fracture stress analysis. Attached Figure Description

[0028] Figure 1 A flowchart illustrating a method for determining the seismic response of an engineering site under seismic faulting, provided in an embodiment of the present invention.

[0029] Figure 2 This is a soil layer information profile of a Class II site provided in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the selection of horizontal boundaries of an engineering site provided in an embodiment of the present invention;

[0031] Figure 4 A flowchart for selecting and processing ground motion records at a Class II normal fault site provided in an embodiment of the present invention.

[0032] Figure 5 This is a schematic diagram of the surface response obtained by inputting the processed acceleration time history record, as provided in an embodiment of the present invention.

[0033] Figure 6 This is a schematic diagram of the surface response obtained from the processed maximum displacement input of the bedrock, provided in an embodiment of the present invention. Detailed Implementation

[0034] The present invention will now be described in detail with reference to embodiments and accompanying drawings. However, it should be understood that the embodiments and drawings are for illustrative purposes only and do not constitute any limitation on the scope of protection of the present invention. All reasonable modifications and combinations included within the inventive spirit of the present invention fall within the scope of protection of the present invention.

[0035] Example 1 below provides an overview of the scheme process, while Example 2 shows the calculation of the simulated response results by substituting specific parameters. The final outputs are Sa(t) and D. 位移 .

[0036] The present invention will be further described below with reference to the accompanying drawings.

[0037] Example 1

[0038] like Figure 1 This embodiment provides a method for determining the seismic response of an engineering site under seismic faulting. It comprehensively considers fault activity characteristics, geological conditions of the engineering site, seismic pulses, and displacement input to determine the seismic response of the engineering site. The method includes the following steps:

[0039] The first step is to determine the bedrock surface of the engineering site.

[0040] To determine the site category, at least two boreholes must be drilled within the site. If active faults exist, at least six joint boreholes with a spacing of no more than 10 meters must be drilled near the active fault location. After completing the above, a comprehensive assessment is conducted based on the existing site category classification (I0, I1, II, III, IV) and the joint borehole profiles. Specifically, for I0 and I1 sites, the bedrock depth Z is determined by considering the bedrock location (depth) when the shear wave velocity is at least 800 m / s and the bedrock location (depth) when the soil-rock displacement between adjacent boreholes in the joint boreholes is no more than 2 meters. For II, III, and IV sites, the bedrock depth Z is determined by considering the bedrock location (depth) when the shear wave velocity is at least 500 m / s and the bedrock location (depth) when the soil-rock displacement D between adjacent boreholes in the joint boreholes is no more than 1 meter.

[0041] Among them, the shear wave velocity V seA ground-excited wave velocity meter was placed in at least two corresponding boreholes to obtain wave velocities at different depths and take the average value. The soil and rock layer division of the joint boreholes was based on geological data near the site and on a comprehensive standard columnar section of soil and rock layers.

[0042] The second step is to establish the dimensional range of the engineering site.

[0043] By collecting and organizing data on fault activity characteristics, seismic activity, geological conditions, and tectonic stress fields in the site area, a source mechanism model, a propagation medium model, and a site condition model were established. Using the near-fault ground motion prediction method based on the kinematic source model, the slip time history was obtained to calculate the load P and displacement U at each node. Horizontal locations with almost no motion or stress (i.e., where the load P and displacement U are 0) were selected as candidate boundary lines for the engineering site, denoted as L. p L u Simultaneously, the value of the horizontal boundary L should not be less than 10 times the depth of the bedrock location Z, i.e., L. z The horizontal boundary is determined by selecting the maximum value among the three as the horizontal boundary L of the engineering site.

[0044] The third step is to select the input seismic waves.

[0045] Based on data from strong-motion seismic stations both domestically and internationally, and the distribution maps of active faults in their locations, near-fault ground motion records with a magnitude Ms greater than 6.5 within 2 kilometers of active faults were selected, and their site categories were assigned. Then, for each strong-motion record, at least three near-fault seismic acceleration time histories of the same site category were selected. After normalization, these acceleration time histories were calculated and transformed into acceleration time histories A1(t) and displacement time histories S0(t) with zero displacement integrals.

[0046] Specifically, the acceleration time history record A1(t) with zero displacement integral is obtained by filtering and baseline correction from 0.1Hz to 50Hz and handling displacement drift on the basis of the original acceleration time history record A0(t). The initial ground motion acceleration time history A0(t) is then baseline-calibrated and filtered using seismic wave processing software (0.1Hz to 50Hz filtering can be performed using constant baseline calibration and the Butterworth function, respectively). The displacement time history record S0(t) is obtained by directly performing a second integral on the original acceleration time history record A0(t). Then, based on the seismic fortification intensity of the project site, it is converted into peak ground acceleration, and the acceleration time history record A2(t) at the bedrock surface location is calculated. For the displacement time history record S0(t), its maximum surface displacement value D can be further extracted. 地表 .

[0047] Step 4: Site response output under seismic input

[0048] For the acceleration time history record A2(t) at the bedrock surface location obtained in the third step, it is used as the input ground motion for the seismic response analysis of the finite element software. A soil layer calculation model of the site where the proposed project is located is established. The ground acceleration time history A2(t) is calculated and converted into the site response spectrum. Then it is calibrated as the design response spectrum Sa(t). The Sa(t) diagram can be used as the basis for the seismic design of the project structure.

[0049] Step 5: Field response output under dislocation input

[0050] For the maximum surface displacement value D obtained in the third step 地表 Further analysis can be conducted based on the relationship between surface dislocations and bedrock dislocations at different fault dip angles in different engineering sites:

[0051] (1)

[0052] In the above formula, β is the fault dip angle, and D is the maximum displacement value of the bedrock surface. 基岩 Using this as the dislocation input for site seismic analysis in finite element software, a soil layer calculation model for the proposed project site is established based on the project site area. The surface displacement and deformation characteristics are then calculated, and the maximum displacement value D is selected. 位移 It can be directly used as the site design displacement for the project to analyze its fracture resistance.

[0053] Example 2

[0054] This embodiment provides a method for determining the seismic response of an engineering site under seismic faulting, specifically including the following steps:

[0055] Step S1: Determine the bedrock surface of the engineering site.

[0056] like Figure 2 As shown in the figure, this embodiment uses a soil layer information profile of a certain Class II site to determine the soil layer at depth Z where soil layer i is located. i The average shear wave velocity V obtained at the location sei The displacement D between adjacent rock and soil masses is 490 m / s. i The depth is 0.7m, at the depth Z of soil layer i+1. i+1 The average shear wave velocity V obtained at the location sei+1 The displacement D between adjacent rock and soil masses is 520 m / s. i+1 The value is 0.9m. Clearly, the displacement D between adjacent soil and rock masses at soil layer i and soil layer i+1 is... i D i+1 All values ​​are less than 1m, which meets the requirements. However, due to the average shear wave velocity V obtained at soil layer i... seiA depth less than 500 m / s does not meet the requirements; therefore, the bedrock depth selected in this embodiment is Z = max(Z i Z i+1 =Z i+1 That is, the depth Z of soil layer i+1 i+1 The depth is taken as the bedrock depth.

[0057] Step S2: Establish the dimensional range of the engineering site.

[0058] This embodiment uses a near-fault ground motion prediction method based on a kinematic source model. It obtains the slip time history and calculates the load P and displacement U at each node, such as... Figure 3 As shown, the boundary dimension L at the horizontal limit termination of the arc with a load of 0 is... p The boundary dimension L at the horizontal limit termination point of the arc with displacement of 0. u This serves as an alternative boundary for the engineering site; simultaneously, it is considered that the value of the horizontal boundary L is not less than 10 times the depth of the bedrock at the site, i.e., L. Z The horizontal boundary is determined by selecting the maximum value among the three as the horizontal boundary L of the engineering site, i.e., L = max(L p L u L Z )=L p .

[0059] Step S3, Seismic wave input selection

[0060] Based on data from strong-motion seismic stations both domestically and internationally, this patent selects, according to the distribution map of active seismic faults in Turkey, as follows: Figure 4 The three near-fault seismic acceleration time histories recorded at sites a, b, and c near the fault trace shown are from Class II sites, and these acceleration time histories have been normalized.

[0061] For example Figure 4 Taking the original acceleration time history record A0(t) recorded by station a as an example, the acceleration time history record A1(t) with zero displacement integral is obtained by using seismic wave processing software, which employs constant baseline calibration and Butterworth function filtering from 0.1Hz to 50Hz. Then, based on the original acceleration time history record A0(t), a second integration is directly performed to obtain the displacement time history record S0(t). Then, according to the seismic fortification intensity of the project site, it is converted into peak ground acceleration, and the acceleration time history record A2(t) at the bedrock surface location is calculated. For the displacement time history record S0(t), its maximum surface displacement value can be further extracted, such as... Figure 4 As shown in its D 地表 The value is set at 18cm.

[0062] Step S4, Site response output under seismic input

[0063] Due to such Figure 2 The soil layer information parameters of a certain Class II site shown are similar to those of an engineering site in the Turkish earthquake. Therefore, this embodiment is similar to... Figure 5 The same soil layer information parameters were used in the soil layer calculation model of the engineering site shown.

[0064] Then, based on the processed acceleration time history record A2(t) obtained in step S3, it is used as the input ground motion for seismic response analysis in finite element software. The ground acceleration time history A3(t) is calculated and converted into a site response spectrum, which is then calibrated as the design response spectrum Sa(t). The Sa(t) diagram can then be used as the basis for seismic design parameters of the engineering structure.

[0065] Step S5, Field response output under dislocation input

[0066] like Figure 6 As shown, according to the project site area (L×Z=L) p ×Z i+1 ), establish a soil layer calculation model for the project site, and for the maximum surface displacement value D obtained in step S3 地表 Furthermore, based on the relationship between surface dislocations and bedrock dislocations, formula (1) can be obtained. (where the fault dip angle β is 30°).

[0067] This is used as the bedrock dislocation input for site seismic analysis in finite element software, such as... Figure 6 As shown, the surface displacement deformation characteristics can be obtained through calculation, and its maximum displacement value D is selected. 位移 It can be directly used as the design displacement of the engineering site for fracture resistance analysis.

[0068] In summary, Sa(t) and D 位移 This can be used as the final response output value of the engineering site under seismic faulting, and used for seismic design and fracture resistance analysis of the engineering structures on the engineering site.

[0069] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for determining the seismic response of an engineering site under seismic faulting, characterized in that, Includes the following steps: S1. Determine the bedrock surface of the engineering site. Drilling is carried out within the engineering site to determine its site category; Measure the shear wave velocity and combine it with the rock and soil mass displacement to determine the bedrock depth Z; S2. Establish the dimensional range of the engineering site. By collecting and organizing data on fault activity characteristics, seismic activity, geological conditions, and tectonic stress fields in the site area, a source mechanism model, a propagation medium model, and a site condition model are established. Boundary loads and displacements are calculated, and the horizontal boundary L of the engineering site is determined. S3. Selection of seismic wave input Based on data from domestic and international strong-motion seismic stations, the distribution map of active faults at the location, the bedrock depth Z, and the horizontal boundary L, near-fault ground motion records with a magnitude Ms greater than 6.5 within 2 kilometers of the active fault are selected, and their site categories are assigned. Then, for each strong-motion record, at least three near-fault seismic acceleration time histories of the same site category are selected. These acceleration time histories are normalized and then converted into acceleration time histories A1(t) and displacement time histories S0(t) with zero displacement integrals. Next, based on the seismic fortification intensity of the engineering site, the acceleration time histories at the bedrock surface A2(t) are calculated. For the displacement time histories S0(t), the maximum surface displacement D is extracted. 地表 ; S4, Site response output under seismic input For the acceleration time history record A2(t) at the bedrock surface location obtained in step S3, it is used as the input ground motion for seismic response analysis in finite element software. A soil layer calculation model for the engineering site is established, and the ground acceleration time history A2(t) is calculated. After being converted into a site response spectrum, it is then calibrated as the design response spectrum Sa(t). The Sa(t) diagram serves as the basis for the seismic design of the engineering structure. S5, Field Response Output under Dislocation Input For the maximum surface displacement value D obtained in step S3 地表 The relationship between surface dislocations and bedrock dislocations based on fault dip angles at different engineering sites is shown in the following formula: （1） Where β is the fault dip angle, and D 基岩 The maximum displacement value of the bedrock surface is used as the dislocation input for the site seismic analysis in the finite element software. Based on the project site area, a soil layer calculation model is established for the site. The surface displacement and deformation characteristics are calculated, and the maximum displacement value D is selected. 位移 It is directly used as the design displacement of the engineering site for seismic design analysis.

2. The method for determining the seismic response of an engineering site under seismogenic faulting according to claim 1, characterized in that, The specific steps for determining the bedrock surface depth Z in step S1 are as follows: To determine the site category, at least two boreholes must be drilled within the construction site. If there are active fractures in the site, at least six joint drilling operations with a spacing of no more than 10m should be carried out near the location of the active fracture to determine the site category. A ground-excited wave velocity meter is placed in at least two corresponding boreholes to obtain the shear wave velocity V at different depths. se The average value was taken; referring to the geological data near the site, the soil and rock layers of the joint boreholes were divided according to the comprehensive standard columnar section of the soil and rock layers; the bedrock location was determined according to the shear wave velocity of at least 800 m / s for Class I0 and I1 sites, where the bedrock location is a depth, and the bedrock location was determined considering that the soil and rock mass displacement between adjacent boreholes of the joint boreholes was no greater than 2 m, and the maximum depth of the two was selected as the bedrock depth Z; the bedrock location was determined according to the shear wave velocity of at least 500 m / s for Class II, III, and IV sites, and the bedrock location was determined considering that the soil and rock mass displacement D between adjacent boreholes of the joint boreholes was no greater than 1 m, and the maximum depth of the two was selected as the bedrock depth Z; shear wave velocity V se A ground-excited wave velocity meter was placed in at least two corresponding boreholes to obtain wave velocities at different depths and take the average value. The soil and rock layer division of the joint boreholes was based on geological data near the site and on a comprehensive standard columnar section of soil and rock layers.

3. The method for determining the seismic response of an engineering site under seismogenic faulting according to claim 1, characterized in that, The method for determining the horizontal boundary L of the engineering site in step S2 is as follows: Using the near-fault ground motion prediction method based on the kinematic source model, the slip time history is obtained to calculate the load P and displacement U at each node. The horizontal location with almost no motion or force, i.e., where the load P and displacement U are 0, is selected as the candidate boundary of the engineering site and denoted as L. p L u Simultaneously, it is considered that the value of the horizontal boundary L is not less than 10 times the location of the bedrock at the site, i.e., L z The horizontal boundary is determined by selecting the maximum value among the three as the horizontal boundary L of the engineering site.

4. The method for determining the seismic response of an engineering site under seismogenic faulting according to claim 1, characterized in that, The acceleration time history record A1(t) with zero displacement integral mentioned in step S3 is obtained by filtering and baseline correction from 0.1Hz to 50Hz and displacement drifting processing on the basis of the original acceleration time history record A0(t). The initial ground motion acceleration time history A0(t) is baseline calibrated and filtered by seismic wave processing software. The baseline calibration adopts constant baseline calibration, and the filtering adopts Butterworth function to filter from 0.1Hz to 50Hz. For the displacement time history record S0(t), it is obtained by directly performing a second integration on the basis of the original acceleration time history record A0(t).

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