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287 APPENDIX E-5 Port Island Site Site Response in the 1995 M 6.9 HyogokenâNanbu Earthquake General This Appendix presents results of numerical modeling of the response of the Port Island site in the 1995 M 6.9 HyogokenâNanbu earthquake. The site is representative of a deep soft soil profile site that liquefied in the past. The analysis documented herein was performed in general accordance with the âGuidance for Effective-Stress Site Response Analysisâ outlined in Section 8.2 of the main report. Relevant information about recorded ground motions is provided in Appendix B-4. Model Selection Table E-1 lists the software and constitutive models used to calculate response of the Port Island site in the 1995 M 6.9 HyogokenâNanbu earthquake. Detailed information about the selected software is provided in Section 4.2 of the main report. Detailed information about the selected constitutive models (CMs) is provided in Section 4.3 of the main report. Table E-1. Selected Software and CMs SHAKE2000 D-MOD2000 FLAC OpenSeesPL S-I MKZ LE-MC PM4SAND UBCSAND UCSDSAND3 UCSDSAND3 PM4SAND See Appendix A-2 for references and detailed information about CMs used herein. Software listed in this table was run either its native 1D mode (SHAKE2000 and D-MOD2000) or in a simulated 1D mode (FLAC and OpenSeesPL). HyogokenâNanbu Earthquake and Ground Motions Relevant information about the 1995 M 6.9 HyogokenâNanbu earthquake and ground motions induced at the site is reproduced from Appendix B-3 in Table E-2.
288 Table E-2. Hygoken-Nanbu Earthquake â Event and Strong Motion Parameters at the Site. Earthquake Date M R PGA (N-S) ru Hyogokenâ Nanbu January 17, 1995 6.9 15 km Surface (A1) 16 m b.g.s. (Downhole; A2) Within Reclaimed Land 0.348 g 0.576 g > 0.95 (Inferred) M = Moment Magnitude R = Approximate site-to-source distance; PGA = Peak Ground Acceleration (larger of the two horizontal components selected); ru = Maximum recorded excess pore water pressure normalized by the vertical effective stress; N-S = North-South (direction). Site Exploration and Characterization Relevant information about the site, including site location and layout, results of site characterization efforts, and relevant earthquake and Strong Motion information is provided in the site characterization report that is enclosed as Appendix B-3. Interpreted and summarized information is presented in Figure E-1. (a) (b) Figure E-1. Port Island Site â Interpreted Soil Profile with Location of Strong Motion Instruments (Acceleration History at A2 was used as Input). Measured Vs Profile is from Iwasaki (1995).
289 The fill dumped from barges (mostly sand with cobbles and gravel) liquified in the 1995 M 6.9 HyogokenâNanbu earthquake. The upper portion of the reclaimed land immediately below groundwater table (i.e., fill between approximately 3 and 12 m) is identified as the âcriticalâ layer. Advanced Laboratory Testing and Interpretation of the Results Results of advanced laboratory testing are not available for this site. Table E-3 provides basic information about modulus reduction and damping curves assigned to the reclaimed land (âMesa Soilâ) within the Port Island profile. Table E-3 â Summary of Advanced Laboratory Testing Soil RC and TS Reclaimed Land (âMesa Soilâ) N/A (Curve for Monterrey Sand used instead) RC = Resonant Column; TS = Torsional Shear; N/A = Not Available. Element Testing Table E-4 lists the results of element tests performed and documented in this study. The element testing is limited to the CM sub-model testing, i.e., fitting of the modulus reduction and damping curves. Program (i.e., SRA software) names into which CMs are embedded are obscured are obscured for administrative reasons. Table E-4 â Summary of Element Testing Material (Test Type) SHAKE2000 D-MOD2000 FLAC OpenSeesPL Reclaimed Land (âMesa Soilâ) N/A MKZ LE-MC PM4SAND UBCSAND UCSDSAND3 UCSDSAND3 PM4SAND N/A = Not Applicable (Direct Input of Modulus Reduction and Damping Curves). Selected results of the CM sub-model testing are presented in Figures E-2 and E-3. (a) Reclaimed Land (âMesa Soilâ) Figure E-2. CM Sub-Model Testing with the MKZ Model (Program 2). Measured Modulus Reduction Curve is from Dobry et al. (1982) (Monterey Sand; Dr = 45%).
290 (a) Reclaimed Land (âMesa Soilâ) Figure E-3. CM Sub-Model Testing with the UCSDSAND3 Model (Program 4). Measured Modulus Reduction Curve is from Dobry et al. (1982) (Monterey Sand; Dr = 45%). SRA Model Development The site response analysis model of the Port Island site is presented in Figure E-1. It includes idealized soil stratification, groundwater elevation, and an interpreted shear wave velocity profile (red line; corresponds to layering as input in the SRA model). Input motion was applied as a within motion in SHAKE2000 and OpenSeesPL analyses. In D-MOD2000, the transmitting base option was used. In FLAC, the applied acceleration history option was used. The basic material properties, i.e., material properties that are not software-specific are provided for each layer in the Attachment. System Testing Figure E-4 documents the process of system testing (i.e., model testing at the soil profile level) for Programs 2 and 4 (program, i.e., SRA software, names are further obscured are obscured for administrative reasons). Upon completion of the system testing, for both programs, the Rayleigh damping model parameters were fine-tuned in an iterative process. The fine-tuning was performed with the A2 (16 m b.g.s.) record from the 1995 M 6.9 HyogokenâNanbu earthquake scaled down to Peak Ground Acceleration (PGA) of 0.05 g and applied as a âwithinâ motion. The results of the fine-tuning, i.e., Rayleigh damping model parameter (n) and the target viscous damping (D) correspond to spectra indicated in âblackâ in Figure E-4. Note that the n = 5 and D = 5% pair provides the best match for both programs and all three CMs considered.
291 (a) Program 2 (MKZ) (b) Program 4 (UCSDSAND3) (c) Program 4 (PM4SAND) Figure E-4. System Testing with Program 2 (MKZ) and Program 4 (UCSDSAND3 and PM4SAND). Results - Ground Surface Response The Total Stress Analysis (TSA) was performed first to establish a Total Stress (TS) nonlinear reference model. Results of the TSA with selected software are presented in Figure E-5. The recorded ground surface response is shown for reference.
292 (a) Program 1 (S-I) (b) Program 2 (MKZ) (c) Program 3 (LE-MC) Figure E-5. Results of TSA â Recorded and Calculated Surface Response with Selected Software and CMs. The Effective Stress Analysis (ESA) was performed without and with excess Pore Water Pressure (PWP) dissipation. The results of ESA with excess PWP dissipation allowed are presented in Figure E-6. The recorded ground surface response is shown for reference. (a) Program 2 (MKZ) (b) Program 3 (PM4SAND)
293 (c) Program 3 (UBCSAND) (d) Program 3 (UCSDSAND3) (e) Program 4 (UCSDSAND3) (f) Program 4 (PM4SAND) Figure E-6. Results of ESA â Recorded and Calculated Surface Response with Selected Software and CMs. Figure E-7 compares ESA spectra calculated with and without excess PWP dissipation allowed. The effect of excess PWP dissipation on the calculated response spectra for this case history is negligible. (a) Program 2 (MKZ) (b) Program 4 (UCSDSAND3) Figure E-7. Results of ESA â Evaluation of the Effects of Excess PWP Dissipation.
294 Results - Response within Soil Profile Figure E-8 shows selected results of the TSA in a profile view. Input PGA (recorded at approximately 16 m b.g.s.) and PGA recorded within the profile are shown for reference along with inferred peak stress and strain response. This inferred peak stress and strain response is reproduced from Figure E-12(g). The calculated and inferred shear stress are normalized with the initial vertical effective stress. (a) Peak Ground Acceleration (b) Normalized Peak Shear Stress (c) Peak Shear Strain Figure E-8. Results of TSA - Recorded and Calculated Response.
295 Figure E-9 shows selected results of TSA presented in the form of stress-strain. Calculations are for depth of 11.7 m b.g.s., i.e., the approximate depth of the largest shear strain within the critical layer (see Figure E-8). (a) Program 2 (MKZ) (b) Program 3 (LE-MC) Figure E-9. Results of TSA - Calculated Stress-Strain Response at 11.7 m b.g.s. Figure E-10 shows selected results of the ESA in a profile view (results with excess PWP dissipation allowed). As noted above, excess PWP response was not recorded during the 1995 M 6.9 HyogokenâNanbu earthquake. However, the site liquefied and, therefore, presence of very large excess PWP within submerged fill (âCriticalâ Layer) has been inferred. Input PGA (recorded at approximately 16 m b.g.s.) and PGA recorded within the profile are shown for reference along with inferred peak stress and strain response. This inferred peak stress and strain response is reproduced from Figure E-12(g). An excess PWP response is presented herein in the form of normalized PWP ratio (ru). Both ru and calculated and inferred shear stress are normalized with the initial vertical effective stress. (a) Peak Ground Acceleration (b) Normalized Peak Shear Stress
296 (c) Peak Shear Strain (d) Normalized Excess PWP Figure E-10. Results of ESA - Recorded and Calculated Response. Figure E-11 shows selected results of ESA as history of ru buildup. ru ⥠0.95 signals the onset of soil liquefaction. The calculations are for depth of 11.7 m b.g.s., i.e., an approximate depth of the largest shear strain and ru response within the profile (see Figure E-8). The recorded acceleration history is shown in Figure E-10 for reference. (a)
297 (b) Figure E-11. (a) Calculated Excess PWP Response at 11.7 m b.g.s. (b) Input Motion. Figure E-12 shows selected results of ESA presented in the form of stress-strain loops calculated in the middle of the submerged portion of the âcriticalâ layer. Figure E-12(g) shows stress- strain loop as inferred from the interpretation of Newtonâs second law, closely spaced Strong Motion (SM) records, and unit weight of soil between the SM instruments (i.e., a proxy for mass density). (a) Program 2 (MKZ) (b) Program 3 (PM4SAND) (c) Program 3 (UBCSAND) (d) Program 3 (UCSDSAND3) (e) Program 4 (UCSDSAND3) (f) Program 4 (PM4SAND)
298 (g) Inferred from Recordings Figure E-12. Results of ESA - Calculated Stress-Strain Response at 11.7 m b.g.s. References Dobry, R., Ladd, R. S., Yokel, F. Y., Chung, R. M., and Powell, D. (1982). P red i cti on of pore w ater pressure b ui l d up an d l i q uef acti on of san d s d uri n g earthq uak es b y the cy cl i c strai n m ethod . National Bureau of Standards, U.S. Department of Commerce, U.S. Government Printing Office, Washington, D.C. Iwasaki, Y. (1995). âGeological and geotechnical characteristics of Kobe area and strong ground motion records by 1995 Kobe earthquake Tsuchi-to-Kiso.â J apan ese S oc. of S oi l M ech. an d F oun d . E n g rg . , 43(6), 15â20.
299 APPENDIX E-5 Attachment Site Response Model of the Port Island Site Layer No. Soil Type Thickness (m) Depth* (m) Vs (m/s) ksat (m/s) γ (kN/m3) 1 Monterey Sand, Dr = %45 1.50 0.75 52 1.00E-02 19.3 2 1.50 2.25 52 1.00E-02 19.3 3 1.00 3.50 52 1.00E-02 19.3 4 1.00 4.50 52 1.00E-02 19.3 5 1.90 5.95 64 1.00E-02 19.3 6 1.90 7.85 64 1.00E-02 19.3 7 1.90 9.75 64 1.00E-02 19.3 8 1.90 11.65 64 1.00E-02 19.3 9 2.13 13.67 64 1.00E-02 19.3 10 2.13 15.80 64 1.00E-02 19.3 11 2.13 17.93 64 1.00E-02 19.3 Dw (m) H (m) (Vs)avg (m/s) T (s) fs (Hz) 3.00 19.00 199.5 0.381 2.62 Depth* = depth of middle of the layer; Vs = soil shear wave velocity; k = saturated hydraulic conductivity; γ = saturated unit weight; Dw = depth to groundwater table; H = total thickness of soil layer; (Vs)avg = weighted average of soil shear wave velocity; T = 1st natural period of the soil profile; fs = 1st natural frequency of the soil profile.
300 Parameters and Coefficients of the MKZ Model (Program 2) Layer No. MKZ - Nonlinear Stress-Strain MKZ - PWP Dissipation γr (-) β s K2 m n 1 0.00300 3.20 0.74 0.0025 0.43 0.62 2 0.00300 3.20 0.74 0.0025 0.43 0.62 3 0.00300 3.20 0.74 0.0025 0.43 0.62 4 0.00300 3.20 0.74 0.0025 0.43 0.62 5 0.00300 3.20 0.74 0.0025 0.43 0.62 6 0.00300 3.20 0.74 0.0025 0.43 0.62 7 0.00300 3.20 0.74 0.0025 0.43 0.62 8 0.00300 3.20 0.74 0.0025 0.43 0.62 9 0.00300 3.20 0.74 0.0025 0.43 0.62 10 0.00300 3.20 0.74 0.0025 0.43 0.62 11 0.00300 3.20 0.74 0.0025 0.43 0.62 Layer No. MKZ - PWP Generation ν f P F S γtv (%) 1 1 1 0.96 7.5 1 0.025 2 1 1 0.96 7.5 1 0.025 3 1 1 0.96 7.5 1 0.025 4 1 1 0.96 7.5 1 0.025 5 1 1 0.96 7.5 1 0.025 6 1 1 0.96 7.5 1 0.025 7 1 1 0.96 7.5 1 0.025 8 1 1 0.96 7.5 1 0.025 9 1 1 0.96 7.5 1 0.025 10 1 1 0.2 7.5 1 0.025 11 1 1 0.2 7.5 1 0.025 Rayleigh Damping (2) ððð«ð« = 0 ððð«ð« = 6.06e-3 (1) PWP = Pore Water Pressure. (2) Rayleigh damping coefficients, ððð«ð«, and ððð«ð«, are calculated by using the period of the soil layer as 0.381 s, the viscous damping, ðð, as %5, and the ðð value as 0.
301 Parameters and Coefficients of the LE-MC Model (Program 3) Layer No. CM Ïd (T/m 3) G0 (MPa) Sig3 hysteretic damping (4) Rayleigh (5,6) a b x0 1 LE-MC 1.60 57.80 1.00 -0.59 -1.21 1% @ 1 Hz 2 LE-MC 1.60 57.80 1.00 -0.59 -1.21 3 LE-MC 1.60 88.90 1.00 -0.59 -1.21 4 LE-MC 1.60 88.90 1.00 -0.59 -1.21 5 LE-MC 1.60 88.20 1.00 -0.59 -1.21 6 LE-MC 1.60 88.20 1.00 -0.59 -1.21 7 LE-MC 1.60 88.20 1.00 -0.59 -1.21 8 LE-MC 1.60 88.20 1.00 -0.59 -1.21 9 LE-MC 1.60 88.20 1.00 -0.59 -1.21 10 LE-MC 1.60 88.20 1.00 -0.59 -1.21 11 LE-MC 1.12 75.00 1.00 -0.55 -1.22 1. LE-MC used for quasi-static stress initialization phase for all layers. 2. Initial bulk modulus calculated assuming Poisson's ratio 0.3 for all layers. 3. Fitted to MKZ model modulus reduction curves used in D-MOD2000 calibration. 4. Based on Ziotopoulou (2010) MS thesis. 5. Total, i.e., combined stiffness- and mass-proportional. Parameters and Coefficients of the PM4SAND Model (Program 3) Layer No. CM Sig3 (three parameters stress- strain model) (4) Rayleigh Damping (5,6) PM4SAND non-default parameters (5) a b x0 Dr Go hpo 1 LE-MC 1.0000 -0.587 -1.206 1% @ 1 Hz - - - 2 LE-MC 1.0000 -0.587 -1.206 - - - 3 PM4SAND - - - 0.47 729 0.7 4 PM4SAND - - - 0.47 729 0.7 5 PM4SAND - - - 0.39 695.51 0.8 6 PM4SAND - - - 0.39 695.51 0.8 7 PM4SAND - - - 0.39 695.51 0.8 8 PM4SAND - - - 0.39 695.51 0.8 9 PM4SAND - - - 0.47 507.53 0.9 10 PM4SAND - - - 0.47 507.53 0.9 11 LE-MC 1.0000 -0.546 -1.216 - - - (1) CM = Constitutive Model (2) LE-MC used for quasi-static stress initialization phase for all layers. (3) Initial bulk modulus calculated assuming Poisson's ratio 0.3 for all layers. (4) Layers 1 through 10 fitted to MKZ model modulus reduction curves used in D-MOD2000 calibration. Layer 11 based on Ziotopoulou (2010). (5) Based on Ziotopoulou (2010). (6) Total, i.e., combined stiffness- and mass-proportional.
302 Parameters and Coefficients of the UBCSAND Model (Program 3) Layer No. CM Sig3 (three parameters stress- strain model) (4) Rayleigh damping (5,6) UBCSAND non-default parameter (5) a b x0 (N1)60cs (7) kGe kB kGp 1 LE-MC 1.0000 -0.5869 -1.2055 1% @ 1 Hz - - - - 2 LE-MC 1.0000 -0.5869 -1.2055 - - - - 3 UBCSAND - - - 10 793 1717 1000 4 UBCSAND - - - 10 793 1717 1000 5 UBCSAND - - - 7 905 1961 750 6 UBCSAND - - - 7 905 1961 750 7 UBCSAND - - - 7 905 1961 750 8 UBCSAND - - - 7 905 1961 750 9 UBCSAND - - - 10 739 1601 800 10 UBCSAND - - - 10 739 1601 800 11 LE-MC 1.0000 -0.5457 -1.2158 - - - - Layer No. UBCSAND Secondary input Parameters mn160 mPa (kPa) mkge mne mme mkgp mnp mrf mhfac1 1 - - - - - - - - - 2 - - - - - - - - - 3 101.3 877.5 4 101.3 877.5 5 101.3 870.7 6 101.3 870.7 7 101.3 870.7 8 101.3 870.7 9 101.3 870.7 10 101.3 870.7 11 - - - - - - - - - (1) CM = Constitutive Model (2) LE-MC used for quasi-static stress initialization phase for all layers. (3) Initial bulk modulus calculated assuming Poisson's ratio 0.3 for all layers. (4) Layers 1 through 10 fitted to MKZ model modulus reduction curves used in D-MOD2000 calibration. Layer 11 based on Ziotopoulou (2010) MS thesis. (5) Based on Ziotopoulou (2010). (6) Total, i.e., combined stiffness- and mass-proportional. (7) "cs" denotes adjusted for "clean sand."
303 Parameters and Coefficients of the UCSDSAND3 Model (Program 3) Layer No. CM Sig3 (three parameters stress- strain model) (4) Rayleigh (5,6) UCSDSAND3 non- default params a b x0 (N1)60 (4,6,7) 1 LE-MC 1.0000 -0.5869 -1.2055 1% @ 1 Hz - 2 LE-MC 1.0000 -0.5869 -1.2055 - 3 UCSDSAND3 - - - 10 4 UCSDSAND3 - - - 10 5 UCSDSAND3 - - - 7 6 UCSDSAND3 - - - 7 7 UCSDSAND3 - - - 7 8 UCSDSAND3 - - - 7 9 UCSDSAND3 - - - 10 10 UCSDSAND3 - - - 10 11 LE-MC 1.0000 -0.5457 -1.2158 - (1) CM = Constitutive Model (2) LE-MC used for quasi-static stress initialization phase for all layers. (3) Initial bulk modulus calculated assuming Poisson's ratio 0.3 for all layers. (4) Layers 1 through 10 fitted to MKZ model modulus reduction curves used in D-MOD2000 calibration. Layer 11 based on Ziotopoulou (2010) MS thesis. (5) Based on Ziotopoulou (2010). (6) Total, i.e., combined stiffness- and mass-proportional. (7) Input values correspond to "clean sand" ("cs") adjusted values.
304 Parameters and Coefficients of the UCSDSAND3 Model (Program 4) Layer No. CM Thickness (m) Parameters of modulus reduction curve ð ð ð·ð·ððâ²(kPa) ðð (°) ðððð (kPa) ð¸ð¸ðððððð,ðð(%) ðµðµðððð 1 U-Sand3 3.00 0.0 40 30 1.5 10 20 2 U-Sand3 2.00 0.0 40 30 1.5 10 20 3 U-Sand3 7.60 0.0 90 30 1.5 10 20 4 U-Sand3 2.13 0.0 90 30 1.5 10 20 5 U-Sand3 4.27 0.0 50 42 1.5 10 20 Layer No. Parameters for generation of PWP Soil Stiffness ððð·ð·ð·ð· (°) ðððð ðððð ðððð ððð ð ðððð ðð ð©ð©ðð (MPa) ð®ð®ðððððð (MPa) 1 25.30 0.01 3.00 0.40 9.00 0.00 0.30 122.1 56.3 2 25.30 0.01 3.00 0.40 9.00 0.00 0.30 122.1 56.3 3 25.30 0.01 3.00 0.40 9.00 0.00 0.30 186.3 86.0 4 25.30 0.01 3.00 0.40 9.00 0.00 0.30 186.3 86.0 5 30.80 0.01 1.00 0.60 4.60 -1.00 0.30 186.3 86.0 Layer No. ðððððððð (m/s) ð©ð©ðð(GPa) ð©ð©ðð(GPa) ðð (Mg/m 3) Parameters for soil dilation ð ð ðð ð ð ðð ð ð ðð 1 1.00.E-02 2.20 5.50 1.95 0.3 3 -0.3 2 1.00.E-02 2.20 5.50 1.95 0.3 3 -0.3 3 1.00.E-02 2.20 5.50 1.95 0.3 3 -0.3 4 1.00.E-02 2.20 5.50 1.95 0.3 3 -0.3 5 1.00.E-02 2.20 5.50 1.95 0.45 3 -0.4 CM = constitutive model; ðð = pressure dependent coefficient; ððððâ² = reference mean effective pressure; ðð = model friction angle; ð ð 0 = model cohesion; ð¾ð¾ðððððð,ðð = maximum shear strain at reference pressure; ðððððð = number of yield surface; ðððððð = phase transformation angle; ðððð, ðððð, ðððð, ðððð, ðððð = contraction parameters; ðð = Poissonâs ratio; ðµðµðð = bulk modulus; ðºðºðððððð = small-strain shear modulus; ððð ð ððð ð = soil permeability; ðµðµðð = bulk modulus of water; ðµðµðð = combined bulk modulus; ðð = soil density; ðððð, ðððð, ðððð = soil dilation parameters. Rayleigh damping parameters: ð¶ð¶ðð = 1.36 and ð·ð·ðð = 0.001. Parameters and Coefficients of the PM4SAND Model (OpenSees) Layer No. CM Thickness (m) ðð (Mg/m3) Primary parameter Fluid properties ð®ð®ðð ðððððð ðððððððð (cm/s) ðððð (Mg/m3) ð©ð©ðð(GPa) 1 PM4SAND 3.00 1.95 1328 0.44 1.00E-02 1 2.20 2 PM4SAND 2.00 1.95 872 0.51 1.00E-02 1 2.20 3 PM4SAND 7.60 1.95 1034 0.53 1.00E-02 1 2.20 4 PM4SAND 2.13 1.95 873 0.51 1.00E-02 1 2.20 5 PM4SAND 4.27 1.95 801 0.47 1.00E-02 1 2.20 CM = constitutive model; ðð = soil density; ððð¢ð¢ = undrained shear strength; ðºðº0 = shear modulus coefficient; âðððð = contraction rate parameter; ððð ð ððð ð = permeability; ððð¤ð¤ = water density; ðµðµðð = soil and water combined bulk modulus. Rayleigh damping parameters: ð¶ð¶ðð = 0.14 and ð·ð·ðð = 9.8 à 10â5.