440 likes | 699 Views
Microzonation Study of Soil Liquefaction Potential and Damage. Wei F. Lee Taiwan Construction Research Institute Ming-Hung Chen National Center for Research on Earthquake Engineering. Problems and Solutions. Liquefaction microzonation in metropolitan Area Sensitivity- adequate analysis unit
E N D
Microzonation Study of Soil Liquefaction Potential and Damage Wei F. Lee Taiwan Construction Research Institute Ming-Hung Chen National Center for Research on Earthquake Engineering
Problems and Solutions • Liquefaction microzonation in metropolitan Area • Sensitivity- adequate analysis unit • Population- building coverage • Foundation type • GIS application
Southwest Taiwan Liquefaction Potential Microzonation ISSMFE TC4,1993 Grade Data Based Historic data I Geology map Surface map Aerial photo II Subsurface condition Ground surveying III Geotechnical Investigation Zonation
Procedure Level One Geological Environmental Topography and Surface condition Grid Generation Ⅰ Ⅱ Ⅲ
Procedure Level Two Influence Factor Selection Data Collection Level Three In-Situ/ Lab soil Properties Liquefaction Potential Evaluation and Risk Analysis
Structure Coverage Rate Grid Size Below 25﹪ 1600×1600 m2 25﹪~ 60﹪ 800×800 m2 Above 60﹪ 400×400 m2 Grid Setup • Structure Coverage Rate
GIS Application GIS Combined Slope Management Database
GIS Evaluation Digitalized models Topographic map Geological map Geological zonation Weighting system Strike and fault map Geophysics Info. Hydraulic system map River system Past event record categorization
Case Studied • Level I assessment • Kaohsiung City • Level I, II and III, with initial hazard analysis • Taipei City • Evaluation method • Yuan Lin Township
Kaohsiung Liquefaction Potential Microzonation Regular Grid
Kaohsiung Liquefaction Potential Microzonation Modified grid
Kaohsiung Liquefaction Potential Microzonation Level One- Regular grid
Southwest Taiwan Liquefaction Potential Microzonation Level One- Modified grid
Kaohsiung Liquefaction Potential Microzonation Third Level (Seed97)- Regular Grid
Kaohsiung Liquefaction Potential Microzonation Third Level (T&Y)- Modified Grid
Dry SeasonRegular Dry SeasonModified Microzonation Regular Mocrozonation Wet Season
Settlement Evaluation, (Seed97 method, dry season, Regular Microzonation)
Lateral Spreading Evaluation (Bartlett and Youd,EQ Source B, dry season, Regular Microzonation)
Lateral Spreading Evaluation (Bartlett and Youd,EQ Source A, dry season, Regular Microzonation)
Analysis Tool NNT Evaluation
Yuan LinArtificial Neural Network (ANN) Database including 279 cases 80% for training 20% for testing • Liquefied cases 42 • Non-Liquefied cases 237
Selected Input Factors • Depth of liquefiable soil • SPT-Nvalue • Fines Content (FC) • Total Stress • Effective Stress • D50 • Peak Horizontal Acceleration(amax) • Earthquake Magnitude(Mw) • Liquefaction Initiation Evaluation
Artificial Neural Network • Hidden Level:2 • Note:10 moving note structure (Wu,1991) • Connection :Fully Connection • Weighting(Wij):Quickprop (Fahlman,1988)
ANN-1 Model Soil Properties Liquefaction Potential
Input Output ANN-1 model Input and Output
ANN-2 Model Soil Properties Critical State Cyclic Resistance Ratio (CRR)
Input Output ANN-2 model Input and Output
Future Research • More boring? • Visualized Iwasaki method? • Soil maps at different depth • Geophysics Measurement • Analysis Tool • Metropolitan Geotech Database (MGD) • One more big one!
Thank You Questions