1. Lateral spreading in interbedded deposits of sand, silt, and clay
QuakeCoRE Flagship 2
June 21, 2016
Lateral spreading in interbedded deposits of sand, silt, and clay
Sean K. Munter

2. Introduction Postgraduate student at University of California, Davis
Advisor – Dr. Ross W. Boulanger
Collaborators – Chris P. Krage, Dr. Jason T. DeJong
In Christchurch June-July as part of joint fellowship of NSF and RSNZ
East Asia and Pacific “Summer” Institute
University of Canterbury
Advisor – Dr. Misko Cubrinovski
Collaborators – Dr. Sarah Bastin, Dr. Sjoerd van Ballegooy

3. Motivation of previous work
Understand liquefaction-induced deformation in deposits with interbedded liquefiable and non-liquefiable sediments
Challenges with CPT-based liquefaction vulnerability indices (LVIs) in interbedded deposits include:
Spatially variable deposits with laterally discontinuous stratigraphy
Smearing of CPT measurements at interfaces between layers
Decreased tip measurements in thin sandy layers
Goal: avoid undue conservatism in application of LVIs by gaining understanding and eventually updating simplified analysis methodologies

4. Outline Previous work Parametric study with infinite slope
2-D nonlinear deformation analyses (NDAs)
Stochastic profiles of interbedded sand and clay
Çark Canal site in the 1999 M7.5 Kocaeli earthquake
1-D lateral displacement indices with CPT data
2-D NDAs with stochastic profiles conditioned on CPTs
Current work in Christchurch

5. Infinite Slope Study

6. Model description Infinite slope configuration
Varying proportions of clay (non-liquefiable) and sand (liquefiable)

7. Stratigraphic realizations
Transition probability geostatistics describes probability of transition between categories as a function of distance between points (Carle 1999)
Define separate transition probability models for each orthogonal direction (x, y, z) based on field data and/or geologic understanding
Produce realizations using a kriging algorithm

8. Nonlinear dynamic analyses
Finite difference numerical model using FLAC 7.0 (Itasca 2011)
Compliant base with ground motion input as stress time history
Ground motion – 1999 Düzce earthquake, Mudurnu station recording scaled to 0.4 g
Material models
Sand portion – PM4Sand calibrated to qc1N ≈ 105
Other – Mohr-Coulomb with uniform su within each stratum
PM4Sand simulations (Boulanger & Ziotopoulou 2015)

9. Results: effect of clay shear strength
Inter-relationship between clay strength and proportion of sand

10. Çark Canal Site

11. Background Youd et al. (2009): Çark Canal in Adapazari, Turkey
Fine-grained sediments interbedded with sand lenses
1999 M7.5 Kocaeli earthquake
No deformations or cracking observed despite PGA ≈ 0.4 g
Buildings near canal settled up to 100 mm
MLR analyses predict significant deformations
“…absence of lateral spread… indicates that these [liquefiable] layers were most likely discontinuous lenses with sufficient shear resistance in the discontinuities [clays] to prevent lateral spread."
Youd et al. (2009)

12. Stratigraphic realizations
Bin CPT data based on geologic stratum and soil behavior type
Sand-like v. clay-like using Ic cutoff
Stratum of fluvial sediments modeled using stochastic profiles
Proportions and vertical mean lengths estimated from 5 CPTs
Cross-channel mean lengths selected based on understanding of geology
Representative soil properties selected by statistical examination of the properties estimated from CPT data

13. Comparison of results

14. Comparison of results

15. Christchurch

16. Current work in Christchurch
Examine sites where 1-D LVIs poorly predicted manifestation of damage during CES
Detailed analysis for sites where spatial variability in the distribution of liquefiable deposits is expected to have contributed to poor predictions
Further examination of CPTs, including application of thin-layer and interface corrections
Where useful and informative, perform 2-D NDAs to support hypotheses and gain insight

17. Current work in Christchurch
11 potential sites identified
Google Earth (2016)

18. Acknowledgements Collaborators University of California, Davis
Dr. Ross W. Boulanger
Chris P. Krage
Jason DeJong
University of Canterbury
Dr. Misko Cubrinovski
Dr. Sarah Bastin
Dr. Sjoerd van Ballegooy, Tonkin & Taylor
Funding
California Division of Safety of Dams
National Science Foundation
Royal Society of New Zealand

19. References
Boulanger, R. W., and Idriss, I. M. (2014). "CPT and SPT based liquefaction triggering procedures." Report No. UCD/CGM-14/01, Center for Geotechnical Modeling, Department of Civil and Environmental Engineering, University of California, Davis, CA, 134 pp.
Boulanger, R. W., and Ziotopoulou, K. (2015). "PM4Sand (Version 3): A sand plasticity model for earthquake engineering applications." Report No. UCD/CGM-15/01, Center for Geotechnical Modeling, University of California, Davis, CA, 112 pp.
Carle, S. F. (1999). T-PROGS: Transition probability geostatistical software. University of California, Davis, CA.
Idriss, I. M., and Boulanger, R. W. (2008). Soil liquefaction during earthquakes. MNO-12, Earthquake Engineering Research Institute, Oakland, CA.
Munter, S. K., Krage, C. P., Boulanger, R. W., DeJong, J. T., and Montgomery, J. (2016). "Potential for liquefaction-induced lateral spreading in interlayered deposits considering spatial variability." Proceedings, Geotechnical and Structural Engineering Congress, ASCE, Phoenix, AZ, Feb
Youd, T. L., DeDen, D. W., Bray, J. D., Sancio, R., Cetin, K. O., and Gerber, T. M. (2009). "Zero- displacement lateral spreads, 1999 Kocaeli, Turkey, Earthquake." J. Geotechnical and Geoenvironmental Engineering, 135(1),
Youd, T., Idriss, I., Andrus, R., Arango, I., Castro, G., Christian, J., Dobry, R., Finn, W., Harder, L., Jr., Hynes, M., Ishihara, K., Koester, J., Liao, S., Marcuson, W., III, Martin, G., Mitchell, J., Moriwaki, Y., Power, M., Robertson, P., Seed, R., and Stokoe, K., II (2001). "Liquefaction Resistance of Soils: Summary Report from the 1996 NCEER and 1998 NCEER/NSF Workshops on Evaluation of Liquefaction Resistance of Soils." J. Geotech. Geoenviron. Eng., 127(10),
Zhang, G., Robertson, P., and Brachman, R. (2004). "Estimating Liquefaction-Induced Lateral Displacements Using the Standard Penetration Test or Cone Penetration Test." J. Geotechnical and Geoenvironmental Engineering, 130(8),