1. ASCE G-I Case History Night, April 28, 2016
Seismic Earth Pressure Variations in Retaining Walls with Cohesive Backfill Material
Siavash Zamiran, Abdolreza Osouli
Civil Engineering Department
April 28, 2016

2. Outline Conducting numerical models to evaluate seismic earth pressure
Using finite difference method, FLAC software
Assuming soil cohesion for backfill
Assuming soil-wall adhesion
Considering different earthquake loading
Considering hysteretic behavior of soil
Calibrating of the model with centrifuge tests conducted by Agusti and Sitar, 2013

3. Failures of Retaining Walls Due to Earthquake
Caused by Kobe Earthquake in 1995

4. Failures of Retaining Walls Due to Earthquake Loading
Caused by Mid-Niigata Prefecture Earthquake in 2004

5. Seismic hazard map of the USA
Reference: United States Geological Survey

6. New Madrid seismic zone
Reference: United States Geological Survey

7. Analytical methods

8. Some of the analytical methods which consider backfill cohesion

9. Centrifuge Model Based on study by Agusti and Sitar, 2013
Seismic earth pressure on retaining structures in cohesive soils
UC Berkeley
Sponsored by California Department of Transportation

10. Numerical Modeling Geometry

11. Soil Properties Constitutive model: UBCHYST
Soil type: low plasticity lean clay (CL), called Yolo Loam from a borrow pit at the centrifuge facility
Density= kg/m3

12. Interaction of Wall and Soil

13. Computer simulation of retaining wall

14. ACCELERATION AND DISPLACEMENT HISTORY
Kobe
Kocaeli

15. Seismic earth pressure coefficient versus free field acceleration

16. Study phases in progress
Effect of strength properties: cohesion and friction angle
Effect of different earthquakes
Effect of earthquake intensities
Effect of wall rigidity
Effect of soil-wall interaction
Effect of backfill saturation

17. Analyzing the responses
Seismic earth pressure approach
Analytical: Mononobe-Okabe, Shukla, etc, DOTs
Displacement approach
Analytical: Newmark method, AASHTO

18. Fragility analysis
Based on methodology developed by Argyroudis et. al, NIT, (2013)
Development of fragility functions for geotechnical constructions: Application to cantilever retaining walls
Definition of damage states
Numerical modeling, estimation of deformation based on PGA
Probability of damage VS PGA

19. Workshops held in SIUE:
Introduction to Computational Geotechnics, Jan 2016
Numerical Modeling of Foundations Using FLAC3D, Jan 2015
Underground Coal Mine Stability Analysis , Jan 2015
Numerical Modeling in Geotechnical Engineering 2, Oct 2014
Numerical Modeling in Geotechnical Engineering 1, Aug 2014

20. Introduction to Computational Geotechnics, Jan 2016

21. Numerical Modeling in Geotechnical Engineering, Oct 2014

22. Thank you.
Questions?

23. References
Agusti, G. C., & Sitar, N. (2013). Seismic Earth Pressures on Retaining Structures in Cohesive Soils (No. UCB GT 13-02). California Department of Transportation.
Argyroudis, S., Kaynia, A. M., & Pitilakis, K. (2013). Development of fragility functions for geotechnical constructions: Application to cantilever retaining walls. Soil Dynamics and Earthquake Engineering, 50, 106–116.
Shukla, S. K., Gupta, S. K., & Sivakugan, N. (2009). Active Earth Pressure on Retaining Wall for c-ϕ Soil Backfill under Seismic Loading Condition. Journal of Geotechnical and Geoenvironmental Engineering, 135(5), 690–696.
Mononobe, N., & Matsuo, H. (1929). On the Determination of Earth Pressures During Earthquakes. In World Engineering Congress 9 (pp. 177–185).