W01_Lecture

University and Course Information

• University: The University of Queensland

• Course Code: CIVL3210

• Course Title: Geotechnical Engineering

• Instructor: Dr Adnan Sufian

Learning Objectives

• Understand the geotechnical design process and identify key challenges

• Investigate the social, economic, and environmental impact of geotechnical structure failures

• Apply strength and serviceability criteria in a geotechnical context

Required Learning Resources

• Week 01 Lecture Slides

• Extracts from the Coroners’ Report into the Thredbo Landslide

• Journal Article for Case Study: Orzalin et al. (2015), ASCE Journal of Geotechnical and Geoenvironmental Engineering, Vol 141(7)

Geotechnical Design Process

• Review basic concepts from CIVL2210, including:

  • Soil as a three-phase material (solid, water, air) and phase relationships

  • Compaction characteristics

  • Stresses in soils: effective stress, stress distribution, seepage

  • Time-dependent consolidation settlement and shear strength of soils

Key Structures in Geotechnical Engineering

• Types of Structures

  • Retaining Walls

  • Shallow Footings

  • Deep Footings (Piles)

  • Slope Stability

  • Settlement

Design Concerns for Geotechnical Engineers

• Key Considerations

  • Safety

  • Performance

  • Economic feasibility

  • Constructability

  • Environmental impact

• Design Evolution

  • Transitioned from early design based on experiments to more formal theoretical foundations

  • Challenge of soil variability: inhomogeneous material with spatial and temporal variations

  • Importance of water: effective stress critical in geotechnical failures

Geotechnical Design Process Steps

1. Site Investigation

2. Analysis and Design

3. Material Properties

4. Construction

5. Supervision

6. Maintenance and Monitoring

Case Studies

MIT Stata Center

• Examine various stages of the geotechnical design process

Retaining Wall Collapse (2013)

• Incident Summary: Collapse of a 50m section of a retaining wall near Harris Park platform concourse, followed by a further 25m collapse 3 hours later. No deaths or injuries reported.

• Factors Contributing to Failure:

  • Design Issues: Wall too tall, upright, and narrow; non-standard anchoring methods used.

  • Construction Problems: Wall exceeded design height; inadequate rock anchor fitting.

  • Material Issues: Use of compacted sand instead of free draining gravel. Sand was too heavy and held water, increasing hydrostatic pressure.

  • Maintenance Factors: Proper maintenance noted, but damage left unattended until the next inspection period (4 years).

  • Regulatory Standards: Limited actions for maintainers under current standards.

Thredbo Landslide (1997)

• Incident Overview: Slope failure of a road embankment leading to a deadly landslide impacting ski lodges (18 deaths).

• Coroner’s Report: Recommended reading for understanding the geotechnical investigation and design implications.

• Geotechnical Discipline: Highlighted the importance of geotechnical engineering and design practices.

Geotechnical Design Criteria

Strength Criterion

• Limit applied loads to below material resistance/strength

  • Factors Considered: Dead loads, live loads, wind loads, water pressure, earthquake impacts

  • Material Properties: Based on soil properties; for Mohr-Coulomb: cohesion and friction angle

Serviceability Criterion

• Limit deformation to acceptable values

  • Considerations: Allowable deformation (s), allowable differential deformation (δ), allowable angular deformation (δ/L)

Safety Factors in Design

• Aim to increase the safety factor to reduce the probability of failure:

  • Methods to enhance safety:

    • Reducing loads

    • Increasing strength

    • Applying both strategies

Conclusion

• Final Notes: The importance of applying rigorous analysis and professional standards in geotechnical engineering to ensure safety and functionality of structures.

Contact Information

• Lecturer: Dr Adnan Sufian

• School of Civil Engineering, UQ

• Email: a.sufian@uq.edu.au

• Phone: 07 334 61352

• Thank you message addressed to the students.