Design of Retaining Walls to Eurocode 7

Retaining walls represent one of the oldest and most widespread forms of man-made structure - the Hanging Gardens of Babylon were probably retained above ground level by an interconnecting series of retaining walls. Since that time, retaining wall design has evolved from being a purely empirical process to one that requires a detailed knowledge of soil and structural mechanics

Retaining wall design differs from the design of other structures, such as bridges and buildings, in that the applied loads cannot simply be read from a Code of Practice; instead, retaining walls have to resist the actions of a body of soil which may be of variable composition, density and water content and about which the designer may have only limited information. Retaining wall design lies at the boundary of Structural Engineering and Geotechnical Engineering and for this reason can seem daunting to a young engineer with limited experience in either discipline.

The course aims to cut through the mystique surrounding soil/structure interaction. It aims to give the engineer a broad understanding of the loads imposed by a body of soil and provide a simple and practical approach to retaining wall design in accordance with EC7.

This course will enable delegates to:

• Appreciate the difference in approach taken by Eurocode 7 in comparison with earlier Codes of Practice
• Be familiar with the Limit States and the common modes of wall failure
• Understand the difference between active pressure and passive pressure within a soil
• Appreciate how the pressure within a body of soil varies with strain
• Be familiar with common methods for calculating earth pressure
• Understand the difference between total and effective stress design
• Calculate the pressures on a wall retaining multiple layers of soil with different soil properties
• Understand the effects of sloping ground, water pressure and wall friction on earth pressures
• Allow for the effects of compaction of fill behind the wall
• Know how to deal with surcharge loading
• Undertake the design of simple gravity and embedded retaining walls for EQU, STR and GEO limit states
• Understand the difference between the Gross Pressure, Net Pressure and Borland-Smith methods of calculating pressure on an embedded wall
• Distinguish between free end and fixed end conditions in an anchored wall

Introduction: Types of retaining walls, brief history of CP2, BS8002 and Eurocodes, new philosophy and terminology, structure of EC7, approach to design, limit states and modes of failure, partial factors, Annex A and the UK National Annex.

Earth Pressure: KA, Ko and Kp: relationship of earth pressure to strain, methods of Coulomb, Rankine, Kerisel and Absi and Bell, effects of wall friction and sloping ground, cohesionless and cohesive soils: effect of water pressure, Total stress and effective stress, compaction pressures, surcharge pressures, Annex C charts

Design Of Gravity Retaining Walls: Types of wall - mass concrete, brick, reinforced concrete cantilever, virtual back of wall, calculations for stability, calculations for strength, practical considerations

Design of Embedded Retaining Walls: Types of wall - sheet piles, contiguous piles, diaphragm walls, simple cantilever wall: gross pressure method, net pressure method, Burland-Potts method, anchored wall: fixed and free end conditions, calculation of factors of safety, pressures from multi-layered soils: effective stress design

This one day interactive course achieves results through a stimulating mixture of presentation, group exercises, discussion and open workshop.

Graduate engineers and others with little or no experience of retaining wall design, but may also form a useful introduction to EC7 for more experienced engineers.

All delegates must bring a scientific calculator as the course includes group design exercises.