Underwater Embankments on Soft Soil - W.F.Van Impe







Preface

Ground improvement is probably the oldest but, from a technical point of

view, still the most intriguing technique of all common execution methods

in foundation engineering. Indeed, ground improvement was already in use

more than 3000 years ago. In recent decades, the modern methods of ground

improvement are making use of explosives, impact energy, thermal treatment

of the soil, vacuum consolidation, vibratory compaction technologies, stabilization

and solidification of soft soils, as well as combined systems of ingenious

grouting systems, deep mixing techniques, etc.

Throughout the world, deep mixing techniques today are of utmost importance

in dealing with more and more demanding foundation problems. This

tendency has been noticed in Belgium already at a very early stage; with

inventive new developments of soft soil deep mixing technologies and various

advanced high pressure mixing methods. Some initial experiences onshore and

offshore have proved already some years ago that successful solutions can be

attained.

The present work illustrates a challenging example of design and construction

of a quite important large underwater embankment on very soft

soil. Throughout the design staged construction and ground improvement by

deep mixing combined with geotextile reinforcement were proposed to assure

the safety as well as allowable deformations of the construction.

The outcome of monitoring excess pore water pressures and displacements

during the construction shows that when taking account of key aspects of

advanced soil stress-strain behavior, it is possible to appropriately model such

complex problem and even to make rather simple attempts to reach some of

the “type A” foundation behavior predictions.

We may expect this work to be recognized as a valuable reference case

history for the geotechnical engineer, both from the academic as well as from

the practitioner’s point of view, in order to contribute to the art of building

on soft soils.

Our acknowledgments go to the contractors DEME and J. DE NUL, to

the teams of geotechnical experts of Dredging International NV, HydroSoil


Download
*