Expansive soils are found all over the geographical area of the world these soils are one of the most problematic soils because of their volume instability due to seasonal variation in moisture levels. Volume instability causes severe damage to the structures resting on these soils, especially lightly loaded structures.
Expansive soils found in India are popularly known as black cotton soil as they are black in colour and are good for growing cotton. It is observed that in areas of black cotton soil, the road subgrade has generally high strength during dry season but during rainy season when the subgrade absorbs moisture, it heaves and loses its strength considerably. Similarly in case of buildings the cracks and settlements are caused during rainy season when the foundation soil swells and exerts pressure more than the overburden. Hence there is a need to improve the properties of the soil to avoid problems arising out due to volumetric instability.
The primary aim of this reference book is to introduce about the expansive soil, its properties, nature of damages to structures built on these soils and testing of these soils to know its properties. Stabilisation is another important aspect covered in this book to understand the behaviour of such soils with different types and methods of stabilisation.
The book has six chapters. Chapter one introduces the expansive soil. Chapter two describes the methods of identification of expansive soils. Chapter three is about Nature of Damages to Structures Built on Expansive Soils and Construction Practices. Chapter four details about soil stabilisation whereas chapter five presents a case study of black cotton soil stabilisation using lime and fly ash. Finally, chapter six presents brief of findings from case study.
Materials have been taken from already published works and the same have been duly acknowledged at appropriate places as for as possible.
The author wish to acknowledge the moral support provided by the author’s family during the course of writing this book.