This book deals with landslides, earthworks (cut and fill slopes), retaining structures and erosion protection on mountain roads and embraces planning, feasibility study, investigation, design, construction, improvement and maintenance. Non-arterial roads constructed in hilly and mountainous areas are usually characterized by low traffic volume, and are low-cost in the approach adopted in their design, construction and maintenance. This book focuses on these roads but many of the techniques described are equally relevant to more highly trafficked roads and high-investment infrastructure including railways and pipelines. The reason for this is that the techniques of geomorphology and engineering geology, which constitute much of the discussion and illustration contained herein, are among the most valuable tools applicable to any linear infrastructure project in complex and unstable terrain. This is especially true for remote locations where information is frequently lacking on ground conditions.
This book also focuses on the humid tropics and subtropics where heavy seasonal rainfall is responsible for a high incidence of slope instability. Nevertheless, large parts of this book will also be of interest to practitioners working in higher latitudes. Environmental issues of mountain road construction and maintenance are not addressed per se although many of the engineering considerations relating to land use and vegetation cover, earthworks stability, spoil disposal, drainage and erosion are also highly relevant to environmental protection. TRL (1997) discusses environmental and social impact considerations of mountain roads and further review is given in, for example, Corbett & Gaviria (2003); Dhakal et al. (2010)
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Slope Engineering for Mountain Roads
This book provides a complete guide to the study, design, construction and management of landslide and slope engineering measures for mountain roads, with an emphasis on low-cost. The geographical focus of the book is on the tropics and sub-tropics, but is also highly relevant to other regions where heavy rain, steep slopes and weak soils and rocks combine to create slope instability. The causes and mechanisms of landslides are described, and the hazards they pose to mountain roads are illustrated. Methods of desk study, field mapping and ground investigation are reviewed and illustrated, with an emphasis on geomorphological and engineering geological techniques. The design and construction of alignments, earthworks, drainage, retaining structures, the stabilization of soil slopes and rock slopes, and the control of erosion on slopes and in rivers and streams are covered. Slope management as part of road maintenance and operation is reviewed, and procedures for risk assessment and works prioritization are described.