Geosynthetic Reinforced Soil (GRS) Walls

Jonathan T. H. Wu

• Publisher: Wiley-Blackwell
• Year: 2019
• ISBN:
  9781119375869
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Civil Engineering
• Index: Technology & Engineering

The first book to provide a detailed overview of Geosynthetic Reinforced Soil Walls

Geosynthetic Reinforced Soil (GRS) Walls deploy horizontal layers of closely spaced tensile inclusion in the fill material to achieve stability of a soil mass. GRS walls are more adaptable to different environmental conditions, more economical, and offer high performance in a wide range of transportation infrastructure applications. This book addresses both GRS and GMSE, with a much stronger emphasis on the former. For completeness, it begins with a review of shear strength of soils and classical earth pressure theories. It then goes on to examine the use of geosynthetics as reinforcement, and followed by the load-deformation behavior of GRS mass as a soil-geosynthetic composite, reinforcing mechanisms of GRS, and GRS walls with different types of facing. Finally, the book finishes by covering design concepts with design examples for different loading and geometric conditions, and the construction of GRS walls, including typical construction procedures and general construction guidelines.

The number of GRS walls and abutments built to date is relatively low due to lack of understanding of GRS. While failure rate of GMSE has been estimated to be around 5%, failure of GRS has been found to be practically nil, with studies suggesting many advantages, including a smaller susceptibility to long-term creep and stronger resistance to seismic loads when well-compacted granular fill is employed. Geosynthetic Reinforced Soil (GRS) Walls will serve as an excellent guide or reference for wall projects such as transportation infrastructure—including roadways, bridges, retaining walls, and earth slopes—that are in dire need of repair and replacement in the U.S. and abroad.

• Covers both GRS and GMSE (MSE with geosynthetics as reinforcement); with much greater emphasis on GRS walls
• Showcases reinforcing mechanisms, engineering behavior, and design concepts of GRS and includes many step-by-step design examples
• Features information on typical construction procedures and general construction guidelines
• Includes hundreds of line drawings and photos

Geosynthetic Reinforced Soil (GRS) Walls is an important book for practicing geotechnical engineers and structural engineers, as well as for advanced students of civil, structural, and geotechnical engineering.

1
Stresses and Shear Strength of Soils

In the design of earth structures, good knowledge of shear stiffness/strength of soil is of importance because excessive deformation or failure of earth structures may occur as a result of insufficient resistance to shear stress. This chapter presents a review of shear behavior and shear strength of soils that are relevant to the design of earth structures. We begin the chapter with an explanation of stress at a point, followed by a brief explanation of effective stress and Mohr–Coulomb failure criterion. We then discuss commonly used laboratory and field tests for evaluation of shear behavior and determination of the shear strength of soils. We conclude the chapter with a discussion of the design consideration of the shear strength for soils under different loading conditions.

1.1 Stress at a Point

In engineering analysis and design of structures, stress has been proven to be an extremely useful parameter to quantify the effects of internal and external influences on a structure. For earth structures, common influences include external loads, self‐weight of soil and water, seepage force, and temperature change. Stress in a body is commonly referred to a plane. Stress on a plane with cross‐sectional area A when subjected to a force system denoted F can be evaluated by a simple equation:

. This equation, however, is useful only if the force on the given plane is known and if the stress can be approximated as being uniform on that plane. This is generally not the case for a soil mass where the stresses of interest typically occur on a plane other than the plane of load applications, and the stresses may be far from being uniform. To this end, we shall begin the discussion with a review of the stress at a point, a subject we were first exposed to when studying “mechanics of materials” as undergraduate engineering students. We shall discuss three topics that will help us gain a better understanding of stresses at a point: (a) the concept of stress at a point in terms of stress vector, (b) the computation of stress vector on any given plane by the Cauchy formula, and (c) graphical representation of stress at a point by a Mohr circle and the pole of a Mohr circle. A good understanding of these topics will allow us to gain insights into Rankine analysis, a prevailing lateral earth pressure theory, which we will discuss in detail in Chapter 2.

1.1.1 Stress Vector

Let us begin by considering an earth retaining wall subjected to concentrated and distributed loads over the “crest” (top surface of a wall), as shown in Figure 1.1(a). Figure 1.1(b) shows a plane cutting through the soil mass behind the wall at point P. The force acting over a very small area ΔA on the plane of cut surrounding point P is denoted ΔF. If the plan of cut is referred to as the “

plane” (i.e., a plane with its outward normal being a unit vector

; the arrow above the notation “n” is merely a symbol indicating that it is a v...

Table of contents

• Cover
• Table of Contents
• Preface
• 1 Stresses and Shear Strength of Soils
• 2 Lateral Earth Pressure and Rigid Earth Retaining Walls
• 3 Reinforced Soil and Geosynthetic Reinforced Soil (GRS) Walls
• 4 Geosynthetics Reinforcement
• 5 Design of Geosynthetic Reinforced Soil (GRS) Walls
• 6 Construction of Geosynthetic Reinforced Soil (GRS) Walls
• Index
• End User License Agreement