ABSTRACT
The availability of potential construction sites has continued to decline throughout the world due to over-population in coastal and other metropolitan areas. These circumstances have made engineers to build earth structures, highways, and railways over expansive clays and compressive clay deposits. Following heavy rainfall, seepage beneath the tracks often initiates uneven settlement and potentially hazardous problems if not addressed in a timely manner. The extensive ballast maintenance following heavy rainfall is both costly and time consuming. For example, it has been stated that the cost of maintaining Sydney’s rail network was more than two billion dollars in the last decade. Due to the high maintenance costs, the importance of finding appropriate ground improvement techniques tominimise cost can be clearly perceived. Bioengineering aspects of native vegetation are currently being used to improve the soil stiffness, stabilise slopes and control erosion.
