In mountainous terrain, safer operation of highways and railways, power generation and transmission facilities, and the safety of residential and commercial developments often require long term stable slopes and control of rock falls. Many transportation systems were constructed over a century ago in the case of railroads, and decades ago in the case of many highways. At that time, the blasting techniques that were often used in construction caused significant damage to the rock mass. Further, deterioration of stability conditions is likely due to weathering of the rock since the time of construction, and loosening of the surficial blocks by ice and water, and also by the growth of tree roots. All these effects can result in on-going instability that may requires a scientific and economical remediation programs.
Open pit mines tolerate a certain degree of slope instability unless there is a hazard to the miners or there is a significant loss of production. For example, minor failures of benches usually have little effect on mining operations unless the fall lands on a haul road and results in tyre or equipment damage.
A number of method have been adopted to stabilize slopes, each of them found to be appropriate for a particular set of conditions.
1. Application of Slope,
2. Purpose of stabilizing,
3. Time available,
4. Accessibility of the site,
5. Types of construction equipment, and
6. The cost of repair.
Various geotechnical, construction and environmental issues must be considered while selecting and designing stabilization measures appropriate for a site. Construction and environmental issues, which can affect the cost and schedule of the work should also be addressed during design phase of the project. Other issues that are frequently important are equipment access, available work time during traffic closures, and disposal of waste rock and soil.
This chapter provides guidelines for selecting the method of slope stabilization that are most appropriate for the topographical, geological and operational conditions at the site. These methods can be mainly classified into three categories:
(a) Removal and Protection,
(b) Drainage of water, and
Application of various slope stabilising measures