Effect of Compaction on Embankment Stability

Introduction

Embankment stability is an engineering topic that has been characterized with dramatic progress from the time Proctor proposed the fundamental principles of soil compaction in 1933. In the process of constructing earth dams in California, R.R. proctor postulated that the main goal of compaction is to achieve the highest dry density of the compacted soil.

Embankments are normally constructed to elevate the ground level to some height above the existing level so as to support engineering structures such buildings, dams, roads or railways. The durability and stability of such embankments is largely affected by the shear parameters of the compacted soil, which again depend on how well the soil has been compacted.

Engineers worldwide have been presented with catastrophic cases of embankment failure, for example the Brumadinho dam disaster in Brazil, the Patel dam failure in Kenya, and the Swar Chaung dam disaster in Myanmar. These have often led to tremendous loss of life and property, especially in highly populated areas. For this reason, scholars have taken to conducting studies on compaction in a bid to prevent similar disasters in the future. Among them are Shima and Imagawa (1980), Escario and Saez (1986), Maatouk et al (1995), and Wheeler and Sivakumar (1995).

Most of these studies dwelled much on the strength properties of unsaturated compacted soils, such as friction angle and cohesion, as opposed to the mechanical behavior of the same. This study therefore seeks to investigate the mechanical behavior of compacted soil. It is envisaged that the research findings will be useful in the revision of the earthwork guidelines for the construction of embankments for roads, railways, buildings, and dams.

Research Objectives

General objective

The general objective of this study is to investigate the mechanical behavior of compacted soils

Specific Objectives

The specific objectives of this study are:

1. To identify basic procedures of compaction for embankment soils
2. To show the effect of depth and compaction energy on the engineering properties of embankment soils
3. To investigate the behavior of embankment soils during the process of compaction and after the process of compaction
4. To identify the limits beyond which it would be insignificant to further compact embankment soils

Research Design

For the purpose of this study, soil will be compacted in a similar fashion to the Proctor compaction test. Once the compaction process is completed, the test box will have the top half of one of the sides removed to imitate an exposed soil embankment. A weight will then be placed on a tray, which will be subsequently placed on the embankment. The weight on the tray will be incremented in predetermined values until the embankment fails. This process will be repeated for other degrees of compaction.

Research Timeline

References

• Escario, V. and Sáez, J. (1986). The shear strength of partly saturated soils. Géotechnique, 36(3), pp.453-456.
• Seed, H., Lundgren, R. and Chan, C. (1954). The effect of compaction method on the stability and swell pressure characteristics of soils. [Place of publication not identified]: [publisher not identified].
• The factors influencing collapse settlement in compacted soils. (1975). International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 12(9), p.133.
• Venkatarama Reddy, B. and Jagadish, K. (1995). Discussion: The static compaction of soils. Géotechnique, 45(2), pp.363-367.
• Wheeler, S. and Sivakumar, V. (1995). An elasto-plastic critical state framework for unsaturated soil. Géotechnique, 45(1), pp.35-53.