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Abstract

Earth fill structures tend to fail by the nature of their size, geometry, and the materials they are made of and founded on. Their stability is also affected by the loading and other conditions. These failures are often accompanied by very severe consequences which may sometimes include the loss of human lives. For this reason, systems have been developed over the years to monitor these structures and how they respond mechanically to the stresses imposed on them in their service life. One such system involves the use of inclinometers to measure deformations in the embankment. The readings of these deformations ought to be interpreted and standardized for use in establishing alert levels for early warning systems and possibly establishing some generalized relationships and equations.

In a bid to establish trigger levels for an embankment with deformation measurements from an inclinometer, this report studied the use of inclinometers on an actual site and simulated similar conditions with a model embankment. A deformation-based Limit Equilibrium approach was used to study deformations measured in embankments and it was observed that the relationship between deformations and Factor of Safety (FoS) was not linear. It was observed that inclinometers on site would not account for all deformations if their toes are not rooted in the foundation. The position of the instruments also influences the values of the measurements, and the selection of these positions and depths is mostly not guided by theory. The geometry of the slopes of embankments varies, with some embankments having different materials in different regions. These and other varying parameters will not make it feasible to conduct parametric studies for establishing general relationships for establishing trigger levels for embankment monitoring, but such studies could be done on a case-by-case basis for different embankments.

With the approach used in this study, more stable embankments must undergo very large deformations before failure by the Limit Equilibrium (LE) failure criteria of FoS ≤ 1. This problem, therefore, needs to be further studied with a more reliable methodology such as the Critical State Soil Mechanics approach. This will account for strains and deformations, and relate their normalized values to a known Locus of Failure. This method would also account for establishing alert levels for other forms of failure than just slides as with Limit Equilibrium.

 

Course: Civil Engineering with Geotechnical Engineering - MSc

Date Deposited: 2023-02-13

URI/permalink: https://library.port.ac.uk/dissert/dis14098.html