Geosynthetic reinforced earth structures: Effects of facing units and force distribution functions

Geosynthetic reinforced slopes and walls are alternatives to conventional retaining structures and are being increasingly applied. Facing blocks are sometimes used to improve the aesthetic appearance of walls while simplifying their construction. This thesis presents a limit equilibrium analysis of geosynthetic reinforced earth structures utilizing log-spiral failure mechanism. The analysis considers the potential impact of facing blocks. It also considers the impact of the assumed distribution of reinforcement force with height. Design charts are developed for an equivalent lateral earth pressure coefficient and for the trace of the critical slip surfaces. The results of parametric studies indicate that the interface friction at the back and at the base of the facing blocks may lead to significant reduction of the required resistance of reinforcement and to deeper failure. Since the impact is significant, it is prudent in design to downplay the impact of small facing units, especially since the interfacial parameters are unreliable over the long run. The assumed distribution of reinforcement force with height does not have significant impact on the total required resistance of reinforcement; however, it may result in different values of the required resistance of individual reinforcement layers. Uniform distribution produces shallower failures than other distributions. It is observed that seismicity leads to deep failure and higher required resistance of reinforcement.