Estimation of the piled embankment critical height: a systematic review

Differential movements within the embankment above the rigid inclusion (RI) caps produce shear stresses extending upwards into the load transfer platform (LTP). When the LTP’s height is sufficient, those stresses are terminated in a horizontal plane within the embankment. This plane could be named the equal settlement or zero differential settlement plane. Thus, the height from this plane to the caps could be described as a critical height. Failure in accurately quantifying this critical height was reported in many cases as the main reason behind the damage and differential settlement problems associated with the piled embankments. This paper presented a systematic review of the available literature that studied the load transfer and failure mechanisms of rigid inclusion systems. The study also recognized and discussed the most governing factors influencing the efficiency of RI systems and the critical embankment height. Combined with the systematic review, an assessment study was performed using field measurements of nineteen case studies to evaluate the reliability of the different design methods. Results of this assessment revealed that BS 8006 method was relatively superior to the other design methods. It successfully provided a close prediction of the RI efficiency in almost 50% of the cases. Nevertheless, several governmental factors, such as embankment cohesion, and geosynthetics, were ignored in most of the available approaches for estimating the critical height, and they were limited to considering geometrical parameters. At the end of this study, the future needs to improve the current design methods were identified.