Discussion of 'Performance of Geogrid-Reinforced and PTC Pile-Supported Embankment in a Highway Widening Project over Soft Soils' by Mengxuan Zhao, Chunyuan Liu, Tahar El-Korchi, Haichao Song, and Mingjiang Tao

摘要

The authors evaluated the performance of geogrids and prestressed tubular concrete (PTC) piles used to reinforce the embankment and to reduce construction time in a highway widening project in Tianjin, China. The PTC piles were installed in soft ground and then the crush stone layer was placed over the pile caps on the widen area of embankment. The geogrids were embedded in the crush stone layer. The authors presented a general design procedure for a pile-supported, geogrid-reinforced embankment in a widening project based on field measurements. In the paper, the authors determined parameters of the PTC pile in the section titled "PTC Supporting Pile Design," employing some related models. However, the approach may not be suitable for designing the supporting pile because the consolidation behavior of a saturated clay and pile-soil interaction was not considered when the PTC piles were installed in the soft soil. The construction parameters were not tightly calibrated, so the post-construction differential settlement could hardly be controlled in the widening project. With respect to the pile efficiency (E_p), there was also a significant gap between the calculation and the monitored value. To illustrate the effect of the consolidation behavior of clayey soil on the design procedure, the following discussions of some parameters were given as summarized subseuqently: