Pile-net composite foundation has been emerged as an effective alternative successfully adopted worldwide to solve many geotechnical problems. It combines the advantages of the horizontal reinforcement layer and the vertical reinforcement. Related to pile-net-soil cooperative function

pile-net composite foundation is so complicated that designed mainly by experiences

which limits its application. It is very difficult for pile-net composite foundation mechanism to be researched by theoretical analysis. General model test and soil centrifuge modeling test can only solve some problems qualitatively; and some important technical questions need in-situ solution. With in-situ test of a certain high-speed railway trial embankment

pile-net composite foundation has been careful studied in settlement and lateral displacement and contact pressure and the stress and strain of geogrid aspects. The change process in pile-soil stress ratio and the bearing properties of geogrid and settlement have been analyzed. Systematic researches on soft embankment settlement laws

the pile-net composite foundation bearing mechanism and stress transmission mechanism have been performed. How net mat made by geogrid and mat impacts settlement control and how it is designed have been discussed.