Grouted gravel column-supported highway embankment over soft clay: case study

In this paper, a simplified column construction method — the so-called grouted gravel column — and its application to construction of embankments over soft ground are introduced. The construction method, quality assurance (QA), and quality control (QC) of the grouted gravel columns are described. A case study on the application of this method to a highway embankment in China is also presented. The case study shows that about 50% of surface settlement and 60% of the differential settlement between the column head and soil occurred during the construction of the embankment. The column to soil stress ratio was 8.0 for columns with caps and 4.2 for columns without caps. Static load tests were also conducted to assess the bearing capacity of the columns.