Abstract：In a test sector of soft ground on the 200 km/h mixed passenger and freight railway from Suiling—Chongqing，the settlement of the composite ground with the dry jet mixing(DJM) piles reinforced by the geogrid，and the stress on the DJM piles and the ground soil as well as the tensile force of the geogrid were measured to study the reinforcement effect of the geogrid on the composite ground with the DJM piles. As shown by the test，the stresses on the piles and the soil were increased with the height of the embankment linearly. The tensile forces of the geogrid were changed along with the settlement exponentially. Compared to the composite ground with the DJM piles without geogrid，the settlement of the composite ground with the DJM piles reinforced by the geogrid were reduced by 30%–65%，and the stress ratio between the piles and the soil was 3.75.
