A 4 to 6 m thick very soft peat layer underlies the existing grasslands at the Bloemendalerpolder with a groundwater at 0.2 m below ground level. Urban development requires 0.5 to 1.0 m clearance of the ground level above the groundwater table. Two test embankments consisting of sandfill were designed with a height of 3.0 m and a ground area 26 x 36 m2 with slopes 1:2. The GeoImpuls programme aimed to provide a well-described field test with long time monitoring results. In this paper a detailed description of the test embankments is given as well as detailed descriptions of soil investigation, laboratory tests and instrumentation for monitoring. Finally the monitoring data will be presented which form a basis for further analyses for interested researchers. Analyses of the tests regarding the validation of settlement models and the lateral behaviour of the piles due to horizontal soil displacement are presented in two accompanying papers.