Assessment of Landfill Site for Residential Development

摘要

A sand quarry was excavated up to 20 m deep in the south eastern suburbs of Melbourne in the latern1970s and early 1980s. Following exhaustion of resources at the site, the pit was backfilled withrnpredominantly non-putrescible material, most of which was not placed in a controlled manner. Fillingrnwas largely complete to near original ground surface level by 1989. To assess whether the site couldrnbe developed for residential purposes, an understanding of the residual settlement characteristics ofrnthe fill was required. Two trial embankments were constructed to pre-load the ground and inducernsettlement within the fill. The associated settlement monitoring program indicated settlement occurredrnin two stages, an initial “large” settlement occurring in the first few days following load application, withrna “smaller” ongoing settlement continuing at a much slower rate post loading. The results of thernmonitoring program formed the basis on which to assess the risks associated with the construction ofrnmedium density residential dwellings. The understanding of pre-loading and site grading works onrnsettlement of the proposed structures, pavements and services were all identified as risks to therndevelopment. These risks are discussed in this paper along with the adopted approach to preparing thernsite.