Abstract: In recent years,man-made heap hills have become more and more for landscape of urban construction in Jiangsu plain area.Their sizes are growing larger and larger.The heap hills are usually made of engineering spoils,building refuses,garbage and other materials.They are built in wasteland that cannot be used for urban construction.The heap hills not only efficiently use solid waste and waste land,but also beautify very well the urban environment.They are a new fashion in urban construction.However,geological conditions of the waste land are generally complex.It is very close from the surrounding buildings.A heap hill often has a high capacity and occupies a large load area.They are far different from the general engineering projects.If the engineering measures are unreasonable,some environmental geotechnical problems shall be induced easily.For example,a heap hill project was built on soft ground in urban area of southern Jiangsu Province.The design height of this hill is 54meters.The heap hill suddenly collapsed to large-scale when it was filled up to 40meters.This project stopped once.It posed risks to the surrounding roads and buildings.In this paper,with the tests and calculations,the collapse accident of the heap hill is studied in detail.The results indicate that the safety conditions of the heap hill in the soft soil foundation are as follows.The first,the bearing capacity of foundation must meet the requirements.The second,the foundation settlement,especially the discrepancy settlement,should be controlled within a certain range.