Abstract：There are many engineering methods to reinforce soft soil foundation. For different methods，the effect，cost and construction period may be very different，and it is difficult to consider all the aspects well. The step-loading method combined with draining-board has advantages of low cost and good result to soft soils，but the construction period is quite long. In the engineering of rockfill dam for new tailing storage of Wushan copper-mine，a large single layer loading method was used to reinforce the lacustrine soft soil foundation. The data of pore water pressure of foundation together with other parameters were used to control the loading speed. The stability of foundation was kept and the construction period was shortened. With the presented method，the cost，effect and construction period can be well considered simultaneously.
