OPTIMUM DESIGN FOR HIGHWAY EMBANKMENT WITH STONE COLUMN

In this paper discusses how to design the highway embankment with an optimum process to get a minimum area of the highway embankment to reduce the cost of construction, and the problems of soft clay soil in southern of Iraq when construction highway embankment as low bearing capacity and excessive settlement and the way to treat it.At beginning a model of the high way embankment without improving of soft clay soil for height of highway embankments (H=2m and H=3m) was built to note the problems which will be faced when construction of highway embankment in the future. When the height of embankment is (H=2m) the excessive settlement appears but when the height of embankment is (H=3m) the low bearing capacity as well as the excessive settlement will appear. To avoid these problems, the soft clay soil will be improved by using stone columns and design the stone columns also with optimum process to get minimum area of stone columns that can carry the applied load without any problem like low bearing capacity or excessive settlement with lowest cost. When the stone columns are used to improve the soft clay soil, it can note reduce in settlement by (99%) for height of highway embankment (H=2m), and increase in bearing capacity to (15%) for height of highway embankment (H=3m) for certain diameter as minimum increase can carry the load applied on foundation. The highway embankment with stone column modeling with ANSYS software program and this program very useful to help to find optimum design by optimization tool, and use geo slope program to find slope stability for highway embankment by Bishop's method.