Study On Load Transfer Behavior Of Single Diameter Of Cross Section-Varied Soil-Cement Deep Mixed Column

At the present time, the project cost is uneconomic, the degree of the construction disturbance of the crust layer around the pile is large and the natural bearing capacity of foundation can not be taken full advantage if the traditional deep mixing technique is used to improve multilayered soft ground within a certain range of the crust layer. Improving the construction machinery, making two sets of the mixing blades in a same axis of the drill pipe can stretch and two-way mixing, so it can making the soil-cement deep mixing pile transform the diameter of cross section-varied soil-cement deep mixed column.In this paper, two kinds of the single diameter of the cross section-varied soil-cement deep mixed columns will be analyzed. The load transfer behavior of single soil-cement deep mixed column of which the diameter is expanded in the middle and the load transfer behavior of single soil-cement deep mixed column of which the diameter is expanded in the lower will be analyzed by numerical simulation based on field tests which were to be implemented in a high way for soft ground improvement in Anhui Province. The simulative results shows that pile load of soil-cement deep mixed column of which the diameter is expanded in the middle has five attenuation stages which are pile load attenuation during the upper of the pile, pile load surge on the top of the expanding department, pile load attenuation during the expanding department, pile load plummeting on the bottom of the expanding department, pile load attenuation during the lower of the pile. Pile load attenuation and additional stress of the pile attenuation are consistent basically along the depth during two different working conditions. The maximum of pile load and the maximum of additional stress of the pile appear in the top of the pile, when the pile diameter radio exceeds the certain value, the pile load of the top surface of the diameter expansion of the local is maximum under the action of rigid foundation. Pile load of soil-cement deep mixed column of which the diameter is expanded in the lower has three attenuation stages which are pile load attenuation during the upper of the pile, pile load surge on the top of the expanding department, pile load attenuation during the lower of the pile. Pile load attenuation and additional stress of the pile attenuation are consistent basically along the depth during two different working conditions. The maximum of pile load and the maximum of additional stress of the pile appear in the top of the pile under the action of rigid foundation. Side friction of the two kinds of the single diameter of the cross section-varied soil-cement deep mixed columns is larger in the upper of the pile.