Experimental Study On Bearing Capacity Of Disk Pile Group Under Vertical Load

Disk pile is the new type of piles developed in the last20years.Compared with normal straight pile, it has advantages of highbearing capacity,small settlement,saving raw materials,and strongadaptability.Now disk pile group has been applied in many projects in ourcountry and achieved good results.However, the disk pile, as a new typeof pile in theoretical and experimental research are not matureenough.Particularly there is little experimental study on disk pilegroup.And the study on force condition and deformation behavior of diskpile group under vertical load has no relevant reports.In practicalengineering, many pile foundation is to come in the form of pile group.Working behavior of pile group foundation under vertical loading isdifferent from single pile foundation.Pile group under vertical pressurebears the force by soil-pile interaction.The process is relatively complex.Knowledge of the characteristics of this kind of interaction is still notvery clear. It requires more detailed analysis through a lot of tests.This article intends to test on disk pile group by indoor modeltest,and to study the vertical loading mechanism and bearing capacitybehavior of disk pile group.It includes that: (1)It introduced the brief history of Pile foundation and research on diskpile, pile group,equal-diameter pile group,and disk pile group undervertical load at home and abroad.(2)It introduced the calculation method of pile group, and describes thecalculation methods of bearing capacity and settlement of pile groupunder vertical load.By11groups of indoor model test,it analysedworking behavior of disk pile group under vertical load.that is to say,itanalysed bearing behavior of disk pile group with different numbers,different spacing between piles and piles under different soilcharacteristics.This analysis was compared to equal-diameter pile. Itdiscussed the working behavior of disk pile group by the verticaldisplacement at the top pile, changing axis force of pile and soil Pressurearound pile.(3) Research indicates that:In the same condition,vertical bearing capacityof disk pile group is greater than equal-diameter pile group.But by pilegroup effect, bearing capacity of each pile in group pile is less than singlepile. Proportion of load which is passed by the lower disk in pile group islarger than single disk pile. As pile space increases, bearing capacity ofsingle pile becomes larger.Besides,soil pressure near the disk of disk pilegroup is less than soil pressure which is far from the disk.However,soilpressure near the disk of single disk pile is the same as soil pressurewhich is far from the disk.Bearing capacity of disk pile group in sandy soil is larger than in silt soil.