Experimental Study And Numerical Simulation On Influence Factors Of Pile-soil Interface Characteristic

Pile-soil interface characteristic is an important factor affecting the skin resistance of pile,which is an important part of pile bearing capacity.The study of pile-soil interface characteristic hasgreatsignificanceforengineeringdesign.At present,studiesabout influence factors of pile-soil interface characteristic needtobe further carried out.Influence factors of pile-soil interface characteristic are investigatedin this paper.Basedon mucky soil,the studyaboutthe effects of pile material(concrete,steel),normal stress(50kPa?70kPa?90kPa?110kPa)and water content(19%?21%?23% ? 25%)on pile-soil interfacecharacteristic is carried out with material comprehensive measuring instrument.On the basis of the results of direct shear test,thestudyabout influence of normal stress(50kPa?150kPa?200kPa),water content(19%?21%?23%?25%)on pile-soil interface characteristic is carried out with GDS interface shear apparatus.Basedon direct shear test,two-dimensional direct shear model of pile-soil interface is established with Abaqus finite element method tostudythe influence of soil dilatancy angle,pile material and interface friction coefficient on pile-soil interface characteristic.Through the study on influence factors of pile-soil interface characteristic,main conclusions are obtained as follows:(1)Direct shear test and torsional shear test show the shear stress-displacement curves of 19%~35% water content are hardening type,ideal elastic-plastic type and softening type when pile material is unchanged.Furthermore,the specific shape is related to the normal stress.(2)The results of direct shear test and torsional shear test show peak shear stress and residual shear stress decrease with the increase of water content under the same normal stress.(3)Direct shear test and torsional shear test show peak shear stress and residual shear stress are linearly related to the normal stress in the same pile material and water content.(4)Direct shear test shows that when the stress and water content are in the same form,the shear stress-displacement curve is not affected by pile material.Peak shear stress increases with the increase of friction coefficient,which is similar to numerical results.(5)Numerical results show different dilatancy angles have little influence on the shear stress-displacement curve of pile-soil interface under the same interface friction coefficient and normal stress.But soil shear stress-displacement curve is largely effectedrelativeto pile-soil interface.