| The concrete extended-plate pile is derived from traditional filling pile,it increases one or more stressed enlarging disks on the pile body of traditional filling pile,according to the geological conditions,the stressed enlarging disk should be set in suitable soil layer to improve the capacity of compression and uplift,the practice indicates that it has high bearing capacity,small settlement deformation,easy construction and other good qualities.But,the geological conditions is various and very complicated in engineering practice,the disk may be set in different soil layer when using extended-plate pile.The most of theoretical studies about extendedplate pile is that the stressed enlarging disk is set in clayey soil now,but the research on sandy soil properties affect the bearing capacity is less.Other studies have shown that stressed enlarging disk set in fine silty sand soil is possible,the moisture content and density of soil affect the bearing capacity of extended-plate pile greatly.In order to improve the theoretical basis of concrete extended-plate pile under the effect of vertical stress,in this article we further study that the moisture content of fine silty sand soil around the stressed plate influences the destruction state and the bearing capacity on the basis of research results earlier.The research method mainly includes half-section small model pile test and ANSYS finite element simulation,and comparing the results finally,verifying the reliability of the failure mechanism and the bearing capacity theory.Through the experimental study,the horizontal cracks of cutting-edge draw close to the body of pile gradually during the load process,the compressed soil is heart-shaped,and the sliding failure occurred along the cracks.It shows that the damage state of soil around bearing disk conformswith the theory of sliding failure,and estimating pile bearing capacity by the theory.At the same time,the experimental study of moisture content illustrate that the higher moisture content the smaller bearing capacity when the moisture content of fine silty sand soil is in the range of 10%-17.5%,the change of compressive capacity is obvious when the moisture content changed in the range of 14%-17.5%.In addition,through the finite element simulation analysis,the compressive capacity of pile and the maximum displacement were smaller effected by the moisture content when the soil moisture content is less than 14% in the range of 10%-18%,but bigger more than 14%.The destruction state and curve of displacement-load recorded in the test compare with the result of finite element simulation analysis,the influence area and destruction state is consistent,the changed trend of load-displacement curve is similar at the same moisture content,as for the difference of change ratio mainly concerned with the limiting conditions of test and ideal state of simulation analysis,the result of test and simulation analysis is fit in general,the conclusion of study is reliable.So the stressed plate should be set in fine silty sand soil when the moisture content less than 14%.The paper mainly discusses the effect of moisture content of fine silty sand soil on the failure state and the bearing capacity of the concrete plate-expanded pile through the experimental study of half section pile and finite element simulation analysis,it makes up a lack of ignoring the moisture content affects vertical bearing capacity,and it also provide theoretical basis for the application of concrete extended-plate pile in fine silty sand soil. |
