Research On The Mechanical Properties Of Large Diameter Pile Considering Contact Effect

High-rise building with its obvious characteristic of saving land resources havebeen built with china’s economic development, the progress of science and technologyand city urbanization. It will become the mainstream of development of building in thefuture. Pile foundation because of high bearing capacity, good stability, settlement anddeformation difference is small, the advantages of strong adaptability in complexgeological is widely used in high-rise building foundation engineering. Single pilebearing capacity and settlement calculation and analysis is an important procedure in thedesign of pile foundation at present. With simplify the engineering problems and thepile soil contact surface parameters based on factors such as the difficulty in choosing,the soil is usually considered the continuum element, pile soil interface displacementcoplanar, without considering the effect of shear slip between pile and soil, in thesimulation of the traditional engineering design and finite element numerical. Thesimplification is able to meet the demand of practical engineering accuracy in singlepile in the small load, low strain, elastic state, but in the single pile under high load,high strain, plastic state will have larger error with the measured results. Whileconsidering the contact unit is arranged between soil and pile, study on single pile undervertical load settlement, bearing capacity, axial force, side resistance and other traits,without considering between pile and soil foundation, discontinuous shear slip. Themain contents are as follows:(1) Comprehensive review of the contact element type, finite element constitutivemodel status and contact element. To summarize the mechanical mechanism andcalculation method of contact element in finite element, with the detailed study of basictangential relationship, contact interface conditions, coulomb friction type and the weakform to the relationship of interface condition.(2) Study pile’s load settlement relation of pile axial force, pile tip resistance andside friction of pile traits under vertical, through comprehensive analysis of static loadtest data of large diameter bored pile vertical site.(3) Bored pile will be studied through the finite element software, by setting thepile-soil interface contact unit. The results of finite element calculation and themeasured results are compared to verify the contact element can effectively simulate the pile-soil shear slip, load transfer, settlement and bearing capacity of single pile.(4) Research and analysis on settlement of single pile based on MIDAS/GTSsoftware for the numerical simulation of bored pile in the contact unit final shear, shearmodulus, and the elastic modulus of soil parameter, summed up the general law ofcontact surface parameters.