| The wedge-shaped pile is a new type of pile foundation.After wedging into the foundation soil,the wedge-shaped side and the surrounding soil of the pile are squeezed,which increases the mutual friction of the pile-soil contact surface and improves the bearing capacity of the pile foundation.In order to better understand the dynamic behavior of the wedge-shaped pile and guide its design,construction,testing,etc.,it is necessary to carry out a more systematic research on the vibration theory of the wedge-shaped pile.The research content includes the following aspects:（1）Study the longitudinal dynamic interaction of wedge-shaped pile-single-phase soil.Divide the soil and the pile into finite elements,establish the steady-state longitudinal vibration equation,and obtain the pile top displacement impedance function expression by using the impedance function transfer method.The results indicate that the more wedge pile units are divided,the higher the calculation accuracy of the complex impedance;the wedge angle,pile length and elastic longitudinal wave velocity of the pile body will affect the longitudinal vibration of the wedge pile.（2）The longitudinal dynamic response of the wedge-shaped pipe pile in the single-phase soil is studied by using the plane strain model to consider the influence of the surrounding soil and the core soil of the pile.Considering the variable section of the wedge-shaped pipe pile and the stratification of the soil around the pile,the wedge-shaped pipe pile and the soil are divided into finite elements.Using the Laplace transform and the impedance function transfer method,the equation of the pile top displacement impedance function is obtained.The effects of pile geometry and material properties on longitudinal vibration of wedge-shaped pipe piles are analyzed.The results show that the amplitudes of the dynamic stiffness and dynamic damping curves increase with the increase of the wedge angle or the pile length;as the pile wave velocity increases,the vibration frequencies corresponding to the adjacent vibration peaks of the dynamic stiffness and dynamic damping curves increase and decrease.is small,the peaks and valleys of the dynamic stiffness curve are significantly increased.（3）The soil is regarded as a two-phase porous medium,and the longitudinal vibration of wedge-shaped piles in saturated soil is studied on the basis of porous medium theory.Mathematical calculation method and impedance matrix transfer method are used to obtain the pile top complex stiffness of wedge-shaped pile in saturated soil.The results show that as the pile-soil modulus ratio increases,the frequency corresponding to the dynamic damping curve reaching the first resonance peak increases.（4）On the basis of the dynamic interaction of wedge-shaped pile-saturated soil-wedge-shaped pile,the longitudinal vibration characteristics of wedge-shaped pile group in saturated soil are studied by using the superposition principle.On the basis of the study of the longitudinal vibration equation of saturated soil in Chapter 4,the analytical solution of the active pile of wedge-shaped pile is obtained,and the pile-pile interaction factor is obtained by introducing the attenuation function.Impedance research was carried out to analyze the influence of the physical properties of the wedge-shaped pile and soil parameters on the longitudinal vibration of the wedge-shaped pile group in saturated soil.Studies have shown that,as the pile length increases,the complex impedance of the pile top increase,and the pile length can be appropriately increased to improve the resistance to longitudinal deformation of the wedge-shaped pile group.（5）Considering the dynamic interaction of wedge-shaped tubular piles-saturated soil-wedge-shaped tubular piles,the longitudinal vibration characteristics of wedge-shaped tubular piles in saturated soil are studied.Firstly,the vertical shear stress of pile surrounding soil and pile core soil in saturated soil is obtained,and the analytical solution of the pile top impedance of the active pile of the wedge-shaped pipe pile is obtained according to the transferability of the impedance function.The wedge-shaped pipe pile-wedge-shaped pipe pile interaction factor was obtained from the pile displacement,and the dynamic impedance of the wedge-shaped group of pipe piles in saturated soil was studied by using the superposition principle.The research results show that the vertical dynamic impedance of the wedge-shaped group of tubular piles is significantly affected as the wedge angle increases,and the wedge angle can be appropriately increased to improve the seismic characteristics of the piles. |
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