In order to study the mechanisms of soil plugging effect inside sleeve of cast-in-place piles driven by vibratory hammers,finite element and infinite element coupling model were established by using the commercial code ABAQUS,to simulate the full penetration process of the sleeve driven by using high frequency vibratory hammers.The results indicated that the soil plug inside the sleeve forms soil arch during vibratory sleeve driving,which leads to the obvious increase of inner frictional resistance.The soil plug of this section withstands the major part of the inner frictional resistance.The soil strength and cohesive force decrease during vibratory sleeve driving, which is induced by cyclic shearing action in the shear interface.As a result,the soil plug inside sleeve is incompletely plugged mode and the penetration resistance is less than that of other installation methods.The inner frictional resistance decreases with the increase of vibration frequency and sleeve diameter.The inner frictional resistance of sand is larger than that of clay,and decreases with the increase of density.The distributions of soil plug resistance were also studied,and a simplified formula was obtained to calculate the soil plug resistance.
