【摘要】 根据圣维南原理分析瞬态激振后,桩柱式基础桩身内应力波特征。认为盖梁顶部激振、基桩顶面和墩柱结合部激振时,应力波在桩身内仍可满足平截面假定。提出桩身内应力波是否为平面波的判别方法,设计并完成2组现场试验。盖梁顶部激振时,应力波同步到达同一桩身横截面侧壁各拾振区,且计算得到的横截面中心处首波波峰与侧壁处首波波峰到达时刻基本一致,满足低应变法中平截面成立的条件。而基桩和墩柱结合部激振试验则表明,在远离系梁的拾振横截面内,应力波才可认为同步到达各拾振区,且计算得到的拾振横截面中心处首波波峰与侧壁处首波波峰到达时刻基本一致。故对于基桩和墩柱结合部激振激振的情形,远离系梁的桩身内平截面假定才可成立。更多还原

【Abstract】 The propagation of stress waves in a pile-column system was analyzed using the elasticity theory and was verified by in situ experimentation.This study first analyses the propagation of a semi-spherical stress wave after transient shock in a column-pile system according to the SaintVenant principle.The results indicate that the stress wave caused by shock on top of the bent cap or on a combined section of pile and column can still satisfy the plane section.A method is introduced to verify this assumption in which shock is applied to a certain point in a pile-column system,and the peak time of the stress wave is collected in the same section by conducting a multichannel equipment.If the difference of each peak time is less than a certain value,it can be concluded that the wave propagation is unanimous and satisfies the plane section.Two groups of in situ tests were performed on a pile-column system in which shock was applied to the top of the bent cap and to a combined section of pile and column.Stress waves were collected on the section at the top of the column,the combined section of pile and column,and the pile section under the tie beam.When shock was applied to the top of the bent cap,the wave velocity value was in a common range,and the stress waves reached the outer edge of the pile section synchronously.It was considered that the stress wave reached the center of the same section at the same time by calculating the difference in peak time of the stress wave at the outer edge and at center of the section.Thus,it was concluded that the plane section can be applied in such a mode.However,this conclusion is not completely valid when the stress wave in the pile is caused by shock on the combined section of the pile.In the pile section near the tie beam,the value of the peak time of the stress wave in each channel varied;therefore,the stress wave did not reach the center of the section at the same time.However,in the pile section slightly far from the shock point,the value of the peak time of the stress wave in each channel was reached at nearly the same time.The propagation of stress waves were transform to uniformity,thus for the mode of shock on the combined section,the plane section can be applied to the surface at a distance from the shock point.更多还原