爆破地震作用下桩-土-结构相互作用的数值模拟

土-结构动力相互作用是地震工程和结构抗震的重要研究内容,但目前对爆破地震作用下土-结构动力相互作用的研究较少。运用大型有限元软件ANSYS/LS-DYNA,建立了桩-土-结构相互作用体系的三维有限元模型,由桩尖输入实测爆破地震波,取得了良好的计算效果。计算结果表明:考虑桩-土-结构相互作用后,群桩基础中每个桩的位移、加速度和剪应力幅值均呈桩顶大、桩尖小的倒三角分布,桩与承台的接合部比较容易受到损坏;桩-土-结构相互作用体系在爆破地震波冲击后,还会发生几次振动,但是这些振动产生的影响要小于爆破地震产生的影响,这与实测结果相符合;爆破地震波冲击下,群桩基础中,角桩顶部表面的桩土接触压力较大,但在爆破地震波冲击后,中心桩顶部表面的桩土接触压力较大,且具有一定的周期性,直至衰减为零。

Numerical Simulation of Pile-soil-structure Interaction under Blasting Vibration

Soil-structure dynamic interaction(SSDI) is an important content of earthquake engineering and earthquake resistance of engineering structures.However,very few researches have been done on SSDI under blasting vibration so far.A 3D element model of Pile-soil-structure interaction(PSSI) system was developed using finite element software ANSYS/LS-DYNA.Blasting seismic wave is inputted on the tip of pile and better results are achieved.The results show that the displacement,acceleration and shear stress at piles top are larger than those at piles tip,and the distribution laws are inverted triangles.The connections of pile and pile cap are vulnerable to damage.PSSI system sustains its vibration after the impact of blasting seismic waves,but the effect of the vibration is smaller than the blasting seismic waves does,which roughly conforms to the measured results.What’s more,under the impact of blasting seismic waves,the contact pressure between soil and pile is relatively large at top of the corner pile.However,after the impact of blasting seismic waves,the contact pressure at top of the center pile is relatively large.Meanwhile,the contact pressure between soil and pile has certain periodic regularity until it attenuates to zero