广义Voigt土模型条件下桩的纵向振动响应与应用

研究了桩侧土广义Voigt模型条件下,任意层桩土系统的振动特性,并求得了桩顶在瞬态半正弦脉冲荷载作用下,桩顶的时域纵向响应的半解析解,同时结合基桩完整性检测的机械阻抗法和反射波法研究了各主要模型参数以及土层界面、桩身缺陷等对桩顶时、频响应曲线的影响,得到了许多结论.结果表明,得到的理论成果相比于已有理论更加完善并能更好地反映客观实际.将为基桩完整性定量化检测创造条件.

VIBRATION OF INHOMOGENEOUS PILE EMBEDDED IN LAYERED SOILS WITH GENERAL VOIGT MODELS

Vibration of inhomogeneous pile is studied and a new theory is developed, in whi ch layered soils surrounding the pile are described with general Voigt model tha t consists of many Voigt units connected in series. Then, a series of analytica l responses in frequency or time domain are obtained with Laplace transform and invert Fourier transform at the condition of transient half cycle sine wave shap e d excitation on pile top. Based on this, several figures are prepared to illustr ate influences of soil model parameters on the responses, and some important con clusions are drawn for pile integrity testing. It is shown that interfaces betwe en adjacent soil layers have little influence on the response of pile top and th at tangent line slope of velocity amplitude response of pile top at low frequenc y has nothing to do with pile integrity. This tangent line slope is thought to b e proportional to reciprocal of dynamic stiffness of pile, which is usually used to determine allowable capacity of pile and to judge pile integrity in some reg ions in China. It is proved that the new theory is more reasonable and practicable than the cur rent one and that the theoretical curves are in good agreement with those of fil ed measurement by two matching examples between measured curves and theoretical curves.