土工离心模型试验中动力破坏模拟能力分析

Analysis on Modeling Capability of Dynamic Failure in Centrifugal Modeling Test

针对土工离心模型试验中模型与原型在动力响应、动力破坏模拟方面的相似程度,研究了不同层次的相似比尺要求下模型结构材料的选择与设计方法;对所研制的4种不同桩径的抗滑桩缩尺模型,通过离心模型试验分析了缩尺模型在不同承载力条件下动力破坏模拟的规律及破坏特点。结果表明,小桩径抗滑桩在静力条件下因承载力不足而开裂,在动力作用下可导致桩底截面裂缝贯通;较大桩径抗滑桩在静力条件下稳定,但在动力作用下可发生开裂破坏;大桩径抗滑桩在静力和动力条件下均未发生开裂,表明其具有足够的静动抗弯能力,但在高水位时大桩径抗滑桩在动力作用下可发生断裂破坏。由于研制的缩尺模型严格满足原型的相似比尺要求,因此模型试验结果能够反映原型抗滑桩的破坏机理。

Aiming at different similar levels on the dynamic response and the simulation of dynamic failure between the model and the prototype in geotechnical dynamic centrifugal model test, the similar scale and the choice of model material for geotechnical centrifuge modeling were anylyzed, and then the issues of principle and design on the simulation of dynamic response and dynamic failure in geotechnical dynamic centrifugal model test were proposed. Finally, the dynamic response laws and the failure characteristics of model concrete pile in geotechnical dynamic centrifugal model tests were discussed by means of the developed model piles with four kinds of diameters. Results show that the stabilizing piles with the small diameter under the condition of static cracking due to insufficient bearing capacity, can be led to pile section fracture penetration under dynamic action; the stabilizing piles with the larger diameter under the condition of static stability, but can show cracking destruction under dynamic action; the stabilizing piles with the largest diameter under static and dynamic conditions are not crazed, but the fracture damage can occur under dynamic action in the high water level As a result of the scale of the model and the prototype strictly meet the similarity scale, so these model test results can reflect the failure mechanism of the prototype stabilizing piles.