离心模型试验中深水防波堤上波浪循环荷载的模拟研究

研制离心模型试验中新型的非接触式循环荷载加载系统，用于模拟深水防波堤上的波浪荷载，解决了波浪荷载模拟研究中的消能困难、产生附加约束和附加质量以及难以模拟波谷反向荷载等问题，通过计算机控制加载，能够达到模拟风暴荷载的要求。开发动力离心试验的新测控系统，包含高速数据采集、低通数字滤波去除噪声和干扰、改进比例积分微分(PID)加载控制、控制信号生成等功能模块，优化动力离心试验中加载控制和数据采集的功能。通过在离心模型试验中对箱筒型基础防波堤施加非接触式波浪荷载的作用，表明该加载设备可精确、稳定地施加不同的波浪荷载，并可任意调节波浪荷载幅值。得出波浪荷载作用下箱筒形基础防波堤的动位移特征：动倾角的累积值和幅值均有一定的增长，水平位移量以幅值增大为主，而竖向位移量以累积值增大为主；箱筒形基础防波堤主要表现为振动–摇摆耦合运动模式。

CENTRIFUGE MODELING STUDY OF CYCLIC WAVE LOAD ON BREAKWATER IN DEEP WATER

A new non-contact cyclic wave load generation system for centrifuge model test is developed. Through computer controlled load device，the system can simulate storm wave load on breakwater in deep water. The system solves the problems accounted in previous study such as difficulty in energy dissipation，generating additional constraint and mass，and applying of reversal load that is hard to be carried out. Then a new measuring and controlling system is developed for dynamic centrifuge model test，which contains four functional modules：high speed data acquisition，low pass digital filter for signal noise and interference removal，modified proportion integration differentiation(PID) load control and signal generation control. The system also optimizes load control and data acquisition functions in dynamic centrifuge test. The feasibility of non-contact wave load generation system is verified by suction caisson breakwater centrifuge model test. Test results show that the device can apply wave load accurately and steadily，and can adjust load amplitude randomly. Cyclic displacement characteristics of suction caisson breakwater under wave load are as follows：accumulated value and amplitude of dynamic tilt angle both increase；horizontal displacement amplitude increases notably；while accumulated value of vertical displacement increases significantly. Suction caisson breakwater has oscillation-rock coupled motion mode.