基于分离量纲分析理论的模型试验系统相似设计方法--以土–地下管廊振动台试验为例

System similar design method for shaking table test based on separated dimensional analysis and its application in soil-underground pipe gallery interaction

基于量纲分析理论建立的模型试验相似设计方法,在应用于多介质耦合作用动力模型试验设计时,面临着理论计算结果与实际试验相脱节、无法根据各介质特性进行分别相似设计、难以实现介质间接触关联作用相似等问题。针对上述问题,首次提出分离量纲分析理论,基于该理论建立模型试验的系统相似设计方法,将该方法应用于土–地下管廊动力相互作用振动台模型试验的相似设计过程中,通过对土–地下管廊系统整体特性进行分析,将该系统拆分为“土体–地下管廊–接触面–地震波”四个次级子系统,研究土–地下管廊接触作用机制,析出控制“介质间接触关联作用”次级子系统特性的参量,配制保证接触特性相似的亲和相似材料,进而实现4个次级子系统根据各自特性进行分别的相似设计。为探究系统相似设计方法与传统相似设计方法的仿真度高低,分别设计地下管廊原型及不同相似设计方法所对应的地下管廊模型,开展原型及模型的振动台试验,试验结果表明:系统相似设计方法对地下管廊结构加速度响应的模拟无明显优势,但在地下管廊结构应变响应模拟方面,系统相似设计方法具有明显优势,能更加精准反映原型真实规律。

The design methods of scale model test based on traditional dimensional analysis theory,when applied to multi-medium coupling dynamic model design,are faced with some problems,including a large gap between theoretical calculation results and actual test conditions,failure to satisfy the dynamic characteristics of each substance and difficulty in realizing the similarity of contacting and coupling interaction between substances.To solve these problems,the separation dimension analysis theory is proposed,and a system similar design method for model test is established based on the theory.The developed method is then applied to the similar design of shaking table model of soil-underground pipe gallery dynamic interaction.The soil-underground pipe gallery system is divided into four sub-systems of soil,underground pipe gallery,contact surface and seismic wave according to its overall characteristics.The contact mechanism of soil-underground pipe gallery is studied,and the parameters controlling the sub-system characteristics of the contact correlation effect between substances are proposed.The similar materials are prepared to ensure the similitude of contact coupling interaction,and the four sub-systems are separately designed based on their respective characteristics.In order to explore the degree of simulation between the system similar design method and the traditional similar design method,the prototype and the models of the underground pipe gallery are respectively designed by different similar design methods,and the shaking table tests of the prototype and the models are carried out.The test results show that compared with the traditional similar design method,the system similar design method has no obvious advantage in the simulation of the acceleration response of the underground pipe gallery structure but has obvious advantages in the simulation of the strain response of the underground pipe gallery structure,which can accurately reflect the true law of the prototype.