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目前非一致激励下长隧道的抗震研究仅限于理论解析或数值分析,缺乏有效的试验或现场数据验证,而试验技术难点在于如何利用多个离散振动台面来近似模拟实际的连续多点非一致地震激励作用。针对此问题,基于大型线阵协同工作的4个独立振动台,研发了一种用于模拟长隧道多点振动台试验的节段式模型箱,不仅用于承载模型土和模型隧道,而且可以实现离散多点振动台输入到连续非一致输入的等效转换。节段式模型箱研发的挑战在于模型箱尺寸和连接接头的设计,优化目标是使随动箱的加速度响应峰值和主频与主动箱一致,而各箱体之间有合理的时间延迟来反映沿模型箱纵向的行波效应。通过多工况的解析解和数值分析,最终确定了该节段式模型的最优化尺寸为40m×4.5m×1.2m(长×宽×高)以及各箱体间的连接方式(弹性铰接)。最后通过开展一系列的多点振动台空箱试验,研究了节段式模型箱沿纵向传播的非一致地震激励效应。试验结果表明:该节段式模型箱可以有效实现从4个独立振动台面输入到连续多点非一致地震激励的等效转换,真实再现地震动的空间变化特性,从而验证了该模型箱用于长隧道多点振动台试验的可行性。研究成果可为长隧道多点振动台试验模拟提供参考依据。
At present, the seismic study of long tunnel under non-uniform excitation is limited to theoretical analysis or numerical analysis, and lack of effective test or field data validation. The difficulty of the experimental technique lies in how to use multiple discrete vibration table to approximate the actual continuous multi-point non-uniform earthquake Incentive role. In response to this problem, based on the four independent vibration units of the large linear array, a segmented model box for simulating the multi-point shaking table test of a long tunnel has been developed. It is not only used to carry model soil and model tunnels, Realize discrete multi-point shaking table input to continuous non-consistent input equivalent conversion. The challenge of the development of segmented model box lies in the design of the model box size and connecting joint. The objective of optimization is to make the acceleration response peak frequency and the main frequency of the follow box consistent with the active box, and there is a reasonable time delay between the boxes to reflect Traveling wave effect along the longitudinal direction of the model box. Based on the analytic solution and numerical analysis of multi-conditions, the optimal size of the segmented model is finally determined to be 40m × 4.5m × 1.2m (length × width × height) and the connection between the boxes (elastic hinge) . Finally, through a series of multi-point shaking table experiments, the non-uniform seismic excitation effect of the segmented model box propagating in the longitudinal direction was studied. The experimental results show that the model box can effectively transform the input from four independent shaking table into continuous multi-point non-uniform seismic excitation, and can reproduce the spatial variation of ground motion. Feasibility of long tunnel multi-point shaking table test. The research results can provide reference for multi-point shaking table test simulation in long tunnel.