Abstract: Comprising with electrohydraulic driven shaking tables in main stream at present, the servomotor driven shaking table has many advantages, such as compact structure, quiet energy supply, simple maintenance and broad spectrum, which are important in developing the new generation of shaking tables. A new servomotor driven shaking table developed in cooperation with ANCO was introduced and it had a 2.2m×1.2m shear platform able to shake a soil sample of 2 t. Its testing system was equipped with rigid and shear containers, micro CPT and SPT as well as DPT devices. To comprehensively evaluate the whole performance of the shaking table, series of experiments with empty platform, dry sand and saturated sand were designed and performed. The results show that the system has good control effect in repeatability and reliability to random waves, and its output characteristics are observed to relate with iteration times, amplification times and loading quality. The spectral ratios of acceleration time histories indicate that saturated sand layers have significant amplification effect at periods above 1s compared with dry sand layer, especially as pore water pressure reaches the peak value. It is observed that the rigid container has critical end wall effect, and a pair of vertical accelerometers with a distance of 0.2m to the end walls monitor considerable opposedphase motions.

Key words: electromechanical engineering, shaking table, servo motor, performance assessment, liquefaction of sand, spectral ratio〖FGN〗

摘要： 比较目前主流的电液式驱动振动台，伺服电机驱动振动台具有结构紧凑、无油源噪音、维护简单、频带宽等优点，是新一代振动台发展的一个主要方向。介绍了一台与ANCO联合研制的伺服电机驱动振动台，负载2 t、台面2.2 m×1.2 m，其试验系统配置了刚性与剪切试样箱、微型CPT、SPT及DPT试验装置。设计和开展多种地震波下空台、干砂与饱和砂对比试验，综合评价了系统性能，具有较好任意波控制能力和复现精度，给出了输出特性与迭代次数、放大倍数和负载质量之间的关联性。谱比结果表明：饱和砂层对比干砂层在不小于1 s周期上呈现显著放大效应，尤其是孔压达到峰值后。刚性箱具有较强端壁效应，距两端壁0.2 m处一对竖向加速度计记录了较大幅度反相位时程。

关键词: 机电工程, 振动台, 伺服电机, 性能评价, 砂土液化, 谱比