与动三轴仪和动扭剪仪相比较，动单剪仪具有加载条件更接近实际地震作用，且剪应力可以直接施加及剪应变可以直接量测等多方面的优点。然而，现有的动单剪仪仍存在剪应力-应变不均匀、边界条件不稳定、潜在剪切面和试样尺寸效应等技术问题。在比较分析现有动单剪仪加载机构和应力-应变条件的基础上，提出了一种新型立方体铰接机构动单剪仪的研制思路和加载原理。介绍了该仪器的压力室结构、加荷系统、量测系统和自动控制系统。利用有限差分程序模拟了3种不同单剪加载机构对土样剪应变分布的影响，验证了新型单剪仪设计使土样中剪应变分布更加均匀。针对2种原状黄土开展了一系列不同试验条件下的循环单剪试验。测试结果表明，该仪器的加载控制精准且量测信号可以较为真实有效地再现动荷载输入，且竖向应变、剪应变、剪应力和循环周次之间的关系曲线很好地揭示了原状黄土的震陷特性及其变化规律。

Compared with cyclic triaxial and torsion shear apparatuses, the cyclic simple shear apparatus has obvious advantages, e.g., simulating in-situ conditions under earthquakes, and directly applying shear stress and measuring shear strain. However, applications of current cyclic simple shear apparatuses are still limited due to technical problems, such as non-uniform shear stress or strain, boundary condition un-determined, potential shear plane, and size effect of specimen. In this study, a new cyclic simple shear apparatus with hinged structures for a cubical specimen was developed to resolve these problems. The design concept and loading principle were proposed by considering the loading mechanics and stress-strain condition of current simple shear apparatuses. Several main components of the apparatus were presented in detail, including pressure cell, loading system, measurement system and automatic control system. The shear strain distribution of soil specimen subjected to loading from three different loading devices was analyzed by the three-dimensional finite differential program, which proved that the shear strain distribution of soil specimen subjected to loading from the new simple shear apparatus were more uniform than the other two. Finally, a series of cyclic simple shear tests on intact loess specimens were conducted with this developed apparatus under different vertical pressures, water contents and shear strain amplitudes. The results show that the apparatus is reliable and accurate in loading control. The dynamic load input can be reproduced with the acquired data. The formation process of seismic subsidence of loess and the corresponding influencing law are revealed by the relationships between vertical strain, shear stress, shear strain and the number of loading cycles.