Anisotropic deformation characteristics of geomaterials in a wide strain range

自80年代初S以来，离心机模型中的振动筛有了很大的发展，现在世界各地的离心机上都有各种规格的多种型号的振动筛。然而，这些振动筛的振动方向都是水平的，没有能模拟垂直振动的振动筛。东京工业大学正在尝试开发一种二维振动筛，它可以在TIT Mark III离心机上独立地进行振动台的水平和垂直运动，为了创造出两个自由度的运动，振动台至少需要两个执行器。在新开发的2D振动器中，两个水平角度为30度的倾斜伺服液压执行器对称地安装在振动台下方。通过将相同的位移分别加到同相和相反相的两个执行器的气缸上，可以控制垂直和水平运动。主要的Diff…普通内置式卧式振动筛与二维H-V振动筛的更大区别在于，振动台不能直接由直线导轨系统支撑，而直线导轨系统紧紧地固定在反应框架上。直线导轨系统主要有两个功能，一是在离心力作用下支撑振动台和模型的静态竖向重量，二是防止振动台的摇摆。在2D振动器中，静态重量由四个空气弹簧支撑，这样振动台下面的作动器的力就可以完全作用于动态运动。此外，在振动台和直线导轨之间引入了两对平行连杆，以防止工作台的摇摆运动。最大震动质量为200公斤，工作台尺寸为640x510 mm。水平方向和垂直方向的最大输入力分别为35kN和30kN。使用新开发的2D振动器进行了初步试验，以检查其性能。已证实，使用振动筛可以独立控制水平和垂直运动，但仍有许多地方需要改进。较少

Since early 80's there have been a lot of developments for shakers in centrifuge modeling and now many types of shakers with various specification are available in many centrifuges all over the world. However, the shaking directions of these shakers are all horizontal and no shaker which can simulate the; vertical vibration has been developed. In Tokyo Institute of Technology, an attempt has been made to develop 2D shaker, which can make horizontal and vertical motions of shaking table independently in the TIT Mark III Centrifuge.In order to create the motion with 2 degrees of freedom, at least two actuators are necessary for the shaker. In the newly developed 2D shakers, two inclined servo-hydraulic actuators with horizontal angle of 30 degrees are symmetrically mounted underneath the shaking table. Vertical and horizontal motions can be controlled by putting the same displacements to the cylinders of the two actuators with the same phase and opposite phase respectively. The main diff … More erence between normal ID horizontal shaker and 2D H-V shaker is that the shaking table cannot be directly supported by liner way system, which tightly fixed to the reaction frame. The linear way system has two main functions, i.e., supporting the static vertical weight of the shaking table and model under centrifugal acceleration and preventing the rocking motion of the shaking table. In the 2D shaker, the static weight is supported with four air springs so that the force from the actuators underneath the shaking table can entirely act for the dynamic motions. Furthermore two pairs of parallel links were introduced between the shaking table and liner way guides to prevent the rocking motion of the table. The maximum shaking mass is 200 kg and table size are 640x510 mm. Maximum input forces are 35kN and 30kN for the horizontal and vertical directions respectively.Using the newly developed 2D shaker, preliminary tests were conducted to check its performance. It was confirmed that the horizontal and vertical motions could be independently controlled using the shaker, although there remain many things to improve the performance. Less