Soil Strees-Strain Characteristics Using an Automated True Triaxial Testing Device

9452059 Penumadu是一种具有灵活边界的自动化电空控制真三轴测试设备，使学生能够调查应力路径和排水条件对土壤强度的重要性。已经开发了两种使用该设备的实验室实验。第一门课程让学生熟悉静态传感器校准、模数转换、信号调理、软件和硬件增益以及混叠问题的相关概念。第二类是利用预定义的应力路径对土样进行各向同性和各向异性的固结和测试。通过数据采集和控制软件，可以进行应力和应变控制的静态剪切试验，基本上可以模拟任何应力路径。这一实验室能力显示了使用相同测试设备的各种实验室强度测试与实际现场条件的相关性，并说明了与电子数据获取和控制相关的概念。一个重要的好处是，相同的装置可以用来显示各向同性和KO固结土样的排水和不排水的应力-应变特性。样品可以在预定义的应力路径下剪切，并且可以比较观察到的孔压行为(不排水测试)。开发了土壤测试程序，以检查与固结类型、应力路径和加载速率相关的问题。

9452059 Penumadu An automated electro-pneumatic controlled true triaxial testing device with flexible boundaries enables students to investigate the importance of stress path and drainage conditions on the strength of soils. Two types of laboratory experiments that use this device have been developed. The first familiarizes students with concepts related to static transducer calibration, analog to digital conversion, signal conditioning, software and hardware gain and problems of aliasing. The second type deals with the isotropic and anisotropic consolidation and testing of soil samples using a predefined stress path. Stress and strain controlled static shear tests can be performed and essentially any stress path can be simulated through the data acquisition and control software. This laboratory capability shows the relevance of the various laboratory strength tests with actual field conditions using the same testing device, and illustrates the concepts related to electronic data acquisition and control. An important benefit is that the same device can be used to illustrate the drained and undrained stress-strain characteristics of both isotropic and Ko consolidated soil samples. The samples can be sheared under a predefined stress path and the observed pore pressure behavior (for undrained testing) can be compared. Soil testing programs are developed to examine the issues related to type of consolidation, stress path and the rate of loading.