Cyclic Dynamic Triaxial Testing Device

随着岩土工程领域问题的日益多样化和复杂性，以及对岩土材料（土壤和岩石）和类土材料（如矿物材料、rc材料、工业副产品、工业废物和焚烧厂）的经济和可持续利用的要求，需要对它们的机械行为有更深入的了解，正如实验观察到的那样。尽管在过去的几十年里，科学的努力，建立和验证模型来模拟多相岩土材料的复杂耦合的水-力响应仍然是岩土工程中最具挑战性的研究领域。为了实现研究建议的目标，扩展慕尼黑工业大学Geotechnik中心的实验能力，全面检查循环，交替和动态载荷下土壤和类土材料的耦合水力学行为是必要的。所需设备的重点主要在于研究在受控或监测边界条件下剪切载荷期间的行为。使用新设备进行的试验必须涵盖大范围的剪切应变幅值、应力路径、压力和排水条件，这些都与所考虑的不同岩土工程问题有关。到目前为止，慕尼黑工业大学和巴伐利亚大学现有的测试设备并不能满足所有这些要求。因此，本申请中描述的测试设施对巴伐利亚未来的研究具有战略意义。本拨款申请旨在为循环动态三轴测试设备（简称dtx设备）提供部分资金，该设备是计划测试设备的一个组成部分。该装置允许在4兆帕的压力下对直径达150毫米的样品进行循环动态加载。除了新的加载系统和用于在现有测试坑中测试大型模型的测量设备外，测试设施的其他组件还包括共振柱设备（简称rc设备）和全向简单剪切设备（简称odss设备）。在odss装置中，通过在两个运动独立的剪切变形方向上控制剪切应变或剪切应力来施加循环、交变和动态载荷。odss装置和dtx装置允许在中到大剪切应变幅度范围内进行调查。与odss器件相反，dtx器件控制主方向上的应力和应变，而样品中主方向的旋转是使用odss器件的特征之一。在rc装置中，通过使圆柱形试样进入共振，可以确定小剪切应变幅值范围内的刚度和滞回阻尼。

The increasing diversity and complexity of problems in the field of geotechnical engineering and the claim for an economical and sustainable use of geomaterials (soil and rock) and soil-like materials (e.g. mineral materials, RC-materials, industrial by-products, waste from industry and incineration plants) require a much deeper understanding of their mechanical behaviour, as observed experimentally. Despite of the scientific effort in the last decades, the development and validation of models to simulate the complex coupled hydro-mechanical response of multiphase geomaterials still belongs to the most challenging fields of research in geotechnical engineering. In order to achieve the goals of research proposals, an extension of the experimental capabilities of the Zentrum Geotechnik of the Technical University of Munich for the comprehensive examination of the coupled hydro-mechanical behaviour of soil and soil-like materials under cyclic, alternating and dynamic loadings is imperative. The focus of the required equipment lies primarily on the investigation of the behaviour during shear loadings at either controlled or monitored boundary conditions. The experiments to be carried out with the new equipment have to cover the large range of shear strain amplitudes, stress paths, pressures and drainage conditions, which are relevant for the different geotechnical problems under consideration. So far, the testing equipment available at the Technical University of Munich and at universities in Bavaria does not satisfy all these requirements. Therefore, the testing facility described in this application is of strategic importance for the future research in Bavaria. This grant application aims for the partial funding of a Cyclic Dynamic Triaxial Testing Device (in short: DTX-device) which is one component of the planned testing facility. The devices allows the cyclic dynamic loading of samples up to a diameter of 150 mm at a pressure of 4 MPa. Further components of the testing facility are beside a new loading system as well as measurement equipment for testing large-scale models in an existing testing pit a Resonant Column Device (in short: RC-device) and an Omnidirectional Simple Shear Device (in short: ODSS-device). In the ODSS-device, the cyclic, alternating and dynamic loadings is be applied by controlling either the shear strain or the shear stress in two kinematically independent directions of shear deformation. The ODSS-device as well as the DTX-device allows the investigation in the range of medium to large shear strain amplitude. In contrary to the ODSS-device the DTX-device controls stress and strain in the principal directions while the rotation of the principal directions in the sample is one of the features using the ODSS-device. In the RC-device, the stiffness and hysteretic damping in the range of small shear strain amplitude can be determined by bringing a cylindrical sample into resonance.