FOR 1136: Simulation of Geotechnical Construction Processes with Holistic Consideration of Constitutive Lows in Soils

城市环境中的施工需要频繁的开挖基坑。这些矿坑的支撑必须以这样的方式建造，以确保其适用性和附近结构的各自特点。在研究股内，预计将利用土壤的非线性、稳健、现实和现代本构定律，以及有关岩土问题的强大、稳定的数值模拟战略，考虑在一个或多个岩土工程施工过程的整个过程中土壤条件的总体变化。由于岩土工程方法和施工程序多种多样，研究股的意图不是考虑这些施工程序的所有可能变化。此外，研究组将集中精力处理选定的岩土问题。对于所选过程的描述，一方面需要实施静态、循环和动态模拟策略，另一方面必须将土壤视为具有水分和空气含量的颗粒骨架的混合物。除了这些基本考虑因素外，还必须考虑与土与结构之间的接触有关的进一步影响。需要回答的一些基本问题是：(1)施工过程对将要安装的部件的设计或对附近现有结构的适用性是否有重大影响？如果是这样的话，在什么条件下这些影响是显著的，在设计过程中这些影响可以以何种简化的方式实施？(2)是否可以改进现有的本构定律以真实地描述重复加载和卸载？(3)是否可以根据p-u或u-p-u公式，通过固体和流体材料相的动态耦合来分析桩的动态安装(通过振动或动态冲击安装)以及土中整个施工过程中的应力-应变路径的整体考虑，以获得实际的结果？如何才能获得所选算法和方法的数值稳定性？上述问题和其他问题的答案是研究股的工作范围。

Construction in urban environment requires frequently excavation pits. The shoring of these pits have to be constructed in such a manner that its serviceability and the respective of the nearby structures are assured. Within the Research Unit it is expected to consider the overall changes of the soil conditions throughout the entire process of one or of diverse geotechnical construction processes using non-linear, robust, realistic and modern constitutive laws for soils and powerful, stable numerical modelling strategies for the geotechnical problems associated with. Due to the fact that geotechnical methods and construction processes are diverse and manifold, the intention of the Research Unit is not to consider all possible variations of those construction processes. Furthermore, the Research Unit will concentrate the efforts on selected geotechnical problems. For the description of the selected processes it is, on one hand, necessary to implement static, cyclic and dynamic simulation strategies and, on the other hand, the soil has to be regarded as a mixture of grain skeleton with water and air contents. Besides of these fundamental considerations are also further effects related to the contact between soil and structure, which have to be taken into account. Some of the fundamental questions to be answered are: (1) Is there any significant influence of the construction process on the design of the elements to be installed or on the serviceability of already nearby existing structures? If so, under which conditions are these influences significant and in which simplified manner can these be implemented in the design process? (2) May existing constitutive laws be improved for a realistic description of repeated loading and unloading? (3) Can the dynamic installation of piles (installation by vibration or dynamic impact) and the holistic consideration of the stress-strain paths throughout the entire construction process in soil be analysed with a dynamic coupling of the solid and fluid material phases according to the p-u or u-p-U-formulation in order to obtain realistic results? How can the numerical stability of the chosen algorithms and methods be obtained? The answer of the above and further questions are the scope of work of the Research Unit.