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

在城市环境下施工，需要频繁开挖基坑。这些坑的支撑必须以这样一种方式建造，即它的可用性和附近结构的各自性得到保证。在研究股内，预计将考虑在一个或多种岩土工程施工过程的整个过程中土壤条件的全面变化，使用非线性、可靠、现实和现代的土壤本构律以及与之相关的岩土工程问题的强大、稳定的数值模拟策略。由于岩土工程方法和施工过程是多种多样的，研究股的意图不是考虑这些施工过程的所有可能变化。此外，研究股将集中精力研究选定的岩土工程问题。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，土壤必须被视为具有水和空气含量的颗粒骨架的混合物。除了这些基本的考虑之外，还必须考虑到与土壤和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)施工过程是否对将要安装的元件的设计或附近现有结构的可用性有重大影响？如果有，这些影响在哪些条件下是显著的，在设计过程中可以以何种简化的方式实现？(2)是否可以改进现有的本构法，以便对重复加载和卸载进行真实的描述？(3)能否根据p-u或u- p-u公式，对桩的动力安装（振动安装或动力冲击安装）和整体考虑土体中整个施工过程的应力-应变路径进行固-流物质相的动力耦合分析，以获得切合实际的结果？如何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小组的工作范围。

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.