Soil-Structure Interaction under Environmentally Induced Cyclic Loading

大多数岩土结构在其使用寿命内都会受到环境诱导的循环荷载。这些循环荷载可以来自各种来源，例如交通、机器、风浪、建筑或地震。重复加载的范围可以从具有相对较小幅度的大量高概率周期到具有相对较大幅度的少量低概率周期。循环载荷通常是多轴的，并且具有不规则的载荷-时间历史，其幅度和频率随循环而变化。这种荷载可能会导致残余应变和应力变化的累积，从而影响结构的性能或稳定性。目前预测随机循环荷载对岩土结构影响的模型相对粗糙，通常基于有限的现场和比例模型研究。因此，需要进行更多的研究，以解决环境源(如风、海浪和地震)引起的随机循环荷载的不同方面，并为更好的岩土结构预测设计工具提供了解。 本项目的目的将是研究两种类型的土工结构：基础和管道，在随机变幅循环条件下，承受复杂的竖向、水平和弯矩组合荷载时的土-结构特性。将验证和校准循环预测模型，以预测这些岩土结构的行为，支持来自现场测试、缩尺物理模型测试和计算机分析的数据。在开发这些预测方法时，将使用典型随机环境过程的适当载荷和响应时间历史。了解这些岩土系统在循环环境荷载作用下的行为，并优化分析方法，将有助于改进其行为的设计和预测。在资助期间，研究积累的数据和知识将供建筑、地球科学、能源和近海行业的工程师使用。拟议的基础设施将有助于创建：(1)结构和岩土工艺知识；(2)实地行为数据库；(3)设计和施工信息；(4)用于数字和分析方法验证的数据。受这项工作影响的主要应用部门将是风能以及石油和天然气行业。

The majority of geotechnical structures will be subjected to environmentally induced cyclic loads during their life-spans. These cyclic loads can be from a variety of sources, e.g. traffic, machines, wind and waves, construction or earthquakes. Repeated loading can range from a large number of high-probability cycles with relatively small amplitude, to a small number of low-probability cycles with relatively large amplitude. The cyclic loading will commonly be multi-axial and have a loading-time history that is irregular, with amplitude and frequency changes from cycle to cycle. This loading can lead to the accumulation of residual strains and stress changes that affect the performance or stability of the structure. Models for predicting the effects of random cyclic loading on geotechnical structures are relatively crude and are generally based on limited field and scaled model studies. Hence, more research is needed to address different aspects of random cyclic loads induced from environmental sources (e.g. wind, sea-waves and earthquakes) and provide understanding for better predictive design tools for geotechnical structures. The aim of this project will be the investigation of the soil-structure behavior of two types of geotechnical structure: namely, foundations and pipelines, when subjected to complex combinations of vertical, horizontal and moment loads under random variable amplitude cyclic conditions. Cyclic predictive models will be validated and calibrated for predicting the behavior of these geotechnical structures, supported by data from field testing, scaled physical model testing and computer analysis. Appropriate loading and response time-histories for typical random environmental processes will be used in the development of these predictive methods. Understanding of the behavior of these geotechnical systems under cyclic environmental loading and optimization of analytical methods will provide improvements in design and prediction of their behavior. Over the funding period, data and knowledge accrued from the research will be utilized by engineers working in construction, geosciences, energy and the offshore industry. The proposed infrastructure will enable the creation of: (i) knowledge of structures and geotechnical processes, (ii) databases of field-scale behavior, (iii) design and construction information and (iv) data for numerical and analytical method validation. The primary sectors of application impacted by this work will be the wind energy, and oil and gas industries.