Tunnelling-induced Damage Assessment of Vulnerable Historic Structures

该项目属于EPSRC结构工程、地面工程、基础设施和城市系统研究领域。本研究综述涉及历史易损性砌体结构的损伤评估，具有结构与岩土工程交叉学科的特点。人口的快速增长是21世纪的全球性挑战之一。特别是，城市人口增长导致各种基础设施问题，包括交通网络上严重的交通拥堵。基础设施技术的最新发展使地下交通系统的建设能够满足这一需求。然而，隧道施工和深开挖通常会产生垂直和水平的地面运动，这可能会对附近的结构造成破坏。因此，建筑物对隧道和挖掘引起的地面运动的反应需要对安全的地下建筑进行详细的研究。在对历史砌体结构进行隧道损伤建模时，需要考虑多种不确定性因素。例如，确定土-结构分析中的边界条件或砌体建筑中不同结构单元的材料特性和存在的裂缝，都涉及到许多不确定性。在文献中，通过考虑以下步骤确定隧道引起的建筑物损伤：1)研究自由场条件下的地面运动，2)计算自由场地面运动条件下建筑物刚度的影响，3)考虑土-结构相互作用估计建筑物损伤，4)评估建筑物损伤水平。此外，该程序可将物理模型试验和数值模拟计算的结果与实地观测结合起来。在目前的工程实践中，通常通过将建筑物建模为弹性梁或将隧道结构、土壤和建筑物建模为详细的有限元分析来评估现有砌体建筑物隧道引起的损伤风险。然而，虽然弹性梁模型是一种相对粗糙的隧道-地基-建筑相互作用模型，但详细的三维数值分析需要较高的计算成本和时间。本研究的动机是通过提高模型的准确性，同时模拟问题的关键方面，以及与详细的三维有限元模型相比，需要更少的计算时间和成本，开发数字上有效和实用的建模程序，以评估隧道引起的砖石建筑损伤。本研究的总体目标总结为：通过开发实用的新数值模型来模拟复杂的建筑响应，为模型中的单个结构元素开发可用于具体案例研究的详细本构模型，模拟砌体建筑中预先存在的裂缝和不规则开口等特殊特征的行为，改进实用的地基模型以表示土-结构相互作用的影响和隧道诱发的地面的传递使用创新的结构健康监测方法，如光纤传感器和数字图像相关系统，从现场实验中收集建筑响应数据（通过测量整个结构的位移和应变行为）；综上所述，本研究将有助于减少由于隧道引起的地面运动而导致的土-结构相互作用和砌体建筑行为建模过程中的不确定性。研究结果将有助于确定最优的建模策略，从而使未来对砌体建筑隧道损伤的评估更加可靠。

This project falls within the EPSRC Structural Engineering, Ground Engineering, Infrastructure and Urban Systems research areas.The presented research summary is related to the damage assessment of vulnerable historic masonry structures, which features interdisciplinary aspects related to structural and geotechnical engineering. The rapid population growth is one of the global challenges of the 21st century. In particular, urban population growth causes various infrastructure problems, including severe traffic congestion on the transportation network. Recent developments in the infrastructure technology enable responding to this demand with the construction of underground transportation systems. However, tunnel construction and deep excavation usually create vertical and horizontal ground movements, which can cause damage in nearby structures. Thus, the building response to tunnelling and excavation-induced ground movements needs to be examined in detail for safe underground constructions. There are multiple uncertainties to be considered while modelling tunnelling-induced damage in historic masonry structures. For instance, defining the boundary conditions in the soil-structure analyses or the material properties and existing cracks in the masonry building for different structural elements will involve many uncertainties. In the literature, tunnelling-induced building damage is determined by considering the following procedure: 1) the ground movement is investigated in the free-field conditions, 2) the effect of building stiffness is computed for the free-field ground movement conditions, 3) the building damage is estimated by considering the soil-structure interaction and 4) the level of the building damage is evaluated. Additionally, the procedure may combine results from physical model tests and numerical modelling calculations with field observations. The risk of tunnelling-induced damage in existing masonry buildings is typically assessed in current engineering practice by either modelling the building as an elastic beam or by modelling the tunnel construction, soil and the building in detailed finite element analysis. However, while the elastic beam model is a relatively crude approach to model the tunnel-soil-building interaction, the detailed three-dimensional (3D) numerical analysis requires high computational cost and time. The motivation for the this research is to develop numerically efficient and practical modelling procedures to assess the tunnelling-induced damage to masonry buildings by increasing the accuracy of the model while simulating the critical aspects of the problem and by requiring less computational time and cost compared with detailed 3D finite element models.The overall objectives of this research are summarized as;simulating complex building response by developing practical new numerical models,developing detailed constitutive models for the individual structural elements of the model that can be employed to specific case studies,modelling the behaviour of special features such as pre-existing cracks and the irregular openings in the masonry buildings,improving a practical soil-foundation model to represent the effect of soil-structure interactions and the transmission of the tunnelling-induced ground movements to the structureusing innovative structural health monitoring methods such as fibre optic sensors and digital image correlation systems to collect the building response data(by measuring the displacement and strain behaviour of the whole structure) from the field experiments;In conclusion, this research will contribute to decrease the uncertainties in the modelling process of the soil-structure interaction and the masonry building behaviour due to tunnelling-induced ground movements. The outcomes of the research will be useful to identify optimal modelling strategies, which can make future assessments of tunnelling-induced damage in masonry buildings more reliable.