Tunnelling-induced Damage Assessment of Vulnerable Historic Structures

该项目属于EPSRC结构工程、地基工程、基础设施和城市系统研究领域的福尔斯，所介绍的研究摘要与脆弱的历史砌体结构的损伤评估有关，其特征是与结构和岩土工程有关的跨学科方面。人口的快速增长是21世纪世纪的全球性挑战之一。特别是，城市人口增长造成各种基础设施问题，包括交通网络的严重交通拥堵。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，这可能会导致附近结构的破坏。因此，建筑物对隧道开挖和开挖引起的地面运动的反应需要详细研究，以确保地下建筑的安全。在模拟历史砌体结构隧道损伤时，需要考虑多种不确定性。例如，在土壤-结构分析中定义边界条件或在砌体建筑中为不同的结构元件定义材料特性和现有裂缝将涉及许多不确定性。在文献中，隧道引起的建筑物损坏是通过考虑以下过程来确定的：1）在自由场条件下研究地面运动，2）计算自由场地面运动条件下建筑物刚度的影响，3）通过考虑土-结构相互作用来估计建筑物损坏，4）评估建筑物损坏的程度。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察相结合。在当前的工程实践中，通常通过将建筑物建模为弹性梁或通过在详细的有限元分析中对隧道施工、土壤和建筑物建模来评估现有砌体建筑物中隧道施工引起的损坏的风险。然而，虽然弹性梁模型是一个相对粗糙的方法来模拟隧道-土壤-建筑物的相互作用，详细的三维（3D）数值分析需要很高的计算成本和时间。本研究的动机是开发数值高效和实用的建模程序，以评估隧道引起的破坏砌体建筑物，通过增加模型的准确性，同时模拟问题的关键方面，并通过需要更少的计算时间和成本相比，详细的三维有限元模型。通过开发实用的新数值模型来模拟复杂的建筑物反应，为模型的各个结构元件开发详细的本构模型，可用于特定的案例研究，模拟特殊特征的行为，如预先存在的裂缝和砖石建筑中的不规则开口，改进一个实际的土壤-地基模型，以反映土壤-结构相互作用的影响，以及隧道施工引起的地面移动对结构的传递，利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，收集建筑物反应数据（通过测量整个结构的位移和应变行为）;最后，我谨指出，这项研究将有助于减少土壤建模过程中的不确定性，结构的相互作用和砌体建筑的行为，由于隧道引起的地面运动。研究的结果将有助于确定最佳的建模策略，这可以使未来的评估隧道引起的损害砌体建筑物更可靠。

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.