Abstract

Basement excavation inevitably causes stress changes in the ground leading to soil movements which may affect the serviceability of adjacent structures specially in case of masonry building. Because soil stiffness degrades with induced stress release during excavation, it is vital to investigate the masonry façade responses to an adjacent excavation. This paper presents three-dimensional numerical parametric study to investigate damaging effects on an existing brick masonry façade due to an adjacent basement excavation. The orientation of the façade is perpendicular to the basement. An advanced hypoplastic (sand) model with small-strain stiffness is adopted. The model parameters are calibrated against centrifuge test results in sand reported in literature. Effects of excavation depths, wall locations with respect to excavation, sand density and applied loads on the wall are examined. The computed results revealed that differential settlement (with maximum settlement closest to the excavation) was induced in the wall due to excavation-induced stress relief. Consequently, cracks were developed in the façade during excavation. By increasing the relative density from 30% to 90%, the excavation-induced footing settlement decreases by up to 72%. The different loads applied on the top of the façade have significant effects on the responses of the wall due to excavation.

摘要

地下室开挖不可避免地会导致地面应力变化，从而导致土壤运动，这可能会影响相邻结构的可使用性，特别是在砖石建筑的情况下。由于在开挖过程中，土壤刚度会随着应力释放而降低，因此研究砌体立面对相邻开挖的响应至关重要。本文介绍了 3D 数值参数研究，以研究相邻地下室开挖对现有砖砌体外墙的破坏影响。立面的方向垂直于地下室。采用先进的小应变刚度亚塑性（砂）模型。模型参数根据文献报道的沙子中的离心机测试结果进行校准。开挖深度、墙体位置对开挖的影响，检查沙子密度和施加在墙上的载荷。计算结果表明，由于开挖引起的应力释放，在墙体中引起了差异沉降（最大沉降最接近开挖）。因此，在挖掘过程中，立面出现了裂缝。通过将相对密度从 30% 增加到 90%，开挖引起的基础沉降最多可减少 72%。由于开挖，施加在立面顶部的不同荷载对墙体的响应有显着影响。通过将相对密度从 30% 增加到 90%，开挖引起的基础沉降最多可减少 72%。由于开挖，施加在立面顶部的不同荷载对墙体的响应有显着影响。通过将相对密度从 30% 增加到 90%，开挖引起的基础沉降最多可减少 72%。由于开挖，施加在立面顶部的不同荷载对墙体的响应有显着影响。