地面堆载条件下交叉穿越隧道的竖向位移计算方法研究

为研究地面堆载作用下交叉穿越隧道的竖向位移特性和快速分析评估地面堆载对交叉隧道的影响,考虑土体与隧道、隧道与隧道的相互作用,基于Boussinesq解和Mindlin解,提出交叉穿越隧道竖向位移的解析公式,并通过土与隧道的位移协调、隧道结构的弯曲变形分析进行编程求解。与地表堆载作用下的模型试验和三维有限元结果进行对比分析,计算误差在10%左右,验证本文解析方法的合理性。通过参数分析探讨交叉隧道间距及交叉角度对竖向位移的影响,结果表明： 隧道交叉穿越的相互影响导致上部隧道位移减小、下部隧道位移增大; 这种影响随隧道间距和交叉角度的减小而增大,交叉隧道由正交变为上下平行时,上部隧道最大位移减小30%,因此在小角度交叉穿越的隧道中更应考虑两隧道的相互影响。     

Protection of Historical Buildings in Metro Line Construction: A Case Study in Shanghai,China

This research presents a holistic approach to the protection of historical building group adjacent to metro line construction, in which health investigation, protection criterion determining, numerical simulation analyses, corresponding protection measures and field monitoring analyses are incorporated as main procedures. A case relating to the conservation of a seven-storey brick-wood pagoda, Longhua Pagoda, adjacent to the construction of Shanghai Metro Lines 11 and 12 in China, is presented. A reasonable protection criterion is determined rationally by means of numerical simulation based on the health investigation results combined with related standards, which can help to achieve a fine balance between system safety and cost constraints in protection measures determining. A full numerical model is developed to analyze the effect of dewatering, excavation, tunneling, and shield departure/reception, and corresponding measures are adopted to ensure the safety of the pagoda. Especially a brand new method, steel jacket method, is introduced in detail, which has a good performance on decreasing the amount of dewatering and maintaining a stable working face. Results demonstrate the application potential of the proposed approach, as well as its feasibility. The proposed approach can be used in the industry by practitioners to provide positive guidelines on the conservation of historical building group against metro line constructions. The reliable and detailed data in this case can also provide verification for subsequent research.