School of Civil Engineering, Shijiazhuang Tiedao University, Shijiazhuang, China.
State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures, Shijiazhuang Tiedao University, Shijiazhuang, China.
PLoS One. 2024 Apr 16;19(4):e0301428. doi: 10.1371/journal.pone.0301428. eCollection 2024.
In urban areas with limited underground space, the new tunnel construction introduces additional loads and displacements to existing tunnels, raising serious safety concerns. These concerns become particularly pronounced in the case of closely undercrossing excavation at zero-distance. The conventional elastic foundation beam model, which assumes constant reaction coefficients for the subgrade, fails to account for foundation loss. In this study, the existing tunnel is modeled as an Euler-Bernoulli beam supported by the Pasternak elastic foundation, and the foundation loss caused by zero-distance undercrossing excavations is considered. Furthermore, an analytical solution is proposed to evaluate the mechanical response in segments, by establishing governing differential equations and boundary conditions for the excavation and neutral zones, and underpinning loads are also considered. The analytical solution is validated in two case studies. Finally, a parametric analysis is performed to explore the influence of various parameters on the mechanical response of the existing tunnel.
在地下空间有限的城市地区，新隧道的建设会给现有隧道带来额外的荷载和位移，引发严重的安全问题。在近距离零距下穿开挖的情况下，这些问题尤为突出。传统的弹性地基梁模型假设路基的反力系数为常数，无法考虑基础损失。在本研究中，将现有隧道建模为受 Pasternak 弹性地基支撑的 Euler-Bernoulli 梁，并考虑了近距离下穿开挖引起的基础损失。此外，通过建立开挖区和中性区的控制微分方程和边界条件，并考虑支撑荷载，提出了一种用于评估分段力学响应的解析解。该解析解在两个案例研究中得到了验证。最后，进行了参数分析，以探讨各种参数对既有隧道力学响应的影响。
