方拱形波纹钢管廊弯矩解析解及断面参数研究

Analytical Solution of Bending Moment and Section Parameters of Square Arched Corrugated Steel Utility Tunnel

方拱形结构因空间利用率较高而广泛应用于我国地下综合管廊的建设中,但其结构承载特征、力学机制及相关设计方法研究尚少。为研究方拱形波纹钢管廊结构弯矩的解析计算理论以及合理的断面形式,利用结构力学、土力学基本理论和相关规范,推导方拱形波纹钢综合管廊的弯矩解析解,并用二维平面应变模型对弯矩解析式的正确性进行验证,同时建立不同管顶覆土深度的方拱形波纹钢管廊三维地层-结构有限元数值模型,将数值分析结果与弯矩解析式计算的弯曲应力进行对比,分析弯矩表达式的适用覆土深度,基于弯矩解析表达式对管廊断面参数进行优化分析,并给出推荐断面参数范围。研究表明:1)方拱形波纹钢综合管廊的弯矩解析解与数值解相吻合,理论计算的弯矩与数值解的最大误差为5.79%;2)弯矩解析表达式的适用覆土深度为H≤10 m;3)针对依托工程,计算结果表明管廊断面矢跨比、顶板和侧板跨度比均处于0.6~0.8,管廊结构弯矩分布较合理,有利于保障结构安全。

The square arched structure is widely used in the construction of urban utility tunnel projects in China because of its high space utilization rate.However,there are few studies on the bearing characteristics,mechanical behaviors,and design methods of square arched corrugated steel structure.Therefore,the analytical bending moment solution of the square arched corrugated steel utility tunnel is deduced using the basic theories of structural mechanics and geotechnics,as well as the relevant codes,and the effectiveness of the analytical solution is validated by a two-dimensional plane strain model and a three-dimensional finite element model that accounts for variations of cover depths.Moreover,comparison between the analytical solution and the numerical results is conducted to determine the applicable cover depths range of the analytical solution.Based on the analytical solution of the bending moment,the section parameters of the utility tunnel are optimized,providing recommended values.The results reveal the following:(1)The analytical bending moment solution agrees well with the numerical calculation, with a maximum error of 5.79% . (2) The analytical solution is applicable only when the cover depth is lower than 10 m. (3) Numerical results indicate that the rise-span ratio and top arch span-side arch span ratio are in the range of 0.6 -0.8, and the distribution of structural bending moment is rational, guaranteeing structural safety.