Abstract Structural supports used for tunnels and other underground civil structures in soft rock are often prone to severe damage due to large deformation. To overcome this issue, a new steel circular closed support with I-section of sinusoidal corrugated webs is proposed to mitigate such damage caused by deformation. Large scale experiments of the proposed support with corrugated webs were carried out to investigate their buckling behaviors and failure modes. The results showed that the ultimate load of the support increased from 1386.25 kN to 1635.27 kN (18% increment) with the web height increasing from 240 mm to 300 mm (25%). Therefore, the web height had a positive effect on the bearing capacity of steel circular closed supports with I-section of sinusoidal corrugated webs. Finite element (FE) analysis was conducted and then validated by the experimental results. Take specimen YX-1 as an example, the differences between the FE modeling and experiment for the ultimate load-carrying capacity and vertical displacement at the vault were 2.64% and 3.34% respectively, when the support was in the ultimate state. The correlations between major design parameters including cross sectional dimensions, initial imperfections and slenderness ratios, and in-plane elastic as well as elastic–plastic buckling performances were also investigated. The results showed that corrugated web height, flange width and thickness were three dominant parameters for the structural design of such supports. Furthermore, the antisymmetric buckling mode was observed when the slenderness ratio increases to a certain level (>100 in this paper). A formulation was further proposed to estimate global elastic buckling load for such supports under hydrostatic pressure. In combination with the design method of I-section beams with sinusoidal webs under axial compression, a developed design approach for in-plane ultimate bearing capacity of the steel circular closed support with I-section of sinusoidal corrugated webs under pure pressure was obtained.

中文翻译：

---

正弦波纹腹板工字钢圆形封闭支撑的面内稳定性：实验和数值研究

摘要 软岩中隧道等地下土木结构的结构支护往往容易因大变形而发生严重破坏。为了克服这个问题，提出了一种具有正弦波纹腹板 I 形截面的新型钢制圆形封闭支撑，以减轻变形引起的这种损坏。对所提出的带有波纹腹板的支撑进行了大规模实验，以研究它们的屈曲行为和失效模式。结果表明，随着腹板高度从240 mm增加到300 mm（25%），支撑的极限载荷从1386.25 kN增加到1635.27 kN（增加18%）。因此，腹板高度对正弦波纹腹板工字钢圆形封闭支撑的承载力有积极影响。进行了有限元 (FE) 分析，然后通过实验结果进行验证。以试件YX-1为例，当支座处于极限状态时，有限元建模与试验对拱顶极限承载力和竖向位移的差异分别为2.64%和3.34%。还研究了主要设计参数之间的相关性，包括横截面尺寸、初始缺陷和长细比、面内弹性以及弹塑性屈曲性能。结果表明，波纹腹板高度、翼缘宽度和厚度是此类支撑结构设计的三个主要参数。此外，当长细比增加到一定水平（本文中>100）时，观察到反对称屈曲模式。进一步提出了一种公式来估计静水压力下此类支撑的整体弹性屈曲载荷。结合轴压下正弦腹板工字钢梁的设计方法，得到了纯压力下正弦波形腹板工字钢圆形封闭支撑面内极限承载力的设计方法。