一种新型软岩支护结构—波形钢腹板支架的受力性能与关键技术研究

The H-Shaped members with corrugated webs are welded by the flat flange steel plates and very thin corrugated webs (ordinarily 2~3mm). The webs offer good shearing resistance and erection stiffness because of the web corrugations. They are mainly applied in architectures and bridge structures currently. The H-Shaped members with corrugated webs possess a lot of advantages such as simple fabrication, easy installation, elegant appearance and economy, so as to be popular with Europe and the United States. And in China the research on the H-Shaped members with corrugated webs is still at its preliminary stage. A new type of metal support named H-Shaped members with corrugated webs is put forward for the soft rock tunnels or roadways supports. The prominent merit lies in that it can adapt to the large deformation of soft rocks by inducing deformation along the axial support because of the corrugated webs. Based on on-the-spot or indoor experiments, theoretical analysis and numerical calculation, researches of the supports with corrugated webs are focused on elastic and elasto-plastic buckling behaviors，basic mechanic properties under the condition of hydrostatic pressure and other loading boundary conditions, the rigidity and deformation under surrounding rock pressure, the influence of construction procedures on the mechanic properties of supports, interaction between supports and surrounding rock, construction technique study etc.. The reliable design theory and method will be proposed to promote this structure into practice as quickly as possible for the new type of supporting structure.

波形钢腹板工型构件由上、下平钢板翼缘和厚度很薄的波形腹板（通常为2～3mm）焊接而成，由于腹板呈波折状，从而有效提高腹板的剪切屈曲荷载和面外弯曲刚度，目前被主要用于建筑和桥梁结构中。波形钢腹板工型结构以其制作简单，施工快捷、外型美观、经济合理等优点在欧美一些国家得到广泛青睐。在我国波形腹板工型构件的应用和研究仍处于起步阶段。本课题提出一种适用于软岩隧道（巷道）中的新型波形钢腹板支架结构，其突出特点在于腹板呈波形状能产生沿支架轴向的变形从而较好地适应围岩的大变形。通过现场试验、室内试验并结合理论分析和数值计算，重点研究波形钢腹板支架的弹性、弹塑性屈曲性能，在静水压力等多种荷载边界条件下的基本力学性能，围岩压力作用下的刚度及变形；施工过程对支架受力性能的影响，支架与围岩之间的相互作用以及支架的施工技术等，提出其可靠的设计理论和方法，以推动这种结构形式的实用化。

根据软岩隧道（巷道）变形大，稳定性能差等特点，本项目提出了一种新型的可用于软岩隧道（巷道）的波形钢腹板支架结构。波形钢腹板工型构件由上、下平钢板翼缘和厚度很薄的波形腹板（通常为2～3mm）焊接而成，由于腹板呈波折状，从而有效提高腹板的剪切屈曲荷载和面外弯曲刚度，目前被主要用于建筑和桥梁结构中。波形钢腹板工型结构以其制作简单，施工快捷、外型美观、经济合理等优点在欧美一些国家得到广泛青睐,但在我国波形腹板工型构件的应用和研究仍处于起步阶段。波形钢腹板支架的突出特点在于所有构件均在工厂制作,自重轻,便于安装就位; 波形腹板呈波形状，具有较高的抗剪承载力，尤其是波形腹板能产生沿支架轴向的变形从而较好地适应围岩的大变形。主要通过试验研究并结合理论分析和数值计算，开展了波形钢腹板支架结构基本力学性能的研究，包括截面型式比选，建立了其简化力学计算模型。重点研究波形钢腹板支架的弹性、弹塑性屈曲性能，分析支架的截面尺寸各参数、长细比、断面形式其屈曲性能的影响，拟合了弹性屈曲系数与长细比的计算公式，得到了支架平面内弹塑性稳定承载力与支架截面尺寸各参数，长细比，几何缺陷模式以及缺陷幅值之间的关系。并设计了马蹄形、圆形、直墙半圆拱断面波形钢腹板支架稳定承载力模型试验，分析了支架的失稳形态、位移与应变发展规律。给出了波形钢腹板纯压支架的平面内稳定设计曲线，结合现行相关规范，提出了波形钢腹板纯压支架和压弯支架平面内稳定承载力的设计建议公式。针对围岩大变形特征，设计了波形钢腹板支架结构6个螺栓连接和1个套筒连接的可缩性节点的轴压和压弯试验。在此基础上提出了波形钢腹板可缩性节点的初步设计步骤和改进建议,并初步分析了支架与围岩之间的相互作用等。作为一种施工简单，性能优越的新型支护结构形式，还有待下一步开展现场试验，真正将这种波形腹板支架结构应用在软岩隧道支护结构中。