The integrity and stability of underground space mainly depend upon the coordination of primary and secondary support system. This paper presents a novel secondary standing support system, termed fibre-reinforced polymer (FRP)-confined high-water content cementitious grout material column (FCCM), being an alternative structural form for underground space. The attractive feature of the FCCM is its exterior container made of FRP composite with high strength-to-weight ratio and high corrosion resistance. A total of 30 FCCM specimens were prepared and tested to demonstrate its expected structural behaviour under compression. The critical parameters covered the type and the thickness of FRP tube as well as the strength of infill material. Test results verified that the cementitious grout material in the FCCM was effectively confined by the exterior FRP tube, resulting in the significant enhancement of load carrying capacity and deformation ability. The test results also indicated that the water expulsion of confined cementitious grout material may be the other reason for the superior compressive behaviour of FCCMs. The strain hardening FCCM with large axial deformation is particularly suitable for these underground spaces where the integrity and corrosion are the main concerns.

地下空间的完整性和稳定性主要取决于一级和二级支持系统的协调。本文提出了一种新型的二级支撑系统，称为纤维增强聚合物（FRP）约束的高含水水泥灌浆材料柱（FCCM），是地下空间的一种替代结构形式。FCCM的吸引人之处在于它的外部容器由FRP复合材料制成，具有高强度重量比和高耐腐蚀性。总共准备并测试了30个FCCM标本，以证明其在压缩下的预期结构行为。关键参数包括玻璃钢管的类型和厚度以及填充材料的强度。测试结果证明，FCCM中的水泥灌浆材料被外部FRP管有效地封闭，从而显着提高了承载能力和变形能力。试验结果还表明，承压水泥浆材料的排水可能是FCCM具有优异压缩性能的另一个原因。具有较大轴向变形的应变硬化FCCM特别适用于主要关注完整性和腐蚀的地下空间。