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方钢约束混凝土(SQCC)拱架作为复杂条件地下工程中的一种新型支护方式,具备很高的支护强度和后期承载能力,而拱架留设的灌浆孔因局部削弱和应力集中效应而成为拱架的关键破坏部位,对拱架整体承载能力具有很大的影响,需对灌浆孔进行补强处理以提高拱架开孔后的整体强度.针对SQCC开孔短柱进行室内试验及数值试验,对比分析短柱变形破坏形态、荷载位移曲线及极限承载力等力学性能,研究方钢约束混凝土拱架补强机制;建立约束混凝土强度及经济指标,综合对比短柱补强效果.以SQCC150×8短柱为例,留设灌浆孔后短柱极限承载力相比SQCC短柱降低29.9%;侧弯钢板补强(ASS)后短柱的强度指标达148.7%,经济指标为90.8%,补强效果最好,且补强钢板长度在180~240 mm范围内,厚度为8 mm时,侧弯钢板对灌浆孔补强效果最明显,经济指标增长率最大.侧弯钢板补强试验结果在全比尺拱架室内试验中得到充分验证,在现场巷道支护应用中效果良好,研究成果为约束混凝土支护设计提供了依据.
Square steel confined concrete (SQCC) arch as a new type of support in complex conditions of underground engineering, with high support strength and late bearing capacity, while the arch gap leaving the grouting holes due to local weakening and stress concentration effect And become the key damaged parts of the arch, which has a great impact on the overall bearing capacity of the arch, and the grouting holes need to be reinforced to improve the overall strength of the arch after the opening of the arch.According to the laboratory test and Numerical tests were carried out to compare the deformation and failure modes of the short columns, the load-displacement curves and the ultimate bearing capacity, and to study the reinforcement mechanism of the square steel-restrained concrete arch system. The strength and economic indexes of the confined concrete were established, Taking SQCC150 × 8 short columns as an example, the ultimate bearing capacity of short columns after grouting holes is reduced by 29.9% compared with short columns of SQCC; the strength index of short columns after side-bending steel plate reinforcement reaches up to 148.7% and the economic index is 90.8% , And the reinforcing effect is the best, and the reinforcing steel length is in the range of 180 ~ 240 mm and the thickness is 8 mm, the side reinforcing steel plate has the most obvious reinforcing effect on the grouting hole and the economic indicator has the largest growth rate. Full scale Shelf laboratory test to get fully validated in the field roadway support applications with good results, the research results provide a basis for concrete support design constraints.