摘要
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.
The new support way-square confined concrete（ SQCC） arch in complex-condition underground engineering applications has higher supporting strength and post-bearing capacity. The grouting holes become key parts of the arch with local weakening and stress concentration effects and greatly influence the bearing capacity of the whole arch. As such,it is necessary to reinforce this area. In laboratory tests and numerical experiments on SQCC test specimens with grouting holes,the strengthening mechanism was investigated by comparative analysis of the mechanical properties,including the deformation and failure patterns,load displacement curve,and ultimate bearing capacity. To compare the different reinforcing effects,strength and economic indexes were established.The results show the ultimate bearing capacity of a short column with grouting holes to be reduced by 29. 9% compared to the SQCC short column. In a case study of the SQCC150 × 8 short column,the reinforcement method using two-angle steel exhibited better reinforcing effect,improving both the strength and economic indexes of short columns up to 148. 7% and 90. 8%,respectively. When thelength of the reinforcement plate ranges from 180-240 mm and the plate thickness is 8 mm,the reinforcement effect is best,and the economic index also reaches its peak value. Moreover,the angle steel strengthening（ ASS） experiments was conducted in a full-scale laboratory test. The application of SQCC arches in roadway supports has a good effect,and these research results provide a basis for the design of confined concrete support.
出处
《工程科学学报》
EI
CSCD
北大核心
2017年第8期1141-1151,共11页
Chinese Journal of Engineering
基金
国家自然科学基金资助项目(51674154
51474095)
中国博士后科学基金特别资助项目(2017T100116
2017T100491)
中国博士后科学基金面上资助项目(2016M602144
2016M590150)
国家重点研发计划专项资助项目(2016YFC0600901)
深部岩土力学与地下工程国家重点实验室开放基金资助项目(SKLGDUEK1519)
关键词
方钢约束混凝土
灌浆孔
补强机制
全比尺力学试验
现场应用
square confined concrete
grouting holes
strengthening mechanism
full-scale mechanical test
field application
