高应力反复拉压作用下冷压灌浆套筒连接性能研究

Study on connection performance of cold-pressed grouting sleeve under high stress repeated tension and compression

为了降低工程使用成本,设计一种由无缝钢管冷压制成的灌浆套筒,并对其进行高应力反复拉压试验,研究其抗震性能和变形能力;分析了套筒肋间距、肋深、钢筋锚固长度和直径对灌浆套筒性能的影响;采用延性比对灌浆套筒接头的连接性能进行了评估。结果表明:试件的破坏类型分为钢筋拉断和钢筋拔出两种方式;钢筋直径为20 mm的试件极限锚固长度为5.5d(d为钢筋直径);肋深为0.5 mm的套筒u_(20)(u_(20)为接头经高应力反复拉压20次后的残余变形)不满足规范要求;随钢筋直径的增大,试件极限抗拉承载力和极限位移增大;随锚固长度增加,极限位移减小;肋间距和肋深的改变对试件的极限荷载、屈服荷载和位移无显著影响;钢筋直径增加时,套筒表面最大应变值成倍增加,说明钢筋直径越大对套筒结构稳定性越不利;对于该规格的套筒建议选用20 mm及以下直径的钢筋;试件延性比均大于4,且延性比为规范要求最低值的4.122 5倍~7.332 5倍,说明该接头具有较大的安全余量。

In order to reduce the cost of engineering use,a grouting sleeve made of seamless steel pipes was designed and subjected to high stress repeated tension and compression tests to study its seismic performance and deformation capacity.The effects of sleeve rib spacing,rib depth,reinforcement anchorage length and diameter on the performance of grouting sleeves were analyzed.The connection performance of grouting sleeve joints was evaluated using ductility ratio.The results show that the types of failure of specimens can be divided into two types:steel bar fracture and steel bar extraction.The ultimate anchorage length of the specimen with a steel bar diameter of 20 mm is 5.5 d(d is steel bar diameter).The u_(20)(u_(20) is the residual deformation of the joint after 20 cycles of high stress repeated tension and compression)of sleeve with a rib depth of 0.5 mm does not meet the specification requirements.As the diameter of the steel bar increases,the ultimate tensile bearing capacity and ultimate displacement of the specimen increase.As the anchorage length increases,the ultimate displacement decreases.The changes in rib spacing and rib depth have no significant impact on the ultimate load,yield load,and displacement of the specimen.When the diameter of the steel bar increases,the maximum strain value on the surface of the sleeve increases exponentially,indicating that the larger the diameter of the steel bar,the more unfavorable it is for the stability of the sleeve structure.For sleeves of this specification,it is recommended to use steel bars with a diameter of 20 mm or less.The ductility ratios of the specimens are all greater than 4,and the ductility ratios are 4.1225 times to 7.3325 times the minimum value required by the specifications,indicating that the joint has a significant safety margin.