钢管套筒灌浆连接轴向受拉性能模拟试验研究

Experimental study on axial tensile behavior of pipe-to-sleeve grouted connection

为研究钢管套筒灌浆连接轴向受拉破坏过程及破坏机理,试验中设计了16组48个钢管套筒灌浆连接试件,试件采用钢板代替圆钢管,并进行静载试验。分析了灌浆料裂缝扩展过程、荷载-相对位移曲线,并对抗剪键高距比、灌浆料厚度、侧向力等因素对破坏过程及承载力的影响进行分析。结果表明:对于不设置抗剪键的套筒灌浆连接试件,斜裂缝随机产生,裂缝分布不均匀;对于设置抗剪键的套筒灌浆连接试件,裂缝首先出现在底部抗剪键位置处,与水平方向夹角约为30°,随后在中部和上部抗剪键位置处分别出现斜裂缝。由于每个抗剪键上荷载分担并不均匀,与抗剪键接触的灌浆料逐渐达到极限压应力,达到极限状态时,承载力全部由抗剪键间的机械咬合力承担,在连接承载力中,可忽略摩擦力和胶结力作用。随着抗剪键高距比h/s增大,各试件初始剪切刚度相差不大,承载力增大,但增幅逐渐减小,建议抗剪键高距比0.06<h/s<0.1。在一定范围内,随着厚距比t_g/s增大,承载力增大,当达到一定值时,承载力趋于稳定,建议厚距比t_g/s>0.3,同时需要满足灌浆料灌注的施工要求。

In order to study the failure process and failure mechanism of steel pipe-to-sleeve grouted connections under axial tension, 16 groups of 48 pipe-to-sleeve grouted connection specimens were designed and tested. Steel plates were used to replace circular steel pipes. The crack propagation process of the grouting material was recorded. The load versus relative displacement curve of the specimen, the height-to-distance ratio of shear keys and the grouting material thickness were obtained. The influence of lateral force on the failure process and bearing capacity was analyzed. The results show that for the pipe-to-sleeve grouted connections without shear keys, the inclined cracks are randomly generated and the cracks are distributed unevenly. For the pipe-to-sleeve grouted connections with shear keys, the crack first appears at the bottom shear keys of the steel pipe, and the angle with horizontal direction was about 30°. After that there are oblique cracks at the positions of middle and upper shear keys. As the load distribution on each shear key is not uniform, the grouting materials in contact with the shear key reach the ultimate compressive stress one by one. The bearing capacity is all provided by the mechanical interlock force between the shear keys at the ultimate limit state. In the calculation of connection bearing capacity, the friction force and the cementing force can be neglected. With the increase of the height-to-distance ratio of shear key, the initial shearing stiffness of each specimen remains almost constant while the bearing capacity increases, although such increase becomes increasingly less significant. Based on this observation, the height-to-distance ratio of shear key is suggested to be in the range of 0.06 and 0.1 for practice. Similarly, the bearing capacity increases with the increase of the thickness-to-distance ratio before it reaches a threshold value, after which the bearing capacity tends to be stable. It is suggested that thickness-to-distance ratio should be larger than 0.3, and the construction requirements of grouting material should be met at the same time.