竹筋-夯土界面的拉拔试验研究

Pull-out test study on the bamboo reinforcement-rammed earth interface

为了研究竹筋-夯土界面性能,设置4种不同类别影响参数——轴向压力(40、80、120、160 kPa)、竹筋构造形式(无竹节、单竹节和单竹节且端部弯起构造形式)、竹筋宽度(1、2、3 cm)、埋置长度(210、290、370、450 mm)进行拉拔试验.结果表明:轴向压力从40 kPa增加到160 kPa时,拉拔力峰值增加了4.37 kN,增幅达47.7%;竹节和端部弯起构造都能提高竹筋与土体间的端阻力,从无竹节到单竹节且端部弯起构造,拉拔力峰值增加4.76 kN,增幅达42.6%;竹筋宽度与埋置长度增大时,竹筋与土体的摩阻力和侧阻力增大,竹筋宽度从1 cm增加到3 cm时拉拔力峰值增加了5.49 kN,增幅达65.4%;埋置长度从210 mm增加到450 mm,拉拔力峰值增加了5.67 kN,增幅达72.4%.竹筋与夯土界面的作用力主要由化学黏结力、摩阻力和端阻力组成;4种影响因素均可以显著提高拉拔力峰值,而增加埋置长度效果最显著.

To study the interface performance between bamboo reinforcement and rammed earth,pull-out tests were conducted with four different influencing parameters:axial pressure(40,80,120 and 160 kPa),bamboo reinforcement configurations(without nodes,single node,and single-node with bent-up configurations),bamboo reinforcement width(1,2 and 3 cm),and embedment length(210,290,370 and 450 mm).The results show that with an increase in axial pressure from 40 to 160 kPa,the peak pull-out force increases by 4.37 kN,with a growth rate of 47.7%.Both the presence of nodes in the bamboo and bent-up configurations at the ends enhance the end resistance between the bamboo reinforcement and the soil.From configurations without nodes to single-node with bent-up configurations,the peak pull-out force increases by 4.76 kN,with a growth rate of 42.6%.As the bamboo reinforcement width and embedment length increase,the frictional resistance and lateral resistance between the bamboo reinforcement and the soil increase.When the width increases from 1 to 3 cm,the peak pull-out force increases by 5.49 kN,with a growth rate of 65.4%.When the embedment length increases from 210 to 450 mm,the peak pull-out force increases by 5.67 kN,with a growth rate of 72.4%.The forces acting at the interface between the bamboo reinforcement and rammed earth mainly consists of chemical bonding force,frictional force,and end resistance.All four influencing factors significantly increase the peak pull-out force,the increase of embedment length having the most significant effect.