缺陷加固桩荷载分布试验研究与理论分析

Experimental study and theoretical analysis of load distribution of defective reinforced piles

注浆加固夹泥、离析类缺陷桩在恢复桩身承载力方面欠佳,进而工程中改用钢管-注浆进行加固,但其仍缺乏足够的理论依据与试验。开展了室内模型试验,正常桩与缺陷加固桩竖向抗压试验表明:钢管的设置使桩身承载力得到极大的恢复;随着钢管数量的增加,钢管承载百分比呈上升趋势,混凝土与注浆加固体承载百分比总体呈下降趋势,并在钢管数为4时取得最优的加固效果;钢管承担主要补强作用,其长度的增加对缺陷桩桩身整体性有积极作用;钢管与桩截面的截面比为2.54%~2.58%时,缺陷桩桩身承载力恢复最佳。

Concerning the capacity of grouting reinforcement of contained clay and segregated defective piles is insufficient in restoring pile bearing capacity,steel pipe-cement grouting method has been used to reinforced this type of defect piles in actual project.But this method is still lack of enough theory and tests.The laboratory experiments are carried out,and the vertical compression test of normal pile and reinforced defective pile shows that:the pile bearing capacity is greatly strengthened by the setting of steel pipe;with the increase of the number of steel pipes,the bearing percentage of steel pipes is on the rise,while that of concrete-grouting reinforced piles is on the decline,and the optimal strengthening effect is achieved when the number of steel pipes is 4;the steel tube bears the main reinforcing function,and the increase of steel pipe length has a positive effect on defective pile integrity;when the section ratio of steel pipe to pile section is 2.54%~2.58%,the bearing capacity of defective pile body recovers best.