高应变动测技术在如东海域大直径钢管桩基工程中的应用研究

Application of high-strain testing in large-diameter steel pipe pile project in Rudong sea area

基于江苏如东海域三根大直径敞口钢管桩的初打和复打高应变动测试验数据,提出了适用于该海域的桩端折减系数η的推荐值和承载力恢复计算公式,为该海域大直径钢管桩基础的承载力评估提供了技术依据。敞口钢管桩高应变试验数据显示,试验桩侧阻力的恢复系数都远大于端阻力的,且桩侧阻力随时间增长显著,但端阻力的增长却很小。基于此,推荐如东海域大直径敞开钢管桩的桩端阻力折减系数η取0.05进行估算。此外,通过桩基土体恢复和增长机理探讨,提出桩基承载力恢复计算公式,且验证误差在10%以内。

Based on the initial and repeated high-strain test data of three large-diameter open steel pipe piles in Rudong sea area of Jiangsu Province,a pile end reduction coefficient η applicable to the sea area and the formula for calculating the recovery of bearing capacity is proposed,and a technical basis for evaluating the bearing capacity of large-diameter steel pipe piles in the sea area is provided.According to the high-strain test data of open steel pipe piles,the recovery coefficients of the lateral resistance of the test piles are much greater than those of the end resistance,and the lateral resistance of the piles increases significantly over time,but the increase in the end resistance is very small.Based on this,it is recommended to use the pile end resistance reduction coefficient η=0.05 for large-diameter open steel pipe piles in the Rudong sea area.In addition,by exploring the recovery and growth mechanism of pile foundation soil,a formula for calculating the recovery of pile foundation bearing capacity is proposed,and the verification error is within 10%.