单桩静载荷试验的理论模拟及影响因素分析

Theoretical simulation and factors for static loading tests on a single pile

应用基于Mindlin位移解的弹性理论法建立了堆载法和锚桩法单桩静载测试过程的理论模拟方法,对两种测试方法进行了对比分析。重点研究了基准桩布置对两种测试方法结果的影响,结果表明:堆载法和锚桩法测试均夸大了单桩刚度,且锚桩法比堆载法更明显;另外,按照现有桩基检测规范进行的桩基测试在一定的条件下对单桩刚度的影响较大。要充分利用压重平台卸荷或锚桩上拔引起基准桩的上抬和测试桩桩身应力引起基准桩的下沉叠加来降低对测试结果的影响。

A method for simulating the static loading test on a single pile is established based on the Mindlin＇s settlement solution, including surcharge loading tests and anchor pile loading tests. The two kinds of test load are compared, and the factors for the test results are analyzed. The influences of arrangement of a bridge with temporary supports or anchor piles on the static loading tests on a single pile are emphasized. The results show that the surcharge and archor pile loading tests exaggerate the pile rigidity, and the exaggeration of the former is less than that of the latter. Additionally the static loading tests according to the Chinese code in some conditions will cause more errors. Therefore the interaction of the uprising of datum piles due to unloading of the bridge with temporary supports or pulling of anchor-pile and lowering of datum piles due to loading of test piles may be fully used to decrease the influences on the results.