柔性基础下复合地基工作性状的正交法分析

Behavior analysis of composite ground with flexible foundation using orthogonal test

为研究柔性基础下桩体复合地基的工作性状及其影响因素,基于能够考虑该种复合地基系统上下部共同作用、桩土界面上有相对滑移、同深度处桩间土沉降不等的解析解,通过正交试验方法,对与系统荷载传递规律密切相关的桩土应力比、中性面位置和相关影响因素开展分析。正交分析结果表明:桩土应力比、中性面位置的均值分别为9.73和0.655,其可靠度为95%的置信区间分别为5.075～30.162和0.554～0.756,系统中各影响因素对荷载传递规律的影响程度存在差异,且各影响因素之间存在不同程度的相互作用,其中垫层模量、下卧层模量、桩间土模量对桩土应力比和中性面位置均有显著的影响,故必须重视对系统上下部共同作用的深入研究。

The pile-soil stress ratio,neutral plane position and impact factors which were closely related to the systemic load transfer law were studied using orthogonal test method,and based on the analytical solution considering the interaction between upper and lower parts of the composite foundation system with flexible foundation,the relative slippage on pile-soil interface and different settlement of the soil between piles on the same level plane were analysed.Orthogonal analysis shows that the averages of pile-soil stress ratio,neutral surface location are 9.73 and 0.655 respectively,while the corresponding 95% confidence intervals are 5.075 to 30.162 and 0.554 to 0.756 respectively.Each factor in the system has different influences on load transfer law,and different degree of interaction on other factors.Modulus of cushion,substratum and soil between piles have appreciable impact on both pile-soil stress ratio and neutral plane position.Hence further research on the interaction between upper and necessary should be paid attention to lower parts of the system.