基于扰动状态概念的桩–土相互作用的新荷载渐进性传递模型

A new incremental load transfer model of pile-soil interaction based on disturbed state concept

结合扰动状态理论(DSC),详细地分析了桩–土相互作用的荷载渐进性传递机制,提出基于DSC的荷载传递函数及其参数辨识方法。基于Matlab编程,重点分析了模型参数对τ-s曲线的影响规律。分析结果表明,参数η对桩土界面的强度特性的影响具有决定性作用,反映了桩土界面单元强度分布的集中程度,合理地选取参数η可以较好地描述桩–土界面的硬化、软化及弹塑性特性;参数ξ、τ-f对界面的强度特性影响较小,参数的改变只对最大侧摩阻力值产生影响,ξ、τ-f越大,侧阻力的极值也越大,但对τ_s曲线的线形几乎无影响;参数k对界面强度特性和τ-s曲线的线形都有一定的影响,k越大峰值强度越大,界面强度越高,达到侧摩阻力峰值所对应的界面位移越小。结合依托工程,理论模型计算结果与现场试桩实测值吻合较好,检验了该模型的正确与可靠性,对工程实际具有重要指导意义。

A new incremental transfer model of pile-soil interaction is presented on the basis of the disturbed state concept(DSC), and the load transmission mechanism is analyzed as well. According to the result obtained with Matlab, the influence law of the model parameters to the relationship between tau and s is analyzed. It show that, the parameter eta has a decisive influence on the pile-soil interface strength, reflect the concentration degree of the pile-soil interface element strength distribution, which means that the hardening, softening and elastic plastic characteristics of pile-soil interface can be described by choosing the proper parameter. The parameters xi and tau(f) have relatively smaller influence on interface strength, since the change in the parameters only has effect on the maximum value of shaft resistance. The greater the parameters xi and tau(f), the greater the extreme value of the lateral frictional resistance, but it has little influence on the shape of the tau-s curve. The parameter k can affect both the strength interface and tau-s curve in a certain way, the greater the peak intensity of k, the higher the interface strength, the smaller the interface displacement corresponding to the peak of the lateral frictional resistance. Due to the fact that the theoretical curves agree well with the tau-s curves from static loading test, it has a certain guiding significance on engineering practices.