简化平面应变土体模型的精度研究及适用性分析

A study on precision of simplified plane strain model of soil

以严格平面应变解为基础,对简化平面应变土体模型即三个单元Voigt体串联模型的精度进行了研究。在各有关影响因素(如土体剪切模量、密度、剪切波速及结构物截面尺寸等)变化条件下,就两种模型土体作用于结构物交界面上的复刚度的实部和虚部分别进行了对比研究,全面地分析了两种模型复刚度的差异性,并进一步对桩顶受纵向激振力作用下的频域及时域动力响应进行了求解,研究了两种模型下桩顶动力响应的差别。结果表明,对土体复刚度而言,在大多数情况下,简化平面应变模型具有足够的精度,可以满足一般工程应用的需要;对桩顶频域响应和时域响应而言,简化平面应变模型已具有较高的精度,其误差可以忽略,具有很强的工程适用性,为该模型在相关领域的应用提供了坚实的理论依据。

Based on the rigorous plane-strain model,the accuracy of simplified plane-strain model in which the soil is modeled as three Voigt bodies connected in series was studied.Under the change of the relevant factors（such as the soil shear modulus,density,shear wave velocity,cross-section dimensions of structures,etc.）,the constructive studies between the two model were carried on the real part and imaginary part of complex stiffness of the soil-structure interface,the complex stiffness differences of the simplified model and the rigorous one were investigated.Then,the dynamic responses of pile at the top of the pile in the frequency domain and time domain were calculated under the vertical exciting load,and the diffenences of dynamic response between the two model are also studied.From the results of the studies,for the complex stiffness of soil,the precision of the simplified plane-strain model is sufficient to satisfy the needs of general engineering applications;for the dynamic response at the top of the pile in frequency domain and time domain,the simplified model has high accuracy,the error can be ignored,and has a strong engineering applicability.