巴振宁, 张家玮, 梁建文, 吴孟桃. 地震波斜入射下层状TI饱和场地地震反应分析[J]. 工程力学, 2020, 37(5): 166-177. DOI: 10.6052/j.issn.1000-4750.2019.07.0363
引用本文: 巴振宁, 张家玮, 梁建文, 吴孟桃. 地震波斜入射下层状TI饱和场地地震反应分析[J]. 工程力学, 2020, 37(5): 166-177. DOI: 10.6052/j.issn.1000-4750.2019.07.0363
BA Zhen-ning, ZHANG Jia-wei, LIANG Jian-wen, WU Meng-tao. SEISMIC RESPONSE ANALYSIS OF MULTI-LAYERED TI SATURATED SITE SUBJECTED TO OBLIQUE INCIDENT SEISMIC WAVE[J]. Engineering Mechanics, 2020, 37(5): 166-177. DOI: 10.6052/j.issn.1000-4750.2019.07.0363
Citation: BA Zhen-ning, ZHANG Jia-wei, LIANG Jian-wen, WU Meng-tao. SEISMIC RESPONSE ANALYSIS OF MULTI-LAYERED TI SATURATED SITE SUBJECTED TO OBLIQUE INCIDENT SEISMIC WAVE[J]. Engineering Mechanics, 2020, 37(5): 166-177. DOI: 10.6052/j.issn.1000-4750.2019.07.0363

地震波斜入射下层状TI饱和场地地震反应分析

SEISMIC RESPONSE ANALYSIS OF MULTI-LAYERED TI SATURATED SITE SUBJECTED TO OBLIQUE INCIDENT SEISMIC WAVE

  • 摘要: 滨海地区的天然土体在长期的风化和沉积作用下,其水平模量往往会大于其竖向模量,表现出明显的横观各向同性(TI)饱和特性,目前还很少有针对地震波斜入射下TI饱和场地动力响应问题的研究。将HaskellThomson传递矩阵方法拓展到层状TI饱和半空间,求解了直角坐标系下两相介质的Biot动力平衡方程及孔隙流体运动方程,建立了层状TI饱和半空间传递矩阵,并结合地表边界条件求解了地震波斜入射下层状TI饱和场地自由场的时域反应。该文验证了提出方法的正确性,进而以CNTEWGXE波(0.3 g)作为输入地震动,研究了土体TI性质及饱和特性对场地加速度时程及反应谱的影响。结果表明:层状TI饱和场地和各向同性饱和场地地表的动力响应存在一定差异,TI参数的改变使得场地对地震波产生不同的滤波和放大效应;场地的饱和特性对地表的动力响应有重要影响,饱和多孔介质固液耦合作用对地震波具有削弱作用;地震波斜入射时地表加速度时程及反应谱响应小于其垂直入射时的响应,且入射角度对qP1波入射时的场地影响更明显。

     

    Abstract: Under long-term weathering and deposition, the horizontal modulus of natural soil in coastal areas is often greater than its vertical modulus, showing obvious transverse isotropic (TI) saturation characteristics. However, there are few studies on the dynamic response of TI saturated site. Haskell-Thomson transfer matrix method is extended to a layered TI saturated half space. First, Biot dynamic equilibrium equation and the pore fluid motion equation of two-phase medium in a rectangular coordinate system are solved. Then a layered TI saturated half-space transfer matrix is established. Finally, the time domain response of the free field of a layered TI saturated site under the oblique incidence of seismic waves is solved in combination with surface boundary conditions. The paper verifies the correctness of the proposed method, and then takes CNTWGXE wave (0.3 g) as input ground motion to study the influence of soil TI properties and saturation characteristics on the acceleration time history and the response spectrum of the site. Analytical results show that:the dynamic response of the layered TI saturated site and that of the isotropic saturated site are different, and changes in TI parameters cause the site to have different filtering and amplification effects on seismic waves. The saturation characteristics of the site have an important influence on the dynamic response of the surface, and the solid-liquid coupling of saturated porous media has a weakening effect on seismic wave. The peak values of surface acceleration and response spectrum are less than those of the oblique incidence, and the incident angle has more obvious impact on the site for qP1 wave.

     

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