基于平面波势函数,采用间接边界积分方程法(indirect boundary integral equation method,IBIEM)研究了双孔隙流体饱和介质中弹性波入射下二维孔洞的散射特性.推导得到了双孔隙介质中全空间二维线源动力格林函数,并给出了各散射波的位移场和应力场.在数值精度验证的基础上,以双孔隙二维饱和全空间中孔洞为例,解决了平面P、SV波入射下的地震波散射问题.数值结果表明:双重孔隙介质中的位移幅值、环向应力幅值、孔隙压力变化规律与不同入射波形,入射频率,孔隙率和边界排水条件密切相关,位移幅值在低频(无量纲频率η≤2)入射时出现峰值.环向应力幅值与干土条件相比更为复杂,基质孔压与裂缝孔压的存在增大了双重孔隙饱和介质的能量效应,总体震动趋势大于干土条件,环向应力放大可达62％.
Abstract
The scattering characteristics of a two-dimensional cavity under the incidence of elastic waves in a double-porous fluid-saturated medium are studied by the indirect boundary integral equation method(IBIEM)in this article,which is based on the plane wave potential function.The dynamic Green's func-tion of two-dimensional line source in a saturated full space with double pores is derived,and the displace-ment field and stress field of each scattered wave are given.Based on the verification of numerical accura-cy,the problem of seismic wave scattering under the incidence of plane P and SV waves is solved by taking a cavity in the two-dimensional saturated full space with double pores as an example.Numerical results show that the displacement amplitude,hoop stress amplitude,and pore pressure's changing regulation in dual-porous media are closely related to different incident waveforms,incident frequency,porosity,and boundary drainage conditions.The displacement amplitude peak appears at low frequency(dimensionless frequency η≤2)incidence.Compared with dry soil conditions,the hoop stress amplitude is more compli-cated.The existence of matrix pore pressure and crack pore pressure increases the energy effect of the double pore-saturated site,where the overall vibration trend is greater than that of the site under dry soil conditions,and the magnification can reach 62％.
关键词
双重孔隙饱和介质/弹性波散射/间接边界积分方程法/双孔隙介质动力格林函数
Key words
dual-porous saturated media/elastic wave scattering/indirect boundary integral equation method/dual-porous media dynamic Green's function
维普
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