双重孔隙流体饱和介质弹性波散射二维IBIEM模拟  

Two-dimensional IBIEM simulation of elastic wave scatteringin double-porous fluid-saturated media

作　　者：刘中宪[1,2] 孙珺 黄磊 赵瑞斌[1] LIU Zhongxian;SUN Jun;HUANG Lei;ZHAO Ruibin(Tianjin Key Laboratory of Soft Soil Characteristics and Engineering Environment,Tianjin Chengjian University,300384 Tianjin,China;School of Civil Engineering,Tianjin Chengjian University,300384 Tianjin,China)

机构地区：[1]天津城建大学天津市软土特性与工程环境重点实验室,天津300384 [2]天津城建大学土木工程学院,天津300384

出　　处：《应用力学学报》2024年第3期708-718,共11页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金项目资助项目(No.51878434);天津市杰出青年科学基金项目资助项目(No.19JCJQJC62900);天津市研究生科研创新项目(No.2020YJSS074)。

摘　　要：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%。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 function of two-dimensional line source in a saturated full space with double pores is derived,and the displacement field and stress field of each scattered wave are given.Based on the verification of numerical accuracy,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 frequencyη≤2)incidence.Compared with dry soil conditions,the hoop stress amplitude is more complicated.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 

分 类 号：P315.9[天文地球—地震学] TU435[天文地球—固体地球物理学]