局部褶皱对层状地基马蹄形孔洞散射的影响分析  

ANALYSIS OF THE INFLUENCE OF LOCAL FOLDS ON THE SCATTERING OF HORSESHOE CAVITY IN A LAYERED HALF-SPACE

作　　者：李志远[1,2] 钟红 胡志强[1,2] 林皋[1,2] LI Zhi-yuan;ZHONG Hong;HU Zhi-qiang;LIN Gao(State Key Laboratory of Coast and Offshore Engineering,Dalian University of Technology,Dalian,116024,China;Institute of Earthquake Engineering,Faculty of Infrastructure Engineering,Dalian University of Technology,Dalian,116024,China;Earthquake Engineering Research Center,China Institute of Water Resources and Hydropower Research,Beijing 100048,China)

机构地区：[1]海岸与近海工程国家重点实验室,大连理工大学,大连116024 [2]工程抗震研究所,建设工程学部水利工程学院,大连理工大学,大连116024 [3]中国水利水电科学研究院工程抗震研究中心,北京100048

出　　处：《工程力学》2020年第8期237-245,共9页Engineering Mechanics

基　　金：国家重点研发计划项目(2016YFB0201001);国家自然科学基金项目(51979292)。

摘　　要：水平岩层在构造作用下会产生局部褶皱,研究褶皱对层状地基马蹄形孔洞散射的影响,对地表结构地震安全性评价具有重要意义。基于子结构法建立了复杂场地散射问题的控制方程,将地震波散射问题的求解转化具有规则边界条件的层状地基(自由场)的动力刚度和波动响应的求解。通过Fourier变换和引入对偶变量,将波动方程转化为一阶常微分方程,采用精细积分算法对土层可实现高效合并,施加边界条件可得到内部节点的格林函数,进一步得到动力刚度。同时,采用精细积分算法代替原传递矩阵法的层间合并,可得到层状自由场的波动响应。这种改进传递矩阵法对土层厚度和层数没有任何限制。通过与文献中的结果对比,验证了方法的正确性,并分析了局部褶皱对层状地基中马蹄形孔洞散射场的影响。结果表明:局部褶皱对地表位移幅值的影响与入射波类型、入射波频率以及局部褶皱几何构造等因素均有关系;地表位移峰值受马蹄形孔洞和局部褶皱共同作用的影响,其影响特性与入射波类型无明显关系。Due to the tectonic action,the interface of layered rock may be partially folded.The investigation of the influence of irregular interface on the scattering of cavities is of great significance for the seismic safety evaluation of the surface structure.Based on a substructure method,a complex scattering problem is transformed into a radiation problem and the evaluation of wave response of a layered half-space with regular boundary conditions(free field).The Fourier transform and dual variables are used to obtain the first-order ordinary differential wave equation.Besides,soil layers are merged by using the precise integration algorithm and load boundary conditions are applied to obtain the Green's function,and the dynamic stiffness is obtained.Based on a precise integration algorithm,the coefficient matrix of an improved transfer matrix method is proposed,and the wave motion of the layered half-space is calculated.The improved transfer matrix method has no restrictions on soil layer thickness and the number of layers.The accuracy and effectiveness of the proposed method are validated by comparing them with those of the results of the previous study.The scattering effects of horseshoe holes embedded in a complex layered half-space are investigated.The results show that the effect of local folds on the magnitude of surface displacement is related to factors such as incident wave type,incident wave frequency,and local fold geometry.The peak surface displacement is affected by the combined action of horseshoe-shaped cavity and local folds,and its characteristics are not obviously related to the type of incident wave.

关 键 词：土-结构相互作用 地震波散射 人工边界条件 褶皱场地 马蹄形孔洞 

分 类 号：TU470[建筑科学—结构工程]