水平单轴应力与横波反射系数

发布时间：2018-01-08 08:37

本文关键词：水平单轴应力与横波反射系数　出处：《地球物理学报》2016年04期 　论文类型：期刊论文

【摘要】：地球物理勘探中,地下应力的估测是非常重要的.本文利用应力诱导的弱各向异性的各向异性参数,借助已有的具有水平对称轴横向各向同性介质顾及高阶小量的横波反射系数近似公式,针对下介质为各向同性受单轴应力作用情况随应力的增加求取应力精度降低的问题,从横波反射系数近似公式的推导出发,联合SH波与SV波反射系数给出新的改进的单轴应力与横波反射系数的直观表达式;计算并对比了受单轴应力作用的各向同性介质的横波近似和严格的反射系数,并利用理论得到的横波反射系数对应力进行了估值.结果表明,利用改进后横波反射系数与应力的直观表达式,当应力增加时,应力估值精度有了明显的改善,这为利用横波反射数据直观估测应力提供理论依据.
[Abstract]:In geophysical exploration, the estimation of underground stress is very important. In this paper, the anisotropic parameters of weak anisotropy induced by stress are used. With the help of the existing transversely isotropic medium with horizontal symmetry axis and taking into account the high order small quantity, the approximate formula of reflection coefficient of shear wave is obtained. In view of the problem that the stress accuracy decreases with the increase of stress, the approximate formula of the reflection coefficient of shear wave is derived from the problem that the medium is isotropic subjected to uniaxial stress. The reflection coefficient of SH-wave and SV wave is combined to give a new intuitionistic expression of the uniaxial stress and the reflection coefficient of S-wave. The shear wave approximation and strict reflection coefficient of isotropic medium subjected to uniaxial stress are calculated and compared, and the stress is estimated by using the theoretical reflection coefficient. By using the improved expression of reflection coefficient and stress of shear wave, the accuracy of stress estimation is obviously improved when the stress increases, which provides a theoretical basis for the intuitive estimation of stress by using the reflection data of shear wave.
【作者单位】：吉林大学物理学院;
【基金】：国家自然科学基金项目(41474098;41004044;11134011)资助
【分类号】：P631.4
【正文快照】： 1引言地应力在地下是普遍存在的,在地球物理勘探中开展地应力研究具有重要意义.近年来,声弹性理论的发展和应用为地下应力的检测提供了新途径,为从地震数据估测应力提供了新手段.在有限静应力引起的非线性形变上激发小扰动波场是典型的非线性声学中的声弹性问题(Pao et al.,19

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