论文部分内容阅读
提出了两种在作二维线弹性问题有限单元分析时根据区域内部应力方向观测结果反演区域边界作用力的方法,即约束反演法和应力张量拟合法.用边界受力的圆盘问题对方法的有效性作了检验.应用所提出的反演方法,根据中国东部及附近地区的主压应力轴方向观测结果,采用二维线弹性有限单元模型,反演出了周围板块边界作用力的相对大小.结果表明,为了在总体上拟合观测资料,菲律宾海板块沿琉球岛弧对中国东部的挤压力不可能太大;台湾地区受到的指向北西方向的挤压力很强;太平洋板块向北西西方向的挤压与北部西伯利亚地台的抵挡,二者的联合作用可以成为我国华北和东北地区主压应力轴取北东东方向的原因.在反演出的边界力作用下,长江流域和东南沿海之间出现一片低剪应力区,正好与少震区的位置大体一致.
Two methods are proposed to invert the regional boundary force according to the observation results of the internal stress direction in the finite element analysis of two-dimensional linear elastic problems, namely the constrained inversion method and the stress tensor fitting method. The validity of the proposed method is tested.According to the results of the principal compressive stress axis in eastern China and the surrounding area by using the proposed inversion method, the 2D linear elastic finite element model is used to inverse the boundary force The results show that in order to fit the observed data in general, the compression of the Philippine Sea plate along the Ryukyu Island arc to eastern China is unlikely to be too large. In Taiwan, the crushing force to the NW is strong. The compression of the plate to the northwest and west and the resistance of the northern Siberian platform can be the reason why the main compressive stress axes in North China and Northeast China take the NE direction. Under the action of the inverted boundary force, A low shear stress zone between the basin and the southeast coast coincides with the location of the small earthquake zone.