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我国及邻区的现代构造应力场作为一平面应力问题用有限单元法进行了计算。将本区地壳看成是一不均匀的弹性板,根据各地区杨氏模量E、泊松比v和地壳厚度T的不同,组成12种材料区。全区被分成288个三角形单元。考虑了五种应力和位移边界条件,这些边界条件分别反映了印度洋板块、太平洋板块及菲律宾海板块对我国及邻区施加应力的相对大小。将计算得到的最大剪应力值与强震分布进行对比,将最大主压应力方向与震源机制解的最大主压应力方向进行对比,选择一种和实际符合得最好的边界条件作为可取的模式。结果表明:来自印度洋板块的作用力最大,大约是来自太平洋板块和菲律宾海板块作用力的两倍。
The modern tectonic stress field in China and its neighboring areas has been calculated by the finite element method as a plane stress problem. The crust in this area is regarded as a non-uniform elastic plate. According to the Young’s modulus E, the Poisson’s ratio v and the crustal thickness T in each area, 12 material areas are formed. The whole area is divided into 288 triangular units. Five stress and displacement boundary conditions are considered, and these boundary conditions respectively reflect the relative sizes of the Indian Ocean Plate, the Pacific Plate and the Philippine Sea Plate in applying stress to our country and the neighboring areas respectively. Comparing the calculated maximum shear stress with the strong earthquake distribution, the direction of the maximum principal compressive stress is compared with the direction of the maximum principal compressive stress of the focal mechanism solution, and a boundary condition that best meets the actual condition is selected as the desirable mode . The results show that the forces from the Indian Ocean plate are the largest, about twice as much as those from the Pacific plate and the Philippine Sea plate.