Abstract: A three dimensional elasto-plastic model was established to explore the mechanical aspects of the India-Asia continental collision by finite element modeling. The results show that the orientations of the principal stresses and the potential faulting types depend on the loading boundary conditions. The push force of the moving India plate results in stress state of thrust and strike-slip types within the Asia continent. The iso-lines of the equivalent stress are characterized by northwest trending arc-form distribution which is consistent with the tectonic feature of west China. The heterogeneity of the model could rise significiant effects on the patterns of the crustal deformation and the stress distribution. The plastic flow in the lower lithosphere and the asthnosphere could make the stress transmitting in the upper lithosphere reach to a much greater extent. The existence of the harder blocks lead to appearance of the relative highstress gradient. For the India-Asia continental collision, the low-angle underthrustingmodel seems to be more reasonable and acceptable than the horizontal indenting model.

Key words: Continental collision, Stress of plate interior, Three dimensional model, Numerical modeling

摘要： 用三维有限单元模型模拟了印度—亚洲大陆碰撞在板内的力学效应。结果表明,印度板块北东方向的推挤力作用在亚洲大陆内造成逆断层和走滑断层型的应力状态,以及北西走向的平行的弧形应力等值线。岩石圈下伏岩层的塑性变形导致地壳变形范围扩大,垂直位移的水平梯度减小,应力传递的水平距离显著增加。在相对坚硬的地盾型构造区边缘,出现应力梯度较高的特征。对比了刚体水平挤入和低角度俯冲这两种大陆聚合模型,计算结果表明低角度俯冲是较合理的模型。

关键词: 大陆碰撞, 板内应力, 三维模型, 数值模拟