双核型旋扭构造力学研究

MECHANICAL RESEARCHES ON BINUCLEUS-TYPE TORSIONAL STRUCTURES

本文提出了一种新的旋扭构造类型——双核型旋扭构造。它以具有两个砥柱为特点,区别于单核型旋扭构造。双核型旋扭构造旋回面组合形态最常见的有S形、反S形,其次有椭圆弧形、双曲线形,有时还可见涡轮状等。在野外构造研究基础上,文中提出了绕双砥柱旋扭运动的力学模型。采用流变学原理与方法,得到了这种构造型式的应力场与变形场的伯格斯粘弹性解析解。并进行了模拟实验。理论计算与实验结果表明,所提出的力学模型是合适的。

A new type of torsional structures, binucleus-type torsional structure, is presented in this paper. It is characterised by its two nuclear columns, which differ it from uninucleus-type torsional structure. The nuclear columns are plutons, ring structures, blind nuclear columns or arches. The developed vortical surfaces are mostly of sigmoid and reverse sigmoid forms, with subordinate elliptic and hyperbolic ones, and occasional turbine-like volute surfaces. Four examples of binucleus-type torsional structures are given in the paper. They are found in Liancheng of Fujian, Yegezikala of Xinjiang, Liuyang of Hunan and Leye, Guangxi.Based on field geological studies, a mechanical model, the torsional movement around two nuclear columns, is presented. The analytic solutions of its stress field and deformation field in Burgers viscoelastic medium are obtained as a result of theological investigations. The results of theoretical computation and simulative experiments indicate that the torsional movement around two nuclear columus can form sigmoid, reverse sigmoid, elliptic arc, hyperbolic and turbine-like structures. These are in accordance with the conclusion drawn by structural analysis. It is also considered that the uninucleus-type torsional structure may be taken as a special case of binucleus-type torsional structures.