褶皱构造应力场及其演化

为了弄清褶皱构造形成过程中应力场的分布及动态演化状况,运用弹性力学理论对褶皱构造形成过程中的应力场进行了分析并对其动态演化进行了探索。通过分析给出了单一岩层褶皱启动时应力场的解析式;根据解析式求出了褶皱波长与岩层厚度、刚度模量之间的关系,从而揭示了褶皱等距性的成因;同时研究了褶皱驱动应力与岩层厚度、刚度模量以及褶皱波长之间的关系,从而指出褶皱作为"古地应力记录仪"用以测量古地应力的可能性。通过对不同结合状态复合岩层的分析,揭示了平行褶皱、相似褶皱、不协调褶皱的成因;在单一岩层褶皱启动时应力场解析式的基础上,提出了能体现褶皱应力场演化状况的解析式并做了部分求证,进而对褶皱应力场的演化做了分析。

STRESS FIELD OF FOLD STRUCTURE AND ITS EVOLUTION

The theory of elastic mechanics is applied to find out distribution and dynamic evolution of stress field in the forming process of fold structure. The analytical expression of stress field when a single fold starts is deduced, through which the relationship between fold wavelength and the thickness and stiffness modulus of rock formation is obtained, and the cause of fold equidistant distribution is revealed. The relationship between fold driving stress and rock layer thickness, stiffness modulus and fold wavelength is obtained, and the possibility of fold as "paleogeostress recorder" to measure paleogeostress is proposed. Based on analysis of the composite strata in different binding states, the causes of parallel fold, similar fold and incongruous fold are revealed. According to the analytical expression of the stress field when a single fold starts, an analytical expression reflecting the evolution of fold stress field is proposed and partially verified, and then the evolution of the fold stress field is analyzed.