地质科技通报 (Sep 2021)
Analysis of deformation and stress evolution of thrust structure: A case of Jurassic in east Kuqa Subbasin
Abstract
Thrust structure is a relatively common structural form, and its deformation process from weak to strong and the quantitative distribution of stress are not very clear. This study analyzes the tectonic profile in the eastern part of Kuqa Subbasin, and according to the complexity of deformation, the thrust tectonic activity can be divided into four stages: initial stage, development stage, mature stage, and reformation stage. And it uses the finite element calculation and analysis method to carry out detailed numerical simulation calculation on the different stages of the section. Research suggests that the expansion of the thrust structure is not a simple linear development process, but a process of continuous migration and advancement of the front and rear wings. A simple thrust fold is the initial stage of the thrust structure, and the stress is mainly concentrated on the rear wing; after deformation, it expands to the rear wing and the end area increasing continuously is the development period of the thrust structure, and the stress is mainly concentrated on the end; it expands to the front wing after deformation and the wing range beginning to increase is the mature stage of the thrust structure, and the stress is mainly concentrated on the end and the front wing near the end; the rear wing is tilted, the front wing is vertical, and a large number of new thrust faults developed at the front edge of the front wing are thrust structures; it is the period of thrust structural transformation, and the stress is mainly concentrated on the front edge of the front wing. To clarify the difference in the deformation process of the thrust structure and the distribution range of the stress concentration will lay a good foundation for the prediction of the fracture development position and the abnormal development zone of overpressure in the later stage.
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