中科大地球与行星物理学术报告通知-张诗淮

报告地点:教学行政楼706

报告时间:2022-11-25 从 15:00 到 16:30

报告人:张诗淮 (苏黎世联邦理工学院)

报告人简介:

张诗淮,2019年于北京科技大学获岩土工程博士学位,2019年起受瑞士国家科学基金项目资助于瑞士苏黎世联邦理工学院做博后研究。目前主要研究方向为岩石力学及地质力学,具体包括:1)非常规油气储层岩石时效变形及强度特性;2)地壳应力时空演化规律;3)地壳应力评估测试新方法。研究成果发表于Journal of Geophysical Research-Solid Earth, International Journal of Rock Mechanics and Mining Sciences, Rock Mechanics and Rock Engineering等国内外知名期刊。

报告题目:Spatial Stress Variations within a Fault Zone Revealed by Breakout Observations Within an Array of Boreholes in a Granitic Rock Mass

报告内容简介

The in situ stress state within fault zones is technically challenging to characterize. At the Bedretto Underground Laboratory in the Swiss Alps, the breakouts observed in an array of eight inclined boreholes penetrating a major fault zone offer a unique opportunity to characterize the fault-associated spatial stress variations. Synthesizing multiple geophysical logs, natural geological structures intersecting these boreholes are identified, revealing a hierarchy of a major fault zone along with secondary structures. Within the boreholes, breakout rotations occur over multiple scales, spanning individual fractures and the entire major fault zone. Based on the analytical solution of the stress field around a circular borehole and Mohr-Coulomb failure criterion, the observed breakout azimuths are used to invert the orientations and relative magnitudes of the stresses across the fault zone, revealing a decreasingly critical stress state from afar to the fault zone center. Our work provides a workflow to semi-quantitatively estimate the in situ stress variations around fault zones in the absence of direct stress measurements, which is beneficial to a number of scientific and engineering applications.