【摘要】 大地震后发震断裂附近的应力状态是认识和理解地震机理的重要参数。5.12汶川地震后,我国开展了基于地震机理研究的汶川地震断裂带科学钻探项目(Wenchuan Earthquake Fault Scientific Drilling Project,简称WFSD),为研究震后龙门山断裂带附近深部应力状态提供了条件。本文主要介绍适合深部应力测量的非弹性应变恢复法(Anelastic strain recovery method,简称ASR法)的测试设备和流程,并利用ASR法对WFSD-1号钻孔岩心进行了原地应力测量,取得了该钻孔424～1173 m深度范围内7个岩心样品的非弹性应变恢复实测数据,并根据成像测井对岩心进行了定向,确定了原地应力方向,估算了原地应力的大小。WFSD-1钻孔最大主应力的方位为NW69°～NW35°,主应力的大小随深度的增加而增大。更多还原

【Abstract】 The in-situ stress state of seismogenic fault after a strong earthquake is one of the important parameters for understanding the mechanism of the earthquake.The Wenchuan earthquake Fault Scientific Drilling project(WFSD) is a rapid response to the 2008 Ms 8.0 Wenchuan earthquake,which provided the test rock core for recognizing the stress state of the depth of Longmenshan fault on the eastern margin of the Tibetan Plateau.This paper focuses on the measuring instruments and processes of the anelastic strain recovery method(ASR) for the deep in-situ stress measurement.The anelastic recovery strains of seven different deep cores are in the range of 424-1173m in WFSD-1.The direction and magnitude of principal stress were determined and estimated,respectively.The dominant azimuths of maximum principal stress are between NW69° and NW35°,and the magnitude of principal stress increases with the increasing depth.更多还原