地应力测量的非弹性应变恢复法及应用实例  

Anelastic strain recovery method to determine in-situ stress and application example

作　　者：王连捷[1] 孙东生[1] 林为人 崔军文[3] 彭华[1] 高禄[4] 王薇[1] 唐哲民[3] 乔子江[1] 

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]Kochi Institute for Core Sample Research,Japan Agency for Marine-Earth Science and Technology(JAMSTEC) [3]中国地质科学院地质研究所,北京100037 [4]中国地质大学(北京)数理学院,北京100083

出　　处：《地球物理学报》2012年第5期1674-1681,共8页Chinese Journal of Geophysics

基　　金：国家科技支撑"汶川地震断裂带科学钻探井中探测"项目(2008wfsd-03);日本学术振兴会(JSPS基盘B海外-22403008)资助

摘　　要：岩芯非弹性应变恢复法是近年来发展起来的比较经济有效的深部地应力测量方法,汶川5.12地震后,我国大陆首次将该方法应用于汶川地震断裂带科学钻的地应力测量.本文简述了该方法的原理、计算方法和汶川地震科学钻一号孔的典型结果.给出了一号孔在所测深度之处的三个主应力的大小和方向.三个主应力中,最大主应力和中间主应力近于水平,最小主应力近于直立.最大主应力方向为北西.在746m深度,三个主应力的大小为25.2MPa,21.5MPa,18.5MPa.这种应力状态可使龙门山断层产生逆冲兼右行走滑运动,与汶川5.12地震的断层运动一致.该方法得到的结果与震源机制解及其他地应力测量方法得到的结果吻合.测量结果表明,非弹性应变恢复法具有较大的实用价值.特别是在较大深度的钻孔和地层较破碎的复杂地质条件下,应力解除法、水压致裂法等难以实施时,此方法仍有可能获得较可靠的地应力数据,适应性更强.The principle and calculation procedures for a lower cost and effective core-based stressmeasurement technique called anelastic strain recovery （ASR） technique are described. And then an example of its application to the hole-1 of Wenchuan Earthquake Fault Scientific Drilling Project （WFSD-1） is shown. Three principal stress magnitudes and directions of the hole-1 at the tested depth were determined. The maximum ol and middle principal stress o2 are nearly horizontal, and the minimum principal stress o3 is nearly vertical. The azimuth of the maximum principal stress is NW. At the vertical depth of 746 meters, the magnitude is 25.2 MPa for ol, 21.5 MPa for o2, and 18.5 MPa for 03. This stress state can be interpreted as the same stress regime to make Longmen Shan fault to generate thrust and dextral strike-slip movement, which is consistent with fault movement of Wenchuan 5.12 Earthquake. The results obtained by ASR can be compared with that by focal mechanism solutions and other stress measurement methods. The example shows that, ASR method has great practical value. Especially in the larger drilling depth and complex geology conditions, stress relief method and hydraulic fracturing method can hardly be implemented, while ASR can obtain reliable data with good adaptability.

关 键 词：非弹性应变 地应力 地震科学钻 汶川地震 

分 类 号：P315[天文地球—地震学] P541[天文地球—固体地球物理学]