摘要
当前国内外尚无测定三维古构造应力场的理想方法 .提出了一种新方法 :从待测地点取大岩心或新鲜石块 ,从 6个以上方向取岩石试样 ,每方向至少 10个试样 ,以声发射的广义抹录不净现象 ,测定岩石经历的各主要构造运动期的最大主应力值 .而后 ,统计出岩石记忆的最高古应力状态的最大主应力值σmt.由于岩石对最高古应力状态在各取样方向的正应力σmn尚有记忆 ,只不过隐藏于各期较低古应力状态的最大主应力值之间 ,不易区分 ,故以σmt为目标 ,通过“AE反演搜索法” ,则可将隐藏的各σmn搜索出来 ,从而计算出岩石经历的最高古应力状态 .以准平面应力状态模拟实验检验了该新方法的可行性 .
Until now there has been no perfect method for the determination of three-dimensional paleotectonic stress field. In this paper, a new method for this determination is shown in the following steps: Firstly, rock specimens are drilled in six or more different directions out of the large rock cores or fresh rock blocks in the testing site. For each direction, ten or more specimens should be obtained. Secondly, the maximum principal stresses of the main tectonic movements experienced by the rock specimens to be measured are determined by means of the “Acoustic Emission Incomplete Erase Phenomenon in the General Sense”. Thirdly, the maximum principal stress value (σ mt) of the highest paleotectonic stress state left in the rock specimens is obtained via statistical analysis. It has been found that the rock specimens still contain the normal stresses (σ mn) induced by the highest paleotectonic stress state in different sampling directions. However, these normal stresses are hidden between the maximum main stress values induced by the relatively low paleotectonic stress states in different phases, so that they are not easy to differentiate from each other. In this paper, these hidden normal stresses σ mn can be located by means of the “AE inversion searching method” with σ mt as a target. Therefore, the highest paleotectonic stress state experienced by the rock specimens can be calculated. The feasibility of this new method has been confirmed by a simulation experiment in the pseudo-plane stress state.
出处
《地球科学(中国地质大学学报)》
EI
CAS
CSCD
北大核心
2001年第1期99-104,共6页
Earth Science-Journal of China University of Geosciences
基金
国家自然科学基金资助项目! (No .495 72 14 4 )