应用断层泥石英形貌测龄评价桥基断裂活动性

Application of fault dating by the surface textures of quartz grains from fault gouges to the assessment of fault activity in the foundation area of a bridge

简介了断层泥石英形貌测龄的基本原理 ,并实际应用于润扬大桥桥基断层的年代测定。该大桥原有的断层测龄资料都是利用热释光同位素测年法 ,对同一断层会出现不同测年结果 ,致使设计单位难以决断 ,应用该文提出的方法解决了上述难题。研究成果为大桥区主要断层的活动性评价、场区稳定性评价和大桥合理设计提供了可靠地质依据 ,对以后建在断裂带上的大型工程的断层测龄研究也有着重要的参考价值。

The principle of fault dating by the surface textures of quartz grains from fault gouges is introduced in this paper. The problem of obtainig different ages through dating by the thermoluminescence(TL) method for the same fault and the disputation of fault activity in the area of Run-Yang bridge foundation have been solved by the method presented in the paper. This study provides a geological basis for the activity evaluation of major faults and the assessment of site stability as well as the rational design of the oversize bridge built on the fault zone. And this study will be also valuable for the fault dating of large-scale engineering projects.