雅砻江普斯罗坝址深部裂缝带成因的探讨

Discussion on the Origin of Deep-fissure Zones at the Site of Pusiluo Dam,Yalongjiang River

雅砻江普斯罗坝址在工程勘探过程中，发现了深部裂缝带，裂缝带位于100～200m深处，与地表有巨厚的完整岩体相隔，产状与该区的一组NE向断裂基本一致；断层物质的最新形成年龄为2．7～9万年，裂缝面上有水平、斜向和上下擦痕，表明深部裂缝带可能是断裂带新活动的结果。断裂新活动所产生的地震波，受到疏松破碎带的阻挡，导致深部裂缝带出现。这一成因机制，在地下核爆炸和岩石动力学的试验观测中有所证实。

The deep fissure zones have been discovered during the engineering investigation at Pusiluo dam-site, Yalongjiang River. The zones, located 100-200 meters beneath the ground, are separated by thick uninterrupted rock mass between the ground gravity unloading zone and the fissure zone. The occurrence of the deep fissure zone is similar to that of a group of NE directional faults in this area. The newest fault gouge was developed 27-90 thousand years ago and had horizontal, oblique, up-down scratches on the fissure surface. All these observable facts indicate that the deep fissure zone was perhaps caused by the recent activity of the faults, which generated seismi waves and created the deep fissure zone when the stress of waves was larger than rock＇ s tensile strength. The genesis of deep fissure zone has been observed in the ground nuclear explosion and rock dynamics experiment.