三峡库区泥灰质岩石溶蚀作用的微观研究

泥灰质岩石的岩溶,特别是溶蚀作用研究是岩溶研究的一个薄弱环节,同时又是揭示泥灰质风化岩及残坡积类膨胀 土工程特性和成因的关键。通过对三峡库区三叠系巴东组(T2b)不同溶蚀程度泥灰质岩石样品的扫描电镜图象分析,发现泥 灰质岩石的溶蚀作用导致岩石微观结构变化,这种变化可因溶孔形成使岩石力学强度降低,或大量溶孔或残积土变形引起地 面不均匀沉降、地裂缝、滑坡、崩塌和岩溶塌陷等地质灾害的发生。

THE DISSOLUTION PROCESS WITH MICROSTRUCTURAL VARIATION IN MARLITE IN THREE GORGES RESERVOIR AREA

Knowledge about the dissolution process of the marlite karst is a key to understanding the engineering characteristics and genesis of weathering rocks and their residual-to-diluvial-type expansive soil. However, this line of study has not received enough attentions in karstology research. Through analysis of SEM photos of samples of marlite with different weathering degrees from the Triassic Badong formation(T 2b) in the Three Gorges Reservoir area, the authors found that the dissolution within marlite results in the variation of its micro-structures. Such variation could in turn reduce the mechanical strength of marlite when the dissolution of micro-holes occurs. Furthermore, geo-disasters such as differential subsidence, fissures, landslide, collapse and cave-in could result from the development of large dissolution holes or deformation of residual-to-diluvial-type expansive soils.