西南某水电站工程边坡泥化夹层构造形迹成因机理研究

工程区开挖边坡的稳定性受控于地层岩性(含软弱结构面)、向斜构造、微地貌等多种因素。边坡岩体中的层间剪切破碎带、断层破碎带不同程度地赋含泥化夹层,直接影响边坡的岩体结构。然而,工程边坡中泥化夹层却分布不均,是各种破碎带中的弱化带,最危险的潜在滑(弱)面,对重点工程部位的边坡岩体稳定性构成不同程度的安全隐患。因此,寻求其成因机制,优化治理措施,在整个开挖边坡系统中,起着关键性的作用。边坡所发育的煤系地层母岩体经多期强烈的构造挤压与研磨,各种风化的长期作用及地下水不断渗入,形成层间剪切破碎带产出、岩性较为复杂的泥化夹层岩组。枢纽区该泥化夹层岩组在实测地层剖面中,所占比例变化较大(1.77%~27.21%)。针对泥化夹层岩组的成因机理,提出5个成因阶段,对坝区所发育的泥化夹层作X射线粉晶衍射测试,证实其中确含有新(次生)的粘土矿物,为泥化夹层的存在提供强有力的佐证。

Study on formatron of mudding intercalations within an engineering slope at a hydroelectric power station, Southwest China

The stability of excavated slope in the engineering area is controlled by a lot of factors,such as rock properties geological structure,micro-topography etc.The rock mass slope stability is directly influenced by mudding intercalation within the fracture zones and fault zones.However,the mudding intercalations are not homogeneous in the engineering slope.A weak layer in the fracture zones,it is the most potential slip surface in engineering slope and incipient fault in this key project.Therefore,study of its formation and its influence on construction are very important.Because of intense structure compression many times,continuous weathering and ground water seepage later in parent rock of coal,the mudding intercalations were usually formed a along shearing rupture of clay intercalations.At the cross-section graphics in the hub area,the mudding intercalations in the strata ranged from 1.77% to 27.21%.Taking all the geological factors into consideration,five different formation stages are proposed to explain the formation mechanism of these mudding intercalations.The X-ray diffraction analysis on them indicate that there are new clay minerals in mudding intercalations at the dam area.