巴基斯坦卡洛特水电站上第三系软弱夹层研究

Research on weak interlayers in Upper Tertiary of Karot Hydropower Station in Pakistan

巴基斯坦卡洛特水电站坝址岩体为上第三系软岩,发育软弱夹层,按性状可分为破碎夹层、破碎夹泥层及泥化夹层。研究不同类型的软弱夹层特性、分布及形成机制,可为水电站坝型选择、枢纽布置、洞室围岩稳定分析等提供地质依据。在对软弱夹层采用电子显微分析、岩矿鉴定、化学成份分析、软弱夹层分布统计等综合分析的基础上,对其形成机制及成因进行论述。由软弱夹层的形成机制分析得出,坝址区软弱夹层的形成是多种因素综合作用的结果:破碎夹层主要形成于早期构造作用,后期经历卸荷、蠕变、风化和地下水溶液作用形成泥化夹层。研究成果可供类似工程研究借鉴。

There are soft rock mass in the Upper Tertiary in the dam region of the Karot Hydropower Station in Paki⁃stan and weak interlayers developed in this region,which can be divided into broken intercalation,broken mud layer and muddied intercalation according to their properties.Studies on the characteristics,distributions and formation mechanisms of different types of weak interlayers can provide important geological basis for the selection of dam type,project layout,and the stability of the surrounding rock mass of hydropower station.Based on the comprehen⁃sive analysis of weak interlayers with electron microscopy,rock and mineral identification,chemical composition and distribution statistics,the formation mechanism and cause of the weak interlayers are summarized.Analysis on the formation mechanism of weak interlayers shows that the formation of the weak interlayers were affected by many factors in the dam region.The broken intercalation was formed during the early tectonic process,and after experienc⁃ing unloading,creep,weathering and groundwater corrosion,muddied intercalation was formed in later stages.The study results can be as a reference for similar engineering researches.