紫坪铺工程坝区废旧煤洞的分布特征

紫坪铺工程坝区出露地层为三叠系上统须家河组(T33x j)的一套湖相含煤砂页岩地层,属典型的复理式建造沉积,其特点是上下粗细交替有明显的韵律层,横向变化大,标志层不明显。按其成层特点将坝区地层划为15个韵律层。坝区主要发育有F3断层带和层间剪切破碎带L7~L14,主要由煤质页岩组成,内含有煤。当地村民在此开采煤炭的历史在300年以上。废旧煤洞的存在成为了工程的一大隐患,煤洞问题成为工程的主要地质问题之一。系统地对煤洞分布特征进行了研究,从而正确指导了工程处理。

Distribution of Abandoned and Old Coal Mines in the Dam Area at Zipingpu Project

Zipingpu Project dam area foundation rock consists of arenaceous shale with coal of Xujiahe Group of upper Triassic Period,belonging to classical flych sedimentary formation.It is characterized with obvious rhythmic bedding and unclear key bed.The dam area is divided into 15 rhythmic beddings.Fault zone F3 and shear fracture zone L_7~L_(14) are developed in the dam area,most of them are composed of coal shale with coal seam.Local villagers are mining for more than 300 years,so the abandoned and old coal mines are one of main geologic problems.Therefore,distribution of the coal mines is systematically analyzed to guide engineering treatment.