摘要
通过对我国红层上兴建水电工程的总结,环境工程地质问题包括:1.工程作用。由于施工爆破引起岩体各种结构面的拉张和开挖基坑卸荷而增大岩体的透水性;基坑开挖临空岩体沿剪切带的水平位移和垂直回弹,而造成岩体结构松弛和力学强度的降低。2.环境水中硫酸盐对混凝土的溶性及对坝基岩体可溶盐和灌浆材料的溶蚀,导致机械管涌,混凝土疏松,剪切带恶化,坝基强度(包括f值)降低。3.软弱夹层——剪切带在水库运行后,长期泡水和在渗水压力作用下而泥化,摩擦系数f值降低,剪切带中易溶物的溶蚀,还有化学管涌和化学淤堵之虞。4.粘土岩的快速风化。由于粘土岩亲水性和大的比表面积,具有失水收缩干裂,再遇水膨胀崩解的快速风化特征,主要因素是受大气的温度和湿度的控制。红层中兴建水利水电工程所产生的环境工程地质问题是可以认识,有规律可循和可预报防治的。
The Experience of hydro-engineering on red rock beds in China is summedup in this paper to present the knowledge of following environmental engineering geologi-cal problems: 1. engineering actions: such as the increasement of rockmass permeability caused by stuctural interface splitting during construtcion explosion or by unloading dur-ing foundation excavation loosening of rockmass structure and decreasement of thestrength caused by horizontal displacement of shearing zone in free rockmass and verticalrebound after foundation excavation; 2. the occurence of mechanical piping, concreteloosening, deterioration of shearing zone, and decreasement of dam foundation strength(including value of f) induced by erosion due to sulphate in surrounding water; 3. thoseweak intercalated layers, i. e. sheared beds, being saturated with water and undergoingthe action of osmotic pressure for a long time after reservoir's operation, will be slurriedwith decreasement of friction coefficient f and with erosion of soluble substance. Chemicalpiping and chemical choking are also concerned; 4. the quick weathering of clay rock.Since the clay rock is of hydrophilic and possesses a large specific surface, it has the quickweathering feature of shrinkage and cracking when dry and expanding and collapsingwhen re-wet with water, while the major controlling factors are temperature and hu-midity of atmosphere. It is possible to define, to analyse and to predict the environmentalengineering geological problems of hydro-engineering on red rock beds and take preven-tive and mitigative measures against them.
出处
《人民长江》
北大核心
1992年第12期9-15,共7页
Yangtze River
关键词
红色地层
水电工程
环境
工程地质
red rock bed
hydro-engineering
environmental engineering geology
