尼山和波太基山两座高土石坝渗透破坏原因分析结果的异议

Disagreement on Analysis Results about Cause of Seepage Failure of Mud Mountain and Portage Mountain Embankment Dams

波太基山和尼山两座高土石坝心墙渗透破坏原因分析结果颇受国内外工程界所重视。有些学者认为,土料中小于0.005mm颗粒含量小于10%是主要原因,高土石坝防渗土料中小于0.005mm的颗粒含量应保证大于10%。本文分析结果认为,尼山坝渗透破坏原因主要是反滤料过粗,无法阻止心墙土料的管涌破坏。波太基山大坝渗透破坏原因是,目前反滤层的设计方法尚不适合用于砾石或碎石土出现裂缝后保证裂缝自愈的条件,今后需进一步开展这类土的反滤层设计准则的研究。对100m高度以上已建土石坝的资料统计结果表明,心墙土料中80%以上是碎石或碎石土,其中有60%的土料小于0.005mm颗粒含量的平均值不大于10%,并且95%以上的高坝都在正常运行。20世纪50年代以后土石坝在高山峡谷中迅速发展,得益于砾石土的广泛使用,更得益于小于0.005mm颗粒含量不大于10%的砾石土的广泛使用。

The seepage failure of Mud Mountain and Portage Mountain embankment dam cores is deeply focused by the engineering field all over the world. Some scholars think the main cause is that the pereentage of particles in the core soil material, which are smaller than 0. 005 millimeter,is less than 10%, this percentage in high earth - rock dam impervious material should be more than 10%. However, in this article, it is believed the main causing of the seepage failure is that the filter material is too coarse that it can not prevent the core dam from piping. The analysis of the Porage Mountain dam indicates that the design of the filter can not make the gravel soil self - healed after cracked, and the design method need be improved. The statistics of the constructed earth - rock dams with the height above 100m indicates 80% of the core walls are made of soil gravel,and 60% with the particles smaller than 0. 005 milimeter is less than 10% ,and 95% dams are safe. 1950s,high earth -rock dams are quickly developed in the deep canyons. It mainly benefit from the widely use of the gravel soil material, to be exact, the gravel soil material with particles smaller than 0. 005 milimeter less than 10%.