A Research of The Applicability of Excavated Soil in e Downstream Shell of Dam

• Main Authors: Guo Chee Don, 郭啟東
• Other Authors: Lin Horn Da
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/73374071965606620174

碩士 === 國立臺灣科技大學 === 營建工程技術學系 === 83 === Applicability of the excavated soft rock for the construction of the downstream shell of Nanhua earth dam is studied considering laboratory test results and its in-situ engineering behavior. Study shows that the differences between the basic properties of the excavated soft rock and the gravelly soil are quite obvious. The excavated soft rock will slake when soaked with water, but the gravelly soil will not. Because mica, which is the major mineral composition the excavated soil, becomes lubricative when meet with water. On the other hand, the gravelly soil is mostly consisted of Quartz. From the compaction tests, the compaction characteristics of the excavated soft rock is even better than that of the gravelly soil. Both the excavated soft rock and the gravelly soils show almost equal shear strength according to the large-scale triaxial tests. The in-situ engineering behavior is studied by the field compaction test, STABR and FEADAM 84 analysis. The results show that field dry density and permeability vary widely because fine-grain of the excavated soil may aggregate when mixed water. So, the upper bound of the water content at compaction designated in the construction criteria is suggested to be reduced by 3%. In addition, throuth mixing is required to prevent material separatation. In reality, slaking is not expected to occure because the excavated soil is used in the downstream shell and is protected by the dam core and filter. According to the results of STABR analyses, slope stability meets the design requirement. Deformation calculated using FEADAM 84 comparies reasionably with the measured deformation of the downstream shell, which is relatively small. Judging from the result of the laboratory tests and the in-situ engineering behavior, the excavated soft rock is a suitable material for downstream shell construction of an earth dam. However, its suitability for upstream shell and dam core construction needs further study.