大伙房土坝砂质坝壳抗震设计回顾
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摘要
１９５２ 年设计大伙房水库工程时，对砂质坝壳抗震问题进行了广泛探索。遍阅苏、美、英书刊，进行砂料临界孔隙比试验。确定采用相对密度０－８３ ，以防止砂料液化，用与此相应的干密度和抗剪强度及水平、铅直两向Ⅷ度地震加速度系数进行拟静力法坝坡抗震稳定计算。施工时，为了达到相对密度的要求，研制了重型机械夯板。１９９２ 年，在坝体挖５ 个试坑测原状孔隙率、干密度，在试验室测得平均相对密度０－８１ ，其中２ 个试样相对密度达１－０ ，用共振柱法和动三轴试验测得最大剪切模量、最大阻尼比、剪切模量－ 剪应变关系、阻尼比－ 剪应变关系、动孔隙水压力比－ 动剪应力比关系。进行静力、动力有限元分析结合上述试验曲线得到坝壳坝基液化度等值线和坝坡抗震稳定安全系数时程曲线。Ⅷ度地震时，液化度最高处为０－６ ，安全系数最小为１－０８ ，满足抗震要求。
On the design of Dahuofang hydraulic project during 1952, the problem of anti liquefaction for the sandy shell was extensively researched and learned from foreign reference books. With respect to our laboratory result of critical porosity ratio, we adopted the relative density 0 83 for the sand mass,its corresponding dry density and shear strength were cited in the analysis of slope stability by pseudostatic method, and two directions of earthquake inertia force were applied to this analysis. ln order to compact the sand to meet the relative density mentioned above, we developed the heavy machine tamper. During 1992, 5 exploring pits were dug in the sand shell to determine the undisturbed porosities,dry densities,relative densities and the mean value of relative density for 5 samples is 0 81 with 2 samples valued 1 0. The maximum shear modulus,maximum damping ratio,the relationship between shear modulus vers shear strain, damping ratio vers shear strain ,dynamic pore water pressure vers dynamic shear stress were determined by resonance column and dynamic triaxile tests. The static and dynamic stresses and strains of the dam were computed by FEM. The contours of liquefaction degree and the seismic safety factor graph were shown in the paper. The conclusion is: when earthquake with intensity Ⅷ occurs, the maximum liquefaction degree is 0 6,the minimum safety factor is 1 08.
On the design of Dahuofang hydraulic project during 1952, the problem of anti liquefaction for the sandy shell was extensively researched and learned from foreign reference books. With respect to our laboratory result of critical porosity ratio, we adopted the relative density 0 83 for the sand mass,its corresponding dry density and shear strength were cited in the analysis of slope stability by pseudostatic method, and two directions of earthquake inertia force were applied to this analysis. ln order to compact the sand to meet the relative density mentioned above, we developed the heavy machine tamper. During 1992, 5 exploring pits were dug in the sand shell to determine the undisturbed porosities,dry densities,relative densities and the mean value of relative density for 5 samples is 0 81 with 2 samples valued 1 0. The maximum shear modulus,maximum damping ratio,the relationship between shear modulus vers shear strain, damping ratio vers shear strain ,dynamic pore water pressure vers dynamic shear stress were determined by resonance column and dynamic triaxile tests. The static and dynamic stresses and strains of the dam were computed by FEM. The contours of liquefaction degree and the seismic safety factor graph were shown in the paper. The conclusion is: when earthquake with intensity Ⅷ occurs, the maximum liquefaction degree is 0 6,the minimum safety factor is 1 08.
引文
1 Koppejan K W ,Wamelen B M,Weinberg LL.Coastalflow slides inthe Dutch Province of Seeland ,In :Proc 2th ICSMFE.Rotterdam ,Netherland ,1948 ,Ⅴ
2 Hazen A. Hydraulic fill dams . Transactions , ASCE,1920 ,83
3 Middlebrooks T A. Fortpeck slides . Transactions , ASCE,1942 ,107
4 Terzaghi K, Peck R.Soil mechanics in engineering practice . NewYork :John& Wiley ,1948
5 Geuze E. Critical density of some dutch sands .In : Proc 2th ICSMFE.Rotterdam ,Netherlands ,1948 ,Ⅲ
6 Гольдштейн M H. Вoпpocыгеотехники. Государственноеиздательстволитературы. Москва,1953
7 Телегин M Я. Методы уплотнениядорожныхнасыщей.Издательстводорожно- техническойлитературыГушосдора.Москва,1952
8 顾淦臣.土石坝地震工程.南京:河海大学出版社,1989 .166～183
9 Seed H B,Knneth L L,Faiz IB. Dynamic analysis ofthe slide inthe Lower San Fernando Dam during the earthquake ofthe February9 ,1971 .In :Proc ASCE.1975 ,101(GT9)
10 The Com mittee on Soil Dynamics of the Geotechnical EngineeringDivision . Definition ofterms related to liquefaction .In :Proc ASCE.1978 ,104(GT9)
11 Seed H B.A method for earthquake resistant design of earth dams .In :Proc ASCE.1966 ,92(SMI)
12 Huang Wenxi.Investigation on stability of saturated sand foundations and slopes against liquefaction .In : Proc of 5th ICSMFE.1961 ,2
2 Hazen A. Hydraulic fill dams . Transactions , ASCE,1920 ,83
3 Middlebrooks T A. Fortpeck slides . Transactions , ASCE,1942 ,107
4 Terzaghi K, Peck R.Soil mechanics in engineering practice . NewYork :John& Wiley ,1948
5 Geuze E. Critical density of some dutch sands .In : Proc 2th ICSMFE.Rotterdam ,Netherlands ,1948 ,Ⅲ
6 Гольдштейн M H. Вoпpocыгеотехники. Государственноеиздательстволитературы. Москва,1953
7 Телегин M Я. Методы уплотнениядорожныхнасыщей.Издательстводорожно- техническойлитературыГушосдора.Москва,1952
8 顾淦臣.土石坝地震工程.南京:河海大学出版社,1989 .166～183
9 Seed H B,Knneth L L,Faiz IB. Dynamic analysis ofthe slide inthe Lower San Fernando Dam during the earthquake ofthe February9 ,1971 .In :Proc ASCE.1975 ,101(GT9)
10 The Com mittee on Soil Dynamics of the Geotechnical EngineeringDivision . Definition ofterms related to liquefaction .In :Proc ASCE.1978 ,104(GT9)
11 Seed H B.A method for earthquake resistant design of earth dams .In :Proc ASCE.1966 ,92(SMI)
12 Huang Wenxi.Investigation on stability of saturated sand foundations and slopes against liquefaction .In : Proc of 5th ICSMFE.1961 ,2
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