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T he S econd Japan-China Joint Seminar. RESEARCH ON SIMILARITY MODEL TEST OF ANCHORAGE OF QINGFENG SUSPENSION BRIDGE. Jiaping Li Yongsheng Li Geotechnical Department of Tongji University. T he S econd Japan-China Joint Seminar. Content. Purpose of the research Background of the project
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The Second Japan-China Joint Seminar RESEARCH ON SIMILARITY MODEL TEST OF ANCHORAGE OF QINGFENG SUSPENSION BRIDGE Jiaping Li Yongsheng Li Geotechnical Department of Tongji University
The Second Japan-China Joint Seminar Content • Purpose of the research • Background of the project • Test scheme • Test results • Conclusions GEO. Department of Tongji University
The Second Japan-China Joint Seminar Purpose of the research? • More and more gravity anchorage have to be built on soft soil • Present designing method assume that the anchorage do not move under the cable load • Does the hypothesis that the anchorage is immovable right in soft soil ? GEO. Department of Tongji University
The Second Japan-China Joint Seminar Back ground (1) • Constructed on the Yongjiang River in NingBo city. • 280 meters long and 41 meters width • Under-ground gravity anchorage (45m×46.5m×28.7m) GEO. Department of Tongji University
The Second Japan-China Joint Seminar Back ground (2) • Dimension: 45m×46.5m×28.7m • Weight : 950000KN • Cable load: 93000KN • Cable angle: 30° GEO. Department of Tongji University
Back ground (3) Vertical section of anchorage structure GEO. Department of Tongji University
scheme (1) The Second Japan-China Joint Seminar Test Type • WWW: No soil improvement, No pit-supporting structure, No soil around the anchorage • YWW : Soil improvement, No pit-supporting structure, No soil around the anchorage • YWY : Soil improvement, No pit-supporting structure, Soil around the anchorage • YYY: Soil improvement, pit-supporting structure, Soil around the anchorage • YYYT: Soil improvement, pit-supporting structure, Soil around the anchorage and considering time effect GEO. Department of Tongji University
scheme (2) The Second Japan-China Joint Seminar Similarity coefficient • geometrical scale λ : 100 • Body force scale ρ:1.325 • pressure scale ξ :132.5 • concentrated force scale ψ:1.325×106 GEO. Department of Tongji University
scheme (3) The Second Japan-China Joint Seminar Similar material • The anchorage is treated as rigid and was made of steel and a kind of red silt was selected to model field soil • Polythene rod and sheet were used to simulated chemical churning pile and pit-supporting structure respectively GEO. Department of Tongji University
scheme (4) The Second Japan-China Joint Seminar Parameters of the Model Test Soil GEO. Department of Tongji University
scheme (5) The Second Japan-China Joint Seminar Loading system GEO. Department of Tongji University
scheme (5) The Second Japan-China Joint Seminar Measurement system Pull gage &Micrometer gage Soil pressure cell GEO. Department of Tongji University
The Second Japan-China Joint Seminar RESULTS GEO. Department of Tongji University
RESULT (1) The Second Japan-China Joint Seminar Displacement of anchorage GEO. Department of Tongji University
RESULT (2) The Second Japan-China Joint Seminar Displacement of front soil GEO. Department of Tongji University
RESULT (3) The Second Japan-China Joint Seminar Base pressure of the anchorage GEO. Department of Tongji University
RESULT (4) The Second Japan-China Joint Seminar Additional stress in front of the anchorage GEO. Department of Tongji University
RESULT (5) The Second Japan-China Joint Seminar Some effects on anch. Disp. • soil improvement adopted in the model test contribute little to the stability of anchorage. • pit-supporting structure contribute to the stability of the bridge anchorage. • surrounding soil greatly boost the stability of anchorage. GEO. Department of Tongji University
RESULT (6) The Second Japan-China Joint Seminar Disp. of anchorage nek vs. time GEO. Department of Tongji University
The Second Japan-China Joint Seminar CONCLUSIONS(1) • When cable loaded, displacement and rigid rotate take place. • Soil in front of anch. uplifts and moves forward, but decrease while increase the distance from the measuring sites • additional stress in sub-soil increases in the forepart while reducing in the back-end. GEO. Department of Tongji University
The Second Japan-China Joint Seminar CONCLUSIONS(2) • Backfill、Pit-supporting structure may improve the stability ,reduce displacement of the anchorage. • Horizontal displacement and settlement of the anch. increase as time moves. But the rate are slowing down. GEO. Department of Tongji University
The Second Japan-China Joint Seminar Thank You ! GEO. Department of Tongji University