Investigation for the key technologies of ultra-high asphalt concrete core rockfill dams |
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Authors: | Jun Gao Faning Dang Zongyuan Ma |
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Affiliation: | School of Civil Engineering and Architecture, Xi’an University of Technology, No. 5 South Jinhua Road, Xi’an, Shaanxi 710048, PR China;State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi’an University of Technology, No. 5 South Jinhua Road, Xi’an, Shaanxi 710048, PR China |
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Abstract: | The mechanical characteristics of ultra-high asphalt concrete core rockfill dams (UACCRDs) at different periods is investigated via Rankine’s earth pressure theory, and a shear safety control standard for UACCRDs is proposed. The reasonable material parameters of the asphalt concrete core (ACC) and transition material that independently and comprehensively satisfy the shear safety control standard are back-calculated. The engineering measures that reduce the stress level (shear stress) of the ACC are given. Moreover, the engineering measures (straight asphalt concrete core rockfill dams (SACCRDs) are designed as curved asphalt concrete core rockfill dams (CACCRDs)) that reduce the tensile stress of the ACC are proposed. Based on the theory of the straight beam and curved beam on Winkler elastic foundation, the simplified mechanical models of straight asphalt concrete core (SACC) and curved asphalt concrete core (CACC) are established. The improvement effect of CACC that reduces tensile stress is also investigated. The results show that the following value ranges of the internal friction angle, cohesion of ACC and the internal friction angle of transition material for the suitable construction of UACCRDs are recommended: φa ≥ 30.5°, Ca ≥ 0.25 MPa and φt ≤ 43.5° (h = 200 m), with the growth gradient adjusted by 0.5%, 1.5% and ?0.5%/25 m. The stress level of ACC can be obviously reduced by increasing the internal friction angle and cohesion of ACC, and reducing the internal friction angle of transition material. The simplified mechanical models of SACC and CACC can estimate the force and deformation characteristic of the ACC (SACC and CACC) well. The CACC can significantly reduce tensile stress to a level approximately 42.8% lower than that of SACC. |
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Keywords: | Corresponding author at: School of Civil Engineering and Architecture Xi’an University of Technology No 5 South Jinhua Road Xi’an Shaanxi 710048 PR China Asphalt concrete core rockfill dams Rankine’s earth pressure theory Stress level Straight asphalt concrete core Curved asphalt concrete core Beam on Winkler elastic foundation |
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