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| DOI：10.13522/j.cnki.ggps.2025018 |
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| Thermal stress and control measures in concrete-face rockfill dam construction |
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XIAO Yongtao, HE Yucai, LU Lizhi, LIU Shoujun, SU Jiexun, LI Yu, YAN Fanxin
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1. South to North Water Diversion (Kaihua) Water Service Co., Ltd, Quzhou 324300, China;
2. China South to North Water Diversion Group Water Network Water Investment Co., Ltd, Beijing 100071, China
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| Abstract: |
| 【Objective】Controlling surface thermal stress during the construction of concrete-face rockfill dams (CFRDs) is critical for preventing early cracking in the face slabs. This study investigates the effects of bottom constraints and internal-external temperature differences on thermal stress in CFRDs during their construction.【Method】Based on the Kaihua Reservoir project, a finite element model was developed to simulate temperature distribution and thermal stress of the face slab during different construction periods and schemes. The spatial distribution of surface thermal stress and allowable concreting temperatures were analyzed, from which we evaluated the effectiveness of various control measures in mitigating thermal stress.【Result】Bottom constraints significantly influenced surface thermal stress, with a critical friction coefficient of 0.6. The roller-compacted mortar slope protection method implemented at Kaihua Reservoir ensured that the bottom friction coefficient remained below this critical value, highlighting the importance of construction quality. Under fixed bottom constraints, the temperature difference between the inside and outside of the face slab was the primary factor driving surface thermal stress. Greater internal-external temperature differences led to higher thermal stress, whereas applying maintenance blankets could effectively reduce both temperature differences and stress levels. Thinner face slabs exhibited smaller internal-external temperature differences. Maximum surface thermal stress occurred in the middle to lower sections of the slab, approximately 28-52 meters from the toe board. Under cold wave conditions, the design thermal stress of the face slab remained below the allowable tensile strength.【Conclusion】We propose an allowable concreting temperature for the Kaihua Reservoir face slab. Comparisons show that the results of the proposed method are consistent with on-site measurements, and that its actual temperatures remained below the critical threshold. Ensuring a bottom friction coefficient below the critical value and timely application of maintenance blankets after face slab construction can effectively prevent cracking of the CFRD face slabs. Our results provide design guidance for thermal stress control during construction of concrete-face rockfill dams. |
| Key words: face slab; bottom constraint; temperature difference between inside and outside; thermal stress control measures; allowable concreting temperature; Kaihua Reservoir |
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