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| 后帮有限结合重力坝加高理论与实践 |
| Rear-abutment Limited Integration of Gravity Dam Heightening: The Theory and Practice |
| 投稿时间：2025-02-22 修订日期：2025-05-21 |
| DOI： |
| 中文关键词: 重力坝加高 后帮式 有限结合 新老混凝土结合 等效算法 |
| 英文关键词: Gravity dam heightening Rear-abutment method Limited integration New and old concrete integration Equivalent algorithm. |
| 基金项目:国家重点研发计划项目：（2021YFC3090102）,国家科技攻关计划 |
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| 中文摘要: |
| 后帮式是重力坝加高的主要形式,新老混凝土结合和新老坝块分载是两个关键技术难题。结合丹江口大坝加高开展了一系列包括理论分析、数值模拟、室内试验以及大坝原位试验在内的研究工作,提出了‘后帮有限结合’重力坝加高理论,研发了系列技术并成功应用于丹江口大坝加高。1)揭示了新老混凝土结合面开裂机理,当重力坝加高的后帮混凝土厚度处于年变化气温影响范围时,新混凝土水化热温升温降变形和周期性变化的气温引起的新混凝土 “翘-鼓”变形叠加且受到老混凝土约束,使结合面出现超标拉应力和剪应力,是结合面开裂的主要原因；2)加高后坝体不再是均质、连续的整体结构,传统的材料力学计算方法不再适用,提出了应力和稳定的有限元等效计算方法和控制标准；3)提出了‘加大冷却力度,延长一冷时间,控制最高温度,减小降温范围’的综合温控措施,结合表面保温、新混凝土坝块分缝,可有效降低结合面法向拉应力和坡向剪应力；4)提出了“结合面增强、配置锚筋、切割键槽”的结构增强措施,提高了大坝整体联合承载能力,改善了大坝受力状态。 |
| 英文摘要: |
| : The rear-abutment method is the main form of gravity dam heightening, and the integration of new and old concrete and the load sharing between new and old dam blocks are two key technical challenges. A series of research works, including theoretical analysis, numerical simulation, indoor experiments, and in-situ dam experiments, have been carried out in conjunction with the heightening of the Danjiangkou Dam. The "limited integration of rear-abutment" theory for gravity dam heightening has been proposed, and a series of technologies have been developed and successfully applied to the heightening of the Danjiangkou Dam. 1) The mechanism of cracking at the interface between new and old concrete has been revealed. When the thickness of the rear-abutment concrete in the heightening of a gravity dam is within the range of annual temperature variation, the combined effect of the temperature rise and fall caused by the hydration heat of new concrete and the periodic temperature change, restricted by the old concrete, leads to excessive tensile and shear stresses at the interface, which is the main reason for cracking; 2) After the heightening, the dam body is no longer a homogeneous and continuous overall structure, and the traditional material mechanics calculation methods are no longer applicable. Finite element equivalent calculation methods and control standards for stress and stability have been proposed; 3) A comprehensive temperature control measure of "increasing cooling intensity, extending the first cooling time, controlling the highest temperature, and reducing the cooling range" has been proposed. Combined with surface insulation and crack separation of new concrete dam blocks, it can effectively reduce the normal tensile stress and slope shear stress at the interface; 4) Structural reinforcement measures such as "interface enhancement, anchor bar arrangement, and key slot cutting" have been proposed, which can improve the overall joint load-bearing capacity of the dam and the force state of the dam. |
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