底部基座对重力坝强震破坏模式的影响

doi:10.11988/ckyyb.20230447

院报 ›› 2024, Vol. 41 ›› Issue (8): 150-156.DOI: 10.11988/ckyyb.20230447

底部基座对重力坝强震破坏模式的影响

何卫平¹^,²(), 刘聪宇¹^,²(), 乐明锴¹^,², 姚惠芹¹^,²

¹ 三峡大学湖北省水电工程施工与管理重点实验室,湖北宜昌 443002
² 三峡大学水利与环境学院,湖北宜昌 443002

收稿日期:2023-04-25 修回日期:2023-08-24 出版日期:2024-08-01 发布日期:2024-08-13
通讯作者: 刘聪宇(1998-),男,湖北宜昌人,硕士研究生,研究方向为水工结构抗震。E-mail: 2017101230@ctgu.edu.cn
作者简介:
何卫平(1987-),男,河南鲁山人,副教授,博士,研究方向为水工结构抗震。E-mail:heweiping_hwp@126.com
基金资助:
国家自然科学基金项目(51809152)

Influence of Bottom Pedestal on Failure Mode of Gravity Dam under Strong Earthquake

HE Wei-ping¹^,²(), LIU Cong-yu¹^,²(), YUE Ming-kai¹^,², YAO Hui-qin¹^,²

¹ Hubei Key Laboratory of Construction and Management in Hydropower Engineering,China Three Gorges University,Yichang 443002, China
² College of Hydraulic and Environmental Engineering, China Three Gorges University,Yichang 443002,China

Received:2023-04-25 Revised:2023-08-24 Published:2024-08-01 Online:2024-08-13

摘要/Abstract

摘要：

我国西南地区某重力坝工程的左岸非溢流坝段采用独特的方形基座设计,考虑到该地区面临较高强震风险,评估底部基座对重力坝强震破坏模式和极限承载能力的影响十分必要。采用声学单元模拟库水,以弹塑性损伤模型模拟混凝土非线性特征,构建声固耦合-损伤模拟方法,并以Koyna重力坝为算例验证其可行性。随后以带基座坝段和常规坝段为对象,研究基座对重力坝强震破坏过程的影响。结果显示,带基座坝段与常规坝段均在上游折坡、坝踵、下游坝面区域出现破坏。底部基座对重力坝破坏过程的影响有:带基座坝段出现新的破坏区;底部基座有效减弱了坝踵破坏区的深度和面积;带基座坝段在下游坝面的破坏区出现2个发展方向。在抗震极限承载能力方面,常规坝段破坏区贯通对应地震动峰值加速度为0.50g~0.55g,带基座坝段提升至0.55g~0.60g,故底部基座设计提升了非溢流坝段的极限抗震承载能力。

关键词: 混凝土重力坝, 底部基座, 声固耦合-损伤模拟方法, 强震破坏模式, 极限抗震承载能力

Abstract:

A unique square-bottom pedestal has been adopted in the non-overflow sections of a gravity dam in southwest China. Given the region’s susceptibility to severe earthquakes, the influence of the pedestal on the failure mode and the ultimate seismic resistance capacity of the gravity dam is investigated. An acoustic-solid-coupled damage simulation method is proposed with the acoustic element simulating the reservoir water and the elasto-plastic damage model reflecting the nonlinear characteristics of concrete.The feasibility of this method in predicting structural failure modes is verified by analyzing the Koyna gravity dam under the Koyna earthquake. Comparative analyses between the pedestal section and conventional section reveal similar failure areas in the upstream slope, dam heel, and downstream face. Specific impacts of the pedestal include: new failure zones in the pedestal section; effective reduction of depth and area of the failure zone at dam heel; and generation of two development paths in the downstream failure area of pedestal section. According to the criteria of failure area breakthrough, the ultimate ground motion peak acceleration is 0.50-0.55g for conventional section and 0.55-0.60g for the pedestal section. In conclusion, the bottom pedestal enhances the ultimate seismic resistance capacity of the non-overflow dam section.

Key words: concrete gravity dam, bottom pedestal, acoustic-solid-coupled damage simulation, failure mode under strong earthquake, ultimate seismic resistance capacity

中图分类号:

TV312结构动力学

何卫平, 刘聪宇, 乐明锴, 姚惠芹. 底部基座对重力坝强震破坏模式的影响[J]. 院报, 2024, 41(8): 150-156.

HE Wei-ping, LIU Cong-yu, YUE Ming-kai, YAO Hui-qin. Influence of Bottom Pedestal on Failure Mode of Gravity Dam under Strong Earthquake[J]. Journal of Yangtze River Scientific Research Institute, 2024, 41(8): 150-156.

图/表 8

图1 混凝土本构关系与损伤因子

Fig.1 Constitutive relation of concrete and damage factors

图2 Koyna重力坝破坏模拟结果

Fig.2 Simulation of the failure of Koyna gravity dam

图3 重力坝非溢流坝段网格及材料分区

Fig.3 Finite element meshes and material zoning of the non-overflow section of gravity dam

表1 库-坝-地基材料参数

Table 1 Material parameters of reservoir-dam-foundation system

材料区域	密度ρ/ (kg·m^-3)	弹性(体积) 模量/GPa	泊松比 μ	强度/MPa
材料区域	密度ρ/ (kg·m^-3)	弹性(体积) 模量/GPa	泊松比 μ	抗压	抗拉
Ⅰ(C25常态)	2 550	42.00	0.20	26.9	2.69
Ⅱ(C10碾压)	2 550	26.25	0.20	16.2	1.62
Ⅲ(C20碾压)	2 550	38.25	0.20	30.4	3.04
Ⅳ(C25碾压)	2 550	42.00	0.20	37.2	3.72
地基	0	15.00	0.25
库水	1 000	2.07

图4 地面运动加速度及反应谱

Fig.4 Ground motion acceleration and its response spectrum

图5 不同峰值地震动下坝体破坏区分布

Fig.5 Damage zones of gravity dam under different ground motion peak accelerations

图6 破坏区深度及深度指标示意图

Fig.6 Depths and depth indices of damage zones

图7 破坏区深度指标发展过程

Fig.7 Changes in depth indices of damage zones

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底部基座对重力坝强震破坏模式的影响

Influence of Bottom Pedestal on Failure Mode of Gravity Dam under Strong Earthquake

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