首页|复杂地质条件处理前后高拱坝施工期倒悬变形研究

复杂地质条件处理前后高拱坝施工期倒悬变形研究

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  • 国家科技期刊平台
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[目的]高拱坝坝址通常面临复杂的地质条件，包括深部卸荷带、节理、裂隙等。深部节理是深部岩体卸荷破裂引起的一种特殊地质缺陷，在自重、温度和混凝土徐变等因素的综合影响下高拱坝的应力分布和变形情况将进一步加大施工期的倒悬变形，不利于高拱坝的工作状态，从而影响到其稳定性和安全性。[方法]采用全坝全过程反馈仿真分析方法，以西南某在建大坝为例，建立大坝复杂地质条件下的精细模型，根据坝体混凝土整体浇筑、封拱灌浆计划，开展对大坝全坝段施工的仿真模拟分析，全面反映温度场、应力场和施工期变形状况，研究了包括Ⅱ级结构面、Ⅲ级结构面和建基面置换块等地质缺陷对倒悬变形和大坝工作性态的影响。[结果]结果显示，高拱坝从坝基开始随浇筑高度的增大，倒悬度不断增大，1/3坝高以下的倒悬变形值较小;在1/3～2/3坝高内产生倾向顺河向上游的倒悬变形，在2/3坝高以上倒悬变形消失，产生顺河向下游方向的变形。全坝全过程仿真计算结果显示，顺河向上游方向倒悬变形的最大值约为20。000 mm，在1/3～2/3坝高间产生;顺河向下游方向变形的最大值约为13。000 mm，在2/3坝高以上产生。同一高程下，上游面至下游面受温度荷载、徐变等综合因素影响，变形波动在3。400 mm范围内，实际安装布置时需考虑此误差对倒悬变形监测的影响，Ⅲ级结构面和建基面置换块对拱冠梁坝段施工期变形影响较小，Ⅱ级结构面(F2、F2-1断层)位于14#坝段下方，对施工期倒悬变形和坝顶下游方向变形影响较大，最大倒悬变形增幅约为4。000 mm，坝顶顺河向下游变形增幅约为7。500 mm。[结论]根据计算结果，在进行施工期变形数据反演时不仅要考虑高拱坝坝体材料的力学参数，也要重点反演Ⅱ级结构面弹性模量和力学参数。
Study on overhanging deformation of high arch dam during construction period before and after treatment of complex geological conditions
[Objective]The site of high arch dam usually faces complicated geological conditions,including deep unloading zone,joint,crack and so on.Deep joint is a special geological defect caused by the unloading rupture of deep rock mass.The stress distribution and deformation of high arch dam are induced under the comprehensive influence of the factors such as dead weight,temperature and concrete creep,and further increase the overhanging deformation during the construction period is not conducive to the working state of high arch dam,thus affecting its stability and safety.[Methods]This paper adopts the feedback simulation analysis method of the whole process of the dam,and takes a dam under construction in southwest China as an example to estab-lish a detailed model of the dam under complex geological conditions.According to the overall concrete pouring and arch sealing grouting plan of the dam body,the simulation and analysis of the construction of the whole dam section are carried out to compre-hensively reflect the temperature field,stress field and deformation during the construction period.The influence of geological de-fects including grade Ⅱ structural plane,grade Ⅲ structural plane and foundation surface replacement block on overhanging de-formation and dam working behavior is studied.[Results]The result show that the overhang degree of high arch dam increases with the increase of pouring height from the dam foundation,and the overhang deformation value below 1/3 dam height is small.The overhanging deformation tends to flow upstream from 1/3 to 2/3 of the dam height,and the overhanging deformation disap-pears above 2/3 of the dam height,Resulting in the deformation in the downstream direction.The simulation result of the whole dam show that the maximum value of overhanging deformation in upstream direction is about 20.000 mm,which occurs between 1/3 dam height and 2/3 dam height.The maximum downstream deformation is about 13.000 mm and occurs above 2/3 of the dam height.Under the same elevation,the deformation fluctuation from upstream surface to downstream surface is affected by temperature load,creep and other comprehensive factors,and the influence of this error on overhanging deformation monitoring should be considered in the actual installation layout.The displacement block of grade Ⅲ structural plane and foundation surface has little influence on the deformation during the construction period of the arch girder dam section.The Grade Ⅱ structural plane(F2,F2-1 faults)is located below the 14# dam section,which has a great influence on the overhanging deformation and the downstream deformation of the dam roof during the construction period.The maximum overhanging deformation increase is about 4.000 mm,and the downstream deformation increase of the dam roof is about 7.500 mm.[Conclusion]According to the calcu-lated result,the mechanical parameters of the dam body and the elastic modulus and mechanical parameters of the second-order structural plane should be considered in the inversion of deformation data during the construction period.

high arch damgeological defectssimulation calculation of the entire dam processoverhanging deformationcon-struction perioddeformation

郑磊、崔腾洲、齐问坛、王海州、张国新、张磊

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中国水利水电科学研究院流域水循环模拟与调控国家重点实验室,北京 100038

华电金沙江上游水电开发有限公司叶巴滩分公司,四川甘孜 626700

高拱坝 地质缺陷 全坝全过程仿真计算 倒悬变形 施工期 变形

国家重点研发计划国家自然科学基金中国水科院科研专项流域水循环模拟与调控国家重点实验室项目华电集团科技项目华电集团科技项目

2018YFC040670351779277SD0145B072021SKL2022ZD05SS120203A0102022SS120203A0322022

2024

10.13928/j.cnki.wrahe.2024.04.008

水利水电技术(中英文)
水利部发展研究中心

水利水电技术(中英文)

CSTPCD北大核心
影响因子：0.456
ISSN：1000-0860
年,卷(期)：2024.55(4)
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