共查询到18条相似文献,搜索用时 171 毫秒
1.
2.
特高拱坝真实温度荷载及对大坝工作性态的影响 总被引:1,自引:1,他引:0
特高拱坝实际温度荷载与设计温度荷载在初次蓄水期有较大差别:一是承担封拱后温度回升荷载的结构形式不同,封拱后的温升仅作用于封拱之后的部分坝体而不是整体大坝;二是实测库水温与预测库水温不同,中下部高程实测库水温明显高于设计库水温。本文以二滩和小湾特高拱坝为例,研究设计温度荷载与真实温度荷载差异对特高拱坝的影响,并分析了真实温度荷载作用下小湾拱坝受力情况。结果表明,考虑坝体温度回升分层施加过程时,坝踵部位明显呈受压趋势;目前常用的库水温预测方法会低估坝体上游面受压程度。考虑真实温度荷载后得到的小湾拱坝坝踵应力结果与监测结果规律一致,数值相近,结果更为准确。 相似文献
3.
4.
基于多拱梁分载法的高拱坝应力分析 总被引:1,自引:0,他引:1
高拱坝的破坏与安全问题越来越受到人们的重视.针对这个问题,结合小湾拱坝实际工程情况,运用多拱梁法进行了应力应变的计算和分析,讨论封拱过程和蓄水过程对高拱坝位移和应力计算的影响;以找出更接近实际的更安全可靠的高拱坝应力分布情况,为大坝可行性评价、坝体封拱及蓄水过程提供理论依据. 相似文献
5.
6.
用有限元模拟拱坝坝体、非连续接触单元模拟坝肩,计算了在设计地震荷载作用下小湾拱坝坝肩残余位移和坝体应力。以拉应力达到坝体混凝土抗拉强度为控制标准,得出坝肩岩体的动力稳定安全系数。计算结果表明,小湾拱坝坝肩仍具有一定的安全度。 相似文献
7.
8.
在高混凝土重力坝坝体变形和应力状态数值分析中,是否考虑混凝土分层浇筑过程和分步施加自重荷载对其计算结果有重要影响。利用有限元分析软件ANSYS的单元生死功能,模拟大坝浇筑过程,分步施加自重荷载,得到施工期坝体的变形和应力状态,并与一次性施加自重荷载方式的计算结果比较,研究混凝土分层浇筑对坝体变形和应力的影响。结果表明,一次性施加自重荷载的方式使坝体倾向上游的变形增大,坝踵压应力和坝趾拉应力增大;而考虑混凝土分层浇筑过程得出的坝体变形和应力结果更加符合实际。 相似文献
9.
自重工况一般是高拱坝内廊道配筋设计的控制工况,由于高拱坝施工过程的特殊性及复杂性,有限元计算中自重有多种施加方式。结合工程实例,对高拱坝基础廊道结构进行三维有限元分析,比较不同自重施加方式对廊道结构应力及配筋的影响。研究结果表明:按整体自重考虑时,廊道结构应力及配筋面积明显偏小;全部按分缝自重考虑时,廊道结构应力及配筋面积明显大于按施工过程考虑自重的结果;为符合实际施工过程及结构承载规律,保证结构安全及经济合理,在拱坝结构的有限元计算中应按照施工过程考虑自重荷载。该研究成果对泄洪孔结构的应力分析也具有参考价值。 相似文献
10.
基于溪洛渡拱坝初期蓄水期540 m、560 m、580 m、600 m四个不同特征水位坝体各类监测资料的分析,借助三维有限元商业软件对大坝施工形象面貌、蓄水进度计划进行仿真模拟及数值分析计算,对蓄水期拱坝工作性态进行反馈分析、预测及安全评价,进而为拱坝运行期蓄水提供决策参考。数值模拟及反馈分析计算表明:不同特征水位阶段下,坝体及坝基变位合理、变形协调,坝体应力处于设计可控范围之内,灌后横缝均处于压缩状态,其变位、应力分布均符合拱坝整体受力特性。初步判断:溪洛渡拱坝在库水位初次蓄至正常蓄水位600 m高程的各阶段安全可靠受控,处于正常工作状态。 相似文献
11.
混凝土拱坝施工过程中,结构体系的转变、坝体材料性质的变化和外荷载的变化,对拱坝应力和横缝状态具有一定的影响,为此,采用有限元方法,考虑横缝的接触非线性,模拟了分期封拱灌浆过程和提前蓄水过程,并对某高拱坝施工期温度场、应力场和灌浆前横缝开度变化作了较为全面的计算预测分析。分析认为,水管冷却过程及冬季上游蓄水时可能产生较大拉应力,值得引起注意,另外还得到了缝宽在拱圈方向的分布规律。 相似文献
12.
以原型监测数据为基础,采用综合对比分析、FLAC3D数值计算、逐步回归、人工神经网络等多手段相结合的方法,对小湾特高拱坝坝肩抗力体蓄水初期变形特性进行分析和评价。定性分析成果表明,截至1160 m高程库水位,坝肩抗力体在蓄水过程中变形量级非常小,随着水位的上升,坝肩抗力体整体上微微有向下游和向山体内变形的趋势,且变形逐渐收敛。基于有限元计算成果、实测值的混合模型分析成果表明,库水位是分析时段内引起抗力体变形的最主要因素,在1160 m蓄水位条件下,抗力体处于稳定状态。根据模型预测1170 m水位工况条件下,抗力体变形也将处于可控状态。 相似文献
13.
高拱坝的开裂与体形优化 总被引:5,自引:0,他引:5
通过对小湾拱坝的弹性有限元计算,分析了坝踵区在拉应力作用下裂缝出中能性,进而描述了进行拱坝开裂分析所采用的裂缝模型,并给出了小湾拱坝出现裂的可能范围以及坝踵区应力变化的非线性有限元计算成果,讨论了开裂约束条件下拱坝体型优化的数学模型及强度控制指标和开裂深度控制指标。 相似文献
14.
15.
《水科学与水工程》2016,(3)
To study the stress, deformation, and seepage pressure during the initial impoundment of the Jinping-I Arch Dam, monitoring analysis and numerical calculation were used in a dam behavior analysis that focused on the working behavior of the dam during the late period of the initial impoundment up to the end of November 2014. The numerical calculation was performed based on feedback analysis of the deformation and stress of the arch dam through inversion of the elastic moduli(E) of the dam body and foundation, using a three-dimensional finite element model for the linear elastic material of the arch dam. The main monitoring indices presented insignificant changes in the late period of the initial impoundment, and the results of feedback analysis were consistent with monitoring results. Analysis results also show that the deformations of the dam body and dam foundation were within the design range; the dam stress distributions were normal, with values lower than the design control criteria; and the seepage flows through the dam body and dam foundation were lower than the design drainage capacity of the deep-well pump house, demonstrating that the Jinping-I Arch Dam was in good working condition, and the initial impoundment had been successfully completed. The results of the working behavior analysis of the Jinping-I hydropower project during the initial impoundment can provide references for safe operation of similar projects. 相似文献
16.
17.
18.
Reinforcement quality evaluation at the abutment is an important research direction. Prototype monitoring and theoretical derivation were integrated to study the replacement reinforcement quality in abutment contact zones of the Xiaowan ultra-high arch dam. The principles of monitoring layout and design are introduced in detail. Prototype monitoring shows that the increment of the interfacial compressive stress is much larger in the impoundment stage than in the regulating stage. The water pressure and time-effect are two main factors affecting the interfacial stress. The time-effect is the key factor in the initial impoundment stage, and the water pressure is the key factor after impoundment. The contact properties are significantly improved by grouting. This study shows that there are three typical stages in the joint opening hydrographs, namely the compression stage, opening stage, and stable stage. There is a nonlinear relationship between the joint opening and temperature, which can be well described by the S-function. In conclusion, the reinforcement effect is satisfying, and the abutment is safe. 相似文献