四川泸定Ms6.8级地震大岗山特高拱坝变形特征分析

大岗山双曲拱坝坝高210 m,坝址位于鲜水河、安宁河和龙门山三条断裂带交汇处附近,其抗震设防加速度为557.5 cm/s²,是世界上抗震设防标准最高的高拱坝。在泸定Ms6.8级地震中,大坝强震监测系统记录到了完整的地震波形,且顺河向最大峰值加速度达到586.63 cm/s²,是目前国内已建200 m级高拱坝中唯一经历近场强震考验的大坝。依据大坝震后变形宏观现象和监测原观数据,对大坝坝体与地基系统变形进行了分析。结果表明：震后大坝整体向下游变形,径向位移增量在-1.53~20.04 mm之间,弦长拉伸增量在15.27~23.50 mm之间,大坝横缝在地震过程中存在开合过程,低高程横缝存在一定残余张开,增量在-0.08~0.46 mm之间,变形整体协调。同时,大坝左右岸坝肩、坝基置换块、大坝与基础等部位存在一定的残余错动,这是导致大坝产生较大残余变形的主要原因,但大坝坝体本身仍处于弹性工作状态,最终在新的平衡位置上保持稳定,表明大岗山拱坝经受住了本次强震考验。相关成果可为震后大坝安全评估、高拱坝抗震设计及研究提供参考。     

梯级水电枢纽群巨灾风险分析与防控研究综述

伴随超标准巨震、极端暴雨洪水、巨型滑坡等灾害频繁发生,极端载荷作用下梯级水电枢纽群的灾害风险分析与防控等问题成为当前水利工程领域的研究热点。为分析梯级水电枢纽群巨灾风险研究现状,绘制了国内外水库大坝溃坝事件的时间序列图,分析了梯级水电枢纽群的风险特征,总结评述了梯级水电枢纽群巨灾风险分析和巨灾防控研究进展,主要结论如下：1)梯级水电枢纽群巨灾风险是我国水利水电工程风险防控面临的主要问题;2)梯级水电枢纽群风险分析方面主要聚焦于梯级水库连溃概率的分析和计算,对于溃决可能产生的巨灾损失的量化研究不足,缺乏对巨灾因子及其相关影响作用下巨灾风险的评估;3)缺乏对梯级枢纽群灾害链的阻断技术研究和应急避险方案设计研究。为此提出了梯级水电枢纽群可能最大灾难(Probable Maximum Disaster, PMD)的科学内涵,考虑可能遭遇的多种致灾因子和承灾体特征,分析相互因果关系和极端荷载组合情况,初步建立了PMD评估的理论模型,为绘制梯级水电枢纽群在巨灾情景下的灾难空间外包线和估算PMD损失上限值提供科学依据,为梯级水电枢纽群巨灾风险分析和防控提供理论基础和技术支持。     

Experimental study on temperature stress calculation and temperature control optimization of concrete based on early age parameters

Temperature control curve is the key to achieving temperature control and crack prevention of high concrete dam during construction,and its rationality depends on the accurate measurement of temperature stress.With the simulation testing machine for the temperature stress,in the present study,we carried out the deformation process tests of concrete under three temperature curves：convex,straight and concave.Besides,we not only measured the early-age elastic modulus,creep parameters and stress process,but also proposed the preferred type.The results show that at early age,higher temperature always leads to greater elastic modulus and smaller creep.However,the traditional indoor experiments have underestimated the elastic modulus and creep development at early age,which makes the calculated value of temperature stress too small,thus increasing the cracking risk.In this study,the stress values of the three curves calculated based on the strain and early-age parameters are in good agreement with the temperature stress measured by the temperature stress testing machine,which verifies the method accuracy.When the temperature changes along the concave curve,the law of stress development is in consistent with that of strength.Under this condition,the stress fluctuation is small and the crack prevention safety of the concave type is higher,so the concave type is better.The test results provide a reliable basis and support for temperature control curve design and optimization of concrete dams.     

土工格栅加筋包边填砂路堤模型试验研究

为探究包边填砂路堤荷载作用下的极限承载力特性、破坏形态规律及加筋性状,设计了土工格栅加筋包边填砂路堤结构,改装美国GCTS公司的USTX-2000动静三轴加载装置进行加载,通过改变加筋层数、筋材布置长度及包边土厚度对土工格栅包边填砂路堤进行一系列试验。对不同工况下包边填砂路堤的极限承载力、封层及坡面法向累积变形、位移变化进行研究。试验结果表明:土工格栅加筋和增加包边土厚度可以显著提高包边填砂路堤的极限承载力,并能减小封层中、封层右及坡顶、坡中的法向累积变形;无筋路堤的滑动面在路堤内呈折线状且并未通过坡脚侵入地基,在坡顶的黏土和砂芯交界处产生最大位移;土工格栅加筋及增加包边土厚度可以使滑动面向路堤内部迁移但形态不变,且最大位移处向路堤内部迁移。     

杨房沟水电站建设质量智慧管理系统的研发及应用

为提高工程管理效率、控制工程质量、减少人为因素对工程质量的影响,利用信息化、数字化、自动控制等技术对施工过程中的信息、混凝土温度、混凝土振捣、灌浆等环节进行智能监控和管理。为此,杨房沟水电站依托设计施工BIM管理系统的质量管理功能模块,以及由BIM系统集成的智能温控、智能振捣、智能灌浆、全过程影像采集系统,研发形成了大坝智能建造环境下的质量智慧管理系统。通过实现施工质量信息“实时采集-实时分析-决策反馈”的动态质量管理,解决了EPC建设模式以及传统大坝质量管理存在的施工质量控制、信息收集、分析、决策等方面的问题,提高了管理效率和管理质量,取得了较好的管理成效。     

沥青混凝土心墙土石坝水力劈裂计算分析

分析了土石坝水力劈裂原理,针对新疆吐鲁番二塘沟沥青混凝土心墙土石坝,选取河床部位最大断面为典型断面,采用有限元法对其进行水力劈裂计算分析,得出:该土石坝心墙任一高程处的中主应力都小于竖向应力,且中主应力和竖向应力都大于水压力。因此,该坝的心墙不会发生水力劈裂。     

Sediment storage and shallow groundwater response to beaver dam analogues in the Colorado Front Range,USA

Enthusiasm for using beaver dam analogues (BDAs) to restore incised channels and riparian corridors has been increasing. BDAs are expected to create a similar channel response to natural beaver dams by causing channel bed aggradation and overbank flow, which subsequently raise water tables and support vegetation growth. However, lack of funding for monitoring projects post‐restoration has limited research on whether BDAs actually cause expected channel change in the Front Range and elsewhere. Geomorphic and hydrologic response to BDAs was monitored in two watersheds 1 year post‐restoration. BDAs were studied at Fish Creek, a steep mountainous catchment, and Campbell Creek, a lower gradient piedmont catchment from May to October 2018. At each restoration site, the upstream‐ and downstream‐most BDAs were chosen for intensive study in comparison with unrestored reference reaches. Monitoring focused on quantifying sediment volumes in BDA ponds and recording changes to stream stage and riparian groundwater. Despite differences in physical basin characteristics, BDA pools at both sites stored similar volumes of sediment and stored more sediment than reference pools. Sediment storage is positively correlated to BDA height and pool surface area. However, BDAs did not have a significant influence on shallow groundwater. The lack of groundwater response proximal to BDAs could indicate that local watershed factors have a stronger influence on groundwater response than restoration design 1 year post‐restoration. Systematic, long‐term studies of channel and floodplain response to BDAs are needed to better understand how BDAs will influence geomorphology and hydrology.     

江垭水电站碾压混凝土重力坝的温度应力分析

为研究温度荷载对江垭水电站碾压混凝土重力坝的影响,以其非溢流坝段为研究对象,建立有限元模型,根据江垭水电站的水温、气温、坝体温度、地基温度等监测资料,计算分析了大坝运行期的温度场,研究了大坝在温度场影响下的应力变化规律.研究结果表明:温度荷载对大坝运行有较大影响,但是大坝仍满足规范设计要求;夏季持续高温时,应避免大坝在高水位下运行;冬季持续低温时,应避免大坝在低水位下运行.     

小湾拱坝应力监测资料分析

小湾水电站以发电为主,兼顾防洪、灌溉和库区水运等.坝址处河谷基本对称,河谷深切呈"V"字型.为深入研究小湾拱坝坝体的动、静工作性态,对小湾拱坝坝体进行应力监测;根据应力监测资料进行徐变应力计算,得到实际应力,然后利用作图、特征值统计等定性时空分析方法推断出大坝应力无明显异常;通过分析统计结果以及压应力变量分离模型得到了应力的统计模型.     

Methodology for estimating probability of dynamical system’s failure for concrete gravity dam简

Methodology for the reliability analysis of hydraulic gravity dam is the key technology in current hydropower construction.Reliability analysis for the dynamical dam safety should be divided into two phases：failure mode identification and the calculation of the failure probability.Both of them are studied based on the mathematical statistics and structure reliability theory considering two kinds of uncertainty characters（earthquake variability and material randomness）.Firstly,failure mode identification method is established based on the dynamical limit state system and verified through example of Koyna Dam so that the statistical law of progressive failure process in dam body are revealed; Secondly,for the calculation of the failure probability,mathematical model and formula are established according to the characteristics of gravity dam,which include three levels,that is element failure,path failure and system failure.A case study is presented to show the practical application of theoretical method and results of these methods.