Dynamic Risk Assessment Index System for Earth-Rock Dam during Construction

During the construction of earth-rock dam,mutual exclusive construction goals such as quality,safety,progress and cost all have influences on each other,with risk factors being everchanging as the construction progresses.Accurate identification of the risk factors,as well as clearing any possible effect that any risk factors might have on the construction project is the key and foundation to our cooperative control of the construction goals.According to the construction planning of earth-rock dam,the hall3 D structure was used to identify the potential changes of risk factors,and the possible means of any risk factors to interfere with the construction goals.The dynamic risk assessment index system is established by deploying the WBS-RBS(work breakdown structurerisk breakdown structure)method,aiming at the construction goals of earth-rock dam.The case study shows that the index system is very effective at risk management of earth-rock dam during construction,and relatively practicable.

Effect of Seismic Permanent Deformation on Safety and Stability of Earth-Rock Dam Slope

In order to study the effect of seismic permanent deformation on the safety and stability of earth-rock dam, the permanent deformation is considered as the non-design permanent load, and the stress-strain hysteresis curve is also considered when the earth is under cyclic load. The research work can make the calculation results of plastic collapse more accurate by including the effect of the post-earthquake degree of plastic deformation on the stability of the earth-rock dam, and the dam safety factor decreases from 2.50 to 1.90 after the magnitude-8 earthquake. Moreover, the research work will also improve the design of the earth-rock dam under abnormal operating conditions.

Study on life-cycle risk management of high earth-rock dam project

Based on advanced computer technology,internet of things(IOT) technology,project management concept and professional technology and combined with the innovative theories,methods and techniques in earlier hydropower projects,the life- cycle risk management system of high earth- rock dam project for Nuozhadu project was developed. The system mainly includes digital dam,three-dimensional design,construction quality monitoring,safety assessment and warning,etc,to integrally manage and analyze the dam design,constructional quality and safety monitoring information. It realized the dynamic updates of the comprehensive information and the safety quality monitoring in the project life cycle,and provided the basic platform for the scientific management of the construction and operation safety of high earth- rock dam. Application in Nuozhadu earth- rock dam showed that construction safety monitoring and warning greatly helped accelerate the construction progress and improve project quality,and provided a new way for the quality safety control of high earth-rock dam.

一种S波段雷达通信电子战多功能宽带DAM的设计

本文创新性地提出了一种S波段多功能宽带DAM,首先介绍了该型DAM的顶层架构设计,接着介绍了各个功能组成模块的设计过程,最后给出了该型DAM的指标实现情况。该型DAM可以分时实现雷达、通信及电子战功能,最大瞬时带宽可达200MHz,支持任意波形产生,在多功能综合射频系统中具有良好的应用前景。

3个李品种(系)芽需冷量的研究及休眠相关DAM基因的表达分析

【目的】探究3个李(Prunus)品种(系)的芽休眠和需冷量的差异及DAM基因表达与芽休眠的关系。【方法】调查统计了3个李品种(系)需冷量与萌芽率,采用生物信息学的方法对李的DAM基因进行鉴定,并用qRT-PCR对3个品种(系)李的DAM基因在芽的不同休眠阶段表达分析。【结果】7.2℃模型、0~7.2℃模型、犹他模型下“晚熟羌脆李”的需冷量均高于‘羌脆李’和‘脆红李’,且3个需冷量统计模型下‘羌脆李’和‘脆红李’的需冷量相同。鉴定了6个DAM基因(Pd DAM1、Pd DAM2、Pd DAM3、Pd DAM4、Pd DAM5、Pd DAM6),但花芽与叶芽内休眠期与内休眠解除期(需冷区间)高表达基因都为DAM5,且在休眠解除期DAM基因的相对表达量均呈下降趋势。【结论】揭示了3个李品种(系)的花芽与叶芽需冷量的差异,筛选出与休眠解除最相关的DAM基因,结果为李芽休眠及熟期调节提供理论依据。

葡萄休眠相关基因DAMs的克隆分析及对单氰胺的响应

DAM基因是真核生物转录因子之一,在木本果树的芽休眠中起着重要的调控作用,且在不同物种间数量不同。以‘水晶’葡萄为试材,于冬芽休眠期间采集枝条后均匀涂抹2.5%单氰胺,在处理后的不同时间采集冬芽,用于克隆VvDAMs基因序列,对其进行生物信息学和荧光定量分析,并测定冬芽激素含量。结果表明,克隆获得的VvDAM1、VvDAM2和VvDAM3基因的开放阅读框的长度分别为690、696、702 bp,分别编码229、231、233个氨基酸和1个终止密码子,相对分子量分别为25.96、26.76、25.99 kD,理论等电点分别为7.71、10.49、9.10;三者的二级结构形式均呈现α-螺旋>无规则卷曲>延伸链的规律;VvDAM1、VvDAM2、VvDAM3氨基酸序列上有一定的同一性,VvDAM1与欧洲李PsDAM1、VvDAM2与樱桃李PcDAM2、VvDAM3与李PsDAM3之间的同源性均达到98%以上;此外,冬芽休眠解除期间,VvDAM 1、VvDAM 2、VvDAM 3基因的表达量逐渐下降,IAA、GA3+4、ZR的含量和GA3+4/ABA逐渐上升,ABA含量和IAA/ZR逐渐下降,单氰胺处理后使其变化提前且幅度增大,从而使芽提前萌发,为葡萄冬芽破眠、早熟栽培等提供理论依据和实践意义。

Sliding and damming properties of granular debris with different geometric configurations and grain size distributions

Granular debris plays a significant role in determining damming deposit characteristics. An indepth understanding of how variations in grain size distribution(GSD) and geometric configurations impact the behavior of granular debris during the occurrence of granular debris is essential for precise assessment and effective mitigation of landslide hazards in mountainous terrains. This research aims to investigate the impact of GSD and geometric configurations on sliding and damming properties through laboratory experiments. The geometric configurations were categorized into three categories based on the spatial distribution of maximum volume: located at the front(Type Ⅰ), middle(Type Ⅱ), and rear(Type Ⅲ) of the granular debris. Our experimental findings highlight that the sliding and damming processes primarily depend on the interaction among the geometric configuration, grain size, and GSD in granular debris. Different sliding and damming mechanisms across various geometric configurations induce variability in motion parameters and deposition patterns. For Type Ⅰ configurations, the front debris functions as the critical and primary driving component, with energy dissipation primarily occurring through inter-grain interactions. In contrast, Type Ⅱ configurations feature the middle debris as the dominant driving component, experiencing hindrance from the front debris and propulsion from the rear, leading to complex alterations in sliding motion. Here, energy dissipation arises from a combination of inter-grain and grain-substrate interactions. Lastly, in Type Ⅲ configurations, both the middle and rear debris serve as the main driving components, with the rear sliding debris impeded by the front. In this case, energy dissipation predominantly results from grainsubstrate interaction. Moreover, we have quantitatively demonstrated that the inverse grading in damming deposits, where coarse grain moves upward and fine grain moves downward, is primarily caused by grain sorting due to collisions among the grains and between the grain and the base. The impact of grain on the horizontal channel further aids grain sorting and contributes to inverse grading. The proposed classification of three geometric configurations in our study enhances the understanding of damming properties from the view of mechanism, which provides valuable insights for related study about damming granular debris.

DAM中波发射机A/D转换板故障分析和处理

阐述数字幅度调制(Digital Amplitude Modulation,DAM)中波发射机模数(Analog to Digital,A/D)转换原理、A/D转换板主要组成部分及其作用,列举A/D转换板在实际运行中出现的常见故障案例,对常见故障给出分析和处理方法,为今后该板的故障分析和处理工作提供参考。

DAM10KW中波广播发射机维护实操案例分析

本文主要阐述3个DAM10kW中波广播发射机维护实操案例,这些维护案例均来源于实际工作当中,其中每一步的维修理念都是根据发射机的故障现象对照图纸仔细研判,并通过一些测试设备一步一步详细进行的维护经验总结,具有可研性和参考价值。

DAM 10 kW中波广播发射机的技术特点和维护策略

随着我国社会现代化建设进程不断加快,在广播事业发展过程中对中波广播发射机的应用越来越普遍。DAM 10kW中波广播发射机应用了先进的数字调制和功率合成技术,可以有效提高中波发射机的整机效率,工作性能也比较稳定,操作比较方便。本文通过对DAM 10kW中波广播发射机运行原理和优势进行分析,明确了在DAM 10kW中波广播发射机运行过程中的技术特点。并基于技术特点制定了发射机精细化管理策略,以进一步提高发射机的运行稳定性和安全性,避免发射机在运行过程中出现故障问题。

Breach mechanism and numerical simulation for seepage failure of earth-rock dams

In this study,a numerical model,which can capture the full process of the development of seepage passages,the collapse of dams and the failure due to overtopping,is proposed for earth-rock dams.The critical incipient velocity for the occurrence of seepage failure is derived by analyzing the forces acting on soil particles in the seepage passage.The sediment transport formula is proposed to simulate the erosion process and the evolution of breach within the dam.In this model,the grain size distribution,the compaction density and the strength of dam materials are reasonably accounted for.Furthermore,the influences of the direction of seepage paths,the slope of the dam and the velocity of water flow on the amount of erosion are also taken into consideration.The proposed model and the corresponding numerical programs are employed to simulate the development of breaches and discharge of two typical cases due to seepage failure.The development of breaches,the history of discharge and the peak flood flux predicted by the numerical models are rather comparable to the measured data,which confirms the validity of the proposed model and the feasibility of applying the model in evaluating the disaster consequences and preparing the emergency counter measurements in the case of dam collapse.

RESEARCH ON SEEPAGE MONITORING MODEL OF EARTH-ROCK DAM

With the characteristics of seepage flow in earth rock dams, a seepage monitoring model was established based on the finite element method for 3 D seepage flow together with observed data and was used to analyze and monitor the seepage of dams. In order to find out and monitor the seepage status of the whole dam, the separation of seepage amount for dam body, dam foundation and side banks was made theoretically by using the model. Practical example shows that the accuracy of computed results is satisfactory and the separation results are more objective.

Deformation prediction model of concrete face rockfill dams based on an improved random forest model

The unique structure and complex deformation characteristics of concrete face rockfill dams(CFRDs)create safety monitoring challenges.This study developed an improved random forest(IRF)model for dam health monitoring modeling by replacing the decision tree in the random forest(RF)model with a novel M5'model tree algorithm.The factors affecting dam deformation were preliminarily selected using the statistical model,and the grey relational degree theory was utilized to reduce the dimensions of model input variables.Finally,a deformation prediction model of CFRDs was established using the IRF model.The ten-fold cross-validation method was used to quantitatively analyze the parameters affecting the IRF algorithm.The performance of the established model was verified using data from three specific measurement points on the Jishixia dam and compared with other dam deformation prediction models.At point ES-10,the performance evaluation indices of the IRF model were superior to those of the M5'model tree and RF models and the classical support vector regression(SVR)and back propagation(BP)neural network models,indicating the satisfactory performance of the IRF model.The IRF model also outperformed the SVR and BP models in settlement prediction at points ES2-8 and ES4-10,demonstrating its strong anti-interference and generalization capabilities.This study has developed a novel method for forecasting and analyzing dam settlements with practical significance.Moreover,the established IRF model can also provide guidance for modeling health monitoring of other structures.

Characteristics of gully bed scour and siltation between check dams

Check dams are the most commonly used engineering measure for debris flow control worldwide.The scour and siltation characteristics between dams are important factors affecting dam design.In this study,classical dimensional analysis of the variables that influence the development of gully bed scour and siltation was carried out.Flume experiments were conducted to examine the influence characteristics of opening width,flume slope,debris flow density,and opening rate on the characteristics of gully bed scour and siltation.The influential characteristics of variables on the dimensionless scour depth,scour length,siltation length,scour volume and siltation volume were obtained.The experiments showed that,with an increase in the relative opening from 1.5 to 2.5,scour depth increased by 7.4%,scour length decreased by 11.2%,siltation length increased by 22.0%,scour volume decreased by 4.7%and siltation volume increased by 22.0%.With an increase in flume gradient from 0.105 to 0.213,scour depth,siltation length and siltation volume increased by 40.0%,65.9%and 65.9%,respectively,and scour length decreased by 20.1%.With an increase in sediment concentration from 0.303 to 0.545,siltation length and siltation volume increased by 15.4%and 15.4%,respectively,and scour depth,scour length and scour volume decreased by 9.6%,9.1%and 17.8%,respectively.As opening rate increased from 0.08 to 0.32,siltation length and siltation volume increased by 33.3%and 33.3%,respectively,and scour depth,scour length and scour volume decreased by 5.4%,13.7%and 18.4%,respectively.The results showed that the flume gradient was the most influential factor on scour depth,scour length,siltation length and siltation volume,and the sediment concentration was the most influential factor on scour volume.Then,according to the experimental data,some empirical formulas predicting scour depth,scour length,siltation length,scour volume and siltation volume were obtained.The error between the computed values according to the formulas in this paper and the observed values was within±10%.These research results may provide a technological basis for window dam design in debris flow disaster prevention and mitigation.

DAM中波发射机电源电路工作原理与常见故障分析

DAM中波发射机电源故障为多发故障,当出现电源故障时,多数情况下都有相应的故障显示,技术人员可以根据故障显示进行相应的检查处理,但有些电源故障没有故障指示,技术人员只能凭维修经验来分析查找故障原因,延误了维修时间。本文以陕西762厂生产的10k WDAM发射机为例,对电源电路的组成和工作原理进行剖析,并在分析故障案例的基础上论述电源故障的维修方法和技巧,与业内同行共分享。

薄壁DAM盒体精密熔模铸造工艺研究

某DAM铝合金盒体具有结构复杂、壁薄、内腔安装面精度要求高以及批量大等特点,采用现有的机械加工方法存在加工死角,但结合电火花工序又会造成加工成本高、周期长且生产效率低。该文研究了采用精密熔模铸造方法制造该DAM盒体的可行性,从总体工艺路线设计、材料选择、结构工艺性优化和熔模铸造工艺等方面进行了分析和样件验证。样件检测结果表明,采用精密熔模铸造方法制备出的DAM盒体铸件质量、尺寸精度、化学成分均能满足要求,具备批量生产可行性。该研究结果可为DAM盒体类零件的设计和低成本制造提供参考。

DAM大气模型构建与验证

根据热层物理、经验模型原理和代码分析,研究模型构建方法。进而剖析国内热层大气探测和热层模型构建现状,提出存在的困难和未来的发展思路。以GOST模型为基础,分析模型的工作机制、地磁扰动期大气密度预报误差来源和密切相关的模型系数,推导模型密度对相关模型系数的偏导数矩阵。利用天基实测密度,有针对性地构建磁暴期大气模型(DAM)。并通过独立于建模的实测密度数据,验证DAM模型性能。统计发现,地磁活动指数Ap介于100~132时GOST,MSIS00和DAM模型的相对误差均值依次为64.32%,-176.72%,-14.83%。Ap指数80~132时,相对误差均值对应为77.44%,-136.74%,-14.14%,DAM模型性能较GOST和MSIS00均有明显提升。证明通过搭建大气模型框架和实测密度数据估计模型参数的建模方法是可行和有效的。

Flood risk assessment of check dams in the Wangmaogou watershed on the Loess Plateau of China

Check dams have been widely used in China’s Loess Plateau region due to their effectiveness in erosion and flood control.However,the safety and stability of the check dam decrease with the operation process,which increases the probability of dam failure during flood events and threatens local residents’ life and property.Thus,this study simulated flood process of the check dam failure in the Wangmaogou watershed in Yulin City,Shaanxi Province,China,calculated different types of inundation losses based on the flood inundation area within the watershed,and determined the number of key flood protection check dams by classifying the flood risk levels of the check dams.The results showed that 5 dams in the watershed were subject to overtopping during different rainfall return periods,which was related to their flood discharge capacity.Dam failure flood process showed a rapid growth trend followed by slow decrease,and the time of flood peak advanced with increase in the return period.After harmonization of evaluation scales,the magnitude of flood inundation losses can be ranked as:economic losses(212.409 million yuan) > life losses(10.368 million yuan) > ecological losses(6.433 million yuan).The risk value for both individual dams and the whole dam system decreases as the return period increases.The number of key flood protection check dams in the Wangmaogou watershed was 2,3,3,3,4,and 5 for floods with return periods of 10,20,30,50,100,and 200 years,respectively.The results provided a theoretical basis for the safe operation and risk evaluation of check dams in the Loess Plateau Hills watershed.

DAM10kW数字调幅中波广播发射机故障分析及维护

本文主要通过对DAM10kW数字调幅中波广播发射机故障进行详细的分析和维护,并提出了具体的解决方案,希望可以全面提高广播电视台故障信息的处理速度,进而保障我国数字电视台的正常运转.

Dynamic Modeling Framework of Sediment Trapped by Check-Dam Networks:A Case Study of a Typical Watershed on the Chinese Loess Plateau

Check-dam construction is an effective and widely used method for sediment trapping in the Yellow River Basin and other places over the world that are prone to severe soil erosion.Quantitative estimations of the dynamic sediment trapped by check dams are necessary for evaluating the effects of check dams and planning the construction of new ones.In this study,we propose a new framework,named soil and water assessment tool(SWAT)–dynamic check dam(DCDam),for modeling the sediment trapped by check dams dynamically,by integrating the widely utilized SWAT model and a newly developed module called DCDam.We then applied this framework to a typical loess watershed,the Yan River Basin,to assess the time-varying effects of check-dam networks over the past 60 years(1957–2016).The DCDam module generated a specific check-dam network to conceptualize the complex connections at each time step(monthly).In addition,the streamflow and sediment load simulated by using the SWAT model were employed to force the sediment routing in the check-dam network.The evaluation results revealed that the SWAT-DCDam framework performed satisfactorily,with an overestimation of 11.50%,in simulating sediment trapped by check dams,when compared with a field survey of the accumulated sediment deposition.For the Yan River Basin,our results indicated that the designed structural parameters of check dams have evolved over the past 60 years,with higher dams(37.14%and 9.22%increase for large dams and medium dams,respectively)but smaller controlled areas(46.03%and 10.56%decrease for large dams and medium dams,respectively)in recent years.Sediment retained by check dams contributed to approximately 15.00%of the total sediment load reduction in the Yan River during 1970–2016.Thus,our developed framework can be a promising tool for evaluating check-dam effects,and this study can provide valuable information and support to decision-making for soil and water conservation and check-dam planning and management.