To improve the efficiency of water resource utilization in China and promote refined management of irrigation areas,this paper proposes a refined management framework for digital twin irrigation areas based on the current development of irrigation areas.Meanwhile,it studies the key technologies of water supply prediction in irrigation areas,crop water demand prediction,optimal water volume allocation in irrigation areas,and integrated measurement and control gates.A set of"FEDE"platforms for digital twin irrigation areas have been constructed,and five paths of"multi-factor three-dimensional perception","full-cycle water demand forecasting","targeted warning of drought and flood risks","full-process rehearsal of water resources",and"scientific plans for disaster prevention and reduction"are adopted.As a result,comprehensive,intelligent,and scientific management of irrigation areas is realized.Additionally,some functions of the"FEDE"platform of digital twin irrigation areas have been successfully applied to the Liuxi River irrigation area,Guangzhou.The key technology of precise water volume control throughout the entire process of digital twin irrigation areas achieves optimal water resource allocation and improves water resource utilization efficiency by realizing water volume allocation throughout the entire"water supply-water demand-water distribution-water transfer"process.This has a guiding significance for the promotion and application of digital twin irrigation areas.

基于Google Earth Engine使用Landsat长时间序列影像和GEE算法,提取1986—2020年北江清城区河段常流河道范围和监测土地覆盖变化,根据河道提取和土地覆盖的分类结果,分析了清城区河段的时空变化以及驱动该变化发生的主要社会经济因素.结果表明:①土地覆盖分类结果是可靠的,总体准确率在90％～98％之间;②常流河道面积略有扩大,近34 a来的变化率为12.42％;③研究区域内建成区面积不断扩大,植被面积不断减少,水域面积相对保持稳定,沉积物面积呈先增加后减少的趋势;④重点水利工程的建成加固和伦洲岛附近泥沙的疏浚治理是驱动河道变化的关键因素,清城区常住人口的增加和经济的快速扩张是植被向建筑物地类转移的主要原因.

加快建设数字孪生流域是2022年全国水利工作会议的10项重点工作之一.珠江水利委员会在西江干流重点河段开展数字孪生珠江先行先试工作,探索数字孪生珠江防洪"四预"(预报、预警、预演、预案)功能实现路径:构建西江流域L2级数据底板,实现流域物理要素的数字化映射;建立模型评价服务,赋能流域防洪调度智慧化模拟和精准化决策;利用西江流域防洪知识库和调度规则库,构建西江防洪知识图谱;探索构建数字孪生珠江全要素多尺度的洪水预演数字化场景,提高流域防洪管理和工程调度水平,保障粤港澳大湾区防洪安全.

为提升灌区现代化管理水平,解决传统管理存在的空间和时间限制等问题,研发了一套基于H5+技术的灌区管理移动APP.管理人员可随时随地查询灌区各监测站点的实时信息,便于灌区巡检及现场维护、查询用水申请及批复情况,并远程控制灌溉设备开关,实现灌区运维精细化管理,提高了工作效率,具有较高的可推广性.

针对传统水利工程建筑信息模型(BIM)开发周期长、客户端安装复杂及展示不便等问题,采用基于WebGL技术的Three.js框架,通过导入由SketchUp构建的三维模型,在浏览器以Web方式实现了水利工程三维模型可视化展示以及实时人机交互,满足了三维模型跨平台展示需求,增强了模型展示效果和加载速度,提升了用户体验.该方法可应用于水利工程信息化平台的开发.

Accurate flood forecasting is one of the main means to well perform flood control and drainage,and the long-short-term memory neural network (LSTM) has a strong ability to fit time series relationships,which thus is very suitable for simulating and forecasting the complex time series process of basin runoff generation and confluence.To explore the applicability of LSTM in the field of reservoir flood forecasting,this paper established an LSTM model according to different forecast periods in the Baipenzhu Basin and compared it with Xinanjiang model.The LSTM model uses the rainfall and water level data in the basin as input and adopts the water levels of the reservoir at different forecast periods as output.The calibration period is five years,and the verification period is one year.The results show that LSTM has high forecast accuracy when the forecast period is 1~6 h,and the forecast accuracy is the highest when the forecast period is 1h,reaching 0.991.As the forecast period increases,the accuracy of the LSTM model gradually decreases,but its forecast accuracy is higher than that of Xinanjiang model.In addition,reflecting the complexity of the neural network,the prediction period and the number of neurons in the hidden layer will affect not only the forecast accuracy but also the training speed of the model.It is proven that the LSTM model has high forecast accuracy and is of guiding significance to reservoir flood forecasting.

The BP traditional neural network dam deformation prediction model has the disadvantages of slow convergence speed, easy to fall into local extreme points and poor generalization ability, a dam deformation prediction model based on wavelet neural network is constructed by combining the time-frequency local analysis ability of wavelet and the self-learning and self-organizing characteristics of neural network; the measured value of settlement of Lixi barrage in Guangzhou is selected as the research object, From January 2016 to June 2019, a total of 557 sets of data were used as model training set to establish the model; from July 2019 to October 2019, 95 sets of data were used as model verification set to evaluate the model performance. The test set prediction results of wavelet neural network and BP traditional neural network show that the mean square error of deformation prediction model based on BP traditional neural network is 0.138 and the certainty coefficient is 0.748; based on wavelet analysis, the mean square error of the coupled neural network deformation prediction model is 0.025 and the certainty coefficient is 0.927. Wavelet neural network has fast convergence speed, high prediction accuracy and strong generalization ability in dam deformation prediction And other characteristics.

Impulse waves generated by the collapse of pillar-shaped rock masses in Three Gorges, China, have attracted the attention of both researchers and local authorities owing to their catastrophic consequences. In this work, particle imaging velocimetry (PIV) was used to study impulse waves generated by the collapse of granular pillars during a series of physical experiments. Subsequently, the scenes of particles collapsing into water and the resulting impulse waves were analysed in terms of the solid/fluid fields. The energy obtained by the water during this process is mainly derived from the volume encroachment and continuous thrusting of particles. As indicated by the experimental results, as the aspect ratio (a) of the pillar and water depth increased, the potential energy of the granular pillar became more prone to reduction, whereas the efficiency of energy conversion to the liquid phase reduced. At constant water depth and granular pillar width, the maximum amplitude generated by the collapse of the granular pillar remained essentially the same (i.e., "saturation" was achieved) once the aspect ratio exceeded a certain threshold. The maximum impulse wave (the primary wave) formed before the main body of particles collapsed, resulting in the "saturation" of the maximum amplitude. When the kinetic energy of the particles reaches the maximum, the ratio of energy dissipation of the particles is the lowest; as the energy of water reaches the maximum, the particle collapse process does not end. The dynamic analysis of the impulse waves generated by the collapse of granular pillars provides a new approach to obtain an in-depth understanding of landslides and impulse waves. This can provide technical guidelines for disaster prevention and mitigation of impulse waves generated by bank collapse or coastline collapse.

At present, the data of water industry is isolated and disordered, lacking of integrity, and difficult to realize a comprehensive and complete understanding. The traditional water conservancy working mode which is based on experience and summary has been unable to meet the needs of the current development, and there are even irreconcilable contradictions between them. The big data of water conservancy can make full use of its advantages, such as full sample description, law analysis and correlation analysis, and fast real-time processing, etc., It also provides scientific and comprehensive decision-making for the realization of the goal of water control modernization on the base of premise of establishing water conservancy big data cloud platform. This paper proposes to establish the real-time data synchronization between the water industry subsystems and the cloud platform base on SQL Server that from the perspective of data integrity and real-time, combining with the industry characteristics of water conservancy data, which ensures the data integrity and realizes the remote backup of data in the same time, greatly improves the disaster recovery performance of the system, and proposes the establishment of its supporting synchronous monitoring and alarm system to ensure the consistency of data.

碎屑流具有冲程远、危害范围大等特性,难以进行有效预测防范.颗粒级配被认为是影响碎屑流运动距离的重要因素之一.开展了一系列基于单面临空不同颗粒级配颗粒柱体崩塌运动的物理模型试验研究.结果表明:颗粒柱体崩塌后,颗粒运动斜向箱体外,水平板上的颗粒运动呈放射状,堆积平面形式为圆形态,颗粒静止轮廓可分别用抛物线、圆的方程拟合,效果较好;颗粒类型相同时,随着颗粒柱体高度的增加,崩塌后颗粒堆积成圆形态的圆心位置有沿着y轴向前移动趋势;颗粒柱体高度相同时,小颗粒的运动距离比大颗粒的运动距离远;颗粒粒径小时,松散堆积区范围小,颗粒的影响区域为密集堆积区范围;反之,颗粒的影响区域为密集堆积区范围+松散堆积区范围.试验研究成果对预测碎屑流堆积区范围具有一定的参考价值.

Columnar dangerous rock mass is widely developed in many high and steep mountain areas around the world. It often collapses, disintegrates and produces debris flow, which is disastrous. The collapse process of the columnar dangerous rock mass is very similar to the collapse of granular column. In this paper, we report the results of an experimental investigation of the flow induced by the collapse of a column of granular material over a horizontal surface. Two different setups are used, namely, a channelized granular column collapse (i.e., two-dimensional) and an unchannelized granular column collapse (i.e., three-dimensional), allowing us to compare channelized and unchannelized collapses flows. The experimental data suggest that our experimental findings were markedly different from those reported by previous authors (i.e., include the channelized and unchannelized collapse flows showed differences in energy conversion and dissipation). In channelized collapse flows, the maximum vertical speed appears in the free fall regime, while, the maximum speed in the vertical direction of unchannelized collapse flows appears in the spreading regime. During the whole collapse process, i.e., in channelized and unchannelized collapse flows, the conversion of potential energy and kinetic energy does not occur uniformly, and the maximum kinetic energy of the channelized collapse flows is higher than that of the unchannelized collapse flows, and compared with the unchannelized collapse flows, the dissipation energy in the channelized collapse flows is lower. A series of experiments was performed to predict the behaviour of different granular columns (characterized by different initial aspect ratio (a), varying from 1 to 4). The data obtained from 2D experimental model and 3D experimental model have certain amount of difference, such as the particle runout distance (d1), the maximum central height (h2), and the deposition angle (i.e., β1, β2). These differences show that the 2D experimental model does not fully represent the 3D conditions (i.e., the role of side-walls on the channelized collapse flows characteristic is non-negligible). Accordingly, care must be taken when validating 3D models with 2D experimental data. The movement of the tower dangerous rock masses with collapse failure mode could be evaluated using this channelized and unchannelized granular column experimental results.

Towering in many gorges of reservoirs and coastal zones, pillar rock masses may collapse and fall due to foundation crushing, and the impact on water by debris leads to impulse waves. In this study, the process of impulse wave induction by the gravitational collapse of granular piles was investigated using particle image velocimetry. The experimental results showed that the collapse process of partially submerged particles was significantly different from that of dry particles. Near the water surface, particles moved outward in a reversed “S” shape. In the presence of water at the slope foot, the time and the distance traveled by the particles were reduced. The hydraulic effects such as water entrainment, vortex, rolling, and viscous drag exacerbated the energy dissipation of the granular piles, thus reducing particle mobility. Thirty five experiments suggested that the impulse waves induced by granular piles could be categorized as bores, solitary waves and nonlinear transition waves according to the functional inequality, which consisted of the aspect ratio and the relative thickness. The fitted formula for the run-out of partially submerged granular piles and the corresponding maximum wave amplitudes was derived by nonlinear regression of the experimental data. In comparison with previous formulas, these formulas are power functions consisting of aspect ratio and relative thickness and are highly suitable for predicting the collapse of granular piles and the impulse waves induced as the correlation coefficients of calculated results by these formulas and the measured values exceeded 0.93.

The high-density gravitational collapse of granular columns is very similar to the movements of large collapsing columns in nature. Based on the development of dangerous columnar rock mass in fields, granular column collapse boundary condition in the physical experiments of this study is a new type of boundary conditions with a single free face and a three-dimensional deposit. Physical experiments have shown that the mobility of small particles during the collapse of granular columns was greater than that of large particles. For example, when particle size was increased from 5 to 15 mm, deposit runout was decreased by about 16.4%. When a column consisted of two particle types with different sizes, these particles could mix in the vicinity of layer interfaces and small particles might increase the mobility of large particles. In the process of collapse, potential and kinetic energy conversion rate is fluctuated. By increasing initial aspect ratio a , the ratio of the initial height of column to its length along flow direction, potential and kinetic energy conversion rate is decreased. For example, as a was increased from 0.5 to 4, the ratio of maximum kinetic energy obtained and total potential energy loss was decreased from 47.6% to 7.4%. After movement stopped, an almost trapezoidal body remained in the column and a fanlike or fan-shaped accumulation was formed on the periphery of column. Using multiple exponential functions of the aspect ratio a, the planar morphology of the collapse deposit of granular columns could be quantitatively characterized. The movement of pillar dangerous rock masses with collapse failure mode could be evaluated using this granular column experimental results.

碎屑流具有高速度、冲程远、危害范围广等特点,颗粒粒径被认为是影响其运动距离的重要因素之一。为了对碎屑流进行有效的预测和防范,基于单面临空下不同分层堆积模式颗粒柱体的一系列崩塌运动物理试验对其崩塌-堆积过程进行了研究。结果表明:不同分层堆积模式颗粒柱体崩塌后,颗粒的堆积层序和试验前颗粒初始堆积层序保持一致;崩塌后的颗粒堆积层序和试验前颗粒初始堆积层序有关;不同粒径的颗粒相互间运动时,粒径较小的颗粒填充到大颗粒间的空隙之中,并起到润滑作用;颗粒柱体在单面临空面方向崩塌时,颗粒运动方向呈放射状,堆积平面形式是"圆形态";分别以d 7 颗粒为顶层和d 13 颗粒为顶层时,d 7 颗粒最远堆积长度比d 13 的高约6.3%;顶层颗粒（d 7 颗粒）运动能力越强,则最终的堆积范围越大,底层颗粒(d 13 颗粒)的运动能力,对整个堆积体最终堆积范围影响相对较小。上述规律可应用于层状危岩体崩塌过程及其颗粒堆积范围的研究。

Generally, the robotic forward kinematics for redundant manipulators has a maturely analysis formula, but the inverse-kinematics question is analytically troublesome. Many approaches have been adopted to resolve the complicated inverse-kinematics question; for example the previous pseudo-inverse based (PIB) method. It is a general method while brings a lot of defects and limitations. Considering that, it is necessary to indagate other inverse-kinematics schemes through applying the related dynamic methods. Based on many previously excellent researches, the dynamic methods used in this paper consist of direct derivative dynamics (D-3) and Zhang dynamics (ZD). Through using D-3 once and ZD kinematic method once, a scheme called D1Z1 is studied for solving the redundancy question of robot manipulators. As an representative application of D-3 and ZD method, the D1Z1 scheme, that is exploited at the acceleration level instead of the velocity level. Furthermore, simulation results based on robotic manipulators of different links illustrate the reliability and advantage of the proposed D1Z1 scheme.

Wave simulation system has the characteristics of multi-axial, complex motion trajectory, large data volume and high synchronization requirements. This paper has proposed a coupling control system based on PC and CAN bus to solve the problem of large amount of data transmission, control accuracy, synchronization and data transfer speed. For the characteristics of fast operation and storage capacity of PC controller, all the motion trajectory planning can be done by PC controller. The coupling control of Ethernet and field bus manner can optimize the synchronization control for the wave simulation system.

在已研发的数字图像流场测量系统的基础上,运用图像拼接和坐标匹配的方法,融合多套子系统的流场数据,实现了珠江河口整体物理模型流场信息的全方位覆盖,为水利工作者全局研究珠江河口流场演变奠定了基础.经过多次试验表明:该方案实现了多套系统流场的无缝拼接,达到测量更大范围、更大区域流场的目的,试验结果稳定可靠.

A set of salt tide storm flow factors coupled synchronous measurement and control systems has been developed for the physical model studies to combat the natural disaster of salt tide intrusion in the Pearl River estuary.The system can be used to simulate the effects of the tide,wind,flow,waves on the salt tide intrusion and it has provided the necessary conditions and environment for scientific research on the laws of the salt tide movement and relevant estuary regulation.

The principle and composition of the multi-directional irregular wave generator system is analyzed.The monitoring software is designed for the generator system with the modularization method.Relevant solutions are figured out for the problems of the large amount of system data exchange,and strict real time requirement and multiple controlled objects.And the key techniques in the software design is illustrated and fulfilled.