STUDY ON COUPLING MODEL OF SEEPAGE-FIELD AND STRESS-FIELD FOR ROLLED CONTROL CONCRETE DAM

IntroductionRCCDisbuiltwithconcreterolledandcompactedlayeruponlayer.Therefore,thereisonehorizontalconstructioninterfacebetweentwoconterminouslayers.Iftheconterminouslayersarenotcementedclosely ,theconstructioninterfaceswillbecomeweakpartsofRCCDthatinfluencethestrengthandstabilityofRCCD .Ontheotherhand ,theanti_seepageabilityofconstructioninterfacesisthedeterminantofanti_seepagecharacteristicsofthewholeRCCD .Whenadamisconstructedandfilledbywater,seepage_fieldcomesintobeinginthedambody ,w…     

双轴对称截面薄壁圆弧曲梁的弹性稳定平衡方程

基于薄壁构件分析的基本假定,采用双轴对称截面薄壁圆弧曲梁的精确翘曲位移表达式,导出了曲梁考虑几何非线性情况下的总势能,根据欧拉公式得到了曲梁的稳定平衡方程。推导中采用横截面线性和非线性总应变为零的假定,从而无需考虑横向应力的影响,对应变高阶项采用合理的简化处理,使理论推导过程简单明了。在理论推导的基础上分析了简支拱在均布径向荷载和两端等弯矩荷载作用下的平面内和平面外屈曲问题,并与其他研究者的结果进行了比较,追溯了各理论结果存在差别的根源,论证了本文理论推导过程的合理性。使用通用有限元软件ANSYS进行了模拟,与本文的分析结果一致,证明了所得公式的正确性。通过一些无碍结果的近似使所得公式形式简洁,便于在工程中应用。     

空腹设拱重力坝优化设计

本文采用序列二次规划法进行空腹设拱坝断面优化设计,在求解过程中应用了运动极限和约束删除技术。经考核证实本文研制的优化程序收敛速度快,计算结果可靠。     

米箭沟尾矿坝料动力特性试验研究

本文对米箭沟尾矿坝料的组成、结构特征和物理力学性质进行分析,运用振动三轴试验确定尾矿坝料的动力特性参数,分析研究动力特性指标模型,得出动应力、动模量、阻尼比、动剪切摸量随动应变的变化规律,以及动应力与破坏振次,孔压比与振次比的变化规律,并提出符合试验结果的孔压模型,对该尾矿坝的地震动力分析及抗震稳定性评价提供一定科学依据和技术指导。     

二维溃坝波的反射与绕射

本文推导了间断分解公式,建立了Godunov型格式,研究了二维溃坝波的传播、反射和绕射。计算结果符合物理实际,令人满意。方法是有效的,可以提供水工部门作为设计和防护的依据。     

水舌空中左右碰撞的水力特性及其作用下的河床基岩冲刷平衡深度估算

应用紊动射流理论和水流动量方程，提出了水舌空中左右碰撞时合水舌的碰撞流速矢量、碰撞消能效率的计算公式。分析和比较了水舌空中左右碰撞与上下碰撞方式下合水舌的碰撞角，碰撞消能效率和其空中扩散方面的差异，提出了水舌空中左右碰撞作用下河床基岩冲刷平衡深度的一种估算方法。以模型实验资料验证，预测值和实测值基本吻合。因此表明，对水舌空中碰撞的水力特性分析是正确的，河床基岩冲刷平衡深度的估算方法是合理可行的。研究成果可为高坝下游消能防冲参考。     

Modelling the impact of dam failure scenarios on flood inundation using SPH

Flooding resulting from collapse of a dam is a highly destructive event. It is important to accurately predict the flow behaviour so that potential mitigation strategies can be investigated for disaster management planning. The meshless SPH method has previously been able to model this class of extreme flow events. In this paper, we extend the method to include modelling of dam wall fragments. Collisions between dam wall fragments, between fragments and terrain and full two-way coupling between fragments and the free surface water flow is included. This gives a method that can specifically investigate the impact of the dam wall failure scenario on the subsequent inundation. The historical St. Francis dam failure is used to demonstrate the impact of including the dam fragments. It also provides a means of quantitatively investigating their effect in terms of arrival time and water height at a downstream power station. The scenario with multiple independently timed failures of different parts of the wall (which closely matches the historical failure) gives excellent agreement with the observed data and gives the best match of all failure scenarios. Traditionally such modelling is performed by solving the two dimensional shallow water equations which is not able to capture the three dimensional nature of the flow in earlier stages of dam flooding. We specifically investigate the three dimensional nature of flow structures and formation of multiple downstream hydraulic jumps. These strongly influence water height and therefore control the extent of flooding of tributary valleys.     

基于灰关联综合评估的水利枢纽工程坝型优选

综合考虑影响坝型选择的众多因素 ,建立了分三层五个子系统的坝型优选模型 ,运用灰关联综合评估对模型进行求解 ,解决了水利枢纽工程坝型优化选择问题 .对于模型中定性影响因素定量化的问题 ,采用了集值统计法处理 .最后利用模型进行了实例分析决策 .     

Finite element analysis of arches undergoing large rotations - II: Classification

Four different elements are developed using Green strains and second Piola-Kirchhoff stresses to analyze thin/thick arches undergoing large displacements and large rotations. Effects of arc length and thickness on the load-displacement characteristics of various arches undergoing large displacements are studied. Based on these studies, parameters necessary to classify the arches are established.     

一维浅水方程的格子Boltzmann模拟

通过无量纲化变换 ,建立了一个一维浅水方程的LB模型 ,对一维溃坝波进行了模拟计算 ,并分别与文献结果和精确解作了比较 ,说明了此种模型的进步之处和可行性 .