富水水库防洪能力复核

根据收集的原勘测、设计、施工及以往安全鉴定等资料,按照现行的规程、规范,对富水水库的防洪标准、设计洪水、调洪计算、大坝抗洪能力进行复核,认为富水水库的防洪标准及大坝抗洪能力均满足规范要求,洪水能够安全下泄,大坝防洪安全性评价为A级.     

瓜渚湖直江引水对通航影响的数值计算和分析

利用二维河流数学模型对管墅直江引水进行了通航的影响计算,分析表明,工程按照设计取水流量运营时,原航道的最大横向水流流速、纵向影响流速、纵向回流流速均满足规范要求,当取水口突然停止运营,取水口所在河汉内回流的最大流速为0．06m／s,对运河航段水流影响不明显;取水口运行时计算航段内水位最大差值约0．03m,对附近运河水域水位影响很小,对航道水深及往来行船安全无影响．     

装配式桥梁架桥机施工力学特性及工艺研究

为满足山区不等跨径装配式桥梁的架设要求,提升预制梁架设施工的精度及质量,探明架桥机在架设典型工况下关键构件的结构强度、刚度和稳定性,验证架桥机机型的安全可靠,以遂德高速公路九岭岗大桥架梁施工阶段为依托,对架桥机施以满载吊设,利用有限元法分析了架桥机在3种工况下的应力状态、变形规律和整体结构稳定性。研究结果表明：架桥机主要构件在过孔、架中梁、架边梁三种不利荷载工况下的强度,均满足材料性能要求;悬臂工况下主梁前支腿端竖向位移变形量最大,跨中工况下前支腿与中支腿间主梁简支段竖向位移变形量最大,构件刚度满足规范要求;架桥机失稳主要在主梁跨中桁架杆位置,所选机型稳定性满足要求;所选架桥机满足该桥最大跨径预制梁架设安全要求,对于该桥不同跨径主梁架设也是安全的。分析确定了架桥机在3种工况下最不利控制位置,得出了相应施工流程及注意事项,为类似山区预制梁架设施工提供了参考。     

乌江思林水电站溢流坝弧形工作闸门流激振动试验

为研究乌江思林水电站溢流坝弧形工作闸门可能出现的闸门流激振动问题,通过制作几何比尺为1/35的完全水弹性模型进行流激振动试验,研究该闸门在有止水和无止水2种工况下的静动力特性及不同开度的动力响应,提出了该闸门安全运行的合理化建议.检测采用电测法,共进行静力试验2组,动力试验16组.静力试验结果表明该闸门结构设计合理,结构强度满足规范要求.动力试验结果表明结构的自振频率范围避开了水流脉动压力的高能区,正常运行情况下(止水良好)产生强烈振动的可能性不大,结构加速度最大值为0.228g,动应力最大值为0.92 MPa,各测点动力系数小于1.08,动力响应满足闸门抗振设计要求.闸门振动不利开度为0.6H和0.7H左右(H为水头).在漏水工况下运行时闸门振动加剧.     

含建筑垃圾水稳碎石路面基层材料的使用性能

在建筑垃圾再生集料性质研究的基础上,通过实验室试验,探讨了含不同掺量再生集料水泥稳定碎石路面基层混合料的强度、刚度、抗冲刷、抗冻、收缩等使用性能。试验结果与分析显示:与天然集料相比,再生集料密度小、吸水率大、压碎值偏大,但基本满足规范要求;混合料的强度随再生集料掺量增加存在峰值,7d无侧限抗压强度和90d劈裂强度均满足规范要求;混合料刚度随再生集料的掺量增加也存在峰值,再生集料的掺加可以提高材料的回弹模量;再生集料削弱材料的抗冲刷能力,但对抗冻性能影响不大;再生集料减小材料干缩系数,但增大温缩系数,必要时应控制其掺量。     

考虑闸门实际运行的雅砻江下游梯级水库联合防洪优化调度

针对当前梯级水库防洪调度侧重以水库为基本单元的算法研究且较少考虑闸门实际运行的问题,提出了基于闸门运行调度规则和多步次逐步优化 (MSPOA) 算法的防洪调度模型。根据水库实际情况建立闸门数字化代表性组合策略,采用MSPOA优化计算各梯级水库的泄洪流量,应用二分法在组合策略中进行快速定位,通过二次计算确定各道闸门的准确开度进而实现泄洪流量的闸门分配。对两场典型洪水的优化结果显示,MSPOA计算时间较POA分别减小43.2%、64.0%,收敛速度更快,且能有效克服局部最优缺陷;配合组合策略进行闸门调度,满足了实际要求,提高了计算效率,具有很好的实用性和可操作性。     

预应力混凝土简支T梁桥荷载试验

结合某预应力混凝土T梁桥,介绍了静力荷载试验的内容与方法,包括测点布置、荷载布置、加载方式以及试验结果与计算结果的对比分析等.通过静力荷载试验与有限元软件相结合的手段,测试桥跨结构强度、刚度,检验桥跨结构在正常使用状态下承载能力和结构变形是否符合设计要求.结果表明,该桥结构处于正常受力状态,结构刚度、强度均满足规范要求...     

基于Auto bank的某水库大坝渗流安全评价

以富水水库为例,依托达西定律和渗流理论基础,并结合Auto bank有限元软件分析了水库在正常高水位、设计洪水位、校核洪水位下坝体及坝基的渗流状况,计算结果表明水库日渗漏量远小于允许日渗漏量,水库渗漏量满足规范要求。大坝各工况最大渗透坡降均小于规范允许值,渗透变形满足规范要求。左坝肩存绕渗现象,建议加强监测。     

汶川地震震损水库典型土石坝除险加固分析

四川省目前已建成各类水库近7000座。“5·12”汶川大地震对四川的水利工程造成了很大的灾害。根据四川震损水库基本情况,以苍溪县红旗水库的典型震损土石坝为例,对其进行除险加固分析。分析表明,整治前校核、设计、正常水位降至死水位的3种工况坝坡稳定最小安全系数仅为1.098~1.145,小于规范要求值1.15~1.25,经整治后提高到1.262~1.698,满足了要求,最后对整治后的大坝进行地震工况坝坡稳定计算,其抗震稳定安全系数为1.451~1.654,满足规范的要求。研究为震损水库的整治和处理提供了借鉴。     

后装压缩式垃圾车压实板的有限元分析

后装压缩式垃圾车压实板在工作过程中易出现强度和刚度不足,从而造成作业效果不佳、使用寿命降低等,为验证所设计压实板是否满足使用要求,运用三维设计软件CATIA的Product模块和AnalysisSimulation/Generative Structural模块建立压实板的有限元模型,进而计算和分析在正常工况下压实板的强度和刚度。分析结果表明,压实板的最大应力小于材料许用应力,满足强度和刚度的工作要求。     

突变理论在地质力学模型试验失稳判据中的应用

地质力学模型试验是研究高坝工程稳定安全性的重要方法之一,如何较准确的通过测试结果建立大坝失稳判据,判断坝与地基的失稳破坏过程,得到综合稳定安全系数,是地质力学模型试验的关键技术问题。本文由突变理论及其相关性质,选用较为成熟的尖点突变模型及其标准势函数公式,推导出相应的失稳突变判别式,建立基于尖点突变理论的失稳判据,并通过相关算例进行有限元分析,依据计算成果的变位—超载倍数关系,提出超载安全系数,并与有限元塑性区贯通、计算不收敛等失稳判据对比分析,印证尖点突变模型失稳判据的可靠性和适用性。再将其应用于丹巴水电站地质力学模型试验中,试验结果给出了闸坝在正常蓄水位和降强之后超载作用下的位移场,获得了闸坝的变形及分布特征、揭示了裂缝发展的全过程及其破坏机制,得到降强系数为 1.18,超载系数为 1.8～2.0,确定了闸坝整体稳定安全系数为 2.12～2.36。根据尖点突变理论,由试验测试成果建立相关失稳判据,据此提出破坏过程及综合稳定安全系数,并与常规地质力学模型试验分析成果进行对比,分析结果验证了基于地质力学模型试验测试成果的尖点突变模型失稳判据的合理性。     

岳城水库主坝浅层滑坡原因分析

一般认为库水位骤降时对土坝安全的影响较大,而不太注意库水位变幅很大时,渗透力对土坝安全的影响。本文通过对岳城水库主坝浅层滑坡原因的分析,说明库水位大幅度消落导致的渗透力对土坝安全的影响是很大的,应该引起足够的重视。并从水库运行的角度,说明了均质土坝不宜过高。     

基于损伤本构关系的高拱坝安全度评价方法

基于损伤本构关系的非线性有限元能较为精确地模拟拱坝的实际工作性态,主要依据大坝的变形和应力分布及大小、损伤破坏情况等对坝体安全进行评价.但也存在一些问题,如以建基面相对损伤面积作为控制指标时,要先确定建基面的容许损伤范围.在介绍了损伤本构关系的基础上,提出了以大坝整体刚度不改变为基准的建基面容许相对损伤面积确定方法,为损伤本构关系用于高拱坝安全度评价的控制标准提供了一个新的思路,并以溪洛渡高拱坝为例进行了计算.     

碗窑水库上游闸门井壁渗漏分析及水下处理

碗窑水库主坝两个坝体排水孔出现较大流量的漏水，为排除该漏水对大坝安全稳定的影响，通过分析漏水的原因，潜入水下查明漏水的部位，采用下水高分子聚合物砼在漏水的源头上游闸门井内壁进行水下直接封堵，用较低的成本，很短的时间，取得了很好的处理效果。     

Research advance in safety analysis methods for high concrete dam

High tensile stresses occurred in high concrete dams and in their foundation lead to the growing importance of their safety with the increase of concrete dam height. Without any exiting specification or successful experiences of concrete dams up to 300 m at home and abroad for reference, experts feel obliged to figure out how to perform safety analysis on high concrete dam. This paper involves the main contents and mechanical features of the safety analysis on high concrete dam and shows the current state and progress of the analysis methods. For the insufficiency and problems existing in normative methods, study on modern numerical method such as finite element method must be strengthened to find out the stress control criterion which is in accordance with the methods. Two aspects of the safety analysis of high dam—local damage from material level and integral destruction from structure level—should be considered. For the local damage, we should consider the non-homogeneity of material and strengthen the research of meso-damage mechanics. While for integral destruction of the system of high dam and its foundation, a study on non-strength theory should receive enough concerns. Further, attention should be paid to the research on the failure modes and criterions of high concrete dam failure analysis and safety evaluation, and the effect of uncertainty and classification of safety should be considered too.     

毛细水作用对粉土路基稳定性的影响

为了探索毛细水对粉土路基稳定性的影响,通过实验研究了粉土毛细水作用高度与含水量、含水量与回弹模量的关系,进而拟合了毛细水作用高度与压实粉土回弹模量的关系式。实验研究了含水量与压实粉土抗剪强度的关系,研究表明毛细水对粉土路基的刚度和抗剪强度的衰减影响显著。应用Abaqus 6.10有限元分析软件模拟计算不同水位下毛细水对粉土路基稳定性的影响,采用强度折减法计算不同水位粉土路基在标准轴载作用下的安全系数,得到毛细水作用高度与粉土路基稳定性的规律,为粉土路基的设计与施工提供了依据。     

Research advance in safety analysis methods for high concrete dam

High tensile stresses occurred in high concrete dams and in their foundation lead to the growing importance of their safety with the increase of concrete dam height.Without any exiting specification or successful experiences of concrete dams up to 300 m at home and abroad for reference,experts feel obliged to figure out how to perform safety analysis on high concrete dam.This paper involves the main contents and mechanical features of the safety analysis on high concrete dam and shows the current state and progress of the analysis methods.For the insufficiency and problems existing in normative methods,study on modern numerical method such as finite element method must be strengthened to find out the stress control criterion which is in accordance with the methods.Two aspects of the safety analysis of high dam--local damage from material level and integral destruction from structure level--should be considered.For the local damage,we should consider the non-homogeneity of material and strengthen the research of meso-damage mechanics.While for integral destruction of the system of high dam and its foundation,a study on non-strength theory should receive enough concerns.Further,attention should be paid to the research on the failure modes and criterions of high concrete dam failure analysis and safety evaluation,and the effect of uncertainty and classification of safety should be considered too.     

Study on real working performance and overload safety factor of high arch dam

Considering the fact that high arch dams have problems such as complicated stress, high cost, and hazards after being damaged, this paper intends to study the effects of load, material strength, and safety analysis method on dam safety and working performance of arch dams. In this article, the effects of temperature, self weight exaction way and water loading on structure response are first discussed, and a more reasonable way of considering is then put forward. By taking into consideration the mechanical property of materials and comparing the effects of different yield criteria on overloading safety of high arch dams, this paper concludes that brittle characteristics of concrete should be fully considered when conducting safety assessment for high arch dams to avoid overestimating the bearing capacity of the dams. By comparing several typical projects, this paper works out a safety assessment system of multiple safety and relevant engineering analogical analysis methods, which is closer to the actual situation, and thus is able to assess the response of high arch dam structure in a more comprehensive way, elicit the safety coefficients in different situations, and provide a new way of considering the safety assessment of high arch dams.

     

纵向增强体土石坝内置心墙受力安全性分析

纵向增强体土石坝是基于“刚柔相济”建坝思路提出的一种新坝型,在土石坝中设置刚性防渗心墙与原土石坝体一起形成坝体结构。纵向增强体将坝体分为上游临水一侧和下游背水一侧,增强体同时受到上、下游侧的水土压力作用,起到双向挡土墙的作用。随着上游库水位的变化,作用在增强体上的水土荷载也产生动态变化,从而引起增强体位移方向和大小变化,导致增强体上下两侧游堆石区存在主动力区与被动力区的转换。本文提出了纵向增强体受力安全系数的概念,应用库伦土压力理论分析增强体在竣工期、正常蓄水期和水位骤降三种典型工况下的受力状态,分别给出了三种典型工况下纵向增强体受力安全系数的表达式。在此基础上,从纵向增强体双向挡土墙不同于常规挡土墙单向受力的特点出发,根据增强体受力安全系数研究其与坝坡稳定性之间的关系,提出了临界坝坡法计算被动土压力系数。研究表明：作为双向挡土墙的增强体无论受力、变形还是自身稳定都与坝坡稳定性有关,纵向增强体蓄水期的被动土压力将随主动压力的增长而得到激发,受力程度也将得到更好地发挥,实现等强增效的力学特点;非临界坝坡设计中采用由本文临界坝坡法计算得到的被动土压力折减系数是偏于安全的,增强体土石坝断面可以进一步优化。     

Study on real working performance and overload safety factor of high arch dam

Considering the fact that high arch dams have problems such as complicated stress, high cost, and hazards after being damaged, this paper intends to study the effects of load, material strength, and safety analysis method on dam safety and working performance of arch dams. In this article, the effects of temperature, self weight exaction way and water loading on structure response are first discussed, and a more reasonable way of considering is then put forward. By taking into consideration the mechanical property of materials and comparing the effects of different yield criteria on overloading safety of high arch dams, this paper concludes that brittle characteristics of concrete should be fully considered when conducting safety assessment for high arch dams to avoid overestimating the bearing capacity of the dams. By comparing several typical projects, this paper works out a safety assessment system of multiple safety and relevant engineering analogical analysis methods, which is closer to the actual situation, and thus is able to assess the response of high arch dam structure in a more comprehensive way, elicit the safety coefficients in different situations, and provide a new way of considering the safety assessment of high arch dams.