土石坝边坡稳定性分析的温控参数折减有限元法     

欧阳君  徐千军  侍克斌  严新军  宫经伟 《岩土力学》2011,32(8):2549-2554

将土石坝渗流的有限元计算和坝坡稳定分析的强度折减有限元法相结合,对土石坝坝坡的稳定性进行分析。考虑渗流作用时,首先采用有限元法计算坝体渗流场,通过迭代计算出稳定渗流的逸出点和浸润线位置,并根据水力梯度计算坝体所受的渗透力;然后将渗流分析所确定的渗流力与土体自重、浮力、地震力等荷载共同施加在坝体上,采用温控参数折减有限元法计算土石坝坝坡的临界失稳状态及其所对应的安全系数。分析结果表明,采用此方法进行土石坝坝坡稳定分析是合理的,且大大提高了计算效率  相似文献   

基于响应面法的高堆石坝瞬变-流变参数反演方法     

杨荷  周伟  马刚  李少林  常晓林 《岩土力学》2016,37(6):1697-1705

如何准确确定原级配堆石体的力学参数是高堆石坝建设中亟待解决的一个关键问题,参数反演是解决这一问题的可行方法之一,传统的参数反演方法因需要进行大量的有限元正分析,其计算工作量大,反演效率较低。响应面法可以有效克服以上问题,但已有方法仅针对堆石体的瞬变参数,未考虑流变参数,不能满足堆石坝长期变形预测的需要。综合考虑瞬变和流变参数,通过构造更加合理的响应面函数,提出了基于响应面法的高堆石坝瞬变-流变材料参数反演方法,大大提高了反演的效率和精度。以水布垭面板堆石坝为例,采用该方法对坝体瞬变和流变参数进行了反演分析。反演结果表明,计算值与实测值在数值和变化规律上总体符合较好,反演结果合理可靠且更加高效。  相似文献   

石佛寺水库主坝坝基液化分析与防治     

王奎峰  ;孙春圃 《中国煤炭地质》2009,(3):45-48

运用标贯法和seed简化方法对坝基的抗震液化进行了分析判别,发现坝基中粉砂和细砂层存在严重液化问题,中砂层局部存在液化问题,液化深度一般为7～9m,最大液化深度可达13.2m。依据坝坡稳定分析结果,确定上、下游坝脚内15m,坝脚外5m为坝基液化处理范围,粉砂、细砂层为主要处理地层。在实际防治工作中,采用振冲碎（砂）石桩或振动沉管砂石桩,结合水平排水对坝基的地震液化进行处理。处理后对各区砂土层的密实度及饱和砂土的地震液化进行检验,结果表明处理厚的坝基基本上达到了基础处理的目的。  相似文献   

泥石流防治工程设计的若干问题初探     

江峰 《中国地质灾害与防治学报》2009,20(4):36-40

本文以南靖县帮科泥石流防治工程设计工作为例,选取了影响该泥石流形成的10项因子,利用模糊数学综合评判法对该泥石流危险程度进行了评价,为福建省泥石流预测预报及防治提供了定量的数学分析方法,有利于福建省科学防灾工作的进一步开展。此外,本文还对帮科泥石流防治工程中拦挡坝的设计方法进行了初步探讨,明确提出设计中坝体的稳定性演算可以简化为抗滑稳定演算等三个注意事项,并针对福建省的气候、土壤条件,提供了泥石流生物治理措施中的几种优势树种及其基本种植方案。相信本文对福建省其他泥石流防治工程设计具有借鉴意义。  相似文献   

考虑湿化效应的堆石料Gudehus-Bauer 亚塑性模型应用研究     

岑威钧  Erich Bauer  Sendy F.Tantono 《岩土力学》2009,30(12):3808-3812

在扼要分析堆石料主要力学特性的基础上,在亚塑性理论框架内,采用扩展的Gudehus-Bauer亚塑性模型对堆石料因含水率发生变化引起的湿化行为进行建模预测。扩展模型除能考虑含水率对颗粒硬度的影响外,还能反映土体密实度、应力状态和含水率等对堆石料非线性和非弹性变形的影响。将该模型应用于心墙坝初次蓄水时应力变形的亚塑性计算分析中。结果表明,扩展模型能较合理地反映心墙堆石坝的湿化变形规律。  相似文献   

Numerical study of the effects of check dams on erosion and sedimentation in the Pachang River   总被引：2，自引：0，他引：2  

Hui-ming HSIEH  Ching-ruey LUO  Jinn-chuang YANG  Rou-fei CHEN 《国际泥沙研究》2013,28(3):304-315

Scouring and deposition processes resulting from variable rainfall and typhoon occurrence in tropical climatic conditions induce significant changes in the riverbeds of Taiwan. Along the Pachang River of western Taiwan, severe damage occurs during typhoons due to large and sudden variations in discharge, erosion, sediment transport and deposition. In order to simulate this process, the NETSTARS numerical modeling tool was used in the present paper. The influence of existing and planned check dam structures on flow control was also analyzed to determine their capacity to resist river erosion or to not be buried beneath sediments. Not only does the modeling tool allow calculation of the erosion-deposition behavior at the scale of the whole river, but it also provides local determination of the optimum location and characteristics such as foundation depth and lateral encroachment of future check dams. The results of a 10-year, long-term modeling simulation in terms of riverbed stability and scouring potential thus provide insights about unsafe future behavior at 4 sites. This numerical model provides a better general understanding and useful information for the optimal prevention of both the scouring damage and the burial related to sediment deposition with large changes in discharge and sediment transport.  相似文献   

Earthquake response of concrete arch dams: a plastic–damage approach     

Omid Omidi  Vahid Lotfi 《地震工程与结构动力学》2013,42(14):2129-2149

There are several alternatives to evaluate seismic damage‐cracking behavior of concrete arch dams, among which damage theory is the most popular. A more recent option introduced for this purpose is plastic–damage (PD) approach. In this study, a special finite element program coded in 3‐D space is developed on the basis of a well‐established PD model successfully applied to gravity dams in 2‐D plane stress state. The model originally proposed by Lee and Fenves in 1998 relies on isotropic damaged elasticity in combination with isotropic tensile and compressive plasticity to capture inelastic behaviors of concrete in cyclic or dynamic loadings. The present implementation is based on the rate‐dependent version of the model, including large crack opening/closing possibilities. Moreover, with utilizing the Hilber–Hughes–Taylor time integration scheme, an incremental–iterative solution strategy is detailed for the coupled dam–reservoir equations while the damage–dependent damping stress is included. The program is initially validated, and then, it is employed for the main analyses of the Koyna gravity dam in a 3‐D modeling as well as a typical concrete arch dam. The former is a major verification for the further examination on the arch dam. The application of the PD model to an arch dam is more challenging because the governing stress condition is multiaxial, causing shear damage to become more important than uniaxial states dominated in gravity dams. In fact, the softening and strength loss in compression for the damaged regions under multiaxial cyclic loadings affect its seismic safety. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Sedimentation and new operational curves for Mosul Dam,Iraq     

Issa E. Issa 《水文科学杂志》2013,58(7):1456-1466

Abstract

Mosul Dam is one of the biggest hydraulic structures in Iraq. Its storage capacity is 11.11 × 10⁹ m³ at a maximum operation level of 330 m a.s.l. The dam became operational in 1986 and no survey has been conducted to determine its storage capacity and establish new operational curves since this date. A topographic map of scale 1:50 000 dated 1983 was converted into triangulated irregular network (TIN) format using the ArcGIS program to evaluate the operational curves. Then the reservoir was surveyed in 2011 to establish the reduction in its storage capacity and to develop new operational curves. The results indicated that the reduction in the storage capacity of the reservoir was 14.73%. This implies that the rate of sedimentation within the reservoir was 45.72 × 10⁶ m³ year^?1. These results indicate that most of the sediment was deposited within the upper zone of the reservoir where the River Tigris enters the reservoir.

Editor D. Koutsoyiannis

Citation Issa, E.I., Al-Ansari, N., and Knutsson, S., 2013. Sedimentation and new operational curves for Mosul Dam, Iraq. Hydrological Sciences Journal, 58 (7), 1456–1466.  相似文献   

Ancient dams,settlement archaeology and Buddhist propagation in central India: the hydrological background     

《水文科学杂志》2013,58(2):277-291

Abstract

A group of ancient dams (c. second—first century BC) was located during an archaeological study of the Sanchi area in central India. Comparison of reservoir volumes with estimated inflows suggests that their design was based on hydrological understanding.  相似文献   

Response of an arch dam to non-uniform excitation generated by a seismic wave scattering model     

《Soil Dynamics and Earthquake Engineering》2013

Non-uniform ground motions are generated based on a single record available at a site and seismic wave scattering analysis. The Chino Hills 2008 earthquake records at the Pacoima Dam site are used to indicate the accuracy of the method. Dynamic analysis of the Pacoima dam-reservoir-foundation under uniform and non-uniform ground motions is carried out using the EACD-3D2008 software, and the results are compared to recorded responses at different locations on the dam. There is good agreement between computed and recorded displacements of the dam for non-uniform excitation. For uniform excitation, the displacements are underestimated in comparison with those obtained from recorded excitation. Significant intensification of stresses, especially near the foundation, and different patterns of stress distribution are observed for non-uniform excitation in comparison with uniform excitation. For uniform excitation maximum stresses occur in the crown cantilever near the crest, but for non-uniform excitation the maximum stresses occur along the sides and near the foundation.  相似文献