海洋钢筋混凝土结构牺牲阳极保护系统电极行为的研究

于１９８９－１９９０年在室内条件下，用牺牲阳极保护浸泡于海水中的多种钢筋凝土试件测试不同试件中钢筋极化与阳极布局、涂层质量，涂层厚度及试件浸水情况的关系。结果表明，牺牲阳极能有效地保护全浸海水中的混凝土试件，对间断浸淋海水的试件也有一定的保护作用，通过改善阳极安装工艺，保护作用可望提高；电偶电流在各阴阳极上的分布将随涂层质量，涂层厚度和试件浸水情况不同而异，回路中电阻和电极极化情况是影响电流分布的     

Structural modeling and testing of a concrete canoe

A finite element model is set up and experimental tests are performed to help understand the behavior of a concrete canoe and subsequently optimize its design. First, the performance criteria that must be satisfied to participate at the annual ASCE/Master Builders competition are described. Then, the finite element model and the different loading cases that were studied are presented. Results from these loading cases are discussed and used to optimize the material properties as well as the thickness of the hull and the dimensions of the gunwale and reinforcing ribs. Static and dynamic experimental tests were also conducted to validate the results of the finite element analyses. The results indicate that the main stresses and strains are caused by the static load cases. The additional stresses caused during races are small.     

水布垭面板堆石坝的三维弹塑性数值分析研究

在建的清江水布垭面板堆石坝高达233 m,是目前同类坝型中最高的.采用MSC.Marc非线性有限元程序,发展了三维子模型法,对该坝进行了三维弹塑性有限元仿真分析,模拟了面板的分缝、坝体材料分区、填筑及蓄水过程,采用双屈服面弹塑性模型模拟堆石体的变形特征.根据数值分析的结果,对坝体和面板的应力变形分布规律进行了探讨.     

隧洞衬砌中湿喷钢纤维混凝土的应用

基于湿喷钢纤维混凝土的性质，讨论了喷射混凝土的特点及其在暂时支护与永久支护中的应用。     

新型砌块水土保持系统的应用研究

我国江河湖库众多，同时水土流失日趋严重，流失面积及速度已逐年增加。每年水库除险加固和河流治理等投资数百亿元，随着人们环保意识的加强，特别在近几年以长江和黄河为重点的堤防建设护岸工程中，联锁式砼砌块水土保持系统已逐渐成为我国水土保持领域中最重要的一种全新解决方案，被广泛采用。该系统既能有效防止水土流失、长久地防止坡面冲刷和保持坡体稳定，又能代替成本较高的常规护面，具有较广的推广应用前景。联锁式砼砌块水土保持系统是由多个独立的砼砌块相互啮合组合在一起的联锁矩阵，联锁式砼砌块铺面在各种动、静水条件下具有良好的整体稳定性，铺设于渗水土工布上。能有效保护土体不受水流冲刷和浸泡破坏。该系统在欧美已有多年的历史，是被工程实践证明了的性能卓越、经济实用、美观环保、可持续发展的水土保持系统，可广泛应用于河道和灌渠衬砌、沿海防潮堤、水库大坝边坡加固、铁路、高速公路边坡等防护和城市绿化工程。     

巴彦淖尔市水泥混凝土施工冻害指数分析

为了便于开展冬季水泥混凝土施工气象服务,选用临河和海流图（乌拉特中旗）测站近10a的气象资料分别作为河套和后山地区的气象数据．选取逐日最高气温、最低气温、定时相对湿度、最小相对湿度、降水量、定时风速,经过筛选、统计、计算,得出河套地区水泥施工适宜时段为4月上旬末至10月中旬,后n1地区水泥施工适宜时段为4月中旬末至10月上旬．这一研究结果町以提升冬季建筑施工气象服务的针对性和实用性。     

基于GP RMax的隧道衬砌检测数值模拟及应用

利用基于时间域有限差分法( FDTD)的GPRMax,针对常用的400、900、1500 MHz三种不同中心频率的天线,数值模拟了隧道衬砌不同钢筋网密度、不同钢筋直径及其下方的钢拱架、空气界面等目标体的探地雷达反射及干扰信号图像特征;在混凝土试件上开展实验研究,并运用克希霍夫积分偏移处理了数值模拟和实验数据,压制了钢筋的绕射波和多次波,提高了钢筋网下方弱反射信号的成像效果;通过对比分析数值模拟、实验测量和工程实测结果,为探地雷达在隧道衬砌检测中取得更好的探测效果提供了借鉴。     

海上孤立混凝土构筑物的爆破拆除

在海洋工程中,采用爆破手段拆除海上孤立混凝土构筑物或清理孤立大块石是一种快速、有效的方法。文中详细介绍了爆破方案的确定、爆破孔网参数的设计、爆破药量的计算以及安全防护措施,对于类似工程的实施具有重要的参考价值。     

Modelling the flow of self‐compacting concrete

A Lagrangian particle‐based method, smooth particle hydrodynamics (SPH), is used in this paper to model the flow of self‐compacting concretes (SCC) with or without short steel fibres. An incompressible SPH method is presented to simulate the flow of such non‐Newtonian fluids whose behaviour is described by a Bingham‐type model, in which the kink in the shear stress vs shear strain rate diagram is first appropriately smoothed out. The viscosity of the SCC is predicted from the measured viscosity of the paste using micromechanical models in which the second phase aggregates are treated as rigid spheres and the short steel fibres as slender rigid bodies. The basic equations solved in the SPH are the incompressible mass conservation and Navier–Stokes equations. The solution procedure uses prediction–correction fractional steps with the temporal velocity field integrated forward in time without enforcing incompressibility in the prediction step. The resulting temporal velocity field is then implicitly projected on to a divergence‐free space to satisfy incompressibility through a pressure Poisson equation derived from an approximate pressure projection. The results of the numerical simulation are benchmarked against actual slump tests carried out in the laboratory. The numerical results are in excellent agreement with test results, thus demonstrating the capability of SPH and a proper rheological model to predict SCC flow and mould‐filling behaviour. Copyright © 2010 John Wiley & Sons, Ltd.     

Review and enhancement of 3D concrete models for large‐scale numerical simulations of concrete structures

The present paper focuses on selected plasticity and damage‐plasticity models for describing the 3D material behavior of concrete. In particular, a plasticity model and a damage‐plasticity model are reviewed and evaluated. Based on the results of the evaluation, enhancements are proposed, aiming at improving the correspondence between predicted and observed material behavior and aiming at implementing a robust and efficient stress update algorithm in a finite element program for performing large‐scale 3D numerical simulations of concrete structures. The capabilities of the concrete models are demonstrated by 3D numerical simulations of benchmark tests with combined bending and torsional loading and combined compression and shear loading and by a large‐scale 3D finite element analysis of a model test of a concrete arch dam. Copyright © 2011 John Wiley & Sons, Ltd.