北河桥闸工程水工断面模型试验研究

为解决北河桥闸工程下游消能问题,采用水工断面模型试验的方法对其消能工程进行优化。试验表明,原设计方案闸孔下泄水流在消力池内未形成淹没水跃,不满足设计提供的闸门调度运行要求。考虑工程安全并结合类似工程,模型推荐方案为:在原设计方案消力池内加设消能墩,水流在消力池中形成强迫水跃。     

铅芯橡胶隔震桥梁结构的地震反应动力分析

以一端铰支一端滚动的简支桥和采用铅芯橡胶隔震支座的简支桥为研究对象,分别进行地震作用下的弹塑性动力反应分析。为考察铅芯橡胶隔震支座对桥梁隔震效果的影响,分别在隔震和未隔震情况下输入不同幅值的Elcentro地震波,计算出上部结构的加速度反应和相对位移。地震反应分析结果表明:动力分析中所用的结构计算模型、恢复力模型和参数及计算程序是可行的。通过对地震动力反应数据的分析,选择适当尺寸参数的铅芯橡胶支座作为隔震装置,改善结构动力特性,可以降低桥面及桥墩的地震响应,在整体上提高了结构的安全性及抗震性能,增强桥梁结构的抗震能力,从而得到较好的抗震效果。     

抗生素在土壤中的吸附行为研究进展

抗生素是畜禽养殖和水产养殖中常用的一类化学品,其使用量大,体内代谢率低,可通过畜禽粪便的农业施用直接进入土壤环境,在土壤中易残留,富集到一定水平就可能影响生态健康和安全.目前,抗生素污染最令人类担忧的风险是抗性基因和抗性病菌的滋生和传播.抗生素在土壤中的吸附作用是影响其持留、分布、迁移、转化及最终归趋的关键过程.本文选择四环素类、磺胺类、大环内酯类和喹诺酮类4类常用抗生素,论述了pH值、离子强度和金属离子、有机质以及其他土壤理化性质等因素对其吸附的影响,并对抗生素在土壤中的吸附机理进行了初步的探讨.     

关于桥面板式橡胶伸缩装置耐久性的研究

本文通过大量调查对板式橡胶伸缩装置进行了深入研究。找出其亏损的主要原因,并从设计、材料和施工工艺入手。切实解决板式橡胶伸缩装置的耐久性的问题。     

Wind Tunnel Tests of Long Span Half - through Arch Bridge Section Model

Wind induced vibration is one of the main control factors in the Long span bridge structure design. The wind tunnel tests for measuring the static wind forces on the bridge girder and the section model wind tunnel dynamic testing for Caiyuanba Yangtze River Bridge in Chongqing are introduced in this paper. The wind tunnel testing for measuring static wind forces and vortex- induced vibration test on the arch are introduced taking account of the influence between two arches. The main contents and outcomes of testing are presented. It is indicated that the bridge girder has excellent wind stability and the arch mechanical characters are rather complicated. The drag force on the hind arch varied a lot because of the font arch interference on the wind flow. The drag force on the hind arch will be negative when two arches are close to each other. It increases with the space of two arches. The results of testing will give the data of buffeting and vortex - induced vibration and flutter analysis of the bridge.     

Analysis of Construction Risk for Water Piers and Foundations with Double-wall Steel Cofferdam Based on the Fuzzy Fault Tree Theory

Construction risk for water piers and foundations with double-wall steel cofferdam was analyzed by the fuzzy fault tree theory. An evaluation method of construction risk for water piers and foundations with double-wall steel cofferdam was proposed. Fuzzy fault tree of construction risk for water piers and foundations with double-wall steel cofferdam was established based on Yingwuzhou Yangtze River Bridge. 31 bottom events were considered in fuzzy fault tree model according to 2 water pier and foundation with double-wall steel cofferdam. Key process of construction risk was obtained and risk prevention measures were proposed.Results showed that fuzzy number of construction risk probability for water piers and foundations with double-wall steel cofferdam was(0.05015,0.05278,0.05542). Construction risk of 2 water pier was highest. And weld leakage, pile broken and sand boiling were the key processes with higher construction risk. There fore appropriate prevention measures would be taken to reduce the construction risk for water piers and foundations with double-wall steel cofferdam.     

四方台大桥主墩承台混凝土冬季施工配比设计

本文重点介绍了四方台大桥主墩承台大体积混凝土冬季施工配比的设计。试验表明：配制大体积混凝土，水泥应选用低水化热水泥，尽量采用级配良好的骨料，掺入适量的缓凝剂，可以降低大体积混凝土早期的水化放热速率，还可以降低水泥水化过程中的放热峰值，从而使混凝土内外温差减小。     

土—端承桩—结构相互作用对连续梁桥自振特性的影响

本文根据连续介质力学理论,用传递矩阵法求得分层土端承桩的阻抗函数。由于桩基础的阻抗函数随频率变化,所以结构的刚度矩阵也是频率的函数。为求解非线性特征值问题,采用了逐步逼近的方法,反复调用广义雅克比程序,直到求得真实的自振频率和振型为止。将本文的计算结果和刚性地基的计算结果作了比较表明:考虑桩基础参与振动时求得的自振频率和振型变化较大,还没有达到可以忽略的程度。     

太浦河工程水量水质联合调度对金泽水库及松浦大桥取水口水质影响研究

金泽水源地及黄浦江松浦大桥备用取水口是黄浦江供水系统的重要组成部分,改善金泽、松浦大桥断面水质对保障上海市西南五区供水安全具有重要意义.研究了近年太浦河工程实况调度,设计了太浦闸流量分级调度方案、太浦闸水质超标分级调度方案并进行优选,在此基础上拟定了1个常规流量分级调度方案、2个水量水质联合调度方案,并采用对重点研究范...     

泸州长江二桥非对称大跨连续刚构的施工控制

泸州长江二桥为大跨度非对称连续刚构，采用悬臂浇筑施工．由于施工过程复杂。结构的内力和变形变化较大，必须对其进行施工过程的控制．主要介绍了施工监控技术的原理和方法．通过有效地施工控制，给出了线形和应力控制的结果，为提高桥梁施工质量和安全可靠提供科学保证．