古河道对工程场地地震动参数的影响

以上海浦东机场二期航站楼软土场地为例,应用二维土体模型和一维土体模型分别计算了深覆盖土层的地震反应,讨论了古河道对场地地震动参数的影响。此外,在二维土层地震反应分析中,进一步对比了基岩面地震波行波输入和一致输入下,场地地震动参数的差异。     

Pseudo‐dynamic testing of bridges using non‐linear substructuring

Pseudo‐dynamic tests on a large‐scale model of an existing six‐pier bridge were performed at the ELSA laboratory using the substructuring technique. Two physical pier models were constructed and tested in the laboratory, while the deck, the abutments and the remaining four piers were numerically modeled on‐line. These tests on a large‐scale model of an existing bridge are the first to have been performed considering non‐linear behavior for the modeled substructure. Asynchronous input motion, generated for the specific bridge site, was used for the abutments and the pier bases. Three earthquake tests with increasing intensities were carried out, aimed at the assessment of the seismic vulnerability of a typical European motorway bridge designed prior to the modern generation of seismic codes. The experimental results confirm the poor seismic behavior of the bridge, evidenced by irregular distribution of damage, limited deformation capacity, tension shift effects and undesirable failure locations. Copyright © 2004 John Wiley & Sons, Ltd.     

1∶25万修测区数字地质填图前人剖面资料录入、验证的工作方法——以广西1∶25万玉林市幅为例

进行过大量 1∶5万区调填图、研究程度较高地区的 1∶25万区域地质调查,其核心任务是充分挖掘利用前人资料及二次开发,在广西 1∶25万玉林市幅PRB数字填图试点过程中,经过两年多来的摸索研究,初步总结出一套前人剖面资料录入、验证、批注、修测和成图过程的工作方法,已基本上达到了在 1∶25万区调修测区推广应用的“实战性”要求。     

塔里木河下游断流河道应急输水与地表植被响应

通过对塔里木河下游5个断面、30个植物样地的调查和对天然植物当年生小枝的长度、当年生小枝上胡杨的叶数、50片以上叶长、宽及叶重、芦苇的高度和叶长、宽、重量等的测试分析，揭示了塔里木河下游断流河道输水后地表植被的响应范围。研究表明，随着输水后地下水位的抬升，地表植被产生了明显变化。在横向上，芦苇的反应敏感区范围在100～150m区间；对胡杨的横向影响范围在200～250m之间；在纵向上，平均叶数从下游上段至下游下段，分别较末端断面增加57％、22．2％、9．2％；河道两岸地下水位较下游下段抬升幅度大，横向上对植被的影响范围也较下游下段宽。输水历时的长短和输水量对塔里木河下游植被恢复密切相关。