Optimal operation model of a single reservoir with drought duration explicitly concerned

In this paper, a new model for a single reservoir operation optimization is proposed. The proposed model can design the optimal operation policy of a reservoir with explicit consideration of drought duration. The authors model this problem by formulating a single-stage loss function as a function of both the reservoir release and drought duration. Thereby the expected loss per period which is calculated based on the above extended single-stage loss function is minimized in infinite time horizon on the basis of Markov decision process (MDP) theory. The reliability indices are estimated as expected loss per period for specified extended loss functions. Finally, the features of the proposed model are illustrated through numerical analysis.     

苍山十八溪的水石流及其防治

云南省苍山十八溪发育十分典型的水石流,流动时表面为高含沙洪水,底部为粗相沙砾和巨石,固液两相离析为非均质两相流。流体具有很大的动能和冲击力,对富绕的苍洱平坝区造成危害。为了治灾除害,保护生态环境,本文对防治目的、治理目标、防治方针与方法,以及实施顺序、程序、方案、技术措施等问题作了阐述。     

汶川县南沟滑坡与防治

滑坡位于汶川县城关镇南沟,属深层牵引式土质滑坡。该滑坡正处于活动期,一旦大规模活动,将危及县政府等几十个机关、学校和居民的安全,给数千人的生命、财产带来极大的损失。本文提出了筑坝、排水、封山育林等具体防治方案和措施。     

辽东湾丛式钻井陀螺侧钻及导向钻井防碰技术

本文介绍渤海辽东湾实验区AI平台丛式定向井最后钻完的3口侧钻绕障井。在有邻井和本井套管磁干扰情况下,特别是与邻井间距最小仅为0.6m,采用陀螺定向侧钻以及导向钻井技术相结合,安全顺利的钻完了这3口井。总结和介绍了侧钻、防碰的工艺特声,以及安全措施。研究和分析了使用陀螺定向侧钻,钻速与造斜率,井眼轨迹合理控制等问题。     

近景摄影测量在宋陵石刻测绘中应用的几个问题

本文论述了在宋陵石刻近景摄影测量中的几个技术问题，并进行了精度估算，实际应用证明这种方法是有效的。     

Field compaction control studies on road bases in a new settlement area in Ghana

Summary Among the major causes for failure of roads in the tropics is inadequate compaction during construction. There is, therefore, the need to strictly control the compaction of the pavement layers if the design life of the road is to be attained; thereby eliminating large maintenance costs.This note reports on pavement compaction control studies undertaken on the road bases of service roads in a new settlement area in Ghana. These roads were to be provided with bituminous surfacing immediately after compaction. Studies concerning particle breakdown during field compaction by two contractors executing the works under the same conditions have been made, together with an assessment of contractor efficiency.It was found that the placement moisture contents varied greatly from the optimum. One contractor was compacting the gravels on the dry side of optimum, consequently achieving relatively high densities. The other contractor was compacting on the wet side and achieving lower density levels. This was still the case even after initial test sections were found to have been undercompacted.Compaction levels achieved in the crowns were generally found to be higher than those at the shoulders of the road test sections. The breakdown of coarse particles due to compaction was quite significant. There is therefore the need for highway material engineers to ensure that in addition to meeting the grading requirements, road base materials must adequately meet the requirements on weathering and mechanical strength properties.     

瑞典硫化物矿山尾矿淋滤水的控制

在瑞典,硫化物矿尾矿污染水的淋滤造成巨大的环境污染问题。本文概述一项利用天然土覆盖尾矿、最大限度地减少淋滤水的调查报告。研究表明,天然土渗水性是如此之高,以致于起不到明显的隔水效果。天然土盖层只能减少高降雨量期或迅速化雪期的渗水量,而且只对淋滤水峰值有作用。但是,作为一种蓄水体,位于尾矿顶部的密封盖层具有重要意义,它可以增加蒸腾损失。     

采用小径密抗桩一条龙抢治滑坡的方法及效果

以往整治滑坡,较多地使用大口径挖孔桩或钻孔灌注抗滑桩,周期长、成本高。川地208队在治理重庆制药五厂已处于危急态势的滑坡中,采用“天平式”控制、勘治结合、快速抢险,用三排小径密抗桩(300mm口径)整治,取得明显成效。实践表明:浅层滑坡采用较小口径的密抗桩,并辅以排水,能达到事半功倍的效果。     

重庆大学危岩锚固工程简介

重庆大学18层高层建筑物拟建在嘉陵江高陡斜坡脚下,斜坡上部陡崖为侏罗系上沙溪庙组巨厚层砂岩,岩石原生及岸剪裂隙发育,危岩直接威胁着建筑物。川地208队采用锚杆加固及涂抹砂浆水泥护坡综合防治工程,效果明显。     

A new area for earthquake resistant engineering: the control of seismic responses of structures

This paper summarizes the origin and idea of the control of civil engineering structures and reviews the state-of-the art of recent advances in structural control both theoretically and technologically. The prospects for structural control and key research objects to remain to be solved are put forward at last. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 375–380, 1993.