爆炸液化场地中浅埋钢筋混凝土结构动力响应的现场试验研究

饱和砂土地基在爆炸荷载作用下会发生液化,地基上的结构物将受到爆炸荷载及地基液化的双重作用,从而产生不均匀沉降和破坏性变形。基于大型现场爆炸液化试验,对场地上钢筋混凝土(RC)结构的动力响应和地基液化后RC结构的变形进行了分析研究。结果表明:液化场地中浅埋RC结构产生了明显的不均匀沉降,且最大沉降量达到结构高度的10%,结构差异沉降达到最大沉降量的1/5,结构沉降变形在液化后15 h时基本稳定;RC结构表面未产生明显的裂缝,动态拉、压应变均在400??以内,不会对结构造成显著破坏;结构动力响应表现为柱侧加速度峰值明显大于梁侧,但柱侧动力稳定所需时间较梁侧短,即柱承受了更大的瞬时冲击力且其抵抗瞬时冲击力的能力更强。研究结果可以为在可液化地基中的浅埋RC结构稳定设计等工程情况提供参考。     

A multi‐proxy sediment record of late Holocene and recent climate change from a lake near Ny‐Ålesund,Svalbard

Jiang, S., Liu, X., Sun, J., Yuan, L., Sun, L. & Wang, Y. 2011: A multi‐proxy sediment record of late Holocene and recent climate change from a lake near Ny‐Ålesund, Svalbard. Boreas, Vol. 40, pp. 468–480. 10.1111/j.1502‐3885.2010.00198.x. ISSN 0300‐9483 The Arctic constitutes a unique and important environment with a significant role in the dynamics and evolution of the earth system. Arctic lake sediments, which accumulate slowly over time, contain abundant information about the biological communities that lived within the water body, as well as in the surrounding catchment. In this study, we collected a sediment core from Ny‐Ålesund, Svalbard, performed multi‐proxy analyses on sediment pigments, mineral magnetic susceptibility, various sediment quality (i. e. organic matter content, CaCO₃ content, carbon and nitrogen isotope), and diatom composition, and reconstructed the history of ecosystem responses to environmental variations, especially regarding aquatic productivity and lake catchment surface processes. Ny‐Ålesund has undergone distinct ecological and climatic changes. During the Little Ice Age, the cold climate was unfavourable for the growth of lake algae, and therefore the lake primary productivity declined. After about AD 1890 and during the 20th century, the warming climate and reduced ice cover led to rapid lithological change and growth of lake algae, enhanced lake primary productivity, and increased input of nutrients derived from increased chemical weathering into the lake. The lake ecosystem on Ny‐Ålesund has had rapid responses to climatic and environmental changes in the Arctic.     

西畴县近48年来降水及气温小波分析

利用连续小波分析1962～2009年西畴县年降水量和年平均气温序列的小波变化特征,揭示了西畴县降水量与平均气温存在多时间尺度的周期变化特征。其中降水有2个明显的特征时间尺度,分别是4年和8年,平均气温存在以准2～4年为周期的周期振荡。此外,也可以看出近48年来,平均气温存在明显升高的趋势,降水也有减少的趋势,为掌握西畴县的气候变化规律及今后的气象预报服务工作提供了一定的参考价值。     

Pollen-based reconstructions of Holocene vegetation and climatic change of Tibetan Plateau

A synthesis of Holocene pollen records from the Tibetan Plateau shows the history of vegetation and climatic changes during the Holocene. Palynological evidences from 24 cores/sections have been compiled and show that the vegetation shifted from subalpine/alpine conifer forest to subalpine/alpine evergreen sclerophyllous forest in the southeastern part of the plateau; from alpine steppe to alpine desert in the central, western and northern part; and from alpine meadow to alpine steppe in the eastern and southern plateau regions during the Holocene. These records show that increases in precipitation began about 9 ka from the southeast, and a wide ranging level of increased humidity developed over the entire of the plateau around 8-7 ka, followed by aridity from 6 ka and a continuous drying over the plateau after 4-3 ka. The changes in Holocene climates of the plateau can be interpreted qualitatively as a response to orbital forcing and its secondary effects on the Indian Monsoon which expanded northwards     

湿地的防洪功能分析评价——以东洞庭湖为例

湿地作为生产力最高的土地类型,具有水文、水质、食物链和栖息地等方面的功能以及社会经济价值。其中水文功能主要表现在防洪功能方面,包括调蓄洪水、削减洪峰、滞流和减少侵蚀等。文中通过利用地理信息系统、遥感数据、模拟、统计分析和空间计算等方法,定量分析评价东洞庭湖湿地的防洪功能,提出了湿地防洪功能评价方法。     

水准测量中尺度比参数的附加系统参数的Partial EIV模型解法

针对目前水准测量中尺度比参数的附加系统参数的平差模型,本文对模型进行重构,提出尺度比参数的附加系统参数的partial errors-in-variables（Partial EIV）模型,给出总体最小二乘准则下的解算公式及迭代算法。实际算例和模拟数据结果表明,本文方法与传统方法在处理尺度比参数为附加系统参数时的效果基本一致,并给出相关的理论依据。     

重力数据约束的二维地震层析成像在台湾海峡南部的应用

地震-重力联合反演可以降低多解性,针对大勘探范围内岩石波速-密度关系存在较大散布的问题,引入交叉梯度结构约束构建统一的目标函数是一种有效的解决方案。利用台湾海峡南部HX-13测线进行验证:由于火成岩侵入体的存在,部分区域难以拾取可靠的地震初至,常规的走时反演无法准确恢复基底面的形态。搜集研究区的船测重力资料,根据地震地质条件和数据特点设置合适的反演参数,实现基于物性和结构双重约束的重力-地震联合反演。由对反演结果的分析和解释可以看出,该方法可在很大程度上弥补地震数据不完备的缺陷,使反演过程稳定,并提高模型的可靠性。     

水井测温在地热普查中的应用

利用水井测温方法确定恒温层温度,以恒温层的温度值作为湖顶地热异常区的下限值,用内插法勾绘温度等值线图,高于该下限值范围的即为地热异常区。曹县庄寨地区的地热普查证明该方法是快速有效的。     

澳大利亚拉克兰造山带成矿地质条件与主要矿化类型

澳大利亚拉克兰造山带（又称拉克兰褶皱带,简称LFB）由强烈变形的寒武纪—泥盆纪深海沉积岩、燧石和基性火山岩,以及更年轻的盖层所构成,其造山过程表现为澳大利亚板块向东南方向不断增生的过程。该造山带的长期演化,形成了以维多利亚金矿省为典型代表的造山型金矿床及其它类型的多金属矿床,本质上这些矿床的形成与特殊的成矿地质条件密切相关。对该区相关文献进行分析和总结,提炼出拉克兰造山带金及多金属矿床的主要地质特征,划分出5种主要矿化类型：造山型金矿、花岗岩中细脉浸染型钨—锡矿、斑岩型铜—金矿、火山喷流铜—锌—金硫化物矿床、产于断陷盆地沉积岩中的铜—铅—锌—金矿。5种矿化类型各具特色,空间上有规律性地分布。