三峡水库引水工程(方案)秦巴段地壳稳定性评价研究

三峡水库引水工程（方案）是南水北调的重要补充工程,具有重要的战略意义和经济意义。本文在分析现今构造应力场、地壳结构、构造格架、活动断裂、地震活动、工程地质岩组等影响地壳稳定性主要因素的基础上,利用模糊数学综合评价模型分构造稳定性和岩土体稳定性两个层次评价工程场地的稳定性。评价结果表明,三峡引水工程场地地壳稳定性较高,适合兴建大型引水工程。同时,运用地壳稳定性评价结果对三条规划线路进行了优化比选,结果表明以中线为最好。     

三峡水库下游宜昌—昌门溪河段河床调整分析

建立反映河床调整幅度的体幅指标K,分析2003～2008年三峡水库下游宜昌—昌门溪河段河床调整幅度的沿程变化。研究发现该河段K与河段净冲刷强度不成正相关,而是与河道宽深比成正相关,当床沙中值粒径小于0.5 mm时,K与床沙中值粒径成负相关。初步分析认为:三峡下游粗颗粒泥沙容易达到输送饱和状态,当水流挟沙力减小时出现落淤,使得宽浅河段局部出现较大淤积,净冲刷强度较小,调整幅度较大;当床沙中值粒径小于0.5 mm时,该河段河床冲刷以悬移质输沙为主,河床组成越细,被冲刷的量越大,河床调整幅度也就越大。结合建库前后不同粒径组悬移质输沙量的沿程变化,对水库下游河床粗化方式进行了讨论。     

地幔内变粘度的滞弹性流体运动的三维有限元模型

建立了描述具有无限大Ｐｒａｎｄｌｔ数，变粘度的滞弹性流体运动的稳态和动态三维有限元公式，其中运动方程的有限元公式是由用应力分量表示的平衡方程，再利用牛顿流体的本构关系导出的。这种处理方式，不仅能够分析流体粘度变化所起的动力学作用，而且还能够直接计算温度分布和由流体运动所引起的扰动压力。最后，论证了导出的有限元公式和程序的正确性和可靠性，并给出了具有三维流动特征的算例     

河西地区城镇体系特征及未来发展构想

河西地区城镇体系在空间地域结构上,表现出绿洲城镇的特点;在职能类型结构上,以综合性城镇为主;在规模等级结构上,具有经济不发达地区城镇体系的共性. 未来城镇体系建设,必须从区域整体发展的宏观思路出发,统一构建与绿洲环境相协调的城镇体系格局,使水资源能够支持重点城镇的发展,围绕酒泉市、张掖市、武威市和敦煌市4个区域中心城市,有意识地利用"点-轴"结构,积极培育次级中心,形成空间分布合理、职能类型多样、规模等级协调的城镇体系网络,促进河西地区社会经济的持续发展.     

三峡水库消落带适生树种落羽杉(Taxodium distichum)叶片-细根碳/氮/磷生态化学计量特征

为探究三峡库区消落带落羽杉（Taxodium distichum（L.） Rich.）叶片与细根C、N、P生态化学计量特征,于2018年7月对忠县三峡库区消落带植被修复示范基地3个水淹处理组（深度水淹组,DS;中度水淹组,MS;浅淹对照组,SS）的落羽杉进行叶片与细根采集,并调查其生长特征,测定分析落羽杉叶片与细根C、N、P生态化学计量特征及相关性.结果表明：（1）各水淹处理组落羽杉叶片C含量表现为SS组 > DS组 > MS组,且SS组显著高于MS组;细根C含量在不同水淹处理组之间均无显著性差异.（2）细根N、P含量表现为DS组 < MS组 < SS组的协同增长趋势;叶片N、P含量则表现为DS组 > MS组 > SS组的协同降低趋势,且叶片N、P含量分别约为细根N、P含量的3倍和2倍.（3）各水淹处理组的叶片C/N、C/P比值均显著或极显著低于细根;叶片N/P比值均高于细根,且其比值相对恒定,均表现为SS组 > DS组 > MS组的趋势.（4）相关性分析表明,叶片P含量与细根N含量呈显著负相关关系,叶片N/P比值与细根N/P比值呈显著正相关关系.研究表明,落羽杉叶片与细根在生长和代谢过程中具有整体性,养分和光合产物在地上与地下部分之间分配权衡,以维持营养的动态平衡,使落羽杉具有内稳性,从而更好地适应和响应三峡消落带水位变化.     

Sediment budget and riverbed deformation in the uppermost part of the lower Yangtze River,China

The Yangtze River(YR), similar to most large rivers in the world, has experienced significant changes in its depositional environment due to anthropogenic disturbances and climatic influences in recent decades. However, knowledge of how the river channel and bed deformation respond to these changes in the uppermost part of the lower YR, a 200-km-long branched channel, is limited. In the current study,historical bathymetric data collected from 1992 to 2013 and high-resolution multibeam echo sound...     

长江三峡地区仙女山断裂北端延伸问题探讨

The Xiannvshan fault zone, lying along the western margin of the Huangling anticline, is one of the most important fault zones in the Three Gorges reservoir area. The fault experienced strong activity during the Cenozoic Era. The question of whether the fault zone goes through the Yangtze River has been one of the key problems faced in previous studies as it has a significant influence upon the assessment of geological hazards and earthquake stability in the reservoir area. Based on tectonic and geomorphic observations along the fault zone between the Baixianchi village in Changyang county and Huangkou village in Zigui town, together with the comparisons between the geology in Guizhou and Quyuan town in the north bank of the Yangtze River and the Xiannvshan fault zone, it is suggested that the north end of this fault zone is located around Huangkou village and does not go through the Yangtze rivers northward. The evidence is as follows: ① On the basis of field data collection, it is found that the Xiannvshan Fault zone, which stretches 80km, underwent thrust movement in the Cenozoic period, resulting in ravines and fault scarps, topographically. Whereas, on the northern bank of the Yangtze River, faults are rarely found, and most of the faults are developed in the Jurassic strata,without topographical effects. Therefore, the Xiannvshan Fault zone has not stretched to the north bank of the Yangtze River. ② The fault gouge and tectonite zone were found developed on the Xiannvshan Fault zone at Baixianchi village, but only a tectonite zone was found at Zhouping village. There are also some branch faults close to the northern end of the fault zone. So, the activity of the fault zone weakened from south to north in Cenozoic. The fault zone extends northward and dies out at Huangkou. It doesn’t stretch forward any longer as indicated by continuous strata, sparse joints, and small folds, etc.     

长江三峡非正常含炭粘土沉积及其地质灾害意义

在长江三峡工程库区巫山、奉节、云阳等新县城进行工程地质勘察过程中, 发现在长江岸坡地带存在含炭粘土沉积.对部分含炭粘土进行了14C年龄测定, 年龄测定结果与该含炭粘土层所在高程相当的阶地形成年代不一致, 含炭粘土为非正常沉积.非正常含炭粘土的存在与发现, 一方面揭示出巫山等移民新县城斜坡经历了非正常的形成演化; 另一方面说明长江三峡河谷演化过程中夹杂着突发的地质灾害事件.      

1997年回归与港深管理线

保持香港繁荣与稳定的重要性已在１９８４年的中英联合声明中得到保证。在１９９７年７月之后，香港将回归祖国而成为中国的特别行政区，并且实行“一国两制”５０年不变，从而保持香港现有的繁荣。本文旨在探讨港深管理线在香港成为特别行政区后对保持香港的繁荣和稳定 和香港于１９９７年回归后这条管理线及其接壤地区的规划问题。     

pCO2 distribution and CO2 flux on the inner continental shelf of the East China Sea during summer 2011

Measurements of pH,total alkalinity(TA),partial pressure of CO2(pCO2) and air-sea CO2 flux(FCO2) were conducted for the inner continental shelf of the East China Sea(ECS) during August 2011.Variations in pCO2 distribution and FCO2 magnitude during the construction of the Three Gorges Dam(TGD)(2003-2009),and the potential effects of the TGD on the air-sea CO2 exchange were examined.Results showed that the ECS acts as an overall CO2 sink during summer,with pCO2 ranging from 107 to 585 μatm and an average FCO2 of-6.39 mmol/(m2·d).Low pCO2(<350 μatm) levels were observed at the central shelf(28°-32°N,123°-125.5°E) where most CO2-absorption occurred.High pCO2(>420 μatm) levels were found in the Changjiang estuary and Hangzhou Bay which acted as the main CO2 source.A negative relationship between pCO2 and salinity(R2=0.722 0) in the estuary zone indicated the predominant effect of the Changjiang Diluted Water(CDW) on the seawater CO2 system,whereas a positive relationship(R2=0.744 8) in the offshore zone revealed the influence of the Taiwan Current Warm Water(TCWW).Together with the historical data,our results indicated that the CO2 sink has shown a shift southwest while FCO2 exhibited dramatic fluctuation during the construction of the TGD,which is located in the middle reaches of the Changjiang.These variations probably reflect fluctuation in the Changjiang runoff,nutrient import,phytoplankton productivity,and sediment input,which are likely to have been caused by the operations of the TGD.Nevertheless,the potential influence of the TGD on the CO2 flux in the ECS is worthy of further study.