我国水资源承载力研究现状及展望

概要说明了我国水资源承载力的研究现状,阐述了水资源承载力的概念、内涵及影响因素,探讨了目前几种常用的水资源承载力评价方法,并对当前研究中存在的问题进行了初步分析,进而提出了我国水资源承载力的研究趋势。     

小岩头滑坡稳定性分析

小岩头滑坡位于贵州省威宁县二(连浩特)河(口)高速公路K255 010~K255 240里程右侧,属一个大型古滑坡,发育于二叠系上统峨嵋山组玄武岩(P2β)地层中。在高速公路施工中对路堑进行深挖削坡,可能导致古滑坡中部、线路右侧斜坡失稳破坏,发生滑坡。因此,滑坡稳定性评价是重大工程地质问题之一。根据大量勘察试验资料,系统地揭示了滑坡的特征,分析了滑坡形成的控制因素、成因和形成机制,建立了滑坡体稳定性计算模型,利用反演计算法进行稳定性分析与评价,认为两滑体均处于滑动失稳状态。建议对滑坡体进行处理,采用排水、支挡、减压等措施进行整治。     

Reliability Based Assessment of Shallow Foundations Using Mathcad

A reliability based method was used to design and analyse shallow foundations using first-order Taylor series approximation. The computer program Mathcad was used to facilitate all mathematical and computional efforts. This method is an effective tool to assist the foundation designers and analyists to investigate how reliable their designs or analyses are in relation to the ultimate bearing capacity of the foundations. The approach presented in this paper provides a reliable alternative for design and analysis of shallow foundations, rather than the conventional design methods, which employs the assumptions of a specified saftey factor. Several examples were presented for design and analysis of strip footings embedded in sandy soil, and rectangular and square footings analysis embedded in clayey soils. The program input and output of each example are also presented and discussed.     

低阻油气储层测井解释方法研究

对低阻油气储层的测井响应特征和储层物性特征进行了研究,并针对研究区域低阻储层的特点,以岩心与测井数据的相关性为依据,提出了适合地区特点的储层参数解释方法。通过应用三水导电模型,提高了低阻储层的测井解释精度。     

水环境容量的影响因素及分析研究

本文采用流量级频率分析和统计分析方法,对黄河下游流量及泥沙含量对水环境容量的影响进行了研究分析.分析结果:河流在平滩流量时不仅输沙能力最大[8],而且输运污染物能力也最大,黄河下游水环境容量萎缩是平滩流量降低的必然结果.     

CCSD主孔1113~1600 m花岗质片麻岩单元的变形构造特征

中国大陆科学钻探(CCSD)主孔2000m岩性剖面揭示了1113～1600m花岗质片麻岩段为地表北苏鲁超高压花岗质变质岩剪切构造叠覆岩片中的石湖镇构造岩片的花岗质片麻岩的下延部分。本单元之上下界线为韧性剪切带,内部发育小型韧性剪切变形,仅局部可见旋转碎斑体系等剪切指向标志,以SE向NW的逆冲剪切指向为主,其次为NW向SE的正滑剪切指向,并主要发育于较软弱夹层内,后者成为苏鲁地区存在伸展型穹隆构造的新证据;在1140～1280m岩性段内发育断续、较弱的拉伸线理,拉伸线理总体向SE倾伏,倾伏角为10～36°;花岗质片麻岩单元内部分石英以多晶石英条带的形式存在,花岗质片麻岩主要矿物长石基本没有动态重结晶现象,仅具较弱的形态拉长特征(X∶Z=2左右),总体面理倾向170°E,倾角平均20°,明显不同于其他岩性单元内的面理产状,可能主要代表折返变形之前的近东西向构造,而其他岩性单元受折返变形影响较大,其面理产状主要代表折返阶段形成的NE-NNE向构造;运用电子背散射(EBSD)技术进行石英组构分析并与费氏台测定对比,表明1113～1600m花岗质片麻岩单元经历了中—低温变形,局部残留有高温组构,剪切指向主要为SE向NW的逆冲,其中高温组构与中温组构均显示为SE向NW的逆冲剪切指向,反映折返早期与折返主期岩片的相对剪切方向一     

韧性剪切变形对岩石地球化学行为的制约——以北阿尔金巴什考供韧性剪切带为例

韧性剪切变形对岩石地球化学行为的制约一直是地质学家们探讨的课题。本文以构成北阿尔金红柳沟——拉配泉俯冲碰撞杂岩带与北阿尔金地块边界的巴什考供斜向逆冲型韧性剪切带为例，通过对韧性剪切带内花岗岩变形前后不同变形强度构造岩的地球化学组成进行对比，确定等比线斜率，探讨韧性变形对岩石体积和成分变异的影响。计算结果表明，在糜棱岩化过程中，糜棱岩化花岗岩体积亏损21％，花岗质糜棱岩体积亏损31％。质量平衡计算结果和等比线图表明，韧；陛剪切作用导致SiO2，流失量最大，A12O3、K2O及Ba、Rb、Sr等都有不同程度的丢失，显示出较强的活动性，MnO、P2O5、Sc位于等比线上或附近，表现出相对的稳定性。岩石中活动组分的变异是流体渗滤作用引起的，不活动组分的变异是体．积亏损造成的。     

基于模糊识别的水资源承载能力综合评价

应用模糊识别模型解决水资源承载能力综合评价问题,根据水资源承载能力相关因子自身的数据结构特性,通过模糊识别模型得到样本的级别特征值,从而达到对待评价区域的识别、归类,同时可以得到各相关因子在评价过程中的贡献率,实例部分将模型应用于全国30个省市、自治区的水资源承载能力评价,结果表明该方法的实用性和客观性。     

A multidisciplinary multi-scale framework for assessing vulnerabilities to global change

Terrestrial ecosystems provide a number of vital services for people and society, such as food, fibre, water resources, carbon sequestration, and recreation. The future capability of ecosystems to provide these services is determined by changes in socio-economic factors, land use, atmospheric composition, and climate. Most impact assessments do not quantify the vulnerability of ecosystems and ecosystem services under such environmental change. They cannot answer important policy-relevant questions such as 'Which are the main regions or sectors that are most vulnerable to global change?’ 'How do the vulnerabilities of two regions compare?’ 'Which scenario is the least harmful for a sector?’This paper describes a new approach to vulnerability assessment developed by the Advanced Terrestrial Ecosystem Analysis and Modelling (ATEAM) project. Different ecosystem models, covering biodiversity, agriculture, forestry, hydrology, and carbon sequestration are fed with the same Intergovernmental Panel on Climate Change (IPCC) scenarios based on the Special Report on Emissions Scenarios (SRES). Each model gives insights into specific ecosystems, as in traditional impact assessments. Moreover, by integrating the results in a vulnerability assessment, the policy-relevant questions listed above can also be addressed. A statistically derived European environmental stratification forms a key element in the vulnerability assessment. By linking it to other quantitative environmental stratifications, comparisons can be made using data from different assessments and spatial scales.     

静压预制桩工程性状研究──以河南某电厂技改工程为例

以河南某电厂技改工程为例 ,根据现场检测结果 ,探讨了影响静压预制桩沉桩深度成因 ,分析了静压桩承载力的分布规律。研究结果证明静压桩的沉桩深度和承载力与地基土的性状密切相关。对于河南某电厂技改工程场地 ,尽管桩端进入砂较小深度 ,却可以在桩端平面附近良好土层的作用下提供较大的端阻力。