山区房后边坡安全评价的探讨——以安溪县为例

由于地质灾害的突发性和引发因素的复杂性,在及时和有效地掌握潜在隐患部位上还亟待进一步探索与细化,力求防灾抗灾工作有的放矢,以确保人民群众的生命财产损失降到最低限度。本文就基于山区的基本特征和房后边坡潜在地质安全隐患基本信息调查,简要分析房后边坡孕灾致灾环境,并针对它们的影响程度,采取层次分析（AHP）等方法来确定安全评价因子权重和安全系数,对构造安全评价结构作进一步研究。     

Fluid Geochemistry as Indicator of Tectonically-Related,Deep Water Circulations in the Sardinian Rift-Campidano Graben (Italy): New Insights from Environmental Isotopes

The EC funded Geochemical Seismic Zonation program (EEC GSZ Project 1996–1998) chose Sardinia as a low-seismicity site, in which the relationships between fluid geochemistry and seismo-tectonics had to be investigated and results compared with outcomes from other selected high-seismicity sites. A first article, examining the role of fault segmentation and seismic quiescence on the geochemical composition of groundwaters and gases, has already been presented (Angelone et al. 2005). This article deals with environmental isotopes which, together with selected hydrochemical data, give hints on tectonically-related fluid circulations. Four water-dominated hydrothermal systems were considered, all located along regional fault systems and discharging groundwaters belonging to the Na–HCO₃ and Na–Cl facies. In the considered systems, groundwater circulation takes place, principally, in the Palaeozoic Crystalline Basement (PCB), with the exception of the Logudoro system, where hydrological circuits develop in the Mesozoic Carbonate Platform (MCP). The high CO₂ contents, the non-attainment of fluid-rock equilibrium and the large lithological variability prevent the construction of a unique hydrogeological–geochemical conceptual model. In this case, stable isotopes provide a useful tool to describe the origin of fluids and their subterranean movements. Stable isotopes of water, integrated with hydrochemical data, indicate that fluids are derived from three main end members. The dominant component is a relatively recent local meteoric water; the second one is marine water; and the third one is a fossil freshwater, depleted in heavy isotopes with respect to modern rains. The latter end member entered the aquifer system in the past, when climatic conditions were greatly different from today. At least two circulation systems can be recognised, namely a shallow cold system and a deep hydrothermal system, as well as two distinct hydrological processes: (1) gravity-controlled descent of cold water towards greater depths and (2) convection linked to a thermal gradient, causing deep fluids to rise up from the hydrothermal reservoir towards the surface. The highly variable δ¹³C_TDIC values suggest the presence of two distinct CO₂ sources, namely, a biogenic one and a thermogenic one. The relation between the isotopic compositions of CO₂ and He indicates an increased mantle signature in uprising CO₂-rich fluids.     

An essay on the interactions between climate and society

There has been increasing concern about the lack of involvement by social scientists and humanists in a global change program, although many social scientists are already directly involved in various aspects of research on environmental change, and their research interests are clearly central to a global change research agenda. Based on a historical review, the role of social science disciplines as well as social science institutes in an emerging multidecadal global change program is discussed. Both “plan of action” and “plan of inaction” are suggested to avoid potential pitfalls due to the rush development of a social science program into the existing global climate change problem.     

中国海相探矿权区块定量评价方法

在研究了我国海相油气探矿权区块基本油气地质条件、勘探程度、技术经济条件等要素和特点的基础上,给出了48个评价参数和归一化取值参照表,建立了探矿权区块评价工作流程、评分参数及计算公式。提出对我国海相勘探层探矿权区块评价应该注意:与国外海相碳酸盐岩评价的差别;与国内陆相碎屑岩评价的差别;成藏组合的划分;评价内容的有效性、不确定性和评价参数的可信度;成败经验的总结和勘探程度的研究。     

雁南煤矿北二采区充水因素及开采影响评价

在全面分析大雁矿业集团公司雁南煤矿北二采区的水文地质条件及煤层开采矿井充水因素的基础上,计算了开采27^1号煤层时导水裂隙带发育高度．得出了北二采区各煤层工作面开采即不会受到上部砂砾含水层的影响,雁南煤矿铁路涵洞以西的胜利河冲击沟也不会受到北二采区的采动塌陷影响的结论。     

靖远矿区采煤沉陷区复垦综合评价方法研究

以靖远矿区为例,从土地复垦和恢复生态学的角度出发,建立了靖远矿区采煤沉陷区复垦综合评价系统,选择土壤条件（土层厚度、土壤质地、有机质含量、土壤水分）、地形改造条件（地面坡度、地表破坏程度、改造难易程度）、气候及水文条件（年降雨量、灌溉条件）作为分类及评价因子对复垦潜力进行评价。将采煤沉陷地分为四种潜力区,对每种潜力类型区的复垦开发利用方向进行了优化设计,从理论上和实践上对靖远矿区采煤沉陷地的复垦能力以及复垦过程中用地结构的优化作了探讨,以期对当地沉陷地的复垦提供一定的科学依据。     

Overbreak and underbreak in underground openings Part 2: causes and implications

Summary The newly developed light sectioning method has been used to investigate some of the causes and costs of overbreak and underbreak. Investigations at the Aquamilpa Hydroelectric Project in Mexico have shown decreased overbreak and increased underbreak as a result of increased rock quality and decreased explosive energy. A new measure of explosive energy, the perimeter powder factor (PPF), has been defined and shown to be useful in the context of tunnel-wall rock damage. Tentative results indicate that explosive energy (PPF) may be a more important factor in producing underbreak, whereas rock quality may be a greater factor in producing overbreak. A site-specific equation is given for predicting overbreak or underbreak as a function of rock quality and explosive energy, with an evaluation of the cost of underbreak and overbreak.     

Oil and gas resource assessment: The linkage between geological analysis and discovery process model results

Two widely-used techniques to estimate the volume of remaining oil and gas resources are discovery process modeling and geologic assessment. Both were used in a recent national assessment of oil and gas resources of the United States. Parallel estimates were obtained for 27 provinces. Geological-based estimates can typically see into areas not available to discovery process models (that is areas with little or no exploration history) and thus, on average, yield higher estimates. However, a linear relation does exist between the mean estimates obtained from these two methods. In addition, other variables were found in a multiple regression model that explained much of the difference. Thus, it is possible to perform discovery process modeling and adjust the estimates to yield results that might be expected from geological-based assessments.     

Information structure analysis for quantitative assessment of mineral resources and the discovery of a silver deposit

We propose an information-structure-analysis (ISA) method to quantify the correlations between quantitative and qualitative variables as well as within each type of variable. This method is applied to the evaluation of mineral resources in the western Zheijiang Province of China. The district contains a number of silver-bearing Fe–Cu–Pb–Zn mineral deposits near igneous complexes and FeCuPbZn zones away from the complexes. Silver anomalies occur not only in the known Fe–Cu–Zn–Pb deposits, but also in the country rock, suggesting the possible existence of silver deposits far from the igneous complexes.The tonnage distribution of silver is modeled by Monte Carlo simulation. This simulation is conducted on the basis of the correlations between silver (Ag) and lead (Pb), since no known data on silver is available. The known tonnage distribution of lead in 11 control cells was used to approximate the tonnage distribution of silver in the Monte Carlo simulation. With ISA and Monte Carlo methods, the total amount of potential polymetallic resources in 49 cells in the western Zhejiang Provice is predicted. Significantly, a deposit with about 24 tonnes of silver has been found within our exploration target area.     

首都减灾圈的思考与建议

首都减灾圈,系首都减轻自然灾害预测防治圈。1991年12月20—21日在北京召开了《首都圈自然灾害及其减灾对策研讨会》。本文根据这次会议所提供的材料,在从整体上实现减灾的思想指导下,就首都减灾圈的“成灾背景”、“首都减灾圈的组成”、“首都减灾圈的灾害预测与防治状况”、“首都减灾圈的灾害关联性分析”、“首都减灾圈的减灾实效预估”和“首都减灾圈的减灾对策与实施”等六个带有共同性的问题,进行了讨论。供制定首都圈减灾方案时参考。