Monitoring the Performance of Unsaturated Soil Slopes

Field monitoring is necessary for the geotechnical engineer to verify design assumptions. More importantly, the field data may also be assembled into a comprehensive case record that is available for use when checking validity of any analytical and numerical models. The ongoing process of back-analysis in unsaturated soil engineering can help to refine and improve our understanding, providing guidance for future designs, where the effects of soil suction and hydraulic hysteresis are still being explored. A range of recent field studies of the mechanisms of rainfall infiltration into slopes is presented. In addition, some physical simulations of unsaturated soil slopes subjected to rainfall, rising ground water table and changes of moisture in centrifuge model tests are reported.     

T213物理量场在强降水落区预报中的应用

蒙古低涡和东北冷涡是造成鹤壁市汛期强降水的主要影响天气系统.不同天气系统影响,鹤壁市的降水落区有明显差别.在T213物理量场上,强降水常出现在大值中心所包围的区域内.     

Logging identification and characteristic analysis of marine–continental transitional organic-rich shale in the Carboniferous-Permian strata,Bohai Bay Basin

Currently, global shale gas exploration and exploitation are focused on marine shale. Recently, major shale gas-oil breakthroughs have been made within continental and marine–continental transitional shale in China. This study will show how transitional shale is of great importance. Based on geological field surveys, core observations, thin section analysis, organic geochemistry and X-ray diffraction, we systematically studied the basic geological characteristics (including lithology, mineral composition, and organic geochemistry) of this transitional shale. By comparative analysis of well logging data from 260 wells in the Taiyuan–Shanxi shale, we will show that these methods are effective for identifying organic-rich shale from conventional well logs and determining its thickness distribution in the Carboniferous–Permian strata of the Taiyuan–Shanxi transitional coal-bearing formation.The results indicate that the Taiyuan–Shanxi shale has a high TOC (most 2%–4%) and that the lithology is primarily carbonaceous shale with type Ⅱ₂-Ⅲ kerogens. The high thermal maturation (Ro ≥ 1.1%) favors the generation of gas. The mineral components primarily include clay minerals, quartz, and plagioclase with a moderate brittle mineral content (47 wt.%) and high clay mineral content (51 wt.%) dominated by kaolinite (43%) and mixed-layer illite-smectite (31%). The transitional organic-rich shale on conventional log curves is generally characterized by higher gamma ray (GR), neutron porosity (CNL), acoustic travel time (AC), resistivity (R_t), potassium (K), and uranium (U) readings and a lower density (DEN), photoelectric absorption index (PE) and thorium-uranium ratio (TH/U). After analyzing the log response characteristics of the organic-rich shale, the most sensitive logging curves (such as CNL, AC, DEN, PE and U) were optimized to conduct logging overlays and to construct cross-plots to qualitatively identify organic-rich shale. The identified organic-rich shale amalgamates in the middle-upper member of the Taiyuan Formation and the lower member of the Shanxi Formation consistent with the results of the TOC analysis and practical gas logging. Based on the qualitative evaluation methods of the modified △LogR and a multivariate linear regression model, we calculated the TOC of shale wells in the Taiyuan–Shanxi formation. From this we calculated the characteristic values of organic-rich shale thickness. The results indicate that organic-rich shale in the Taiyuan formation is thicker than that in the Shanxi formation. Additionally, the thickness of organic-rich shale within lagoons and deep reed swamp facies are much thicker (25–35 m and 40–80 m) than other structural profile types, whereas their lateral distribution is less than that of marine shale. The relatively small continuous thickness of the single shale layer and high clay content may have negative effects for developing the shale gas potential.     

国际地磁参考场在中国大陆地区的误差分析

IGRF（国际地磁参考场）是有关地球 主磁场与长期变化的模型，IGRF的误差主要来源于：忽略外源场、球谐级数的截断、台站分 布的不均匀、测量、忽略地壳磁异常场等. 分析我国大陆地区IGRF的误差，有利于我国地磁 研究 人员在工作中合理地应用IGRF资料. 如果不计磁异常与环境干扰都比较大的北京台，29个基 准台的IGRF的误差(均方根差)为146.9nT.     

环境介质中典型新型有机污染物分析技术研究进展

环境中持久性有机污染物(POPs)、药物及个人护理品(PPCPs)和消毒水副产物(DBPs)等新型有机污染物对生态环境和人体健康具有潜在威胁,研究其来源、检测方法、环境分布和迁移转化已经成为热点。新型有机污染物组成复杂,如短链氯化石蜡有7000多种同类物,采用传统分析手段无法实现分离,对这些物质的准确定性和定量面临挑战。近年来在新型有机污染物检测技术开发方面已取得较大进展:根据待测样品的性质可使用快速溶剂萃取、固相微萃取等多种提取方法,凝胶渗透色谱、多层复合层析柱和固相萃取柱是有效的净化手段,采用气相色谱-质谱或液相色谱-质谱实现了对指示性单体准确定性定量,检出限可达ng/g级。但对于环境影响较大的新型有机污染物如手性多氯联苯(PCBs),由于各手性PCBs单体之间在分离过程中发生峰共溢现象,需要应用专门的手性色谱柱进行分析,尚未建立可靠的检测方法。本文认为,一方面需要探索磁性固相基质分散萃取技术等高效的前处理技术对干扰物质进行有效分离;另一方面需要提高全二维气相/液相色谱、傅里叶变换质谱等色谱/质谱检测技术的识别性和灵敏度,开发出简便、标准化的定量方法。     

老厂矿区煤层及煤层气藏水文地质特征

根据老厂矿区特别是老厂四勘区煤田和煤层气勘探的基础资料,重点评价该区及煤层气的水文地质特征,为煤层气成藏条件研究及煤炭资源开采提供依据。     

Functions and organizational structure of the proposed Natural Resources Management Facility in Mozambique

The proposed Natural Resources Management Facility (NRMF) seeks to achieve poverty reduction and employment generation through ecologically sustainable, economically viable and people-participatory management of natural resources (resources of waters and soils, coastal and marine resources, ecotourism, energy resources, mineral and other resources). The NRMF will have five functional divisions for technology policy, environmental education, extramural cooperation, technical facility and information network, and international cooperation. At the heart of the NRMF is a state-of-the-art analytical laboratory (with ICP-AES, GC-ECD, GC-MS, etc.) in Maputo. This will be networked with five field stations which will have portable instruments for water, soil, food, etc. analysis. The NRMF will custom-design integrated natural resource management models for different areas of the country, in the context of their particular biophysical and socio-economic environments. Innovative management techniques have been developed to make the NRMF sustainable and largely self-financing. The NRMF will cooperate with, and assist the member countries of SADC (Southern Africa Development Community) in environmental management for mutual benefit, and could, hopefully, serve as a pilot model for the countries of sub-Saharan Africa. Received: 30 September 1997 · Accepted: 3 February 1998     

CO and CO2 emissions from spontaneous heating of coal under different ventilation rates

Carbon monoxide (CO) and carbon dioxide (CO₂) emissions during a spontaneous heating event in a coal mine are important gases to monitor for detecting the spontaneous heating at an early stage. However, in underground coal mines, the CO and CO₂ concentrations and their related fire ratios may be affected by mine ventilation. In this study, CO and CO₂ emissions from spontaneous heating of a U.S. coal sample were evaluated in an isothermal oven under different airflow ventilation rates ranging from 100 to 500 cm³/min. Laboratory experiments were conducted at oven temperatures of 70, 90, and 100 °C. The temperature at the center of the coal sample was continually monitored, while the CO, CO₂, and oxygen (O₂) concentrations of the exit gas were continually measured. The results indicate that CO was generated immediately after the airflow passed through the coal, while CO₂ was generated in a late phase. The amounts of CO generated under different airflow rates were approximately the same at the initial temperature of 70 °C, while the amounts of CO generated increased significantly as the airflow rates and initial temperatures increased. The ratio of CO/CO₂ was found to be independent of airflow rate and initial temperature, approaching a constant value of 0.2 quickly if there was no thermal runaway. The value tended to decrease when a thermal runaway took place. The CO/O₂ deficiency ratio was dependent on both airflow rates and the initial temperature. The experimental results are in qualitative agreement with some large-scale test and field monitoring results.     

Variability of the bottom-simulating reflector (BSR) and its association with tectonic structures in the Chilean margin between Arauco Gulf (37°S) and Valdivia (40°S)

Multichannel seismic reflection data recorded between Arauco Gulf (37°S) and Valdivia (40°S), on the Chilean continental margin, were processed and modeled to obtain seismic images and sub-surface models, in order to characterize the variability of the bottom-simulating reflector (BSR), which is a geophysical marker for the presence of gas hydrates. The BSR is discontinuous and interrupted by submarine valleys, canyons, as well as by faults or fractures. The BSR occurrence is more common south of Mocha Island due to moderate slopes and greater organic matter contribution by rivers in that area. Tectonic uplift and structural instability change the stability gas hydrate zone and consequently the BSR position, creating in some cases missing or double BSRs. Our modeling supports the presence of gas hydrate above the BSR and free gas below it. Higher BSR amplitudes support higher hydrate or free gas concentrations. In the study area, gas hydrate concentration is low (an average of 3.5%) suggesting disseminated gas hydrate distribution within the sediments. Also higher BSR amplitudes are associated with thrust faults in the accretionary prism, which serve as conduits for gas flow from deeper levels. This extra gas supply produces a wider thickness of gas hydrates or free gas.     

洛带气田上侏罗统遂宁组沉积相及含气地震响应特征

洛带遂宁组气藏为新发现气藏,已提交天然气探明储量上百亿立方米。洛带遂宁组沉积环境以季节性浅水湖为主,发育进积型三角洲前缘亚相沉积,有利的沉积微相是三角洲前缘水下分流河道、河口砂坝和席状砂。物源来自川西坳陷西侧的龙门山,其中坳陷东坡的新都—洛带地区处于中部的砂泥岩互层的三角洲相带,在斜坡带上形成了大型的遂宁组岩性圈闭。洛带地区遂宁组具有多套储盖组合,又靠近下伏烃源岩,对天然气的富集和保存十分有利。通过合成记录的标定、Jason反演表明,遂宁组含气砂岩的地震响应模式为“强波谷、中—强波峰,低波阻抗”模式;砂泥互层型的地震响应是“强中弱”。该大型岩性气藏的发现,说明川西地区浅层气仍然具有大的勘探前景,遂宁组气藏将是浅层扩展评价勘探和风险勘探的重要目标。