轨道交通下立交区间基坑降水技术

根据下立交区间基坑特点,合理制定基坑工程降水方案。经工程实践证明,通过疏干井、混合井、降压井的合理设置,联合使用,科学有效地治理了地下水,较好地控制了因降水产生的工程风险。     

国家基本比例尺数字化地形图生产过程中地貌常见问题探讨

本文以1：10000单色数字化地形图为例，简述了国家基本比例尺数字化地形图生产过程中常见的与地貌相关质量问题。对部分产生质量问题的原因作了初步分析。以SCS多用途数字地形地籍测绘与管理系统软件和CASS5．1软件为例，对数字化地形图存在问题的修改方法进行了探讨。     

Tectonic significance of the present relief of the Betic Cordillera

Tortonian calcarenites of the Betic Cordillera were deposited in coastal or very shallow marine environments and represent an ideal marker for estimating vertical movements from the late Miocene to the Present. A map showing the heights at which these Tortonian marine rocks are situated has a clear correlation with the present relief, indicating that today's relief has been formed since the Tortonian. There is also a good correlation between present relief and the Bouguer anomaly distribution in the Betic Cordillera, as well as with crustal thickness. Likewise, the present relief is directly related to the geodynamic setting of a horizontal N–S to NNW–SSE compression and an almost perpendicular extension, along with isostatic readjustment, existing in the Betic Cordillera from the Tortonian. As a result of these regional stresses, faults and folds have produced notable vertical movements. The highest rates of uplift of the Betic Cordillera coincide with large antiforms, in particular those of the Sierra Nevada and the Sierra Filabres. Several subsiding sectors also exist (for example, the Granada Basin or the Guadalquivir Basin). The foreland Guadalquivir Basin has a complex history because the uplift in its eastern sector and subsidence in the western sector coexisted during the late Tortonian. Today the whole Betic Cordillera is characterized by differential regional uplift, even in the aforementioned subsiding sectors.     

The relief of the Swiss Alps and adjacent areas and its relation to lithology and structure: topographic analysis from a 250-m DEM

In this paper we discuss the large-scale geomorphological characteristics of the Swiss Alps based on numerical analysis of a digital elevation model and compare these to an erodibility map constructed from a geotechnical map of Switzerland and regional geomorphological studies. Comparing the erodibility map with the large-scale morphometry shows an intimate relationship between mountain-scale erodibility and topography. On average, higher mean elevations and steeper mean slopes correlate with regions where rocks of low erodibility prevail. Areas with high peaks as well as the main water divides are controlled by the presence of bedrock with low to very low detachability. The drainage network of the Swiss Alps shows a close relationship to the lithological differences as well. Major longitudinal valleys follow easily erodible units. In the eastern and western part of the Swiss Alps, the highest values of local relief are located to the south of the main water divide, whereas in the central part, local relief is higher to the north of the main water divide. The large-scale geomorphic characteristics regarded in the framework of the geological history of uplift and denudation suggest that low and very low erodibilities lead to the development of areas of high elevations which are likely to persist over periods of 10–15 Ma. As the analysis of the Lepontine area shows, 20 Ma after cessation of exhumation, such high elevations are likely to be worn down and to manifest themselves as high relief only.     

城市化防震减灾经济性研究

本文通过对东南沿海地震背景和地震破坏性经济损失,结合国内外城市化进程中防震减灾经济性对比研究,认为地震破坏的负面效应所带来的经济损失十分巨大。因而必须加强防震减灾工作为保障城市化顺利发展服务。     

The geology of Australian Mars analogue sites

Australia has numerous landforms and features, some unique, that provide a useful reference for interpreting the results of spacecraft orbiting Mars and exploring the martian surface. Examples of desert landforms, impact structures, relief inversion, long-term landscape evolution and hydrothermal systems that are relevant to Mars are outlined and the relevant literature reviewed. The Mars analogue value of Australia's acid lakes, hypersaline embayments and mound spring complexes is highlighted along with the Pilbara region, where the oldest convincing evidence of life guides exploration for early life on Mars. The distinctive characteristics of the Arkaroola Mars Analogue Region are also assessed and opportunities for future work in Australia are outlined.     

Detecting tents to estimate the displaced populations for post-disaster relief using high resolution satellite imagery

Estimating the number of refugees and internally displaced persons is important for planning and managing an efficient relief operation following disasters and conflicts. Accurate estimates of refugee numbers can be inferred from the number of tents. Extracting tents from high-resolution satellite imagery has recently been suggested. However, it is still a significant challenge to extract tents automatically and reliably from remote sensing imagery. This paper describes a novel automated method, which is based on mathematical morphology, to generate a camp map to estimate the refugee numbers by counting tents on the camp map. The method is especially useful in detecting objects with a clear shape, size, and significant spectral contrast with their surroundings. Results for two study sites with different satellite sensors and different spatial resolutions demonstrate that the method achieves good performance in detecting tents. The overall accuracy can be up to 81% in this study. Further improvements should be possible if over-identified isolated single pixel objects can be filtered. The performance of the method is impacted by spectral characteristics of satellite sensors and image scenes, such as the extent of area of interest and the spatial arrangement of tents. It is expected that the image scene would have a much higher influence on the performance of the method than the sensor characteristics.     

分段光滑曲线边界波动方程数值模拟研究

矩形网格有限差分法在地震波传播数值模拟方面具有计算速度快的显著优势,但该方法在处理复杂边界问题上存在着效率低的严重缺陷.本文针对分段光滑曲线边界定义了尖点处的一种正则导数,给出了矩形网格情形分段光滑曲线网格边界点法向导数的一种插值计算方法.采用矩形网格有限差分法对复杂边界地球介质模型进行地震波场数值模拟,并采用波场系列快照技术揭示地震波在起伏地表和复杂介质中的传播规律.模拟结果表明：法向导数插值计算方法为矩形网格有限差分法处理复杂边界提供了有效途径,采用波场系列快照技术可以清晰地展现地震波在反射界面的反射和透射规律、在尖点的绕射规律以及在自由表面的直达波和多次反射规律.     

Landslide Hazard Zonation using Remote Sensing and GIS: a case study of Dikrong river basin, Arunachal Pradesh, India

Landslides are among the most costly and damaging natural hazards in mountainous regions, triggered mainly under the influence of earthquakes and/or rainfall. In the present study, Landslide Hazard Zonation (LHZ) of Dikrong river basin of Arunachal Pradesh was carried out using Remote Sensing and Geographic Information System (GIS). Various thematic layers namely slope, photo-lineament buffer, thrust buffer, relative relief map, geology and land use / land cover map were generated using remote sensing data and GIS. The weighting-rating system based on the relative importance of various causative factors as derived from remotely sensed data and other thematic maps were used for the LHZ. The different classes of thematic layers were assigned the corresponding rating value as attribute information in the GIS and an “attribute map” was generated for each data layer. Each class within a thematic layer was assigned an ordinal rating from 0 to 9. Summation of these attribute maps were then multiplied by the corresponding weights to yield the Landslide Hazard Index (LHI) for each cell. Using trial and error method the weight-rating values have been re-adjusted. The LHI threshold values used were: 142, 165, 189 and 216. A LHZ map was prepared showing the five zones, namely “very low hazard”, “low hazard”, “moderate hazard”, “high hazard” and “very high hazard” by using the “slicing” operation.