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101.
H. A. Elshazly D. H. Hafez M. E. Mossaad 《Geotechnical and Geological Engineering》2008,26(3):323-334
The unit cell idealization has been long adopted in the settlement prediction of stone column-reinforced soils. This paper
tests the accuracy of this modeling concept against trusted settlement values of engineering foundations. It is believed that in order to bestow the outcome of this study adequate generality
different soil properties and foundation geometries need to be considered. It was, nevertheless, found impracticable to collect
field settlement records for all the analyzed cases. The authors, therefore, appealed to the back analysis concept to construct
a reliable mathematical model, calibrated against settlement records of full-scale field load test. This model, which is capable
of reproducing the real field settlements, is then employed as a generic tool to obtain trusted settlement values for a variety of cases with essential geometrical similarity. The investigation revealed that the unit
cell analysis may, in some cases, lead to erroneous estimation for the settlements of foundations with limited extents. Correction
factors, dependent on the treated soil properties as well as the foundation size, are introduced. 相似文献
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104.
预测工后软土地基沉降 总被引:2,自引:0,他引:2
本文简要叙述沉降观测在软土地基施工中的重要性,并提出了基于神经网络的高速公路工后沉降预测方法。结合工程实例运用MATLAB工具箱函数建立网络模型,选择合适的训练函数,使其训练精度和速度达到最优化。 相似文献
105.
Johannes H. Uhl Hamidreza Zoraghein Stefan Leyk Deborah Balk Christina Corbane Vasileios Syrris 《International Journal of Digital Earth》2020,13(1):22-44
ABSTRACTThere is an increasing availability of geospatial data describing patterns of human settlement and population such as various global remote-sensing based built-up land layers, fine-grained census-based population estimates, and publicly available cadastral and building footprint data. This development constitutes new integrative modeling opportunities to characterize the continuum of urban, peri-urban, and rural settlements and populations. However, little research has been done regarding the agreement between such data products in measuring human presence which is measured by different proxy variables (i.e. presence of built-up structures derived from different remote sensors, census-derived population counts, or cadastral land parcels). In this work, we quantitatively evaluate and cross-compare the ability of such data to model the urban continuum, using a unique, integrated validation database of cadastral and building footprint data, U.S. census data, and three different versions of the Global Human Settlement Layer (GHSL) derived from remotely sensed data. We identify advantages and shortcomings of these data types across different geographic settings in the U.S., which will inform future data users on implications of data accuracy and suitability for a given application, even in data-poor regions of the world. 相似文献
106.
云南哀牢山的梯田景观 总被引:4,自引:1,他引:4
云南哀牢山区哈尼族人创造的独具特色的热带山区梯田景观,在与自然环境的协调过程中,巧妙地解决了农耕中的关键要素水分与肥料,创造了较高的粮生产水平,并以聚落分布的适中高度,均衡建构中介,最终内化为一种独特的文化形态,自然与人文在此所形成的高度协调关系,无疑具有重要的理直学研究意义。 相似文献
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The response of shallow foundations under lateral cyclic loading is generally nonlinear and involves rocking, sliding, settlement, and may also involve foundation uplift and soil yielding. Unlike pile foundations, the nonlinear Winkler model is not widely used for modeling cyclic soil–footing–structure interaction (SFSI) problems. Nonetheless, it has some important features that make it more attractive than conventional finite element approaches, and is a recommended approach in the FEMA 356 design guideline. This paper explores the strengths and limitations of the FEMA 356 nonlinear Winkler modeling approach, when used in predicting the cyclic response of various recent SFSI experiments. The results of the study show that the model is capable of satisfactorily predicting all the different cyclic response quantities apart from permanent horizontal displacements. This should therefore be noted when using the approach in design. 相似文献
109.
Kathryn L.E. Berry Mia O. Hoogenboom Diane L. Brinkman Kathryn A. Burns Andrew P. Negri 《Marine pollution bulletin》2017,114(1):505-514
Successful reproduction and larval dispersal are important for the persistence of marine invertebrate populations, and these early life history processes can be sensitive to marine pollution. Coal is emerging as a contaminant of interest due to the proximity of ports and shipping lanes to coral reefs. To assess the potential hazard of this contaminant, gametes, newly developed embryos, larvae and juveniles of the coral Acropora tenuis were exposed to a range of coal leachate, suspended coal, and coal smothering treatments. Fertilisation was the most sensitive reproductive process tested. Embryo survivorship decreased with increasing suspended coal concentrations and exposure duration, effects on larval settlement varied between treatments, while effects on juvenile survivorship were minimal. Leachate exposures had negligible effects on fertilisation and larval settlement. These results indicate that coral recruitment could be affected by spills that produce plumes of suspended coal particles which interact with gametes and embryos soon after spawning. 相似文献
110.
Guang Gao Anthony S. Clare Craig Rose Gary S. Caldwell 《Marine pollution bulletin》2017,114(1):439-447
The incidence and severity of extraordinary macroalgae blooms (green tides) are increasing. Here, climate change (ocean warming and acidification) impacts on life history and biochemical responses of a causative green tide species, Ulva rigida, were investigated under combinations of pH (7.95, 7.55, corresponding to lower and higher pCO2), temperature (14, 18 °C) and nitrate availability (6 and 150 μmol L? 1). The higher temperature accelerated the onset and magnitude of gamete settlement. Any two factor combination promoted germination and accelerated growth in young plants. The higher temperature increased reproduction, which increased further in combination with elevated pCO2 or nitrate. Reproductive success was highest (64.4 ± 5.1%) when the upper limits of all three variables were combined. Biochemically, more protein and lipid but less carbohydrate were synthesized under higher temperature and nitrate conditions. These results suggest that climate change may cause more severe green tides, particularly when eutrophication cannot be effectively controlled. 相似文献