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1.
Characterization of Continental Intercalaire aquifer (CI) in the Tinrhert-East Area-Illizi Basin on the Algerian-Libyan Border 下载免费PDF全文
This paper addresses the characterization of the Continental Intercalaire aquifer(CI) in the Tinrhert-East area of Illizi Basin on the Algerian-Libyan border, which belongs to the SASS1 system, one of the biggest transboundary aquifers in the world. This study concerns a superficies of 4 300 km~2. On the basis of Mud Logging borehole data conducted in this part of the aquifer, a realistic characterization of the aquifer was done. The thickness of the CI aquifer varies from 300 m in the south to 700 m in the north, and the depth ranges from 180 m to 320 m. The interpretation of the logs showed that the aquifer is characterized by a maximum net thickness in its southwestern part(more than 600 m), the porosity is very high, ranging from 30% in the west to 24% at the Libyan borders, the permeability is low to medium around 10~(-5) m/s, and the maximum transmissivity values of about 8× 10~(-3) m~2/s were recorded at the center of the study area. The depth of water varies from 235 m to 312 m, and the water flows from south to north, in accordance with the general direction observed in the CI aquifer in the Northern Sahara Aquifer System(SASS). The porosity values obtained from the interpretation of the sonic and density logs permit to estimate the water reserves of this aquifer considered fossil, at thresholds much higher than what was considered until now. 相似文献
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云南红河县龙然村滑坡为一浅层牵引式破碎松散层滑坡,连续的降雨是诱发滑坡的主要因素。该滑坡的治理应采用“挡+排”的综合治理,“档”即在滑坡上缘设置抗滑桩、档板和毛石混凝土挡墙;“排”即沿滑坡顶、滑坡体两侧分别设置截水和排水沟,将地表水及雨水排出滑坡体外,以保证该滑坡体的稳定。 相似文献
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密度参数是页岩储层评价的重要敏感参数,但通常认为准确获得密度信息难度较大.本文探索提出了一种稳定的基于弹性阻抗的叠前密度反演方法,以提高优质页岩的识别精度.首先,基于不同的参数化弹性阻抗方程开展密度敏感性分析,优选了敏感性最高的Aki-Richards近似弹性阻抗方程作为反演方程.然后,在弹性阻抗方程线性化的基础上,假设反演方程系数矩阵的逆存在,将密度(取对数)表示为多个角度弹性阻抗(取对数)的加权和,通过井旁道弹性阻抗反演结果与测井数据的回归求取加权系数,避免了常规反演方法对大型系数矩阵的求逆计算,从而提高了密度反演的稳定性,同时由于利用测井资料作为匹配目标,密度反演的精度也得到了提高.模型试算和涪陵页岩气田的实际资料应用实践均表明了该方法能够有效地提高密度反演的精度与稳定性. 相似文献
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《China Geology》2020,3(2):339-344
Considering the geological hazards attributed to the highway slope, using a common simple model cannot accurately assess the stability of the slope. First, principal component analysis (PCA) was conducted to extract the principal components of six factors (namely, bulk density, cohesion, internal friction angle, slope angle, slope height, and pore water pressure ratio) affecting the slope stability. Second, four principal components were adopted as input variables of the support vector machine (SVM) model optimized by genetic algorithm (GA). The output variable was slope stability. Lastly, the assessing model of highway slope stability based on PCA-GA-SVM is established. The maximal absolute error of the model is 0.0921 and the maximal relative error is 9.21% by comparing the assessment value and the practical value of the test sample. The above studies are conducive to enrich the assessing model of highway slope stability and provide some reference for highway slope engineering treatment. 相似文献
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Evaluating a process‐based model for use in streambank stabilization: insights on the Bank Stability and Toe Erosion Model (BSTEM) 下载免费PDF全文
Kate Klavon Garey Fox Lucie Guertault Eddy Langendoen Holly Enlow Ron Miller Anish Khanal 《地球表面变化过程与地形》2017,42(1):191-213
Streambank retreat is a complex cyclical process involving subaerial processes, fluvial erosion, seepage erosion, and geotechnical failures and is driven by several soil properties that themselves are temporally and spatially variable. Therefore, it can be extremely challenging to predict and model the erosion and consequent retreat of streambanks. However, modeling streambank retreat has many important applications, including the design and assessment of mitigation strategies for stream revitalization and stabilization. In order to highlight the current complexities of modeling streambank retreat and to suggest future research areas, this paper reviewed one of the most comprehensive streambank retreat models available, the Bank Stability and Toe Erosion Model (BSTEM), which has recently been integrated with several popular hydrodynamic and sediment transport models including the Hydrologic Engineering Center's River Analysis System (HEC‐RAS). The objectives of this paper were to: (i) comprehensively review studies that have utilized BSTEM and report their findings, (ii) address the limitations of the model so that it can be applied appropriately in its current form, and (iii) suggest directions of research that will help make the model a more useful tool in future applications. The paper includes an extensive overview of peer reviewed studies to guide future users of BSTEM. The review demonstrated that the model needs further testing and evaluation outside of the central United States. Also, further development is needed in terms of accounting for spatial and temporal variability in geotechnical and fluvial erodibility parameters, incorporating subaerial processes, and accounting for the influence of riparian vegetation on streambank pore‐water pressure dynamics, applied shear stress, and erodibility parameters. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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提出一种基于支持向量机的岩质边坡稳定性预测方法。该方法地很好的表达了岩质边坡稳定性与其影响因素之间的非线性映射关系,并应用该方法建立了相应的模型。预测结果表明,利用该方法进行岩质边坡稳定性预测是可行的、有效的。 相似文献
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复合采动边坡变形机理及稳定性评价 总被引:1,自引:0,他引:1
在边坡下采煤,井工开采不仅使边坡岩土体结构发生破坏,物理力学强度降低,同时还会引起边坡岩土体中的应力发生重分布,对露天边坡的变形及稳定性将产生较大影响.本文以山西平朔安太堡露天矿东帮边坡在B900工作面井采影响下的位移监测资料为基础,分析总结了露井联合开采条件下边坡变形规律及机理,并结合结构面组合判断、FLAC数值模拟... 相似文献
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夏季平流层盛行强东风,Rossby波能量难以从对流层向上传播至平流层,而冬季平流层盛行西风,Rossby波能量容易上传,因此以往对Rossby波能量向平流层传播的研究多考虑冬季的情况.而事实上,因为夏季高原上空南亚高压反气旋环流,并非只有强东风存在,所以Rossby波能量也可能在南亚高压区向上传播,从而影响平流层的温度、风场及大气成分等.因此,本文利用ERA-interim逐日再分析资料,分析了1979—2015年夏季南亚高压区Rossby波能量穿越对流层顶传播的特征与机制.结果表明:Rossby波能量可以从南亚高压西北部的窗口区上传至平流层,最高可到达平流层顶,而在南亚高压的其他部分,Rossby波能量均不能穿越对流层顶上传或穿越对流层顶后无法继续上传.南亚高压西北区Rossby波能量可以穿越对流层顶传播的原因是盛行西风,且西风急流出现的频率很小,同时涡动热量通量异常引起的垂直分量的第一项对其上传有很大贡献.南亚高压东北区也盛行西风,然而Rossby波能量不能向上穿越对流层顶的原因是强西风出现频率较高,且温度脊与高度脊位相相近,不利于上传.南亚高压南部均盛行东风,在平流层中下层均为稳定层结,因此Rossby波能量很难上传.南亚高压西南区在对流层位于青藏高原环流的伊朗高原下沉区附近,层结稳定,并且温度脊超前于高度脊,所以Rossby波能量很难上传.而南亚高压东南区在对流层位于南海-西太平洋热带幅合带,层结不稳定,存在Rossby波能量较弱的上传,达到对流层顶后无法继续上传,该区域温度脊落后于高度脊的温压场配置也为Rossby波能量在对流层内的传播提供了条件. 相似文献