Anwendung eines neuen Feldanalysenverfahrens zur Untersuchung der Stabilität von Arsen und seinen anorganischen Spezies in aquatischen Systemen

Using of a New Field Analysis Method to Investigate the Stability of Arsenic and its Inorganic Species in Aquatic Systems The stability of arsenic species in aquatic systems is limited by the possibilities of chemical and biochemical reactions. Redox reactions and bioalkylation lead to changes of the species ratios. In this work, the stability of As(III) and As(V) was examined at storage of distilled, de-ionized, and drinking water at different conditions (refrigerator/room temperature; daylight/darkness) and additions (sulfuric acid; ascorbic acid). The determination of these species was carried out by a modified spectrophotometric method, suitable for laboratory analysis as well as for field analysis. The results show that chemical oxidation and biochemical reduction can occur. Sulfuric acid is favourable for the stabilization of total arsenic and of the inorganic species.     

土坡稳定性的极限分析方法

本文应用塑性力学中的极限分析法原理，建立了滑动面为折线时的土坡稳定性极限分析公式。通过工程实例证明，该公式具有使用简便、可靠性强等优点。它对于评价斜坡的稳定性，合理地进行滑坡治理等，都具有实际意义。     

重庆市巫山县环湖路建设对淀粉厂滑坡影响的研究

重庆市巫山县环湖路地质条件十分复杂,沿线经过十几个地质灾害单元体。环湖路经过淀粉厂滑坡区时,以半挖半填的方式经过。环湖路建设对原滑坡体的稳定性影响进行重新评价计算,认为原设计方案不能满足要求,对原方案进行修改设计,完成淀粉厂滑坡的施工治理的环湖路的建设,实现了淀粉厂滑坡和环湖路工程建设的安全稳定。     

席状岩浆房中的岩浆冷却及动力稳定性

关于岩浆房中岩浆的结晶分异方式一直存在着争议,其基本矛盾在于对岩浆冷却历史及热不稳定性可能引起的对流形式的理解各不相同。本文在充分考虑席状岩浆房的基本物理特征的基础上,建立了稳定岩浆体系的动态冷却模型,并以攀枝花层状岩体为例,计算了相应的温度场、密度场及粘度场。同时,提出了一种基于能量守恒的、对热不稳定性进行分析的新方法。计算了热不稳定性可能引起的对流强度、对流区域及对流时间,并深入讨论了在一定的热不稳定状态下,不同的岩浆屈服强度对对流特征参量的影响。结果表明,在该岩体的整个固化过程中,如果曾发生过自发对流,其对流也是极微弱而短暂的,不会影响中下部岩浆房中岩浆的固化和结晶。这一结论与对该岩体的实际观察相符。     

Evaluating a process‐based model for use in streambank stabilization: insights on the Bank Stability and Toe Erosion Model (BSTEM)

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.     

The safety distance of a tunnel under-traversing a slope body with a landslide-prone zone

At present, substantial scientific research achievements have been made in the research on landslide occurrence, movement mechanism, mitigation measures, and structural stability during tunnel excavation. However, the interaction mechanism of a tunnel under-traversing a slope body with potential landslides is still not well understood. Based on the field data provided by previous investigations in the study area, six sets of 1:100 laboratory experiment model tests were conducted to study the stability of the landslide-prone zone of the slope body with an under-traversing tunnel. The selected distances between the tunnel and the sliding surface are 1.5, 3, and 5 times of the tunnel diameter, respectively. The experiment results show the interaction between the landslide-prone zone and the tunnel, elucidating the effect of potential landslides during the tunnel excavation process and the reaction of the landslide slip on the tunnel structure. Several conclusions are obtained: ① During the process of tunnel excavation, the vertical displacement of the tunnel vault decreases with the increase of the buried depth. ② The vertical displacement of the sliding surface increases with the increase of the buried depth of the tunnel. The horizontal displacement of sliding surface decreases with the increase of the buried depth. ③ After the occurrence of a rainfall-induced landslide, the vertical displacement of the tunnel vault in the 1.5-diameter-distance case is 57.29% greater than that in the 3.0-dismeter-distance case.④ For a two-cave tunnel, it is suggested that the cave farther from the landslide toe should be firstly excavated since it may generate less structural deformation.     

地震作用下锚固边坡稳定性数值分析

地震诱发的边坡失稳是一种重要的地震地质灾害类型,本文结合工程实例,利用有限差分软件FLAC3D 建立了一个边坡的数值分析模型。对比分析了静力状态下锚固前后边坡的塑性区、水平位移和滑移面,地震作用下锚固前后边坡的塑性区、各个时刻的水平位移、锚杆轴力分布和塑性状态,然后分析了边坡的稳定性,并探讨了边坡破坏的机理。数值分析结果表明:锚杆对边坡的加固效果十分显著; 锚杆在发挥锚固作用时主要受拉,且随着锚杆位置高程的增加,锚杆的轴力减小; 有无锚杆支护的边坡在地震作用下的破坏方式不同。研究结果为锚固边坡的抗震设计提供了参考依据。     

黄土基底构筑物边坡稳定的研究方法

我国适合露天开采的煤田,主要分布在西部及西北部的黄土高原地区。黄土基底构筑物在加载过程中,曾出现过某些惨痛的工程教训。基于黄土基底排土场形成后黄土底工程性质演化规律及失稳机制分析,提出其边坡稳定的研究方法,对黄土高原地区煤炭资源开发建设具有重要的理论与实际意义。     

基于Richards传导方程的降雨型浅层滑坡稳定性分析

基于描述流体在多孔介质中毛细传导行为的Richards方程,Iverson（2000）推导了斜坡中任意深度处的孔隙水压力对降雨入渗的响应方程,本文在此基础上进一步推导了降雨型浅层滑坡稳定性计算表达式。该表达式考虑了坡体非饱和区饱和度和坡体重度在降雨入渗过程中的变化。算例结果表明：降雨入渗过程中浅层滑坡稳定性系数逐渐降低,且在降雨停止后的较短时间内达到最小值,之后逐渐增大,但增大速率比降低速率要低。这种变化趋势在不同初始地下水位竖向埋深情况下是一致的,但稳定性系数随初始地下水位竖向埋深增大而减小。降雨历时和降雨入渗率对浅层滑坡的稳定性均有显著影响,表现为降雨历时和降雨入渗率越长（大）,稳定性系数降低幅度越大,但后者的影响受到滑坡体竖向渗透系数的控制。     

西南某电站右岸开挖边坡稳定性的FLAC~(3D)分析

西南某大型水电站引水发电洞进水口边坡顶部在开挖过程中出现带状裂缝 ,引起了多方的极大关注。在对该边坡系统的地质调查基础上 ,确立了其变形破坏模式 ;通过FLAC3D模拟开挖过程 ,客观地验证了实际开挖过程中边坡的变形及其顶部平台出现的裂缝 ;并预测了在采取加固措施后边坡内部变形趋势。经计算 ,开挖面临空方向最大位移量达到 5 .4cm。此后 ,经过有效的锚固处理 ,边坡经过变形和应力的调整 ,总体上趋于稳定 ,为确保进水口隧洞的顺利开挖提供了科学依据