Stability behavior of the Lanxi ancient flood control levee after reinforcement with upside-down hanging wells and grouting curtain

The stability of the ancient flood control levees is mainly influenced by water level fluctuations, groundwater concentration and rainfalls. This paper takes the Lanxi ancient levee as a research object to study the evolution laws of its seepage, displacement and stability before and after reinforcement with the upside-down hanging wells and grouting curtain through numerical simulation methods combined with experiments and observations. The study results indicate that the filled soil is less affected by water level fluctuations and groundwater concentration after reinforcement. A high groundwater level is detrimental to the levee's long-term stability, and the drainage issues need to be fully considered. The deformation of the reinforced levee is effectively controlled since the fill deformation is mainly borne by the upside-down hanging wells. The safety factors of the levee before reinforcement vary significantly with the water level. The minimum value of the safety factors is 0.886 during the water level decreasing period, indicating a very high risk of the instability. While it reached 1.478 after reinforcement, the stability of the ancient levee is improved by a large margin.

Failure of levees induced by toe uplift:Investigation of post-failure behavior using material point method

Levees are essential structures in flood defense systems,and their failures can lead to devastating consequences on the surrounding territories.One of the failure mechanisms mostly controlled by the foundation soil stratigraphy is the instability of the land side slope,triggered by the development of high uplift pressures in the foundation.This complex phenomenon has been investigated experimentally with centrifuge tests or large-scale tests and numerically with the limit equilibrium method(LEM)and the finite element method(FEM).In this work,we applied a multiphase formulation of the material point method(MPM)to analyze the development of toe uplift instability mechanism,from the onset of failure to large displacements.The numerical model is inspired by an experiment carried out in a geotechnical centrifuge test by Allersma and Rohe(2003).The comparison with the experiment allows for understanding critical pore pressure triggering large displacements in the foundation soils.Moreover,we numerically evaluated the impact of different values of foundation soils’hydraulic conductivity on the failure mechanism.The results show that hydraulic conductivity mainly influences the time of failure onset and the extension of shear localization at depth.Finally,the advantages of using large displacement approaches in the safety assessment of earth structures are discussed.Unlike FEM,there are no issues with element distortions generating difficulties with numerical convergence,allowing for full postfailure reproduction.This capability permits precise quantification of earth structure damages and post-failure displacements.The ensuing reinforcement systems’design is no longer over-conservative,with a significant reduction in associated costs.

Vague Language of Journalistic English in Syntactic Level

Vagueness is a natural character of language. Vagueness of journalistic English exists in lexical level and syntactic level as well. Lexical vagueness in journalistic English is usually resulted from the indefinite meaning of words, while in syntactic level, it may be resulted from the combined use of vague words or the employment of some sentence patterns. This thesis aims to help readers to understand journalistic English from the perspective of vague language.

Risk analysis of slope instability of levees under river sand mining conditions

Levees are affected by over-exploitation of river sand and river adjustments after the formation of sand pits. The slope stability is seriously threatened, drawing wide concern among experts and scholars in the area of water conservancy. This study analyzed the uncertainties of slope stability of levees under river sand mining conditions, including uncertainty caused by interest- driven over-exploitation by sand mining contractors, and uncertainty of the distance from the slope or sand pit to the bottom of the levee under the action of cross-flow force after the sand pit forms. Based on the results of uncertainty analysis, the distribution and related parameters of these uncertainties were estimated according to the Yangtze River sand mining practice. A risk model of the slope instability of a levee under river sand mining conditions was built, and the possibility of slope instability under different slope gradients in a certain reach of the Yangtze River was calculated with the Monte Carlo method and probability combination method. The results indicated that the probability of instability risk rose from 2.38% to 4.74% as the pits came into being.

Soil and Crop Damages as a Result of Levee Breaches on Ohio and Mississippi Rivers

Whenever levees on the Ohio or Mississippi rivers are breached, there are soil damages in the flooded areas that impact agricultural management capacities and crop productivity. Floodwaters coat the entire flooded land surface with sediments which include a variety of pollutants, nutrients and contaminants. The nature of the sediments in floodwaters varies with the topographical and land use characteristics of the watershed. The soil types, hydro-geologic features, volume of flow, time of year, agricultural use of fertilizers, pesticides, and other chemicals as well as upstream point sources such as sewage treatment plants, storm sewer drainage and other urban land uses will affect the extent of the contamination and fine scale remediation needed. Preliminary characterization and measurement of soils and sediment deposit at three locations that experienced recent natural and man induced levee breaches are analyzed to identify patterns of soil and crop damage. These findings provide guidance to the restoration of craters, gullies, land scoured areas and contaminated sediment depositional sites with a goal to improve decision-making, risk analysis and remedial effectiveness. Recommendations include： （1） improve characterization and measurement of eroded soils and distribution of sediment contaminants after levee breaching; （2） assess contamination effects on soil productivity and long term agricultural production in order to understand the impacts of flooding on agricultural soils; （3） evaluate reconstruction investments needed to repair levees based on return of the land to productivity and increased landscape resilience by reducing vulnerability to future flooding and levee breaching stress.

Why Does the Repaired Len Small Levee, Alexander County, Illinois, US Continue to Breach during Major Flooding Events?

One only needs to study the soil and geologic history and location of the ancient Mississippi and Ohio Rivers to understand why Len Small levee if patched will continue to fail. Much of Dogtooth Bend located in Alexander County, Illinois was originally in the ancient Ohio River valley (Figure 1) alluvial sediments north and east of the confluence with the ancient Mississippi River. The ancient Ohio River valley soils underlain by alluvial sediments and have been easily eroded by the re-aligning modern Mississippi River which now travels through the bedrock controlled Thebes Gap (Figure 2) and into the Ancient Ohio river valley. The primary objectives of this paper are: 1) to explain why Len Small levee, Alexander County, Illinois, US will continue to breach during major flooding events if repaired and 2) to develop a new combined raised causeway and levee system which will provide a Mississippi River floodwater bypass, be sustainable, encourage and fund a land use change, restore the degraded highway road beds, protect remaining Dogtooth Bend farmsteads and farmland that have not yet been degraded by past flooding events and provide floodwater storage during major flooding events at the confluence of the Mississippi and Ohio Rivers.

Addressing Soil Degradation and Flood Risk Decision Making in Levee Protected Agricultural Lands under Increasingly Variable Climate Conditions

Public and private levee systems may not be robust enough to address flooding risk to agriculture under changing climate conditions. Of concern are levee protected riverine bottomlands with intensive agricultural uses and diminished wetland systems that give resilience to floodplain hydrologic functions. In the United States natural and induced levee breaching has caused soil damage, loss of agricultural productivity, and public tension among agricultural landowners, urban residents, and environmental interests. Risk management and adaptive capacity of this humannatural system could be improved by assessments of 1) soil damage and 2) stakeholder values, fears, and knowledge about the riverine bottomland agroecosystem.

Total flavonoid of Litsea coreana leve exerts anti-oxidative effects and alleviates focal cerebral ischemia/reperfusion injury

In this study, we hypothesized that total flavonoid of Litsea coreana leve （TFLC） protects against focal cerebral ischemia/reperfusion injury. TFLC （25, 50, 100 mg/kg） was administered orally to a rat model of focal ischemia/reperfusion injury, while the free radical scavenging agent, edaravone, was used as a positive control drug. Results of neurological deficit scoring, 2,3,5-triphenyl tetrazolium chloride staining, hematoxylin-eosin staining and biochemical tests showed that TFLC at different doses significantly alleviated cerebral ischemia-induced neurological deficits and histopathological changes, and reduced infarct volume. Moreover, it suppressed the increase in the levels of nitrates plus nitrites, malondialdehyde and lactate dehydrogenase, and it diminished the reduction in glu- tathione, superoxide dismutase and catalase activities induced by cerebral ischemia/reperfusion injury. Compared with edaravone, the protective effects of TFLC at low and medium doses （25, 50 mg/kg） against cerebral ischemia/reperfusion injury were weaker, while the protective effects at high dose （100 mg/kg） were similar. Our experimental findings suggest that TFLC exerts neuroprotective effects against focal cerebral ischemia/reperfusion injury in rats, and that the effects may be asso- ciated with its antioxidant activities.

Deformation and Failure Analysis of River Levee Induced by Coal Mining and Its Influence Factor

To study the influence of coal mining on the stability of river levees,a mechanical model of mining-induced river levee deformation was established.This was based on the mining-induced deformation characteristics of river levees and the application of a typical surface subsidence function.Meanwhile,a failure criterion was proposed for river levees.Using some examples,the deformation of,and stress distribution through,river levees under the influence of mining were obtained:the maximum tensile stress on the bottom of the river levee was less than the tensile strength,under which circumstance the river levee remained undamaged.Meanwhile,this research analyzed the influence of three factors including the maximum surface subsidence wmax,half-length of surface subsidence basin L,and foundation coefficient k on the stability of river levees.Results showed that reducing the mining height of the working face and the foundation co-efficient,and increasing the strike length of the working face could reduce the influence of mining on river levees.These results provided a theoretical basis for predicting the mining-induced deformation and failure of river levees.

Establishment of Indication System for Evaluating the Citizenization Level of New Generation Migrant Workers and Its Application

Scientific and reasonable indicator system is the key for evaluating citizenization level of new generation migrant workers. With reference to basic connotation of endogenous and exogenous variables and in view of citizenization characteristics of new generation migrant workers,it built an evaluation indicator system including endogenous indicators based on micro-individual and exogenous indicators based on mesourban environment and macro-national policies. Besides,combining current situation of new generation migrant workers in Jiangsu Province,it evaluated citizenization level of the indicator system,in the hope of providing certain reference for evaluating citizenization level of new generation migrant workers.

Investigation and Research on the Ordinary University High Level Track and Field Sports Teams in Sichuan Province

by using the method of literature, questionnaire and mathematical statistics and comparative analysis and ?research method of sichuan university high level survey of the Track and field team, sichuan university high level Track and field team and the analysis of existing problems and research, in order to sichuan university of high level Track and field teams development to provide the reference.

Experimental Study on Stability of Levee Protection Method

For the retaining wall and technologies to protect river levee, many patents were applied and numerous new technologies were developed according to the installation method and material. This study installed a magic retaining wall block, which was developed as new technology product to protect river levee from running water, in actual size experimental water channel and evaluated the hydraulic performance and the stability of technology based on the increase in the flow velocity and discharge by steps. This study divided the experiment into a total of six steps and conducted it accordingly. According to the experiment results, there was no deformation of the surface of the magic retaining wall block or any soil loss at the bottom either, under the condition of maximum flow velocity of 5.37 m/s (discharge of 7.40 m3/s). To analyze the occurrence of scour and the possibility of soil loss at the bottom of a structure due to a high flow velocity, this study conducted an image analysis of Case 6 under the condition of maximum discharge, using a drone. According to the results of an analysis through the drone, there was no soil loss or flow change due to a scour at the bottom of the magic retaining wall block. The results of this study will serve as references in designing a technology applying a magic retaining wall block, and present the methods and procedures to evaluate and verify the development of any further new technology.

都市防洪堤加高工程对滨水建设用地的影响分析

为有效选择提高防洪标准的合理方式,从建设用地价值角度选取交通条件、基本设施、环境状况、城市规划4个因素,利用德尔菲法、层次分析法、中心点三角白化权函数法及模糊综合评价法,构建了都市防洪堤加高工程对滨水建设用地影响评估模型,分析了都市域内防洪堤加高工程对滨水建设用地的影响,并针对Y市防洪堤加高工程进行了实证分析。结果表明,都市防洪堤加高工程对滨水建设用地会产生一定的不利影响,建议优化防洪堤加高方案,或选择外围工程方案,并确立完善的非工程措施。

高密度电法在汛期堤防渗漏隐患探测中的应用

汛期高水位、高渗透压力下,会造成堤防渗漏缺陷扩大或隐患加剧,快速、准确地开展堤防渗漏隐患应急排查,是指导科学防汛、保障安全度汛的重要举措。针对管涌、散浸、穿堤建筑物等渗漏缺陷及隐患,开展了高密度电法的场地试验,得到汛期堤岸的电性结构,通过比对试验,得到不同渗漏缺陷与无显著缺陷堤岸的电性差异,以此为基准,采用高密度电法对子牙河右堤天津静海段特别是子牙河汇入独流减河段进行隐患排查,划分了渗漏隐患区和潜在风险区,为保障海河流域“23·7”特大洪水期间堤防安全提供了重要技术支撑。

地震正演在深水沉积地层研究中的应用

为提升深水沉积地层的地震解释精度和地震数据信息提取能力,通过对带有峡谷的陆坡沉积进行地震正演,分析了浊流和块体搬运主控的沟谷、水道、峡谷的地震反射特征,并在此基础上对水道天然堤复合体进行精细正演。综合分析认为:块体搬运主控沟谷宽深比小且为对称充填状,内部主要为杂乱弱振幅反射;而浊流主控峡谷宽深比大,内部为波状强振幅反射;地层顶底界面夹角越小,真实尖灭点与地震反射尖灭点间的误差越大;水道天然堤复合体厚度变小使得地震反射频率降低,振幅增强;水道饱含水时的振幅强于饱含气时的振幅。由此进一步明确了不同形态属性特征下多类型深水沉积体的地震响应特征,可以有效提高深水沉积地层地震资料综合解释精度。

平陆运河与沙坪河交汇河段通航水流条件试验研究

平陆运河沿线支流众多且支干落差大,支流突发洪水对运河通航水流条件影响较大。选取入汇角度大、支干汇流比大、河底落差大的沙坪河入汇河段为研究对象,采用1:50正态河工模型试验,对沙坪河入汇河段通航水流条件进行系统试验研究。模型试验结果表明,受支流突发较大洪水和支干河底落差较大影响,运河航道内横向流速大且流态紊乱,加之支流口上游铁路桥限制,消能措施布置长度有限,不能达到较好的消能效果。分析认为主要问题在于支流洪水汇入运河后运河横向流速较大,因此治理方案主要解决“调顺水流+消能”的问题。在交汇处布置导流堤、透空消能墩、底部斜向透空式隔流堤,在支流内采取消力池、消力槛等消能措施并进行系列方案对比试验,发现优化方案Ⅲ的通航水流满足通航要求且不会对支流内铁路桥造成影响。

基于多变量灰色系统的乏信息堤防变形短期预测模型

依据信息模糊和不确定状态下乏信息数据处理理论,提出了一种改进多变量灰色系统的乏信息堤防短期预测模型;引入多变量灰色模型对多测点的沉降变形序列进行拟合,结合混沌粒子群优化算法和分数阶微积分理论,实现了在乏信息条件下对堤防多测点变形的短期预测;由对比结果可知,研究提出的模型可行且有效,填补了堤防乏信息处理模型的空白。

数字金融对农村商业银行风险水平的影响研究

基于2014—2021年108家农村商业银行财务数据,采用系统GMM估计方法研究数字金融与农村商业银行风险水平之间的关系。结果发现:第一,数字金融能够有效降低农村商业银行风险水平,并在使用深度和数字化程度的维度上均能产生显著影响;第二,在中介机制检验中发现,数字金融主要通过提升银行经营效率来降低农商行风险水平,银行竞争加剧会增强数字金融对农村商业银行风险水平的抑制作用;第三,数字金融对农村商业银行风险水平的抑制作用在中西部地区和大规模的农村商业银行中表现得更明显。

大运河枢纽洪泽湖大堤石刻的数字化创新

洪泽湖大堤石刻主要包括工程碑记石刻、御题石刻、吉祥图案石刻、吉祥文字石刻等。石刻内容丰富、镌刻精美,蕴含着丰富的历史信息和文化基因。然而随着湖水的侵蚀、自然气候和人为的破坏,石刻面临着前所未有的损害危机,开展数字化保护已迫在眉睫。本研究选取代表性石刻,对其造型结构、图案与纹饰进行数字化创新性设计与应用,主要方法是将石刻中所蕴含的美好寓意及大堤文化的历史信息与现代化的视觉审美相结合,通过三维模型的处理和图像的深度配合,实现对洪泽湖大堤石刻的三维建模与文化衍生品的设计开发,开展数字化保护与应用,为科普和传承大堤石刻文化和运河水居文化提供参考路径和可行性方案。

Environmental Impact of Kakhovka Dam Breach and Chernobyl Nuclear Power Plant Explosion on Dnieper River Landscape

The Dnieper River headwaters are in Russia’s Valdai Hills and the river flows south to the Black Sea. The Dnieper River provides a waterway in which to transport goods to and from various European nations. In addition, the dams on the river provide hydro power. There are approximately 2260 km of Dnieper waterways in Russia, in Belarus, and within Ukraine. The Dnieper River has numerous urban centers including Smolensk in Russia, Mogilev in Belarus and Kiev and Zaporizhzhya in Ukraine. The worst nuclear accident in history unfolded, in the Dnieper River watershed, in northern Ukraine as a reactor at the Chernobyl nuclear power plant exploded and burned. After an accident, such as Chernobyl, radionuclide contaminated bodies of water via direct deposition from the air, discharge as effluent or indirectly from catchment basin washout. When radionuclides contaminate large bodies of water, they are quickly dispersing and accumulate in water bottom sediments, benthos, aquatic plants, and bottom feeding fish. The main pathways to humans are through contamination of drinking-water, from use of water for irrigation of food crops, and consumption of contaminated fish. Kakhovka Dam on the Dnieper River was destroyed during the Russian-Ukraine conflict and the dam needs to rebuild as soon as possible. Perhaps lessons learned by the US Army Corps of Engineers (USACE), after using TNT to blow up the Birds Point front line levee on the Mississippi River in May of 2011, can be applied to the man-induced 2023 Kakhovka Dam breach. The Birds Point man-induced levee breaches and subsequent flooding of farmland resulted in the loss of the 2011 crops and damaged the future soil productivity. The strong current and sweep of the water through the three man-induced levee breaches on the New Madrid floodway levee created deep gullies, displaced tons of soil, and damaged irrigation equipment, farms, and homes. The New Madrid floodway agricultural lands were restored, and the environmental damages were mitigated. The Kakhovka Dam destruction caused widespread flooding which affected settlements and farmland across the Dnieper watershed. The presence and breach-induced redistribution of Chernobyl-derived nuclides is an additional condition not present at the New Madrid man-induced levee breach. Four canal networks have become disconnected from the feeder reservoir. The canals were the source of drinking water for 700,000 people living in southern Ukraine. The Kakhovka canals also provided irrigation for vast areas of farmland. The water loss from the canals adversely affected food production in the region. The primary objectives of this paper are to assess lessons learned by the USACE and apply them in Ukraine to help restore and manage the Dnieper lifeline and watershed.