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1.
Corrosion behavior of steel in the juncture area of sea clay and sand was studied. The results show that galvanic corrosion occurred between steel samples buried in sea clay and sand, and that the polarity of the galvanic cell reversed after some testing later. The cause of reversing of polarity is discussed. 相似文献
2.
沙漠风积沙稳定性差, 采用水泥作为固化剂进行风积沙固化, 是改善风积沙性质和实现风积沙资源化利用的有效手段。以取自内蒙古库布齐沙漠的风积沙为材料, 制备3%含水量的重塑风积沙, 掺入水泥固化剂并充分拌匀而形成固化风积沙, 开展水泥固化风积沙的抗剪、抗压和抗拔承载性能试验。结果表明, 水泥掺量对固化风积沙黏聚强度的提高程度要大于内摩擦角。含水量3%的风积沙掺入6%的水泥经28 d常温养护的固化风积沙无侧限抗压强度平均值为0.156 MPa。固化风积沙扩展基础抗拔荷载-位移曲线呈现初始弹性段至峰值荷载以及峰值荷载后破坏的两阶段脆性破坏特征。水泥固化提高风积沙抗拔承载性能效果显著, 且与基础底板尺寸、抗拔埋深及基础深宽比等因素有关。 相似文献
3.
Study on rust layers on steel in different marine corrosion zone 总被引：1，自引：0，他引：1
IrmODUCnONTheMossbaureffect(ME)isalsoknOWnasrecoil-thenuclearresonaneabsorp-hon.MossbaursPeCboscoPy(MS)haspIDvedtobeaveryuSefultecheqUeforstudytngcormsionPimessesandcedon-cts.TheInainadvantagsofMSincormsionre-enhare:(l)thenon-deStrutivechateroftheteCboqUe;(2)possibilltyforquali-tativeandqUanitativephaanalsis;(3)uSehassinidenificationofPOOrlycrystal-lizedoramorphouscormsionpnhats.WththedeVfoPmntofInarineresomees,InansteelconstrUctionswerebulltatsea'MSwasusedforanalfongcormsion~t… 相似文献
4.
Xiaohao Wen Baosheng Li Fengnian Wang Yanming Zheng Dongfeng Niu Yuejin Si Xianjiao Ou 《中国地理科学(英文版)》2012,22(1):48-62
The TMS5e sequence from the Tumen section,at the southern edge of Tengger Desert in the northwestern China,is synchronous with Marine Isotope Stage 5e(MIS5e).It consists of 16 layers of aeolian dune sands,11 layers of lacustrine loess-like facies,and 5 layers of lacustrine facies.The results of grain-size analysis shows that the palaeo-mobile dune sands,palaeo-fixed to semi-fixed dune sands and loess-like sandy loams are mainly composed of sands,ranging from 70% to 96%;their silt contents ranged from 4% to 20%,and their clay contents ranged from 1% to 5%;the climate under which the aeolian dune sands were deposited is similar to that under which modern mobile dune sands form,which is caused by the dominance of the cold,dry East Asian winter monsoon.In contrast,the lacustrine loess-like facies and lacustrine facies had a lower sand contents than those of the three aeolian dune sands,but have higher silt and clay contents,most of their sand content ranged from 30% to 60%,their silt contents ranged from 35% to 55%,and their clay contents ranged from 6% to 20%.The lacustrine loess-like facies and lacustrine facies formed under the influence of the warm,humid East Asian summer monsoon based on their similarity with modern sediments.The grain-size indicator Mz(mean grain diameter) and the SC/D value in the TMS5e sequence indicate climatic insta-bility at the southern edge of the Tengger Desert during MIS5e,with at least 14 fluctuations between a warm,humid climate and a cold,dry climate,divided into five stages:TMS5e5(139 kyr to 129.3 kyr B.P.),TMS5e4(129.3 kyr to 124 kyr B.P.),TMS5e3(124 kyr to 119.5 kyr B.P.),TMS5e2(119.5 kyr to 116.5 kyr B.P.),and TMS5e1(116.5 kyr to 113.7 kyr B.P.).These correspond roughly to MIS5e5,MIS5e4,MIS5e3,MIS5e2,and MIS5e1,respectively,in the GRIP ice core data. 相似文献
5.
This paper presents particle breakage and the mobilized drained shear strengths of sand with the purpose of clarifying the influence of particle breakage on the mobilized shear strengths of sand. Several drained triaxial tests were carried out on Silica sand No.5 under 3 MPa confining pressure to produce the pre-crushed sands in simulating the high-pressure shear process on soil to result in particle breakage, and then the pre-crushed sands were re-sheared in series of drained triaxial tests to investigate the mobilized strengths of the pre-crushed sands in detecting the influence of particle breakage. It was found that, by deteriorating strain-stress behavior, particle breakage resulted in change of stress-dilatancy behavior in translation and rotation of the relation of the dilatancy factor and the effective principal stress ratio. For a given initial void ratio, particle breakage resulted in impairment of dilatancy behavior of soil to be more contractive in deterioration of the mobilized friction angle and the mobilized dilatancy angle and reduction of void ratio. However, particle breakage resulted in increase of the mobilized basic friction angle especially before failure. In addition, the influence of particle breakage on the mobilized strengths was revealed to be influenced by the shear stress-strain state. 相似文献
6.
7.
EFFECT OF SULPHATE-REDUCING BACTERIA ON ELECTRO-CHEMICAL CORROSION BEHAVIOR OF 16Mn STEEL IN SEA MUD
ＩＮＴＲＯＤＵＣＴＩＯＮＩｔｗａｓｇｅｎｅｒａｌｌｙｃｏｎｓｉｄｅｒｅｄｐｒｅｖｉｏｕｓｌｙｔｈａｔｔｈｅｃｏｒｒｏｓｉｏｎｏｆｓｔｅｅｌｉｎｓｅａｍｕｄｗａｓｎｏｔｓｅｒｉｏｕｓ.Ｈｏｗｅｖｅｒ,ｉｔｗａｓｌａｔｅｒｆｏｕｎｄｔｈａｔｔｈｅｃｏｒｒｏｓｉｏｎｒａｔｅｏｆｓｔｅｅｌｉｎｓｏｍｅｓｅａｍｕｄｗａｓｈｉｇｈｅｒｔｈａｎｔｈａｔｉｎｓｅａｗａｔｅｒ(Ｋｉｎｇ,1980;Ｓｅｈｍｉｄｅ,1982;Ｇｕｏｅｔａｌ.,1997;Ｈｏｕ,1998).Ｔｈｅｒｅａｒｅｓｏｍｅｒｅｐｏｒｔｓｔｈａｔｔｈｅｃｏｒｒｏｓｉｏｎｒ… 相似文献
8.
Undrained behaviour of sand under low cell pressure was studied in static and cyclic triaxial tests. It was found that very loose sand liquefies under static loading with the relative density being a key parameter for the undrained behaviour of sand. In cyclic triaxial tests, pore water pressures built up during the cyclic loading and exceeded the confining cell pressure. This process was accompanied by a large sudden increase in axial deformation. The necessary number of cycles to obtain liquefaction was related to the confining cell pressure, the amplitude of cyclic loading and the relative density of sand. In addition, the patterns of pore water pressure response are different from those of sand samples with different relative densities. The test results are very useful for expounding scour mechanism around coastal structures since they relate to the low stress behaviour of the sand. 相似文献
9.
hacteria(SRB)canbeashighastenhmesthainseahattOInsetlimentwithouSRB.Theex-perimentsinsimulatingseahattmsedimentswithdifferentconcenhations0fcultUredSRBsh0WedthatheelecthehendcalpoariZaionbehavi0ur0fsteelinseahatt()msedimentwithandwithouSRBwerefferent.SRBalteredthepoarizationbehavi0ur0fsteelsignificanilbyaciopingtheenvironments0thaaP-parenthydrogendepoallzationoccurredandacceleratedthec0meionofsteel.Keywofor:anaerohe,seab0ttomsediment,steelINTRODUCTIONAnaerobesaregenerallypresentins… 相似文献
10.
According to the data of main environmental factors and the depth of localized corrosion of carbon steel and low alloy steels in China seas, combined with the result of grey interrelation analysis, double-factor method was proposed to evaluate and classify seawater corrosiveness. According to the temperature of seawater and the biologically adhesive area on steels, the corrosiveness of seawater from low to high level is classified into five levels （C l-C5）, which was identified by the data of corrosion depth of carbon steel immersed in water for one year. 相似文献
11.
Serious desertification caused by human activity and climate change, in addition to water loss and soil erosion related to arsenic sandstone in the Mu Us Sandy Land, lead to severe scarcity of soil and water resources, which causes worse local agricultural conditions accordingly. Many physical properties of arsenic sandstone is complementary with that of sand, arsenic sandstone is therefore supposed to be blended to enhance water productivity and arability of sandy land. Container experiments are carried out to study the enhancement of water holding capacity of the mixture, the blending ratio of arsenic sandstone and sand, and the proper size of the arsenic sandstone particles, respectively. The results of the experiments show that particle size of 4 cm with a ratio of 1 ： 2 between arsenic sandstone and sand are the proper parameters on blending. Both water content and fertility increase after blending. Water use efficiency in the mixture is 2.7 times higher than that in sand by the water release curves from experiments. Therefore, a new sand control and development model, including arsenic sandstone blending with sand, efficient water irrigation management and reasonable farming system, is put forward to control and develop sandy land so that water-saving agriculture could be developed. Demonstration of potato planting about 153.1 ha in area in the Mu Us Sandy Land in China indicates that water consumption is 3018 m3/ha in the whole growth period. It means that about 61% of irrigation water can be saved compared with water use in coarse sand without treatment. Recycle economic mode and positive feedback of sand resource-crop planting-soil resource are constructed, which changes sand into arable soil and make it possible to develop water-saving agriculture on it. The proposed model will be helpful for soil-water resources utilization and management in the Mu Us Sandy Land. 相似文献
12.
庙西南凸起蓬莱A构造区馆陶组有良好油气发现,但储层厚度多小于5 m,难以被精确识别刻画。以薄层砂体为研究对象,综合地震、测井、钻井岩心、古生物等基础资料,明确研究区馆陶组沉积时期受北东向物源供给沉积,发育河流-浅水三角洲相。基于90°相位化处理确定砂体地震响应特征;分频解释处理判断相对等时地震同相轴,构建馆陶组高频层序地层格架（三级层序SQ1-3）,优选60Hz地震数据体进行地层切片划分;地层切片高精度沉积学解释揭示研究区馆陶组SQ1层序至SQ3层序依次发育河流-席状化浅水三角洲-朵叶状浅水三角洲-水下河道型浅水三角洲。其中SQ1层序中河道砂体以及SQ2-3层序中浅水三角洲前缘砂体皆为有利储层。此次研究丰富发展了渤海海域河流-浅水三角洲相中地震沉积学在砂体预测中的研究成果。 相似文献
13.
Pore water pressure and water content are important indicators to both deposition and consolidation of debris flows, enabling a direct assessment of consolidation degree. This article gained a more comprehensive understanding about the entire consolidation process and focused on exploring pore water pressure and volumetric water content variations of the deposit body during natural consolidation under different conditions taking the viscous debris flow mass as a study subject and by flume experiments. The results indicate that, as the color of the debris changed from initial dark green to grayish-white color, the initial deposit thickness declined by 3% and 2.8% over a permeable and impermeable sand bed, respectively. A positive correlation was observed between pore water pressure and depth in the deposit for both scenarios, with deeper depths being related to greater pore water pressure. For the permeable environment, the average dissipation rate of pore water pressure measured at depths of 0.10 m and 0.05 m were 0.0172 Pa/d and 0.0144 Pa/d, respectively, showing a positivechanging trend with increasing depth. Under impermeable conditions, the average dissipation rates at different depths were similar, while the volumetric water content in the deposit had a positive correlation with depth. The reduction of water content in the deposit accelerated with depth under impermeable sand bed boundary conditions, but was not considerably correlated with depth under permeable sand bed boundary conditions. However, the amount of discharged water from the deposit was greater and consolidation occurred faster in permeable conditions. This indicates that the permeability of the boundary sand bed has a significant impact on the progress of consolidation. This research demonstrates that pore water and pressure dissipations are present during the entire viscous debris consolidation process. Contrasting with dilute flows, pore pressure dissipation in viscous flows cannot be completed in a matter of minutes or even hours, requiring longer completion time — 3 to 5 days and even more. Additionally, the dissipation of the pore water pressure lagged the reduction of the water content. During the experiment, the dissipation rate fluctuated substantially, indicating a close relationship betweenthe dissipation process and the physical properties of broadly graded soils. 相似文献
14.
马士德 《中国海洋湖沼学报》1989,7(3):271-273
The effect of barnacles on corrosion of low alloy (16Mn) steel was studied by immersing steel panels in seawater at Zhonggang.Qingdao, for 41 months. It was found that the secondary attachment on this kind of steel by barnacles had less effect on its corrosion while the primary attachment had a greater effect; that different seasons have different effects on the form and extent of local corrosion in this steel, and that primarily attached barnacles cause more serious local corrosion in high breeding seasons when there are more attachments. 相似文献
15.
《中国海洋湖沼学报》2020,(2)
Copper has long been utilized as a disinfectant for bacteria,but its impact on microbial communities attached to the steel surface in seawater remains unknown.In the present study,3 mooring chain steels of different copper contents are subjected to a 3-month marine field exposure,and the corrosion rate increases in the order of BR5 steel(without copper) BR5 CuH steel(0.8% copper) BR5 CuL steel(0.4% copper).The microbial community results show that copper introduction does not result in an obvious change in microbial quantity,but it alters the diversity,richness,and structure of microbial communities due to the variation in copper-resistance of different species.BR5 CuH steel holds microbial communities with the highest percentage of some well-known corrosive microbes including sulfate-reducing bacteria,sulfuroxidizing bacteria,and iron-oxidizing bacteria,but possesses the lowest community diversity/richness owing to the toxicity of copper.The microbial community diversity/richness is stimulated by the low-copper content of BR5 CuL steel,and this steel also carries an intermediate proportion of such corrosive bacteria.Both well-known corrosive bacteria and microbial community diversity/richness seem to be involved in the corrosion acceleration of copper-bearing mooring chain steels. 相似文献
16.
经济的快速发展, 对砂石料的需求巨大, 海砂的开发成为当前的热点。琼州海峡东口海砂资源丰富, 资源潜力概算可达数十亿方。依据前期调查数据, 选取含泥量、含砂量、粒级、海砂厚度、水深和离岸距离6类指标, 采用层次分析法, 构造判断矩阵计算评价因子的权重, 运用ArcGIS空间分析功能进行叠加, 对琼州海峡东口的海砂进行了开发适宜性评价。结果表明: 经计算将研究区分为开发适宜性好、较好、中等、较差、差5个等级, 其中浅滩区域海砂规模大、质量好、水深浅和开采环境影响小, 其开发适宜性最佳。分析了不同的指标对海砂开发适宜性的影响, 在浅滩区, 厚度和含砂量指标贡献较大; 在近岸海湾, 环境影响是主要因子; 在琼州海峡深槽区, 水深条件则成为海砂开发的主要限制条件。根据海砂资源的特点, 建立了以资源自然属性、开发技术条件、生态环境影响和行政管理为主要因子的海砂开发利用适宜性评价体系, 具体工作可选取不同的指标开展评价。研究结果可以为研究区海砂的开发利用和其他区域海砂开发适宜性评价提供参考。 相似文献
17.
《中国海洋湖沼学报》2017,(5)
Defects in protective-coating systems on steel surfaces are inevitable in practical engineering applications.A composite coating system,including a primer,middle coat and topcoat,were used to protect carbon steel from corrosion in a marine environment.Two environmental additives,glass fi bers and thiourea,were applied in the middle coat to modify the coating system.The long-term corrosion durability and self-healing ability of the scratched coating system were evaluated by multiple methods.Results of the electrochemical technologies indicated that the coating system that contained 0.5 wt.%fi bers and 0.5 wt.%thiourea presented good corrosion protection and self-healing for carbon steel when immersed in 3.5%Na Cl for 120 d.Evolution of localized corrosion factors with time,as obtained from the current distribution showed that fi bers combined with thiourea could inhibit the occurrence of local corrosion in scratched coating systems and retarded the corrosion development signifi cantly.Surface characterization suggested that adequate thiourea could be absorbed uniformly on fi bers for a long time to play an important role in protecting the carbon steel.Finally,schematic models were established to demonstrate the action of fi bers and thiourea on the exposed surface of the carbon steel and the scratched coating system in the entire deterioration process. 相似文献
18.
设计一种新型光纤光栅锈蚀传感器,主要由锈蚀体、不锈钢体和2段串联的光纤布拉格光栅（FBG）组成。缠绕于锈蚀体表面的FBG监测钢筋的锈胀应变,缠绕于不锈钢体表面的FBG用作温度补偿器,消除温度变化对锈胀应变监测的影响。此外,设计电化学加速腐蚀实验,探究该传感器在不同强度等级混凝土中的工作性能。结果表明,该传感器监测质量腐蚀率的灵敏度为0.02%,监测范围大于1%,可实时监测混凝土中钢筋的锈蚀过程及特征,为预警钢筋锈蚀引起的钢筋混凝土结构耐久性损失提供阈值,在结构健康监测领域具有较大的应用价值。 相似文献
19.
SEDIMENTARY ENVIRONMENT IN TAIWAN SHOAL 总被引：8，自引：0，他引：8
Taiwan Shoal sediments are well sorted and rounded medium-coarse sands eontaining a large amount of shell and beach rock fragments and basalt gravels, and are of deltaic, coastal and eolian origin. Underwater sand waves are formed by the combined tidal currents and are remolded by storm waves. 相似文献
20.
在室内水泥池,利用沙层自净养殖模式和直接铺沙养殖模式对不同规格的方斑东风螺(Babylonia areolataLink)进行了高密度养殖的研究。结果表明,沙层自净养殖模式养殖小螺、中螺、大螺组日均增重分别为0.031、0.088、0.098 g/d,沙层NH4+-N最高含量w分别为1.3、2.1、3.1 mg/L,H2S最高含量w分别为0.03、0.07、0.14mg/L,各规格组东风螺保持正常生长和活动,成活率92.9%以上;直接铺沙养殖模式养殖小螺、中螺、大螺日均增重分别为:0.023、0.051、0.068 g/d,成活率分别为95.2%、86.7%、84.9%,沙层NH4+-N最高含量w达到13.7mg/L,H2S最高含量w达到0.47 mg/L,沙层底质恶化,东风螺活动异常、不摄食。可见,沙层自净养殖模式对方斑东风螺的生长、成活率、沙层水质控制效果显著,在一定程度上克服了直接铺沙养殖底质恶化问题。 相似文献