不同因素影响下层间错动带颗粒破碎和剪切强度特性试验研究   总被引：2，自引：0，他引：2  

赵阳  周辉  冯夏庭  邵建富  江权  闵弘  江亚丽  黄可 《岩土力学》2013,34(1):13-22

为了获得不同初始颗粒粒径分布和含水率对层间错动带颗粒破碎和剪切强度特性的影响,通过对比泥夹碎屑、泥夹粉砂、全泥型3种不同层间错动带类型与现场3种不同含水率（10%、7%和3%）试样在法向压力2～10 MPa作用下的反复直剪试验和剪切面颗粒粒径分析试验结果,可得出以下结论：①粗颗粒越多（d60越大）,采用相对颗粒破碎势Br量化的颗粒破碎程度越大;②较干颗粒（低含水率）由于磨损产生了更多的细小颗粒,而较湿颗粒（高含水率）由于破裂和摩擦产生了较大颗粒;③粗颗粒仅对峰值抗剪强度产生一定的影响,且粗颗粒越多,残余强度包线非线性越强;④黏聚力和内摩擦角随含水率线性减小,且低含水率试样残余强度包线非线性最强;⑤残余内摩擦角随颗粒破碎后的黏粒含量（<2 μm）线性减小。提出的残余内摩擦角初步预测公式可供实际工程参考。  相似文献   

真空加载方式对吹填流泥加固效果及土颗粒移动的影响研究   总被引：2，自引：0，他引：2  

武亚军  杨建波  张孟喜 《岩土力学》2013,34(8):2129-2135

考虑加载方式的影响开展室内模型试验,对4组相同性质的泥浆试样（含水率为100%）分别采用不同的加载方式,即-80 kPa、-60 kPa→80 kPa、-40 kPa→-80 kPa、-20 kPa→-80 kPa进行加载,加载过程中对试样的出水量、沉降量和侧向变形进行跟踪监测,并对处理后土体的含水率、塑性指数和十字板剪切强度等的空间分布与变化规律进行研究。试验结果表明,（1）真空加载方式对吹填流泥的固结具有比较明显的影响;（2）初始真空荷载为-20 kPa时所得到的土体沉降量最大、强度最高,始终保持-80 kPa荷载情况下所得到的土体沉降量最小、强度最低;（3）从塑性指数的分布特征来看,土颗粒随着土中水的排出发生移动,初始真空荷载越大,这种趋势越明显,部分土颗粒会聚积在排水板周围而导致土体渗透性能的降低,严重时会影响土体的后续固结。建议在流泥淤泥的真空固结过程中采用低初始荷载方式进行加载。  相似文献   

粗颗粒盐渍土溶陷性影响因素研究   总被引：2，自引：0，他引：2  

程东幸  刘志伟  柯学 《工程地质学报》2013,21(1):109-114

粗颗粒盐渍土是近年来西北地区工程建设中常遇到、且比较棘手的一种特殊土。为了研究该类特殊土的工程特性,本文在新疆东北部和甘肃河西走廊地区选择了4个试验场地的28个现场试验点和576件室内试样对进行了溶陷性研究,结果显示:当地基土中易溶盐含量超过0.5％ ～1％以上,且地基土渗透系数不小于10-7 时,常会发生溶陷现象。同时发现在温度、易溶盐成分、水等共同作用下的地基土周期性胀缩现象比单一的盐胀或溶陷对建筑物安全影响更大。  相似文献   

砂岩常规三轴的颗粒流数值模拟     

朱涵成  韩文喜  陈超 《地质灾害与环境保护》2013,24(3)

以砂岩的室内试验数据为参照,使用颗粒流数值程序PFC3D,建立刚性颗粒组成的模型.通过设置颗粒接触模量、颗粒刚度比和接触粘结强度等细观力学参数,得到有合适宏观力学反应的模型.通过数值模拟获得砂岩微裂隙发展的过程,得到不同围压下砂岩的应力-应变曲线,反应出砂岩试样的弹性模量随围压增大而增大的性质.结果表明,PFC3D程序能够较好地模拟荷载作用下岩石的细观力学特性和宏观力学反应.  相似文献   

基于个体模型的东海鲐鱼渔场形成机制研究   总被引：4，自引：2，他引：2  

李曰嵩  潘灵芝  严利平  陈新军 《海洋学报》2014,36(6):67-74

鲐鱼Scomber japonicus资源丰富,在我国近海渔业中占有重要地位。其渔场的形成受海洋环境的制约,本文确定鲐鱼运动和物理环境之间的响应关系,建立起了基于个体的东海鲐鱼生长洄游模型。结果显示,鲐鱼集群分布与捕捞生产渔场基本吻合,鲐鱼聚集主要受台湾暖流、大陆沿岸水、黑潮影响,往往集群在一定温度范围内并在冷暖交汇区温盐梯度大偏暖水一侧。在台湾暖流和沿岸水交汇的锋面附近、台湾暖流暖水舌前端、黑潮与中国大陆沿岸水形成的潮境区域均有大量的鲐鱼聚集,并形成渔场。产卵位置的变动使偏西产卵位置的鲐鱼由于受台湾暖流影响较大,鲐鱼会呈长带状大量聚集在台湾暖流和沿岸水的锋面附近,并使在台湾暖流暖水舌前端的聚集数量增多,而偏东的产卵的鲐鱼受黑潮影响较大,聚集分布范围较大,会使黑潮形成的锋面附近聚集数量增多,而使台湾暖水舌的前端的聚集量减少。正常产卵位置在生存率方面是最佳产卵位置。研究表明鲐鱼所处空间位置不同,会影响其集群的位置,用数值模型验证了物理环境会对鲐鱼的洄游和渔场的形成产生影响。  相似文献   

Optical properties of estuarine dissolved organic matter isolated using cross-flow ultrafiltration   总被引：1，自引：0，他引：1  

YI Yueyuan  ZHENG Airong  GUO Weidong  YANG Liyang  CHEN Ding 《海洋学报(英文版)》2014,33(4):22-29

Dissolved organic matter(DOM) from freshwater, mid-salinity, and seawater endmember samples in the Jiulong River Estuary, China were fractionated using cross-flow ultrafiltration with a 10-kDa membrane. The colloidal organic matter(COM; 10 kDa–0.22 μm) retentate, low molecular weight(LMW) DOM(10 kDa) permeate, and bulk samples were analyzed using absorption spectroscopy and three-dimensional fluorescence excitation-emission-matrix spectroscopy. The UV-visible spectra of COM were very similar to those obtained for permeate and bulk samples, decreasing monotonically with increasing wavelength. Most of the chromophoric DOM(CDOM, expressed as the absorption coefficient a355) occurred in the LMW fraction, while the percentage of CDOM in the colloidal fraction was substantially higher in the freshwater endmember(13.4% of the total) than in the seawater endmember(6.8%). The bulk CDOM showed a conservative mixing behavior in the estuary, while there was removal of the COM fraction and a concurrent addition of the permeate fraction in the mid-salinity sample, implying that part of the colloidal CDOM was transformed into LMW CDOM. Two humic-like components(C1: 250, 325/402 nm; and C2: 265, 360/458 nm) and one protein-like component(C3: 275/334 nm) were identified using parallel factor analysis. The contributions of the C1, C2, and C3 components of the COM fraction to the bulk sample were 2.5%–8.7%, 4.8%–12.6%, and 7.4%–14.7%, respectively, revealing that fluorescent DOM occurred mainly in the LMW fraction in the Jiulong River Estuary. The C1 and C2 components in the retentate and permeate samples showed conservative mixing behavior, but the intensity ratio of C2/C1 was higher in the retentate than in the permeate fractions for all salinity samples, showing that the humic component was more enriched in the COM than the fulvic component. The intensity ratio of C3/(C1+C2) was much higher in the retentate than in the permeate fraction for mid-salinity and seawater samples, revealing that the protein-like component was relatively more enriched in COM than the humic-like component. The contribution of the protein-like component(C3) to the total fluorescence in the retentate increased from 14% in the freshwater endmember to 72% for the seawater endmember samples, clearly indicating the variation of dominance by the humic-like component compared to the protein-like component during the estuarine mixing process of COM.  相似文献   

Occurrence and distribution of dissolved tellurium in Changjiang River estuary     

吴晓丹  宋金明  李学刚 《中国海洋湖沼学报》2014,32(2):444-454

With the implementation of the GEOTRACES program, the biogeochemical cycle and distribution of tellurium （Te） in marine environments are becoming increasing environmental concerns. In this study, the concentration of dissolved Te in the Changjiang （Yangtze） River estuary and nearby waters was determined in May 2009 by hydride-generation atomic fluorescence spectrometry to elucidate the abundance, dominant species, distribution, and relationship with environmental factors. Results show that： （1） dissolved Te was low owing to its low abundance in the Earth＇s crust, high insolubility in water, and strong affinity to particulate matter; （2） Te（IV） and Te（VI） predominated in surface water. Te（VI） was the dominant species in bottom water, and Te（IV） was the minor species; （3） Horizontally, resulting from low phytoplankton metabolism and the weak reduction from Te（VI） to Te（IV） in the shore, Te（IV） was concentrated in the central zone instead of the coastal region. However, Te（VI） was abundant near the mouth of the Changjiang River where the Changjiang water is diluted and in the area to the south where the Taiwan Warm Current invaded. In the adsorption-desorption process, Te（IV） was negatively related to suspended paniculate matter （SPM）, indicating that it was adsorbed by particulate matter. While for Te（VI）, the positive correlation with SPM suggested that it was desorbed from the solid phase. In the estuary, dissolved Te had a negative correlation to salinity. However, it deviated from the dilution line in high-salinity regions due to the invasion of the Taiwan Warm Current and the mineralization of organic matter. The relationship between Te（IV） and SPM nutrients indicated that it was more bioavailable and more related to phosphorus than to nitrogen. Progress in the field is slow and more research is needed to quantify the input of Te to the estuary and evaluate the biochemical role of organisms.  相似文献   

Soil Moisture Effects on Sand Saltation and Dust Emission Observed over the Horqin Sandy Land Area in China   总被引：1，自引：1，他引：0       下载免费PDF全文

LI Xiaolan  ZHANG Hongsheng 《Acta Meteorologica Sinica》2014,28(3):444-452

In this study, the effects of soil moisture on sand saltation and dust emission over the Horqin Sandy Land area are investigated, based on observations of three dust events in 2010. The minimum friction velocity initiating the motion of surface particles, namely, the threshold friction velocity, is estimated to be 0.34,0.40, and 0.50 m s-1under the very dry, dry, and wet soil conditions, respectively. In comparison with the observations during the dust events under the very dry and dry soil conditions, the dust emission flux during the wet event is smaller, but the saltation activities of sand particles(d 50 μm) are stronger. The size distributions of airborne dust particles(0.1 d 20 μm) show that concentrations of the finer dust particles(0.1 d 0.3 μm) have a secondary peak under dry soil conditions, while they are absent under wet soil conditions. This suggests that the surface soil particle size distribution can be changed by soil moisture. Under wet soil conditions, the particles appear to have a larger size, and hence more potential saltating particles are available. This explains the occurrence of stronger saltation processes observed under wet soil conditions.  相似文献   

纵览九州     

《南方国土资源》2014,(6)

正望江:"五个注重"践行群众路线2014年,安徽省望江县国土资源局紧紧围绕"五个转变"目标,做到"五个注重",将党的群众路线教育实践活动引向深入。一是注重"民盼",助力美好乡村。2014年,已完成5 266公顷高标准基本农田建设任务,完成146公顷补充耕地任务,完成33公顷增减挂钩项目实施,清理矿区周边垃圾110余吨,清理尾矿300余吨,削坡减载6处,道路整治300余  相似文献   

Autumn photoproduction of carbon monoxide in Jiaozhou Bay,China   总被引：1，自引：0，他引：1  

Chunyan Ren  Guipeng Yang  Xiaolan Lu 《中国海洋大学学报(英文版)》2014,13(3):428-436

Carbon monoxide(CO) plays a significant role in global warming and atmospheric chemistry. Global oceans are net natural sources of atmospheric CO. CO at surface ocean is primarily produced from the photochemical degradation of chromophoric dissolved organic matter(CDOM). In this study, the effects of photobleaching, temperature and the origin(terrestrial or marine) of CDOM on the apparent quantum yields(AQY) of CO were studied for seawater samples collected from Jiaozhou Bay. Our results demonstrat that photobleaching, temperature and the origin of CDOM strongly affected the efficiency of CO photoproduction. The concentration, absorbance and fluorescence of CDOM exponentially decreased with increasing light dose. Terrestrial riverine organic matter could be more prone to photodegradation than the marine algae-derived one. The relationships between CO AQY and the dissolved organic carbon-specific absorption coefficient at 254 nm for the photobleaching study were nonlinear, whereas those of the original samples were strongly linear. This suggests that: 1) terrestrial riverine CDOM was more efficient than marine algae-derived CDOM for CO photoproduction; 2) aromatic and olefinic moieties of the CDOM pool were affected more strongly by degradation processes than by aliphatic ones. Water temperature and the origin of CDOM strongly affected the efficiency of CO photoproduction. The photoproduction rate of CO in autumn was estimated to be 31.98 μmol m-2 d-1 and the total DOC photomineralization was equivalent to 3.25%- 6.35% of primary production in Jiaozhou Bay. Our results indicate that CO photochemistry in coastal areas is important for oceanic carbon cycle.  相似文献