粘性土及粘性土夹沙的起动规律研究

从水流脉动的机理出发,以粘性土的宾汉应力作参数,建立了粘性土的临界起动剪切力公式.根据一系列实验结果,分析了不同情况下粘性土夹沙的起动条件,归纳出统一的表达式.此外,还对上部水流为浑水的情况下,粘性土及粘性土夹沙的起动条件作了定性分析.     

祁连山北缘酒西盆地新生代沉积通量变化对周缘山体构造隆升-风化剥蚀历史的响应

酒西盆地是青藏高原东北缘的一个内陆沉积盆地,发育了巨厚且连续的中-新生代地层,详细记录了盆地及周缘山地的构造、环境演变历史。本文在利用平衡剖面法恢复不同时期酒西盆地原始盆地边界基础上,通过盆地天然露头控制剖面和钻井资料的地层厚度,恢复了酒西盆地新生代各组沉积等厚图。根据不同时期盆地大小和沉积等厚图的计算,获得了酒西盆地新生代不同时期的沉积通量。结合前人对该区构造与古气候研究成果,认为古近纪持续干旱的气候条件下从火烧沟组(40.2~33.4 Ma)到白杨河组(30.9~23.8 Ma)盆地沉积通量增加主要由青藏高原持续挤压使祁连山快速构造隆升导致风化剥蚀量增加所致;中新世早期(疏勒河组弓形山段,23~14 Ma)虽然气候相对温暖,但此时祁连山构造带相对稳定,控制了物源区祁连山风化剥蚀量相对前期减小,使盆地沉积通量相对减小;中新世中期(疏勒河组胳塘沟段,14~8.3 Ma)盆地沉积通量增大可能是气候和构造共同作用的结果;中新世晚期以来(<8.3 Ma,疏勒河组牛胳套段-玉门组)盆地沉积通量呈阶段性大幅陡增,主要由祁连山晚新生代以来阶段性急剧构造隆升导致风化剥蚀量猛增所致。     

杭州湾北岸芦潮港潮滩沉积物磁性特征的年际变化及其粒度控制

对杭州湾北岸芦潮港潮滩2007—2010年固定点沉积物进行了逐月的磁性测量和粒度分析,探讨了磁性特征的月际、年际变化及其与粒度的关系。结果显示,2007—2009年,芦潮港潮滩沉积物的磁性特征呈现出相似的季节性变化特征,磁性参数χ、χARM、SIRM以及比值χARM/SIRM总体上在12月次年7至月表现为高值,8—11月为低值,S-300变化趋势与之相反。粒度分析显示,每年12月至次年7月沉积物粒度总体较细,8—11月较粗,这说明潮滩较细沉积物中含有较多的亚铁磁性矿物,与已报道的2004—2005年研究结果相似。相比前三年,2010年1—7月及12月沉积物磁性矿物含量相对下降,8—11月份磁性     

潮滩表层沉积物磁性特征的季节性变化及其对沉积动力作用的响应:以杭州湾北岸为例

根据2004年9月—2005年8月杭州湾北岸中潮滩固定观测点重复采集的表层沉积物的磁学参数和粒度分析,探讨了研究区域潮滩沉积物磁学性质的季节性变化及其对沉积动力的响应。 结果表明, 该观测点潮滩沉积物磁学参数存在显著的月际变化,2004年12月底—2005年5月上旬的半年中,SIRM、χARM、χfd%、χARM/χ、χARM/SIRM等参数出现高值,指示了沉积物中含有较多的细晶粒亚铁磁性矿物,对应于潮滩淤积时段和较细的沉积物粒级组成,其余各月上述磁参数值较低,对应于潮滩沉积物较粗的侵蚀期。上述结果表明,沉积物的磁性特征可以很好地反映潮滩冲淤过程中沉积动力的变化。     

Multilinear Regression Analysis for Seismic Response and Engineering Properties of Liquefiable Coromandel Coastal Soil Deposits

This paper investigates the seismic characteristics and geotechnical properties with respect to the liquefaction potential of the deposits in the Coromandel coastal line of Nagapattinam town, Tamilnadu, India. A series of field tests were conducted using standard penetration test, cone penetration test and plate load test. Laboratory tests were conducted on the collected samples. From the results, a microzonation map was developed for the liquefaction potential and settlements. Some multilinear regression models between permeability, fines content, relative density, coefficient of curvature, coefficient of uniformity, mean particle size, factor of safety, settlement, standard penetration test values and cone penetration test values were developed. The shear wave velocity and shear modulus were calculated from the field penetration tests and correlations between the normalized values of peak ground accelerations, velocities and displacements, which were obtained from the equivalent linear ground motion analysis using SHAKE software, with other parameters of soil. From the results, it was found that at some of the areas are vulnerable to high amplification of waves even for small earthquake.     

Effects of Activated Irrigation Water on Soil Physicochemical Properties and Crop Growth and Analysis of the Probable Pathway

With the problem of shortage of water resources becoming increasingly prominent, the improvement of production efficiency of agricultural water resources in China has become an important research content of modern irrigated agriculture. The technology of activated irrigation water provides a new way to excavate the physiological production potential of irrigation water and improve the comprehensive efficacy of irrigation water in agro-ecosystems. In this study, the research progress of the variable characteristics of physicochemical properties of activated irrigation water, the transport and transformation of soil material by activated irrigation water, and the promotion of crop growth by activated irrigation water were comprehensively analyzed. On this basis, according to the basic theories of soil physics, crop physiology, and material transport dynamics, the effects of activated irrigation water on soil material transport, soil material transformation, water and nutrition uptake by root, and crop yield formation and the probable pathway were analyzed. The key problems of basic science and applied technology in the future research are put forward to provide reference for the scientific and reasonable utilization of activated irrigation water technology.     

A Review of Study on Fe-C Interaction and Their Adsorption Properties to Soil Heavy Metal

Nowadays, the Fe-C coprecipitate mechanism is recognized by more and more scholars and becomes the hot topic in the environmental science. On the basis of discussing the interaction between iron oxide and organic matter, and the adsorption research progress of Fe-C complexes on heavy metals, the immobilization potential of Fe-C complexes on heavy metals in polluted soil were illustrated. The surface properties and physical characterizations of iron oxide are changed regularly with the interaction of organic matter, which lead to the higher adsorption capacity of Fe-C complexes in contrast to single iron oxide. Besides, the influences of pH values, organic matter types and surface properties of iron oxides on the adsorption capacity of Fe-C complexes on heavy metals were discussed. The excellent adsorption performance of Fe-C complexes in certain conditions will provide important theoretical basis for contaminated soil remediation.     

不同深度冻土微生物数量特征及其与土壤理化性质的关系

分别以乌鲁木齐河源区不同层位深坑冻土样品为研究材料,利用荧光显微计数技术、寡营养恢复培养技术等研究了微生物数量特征及其与土壤理化参数的关联度.结果表明:可培养细菌数量与冻土深度、土壤含水量、总C和总N含量都成显著的正相关,与pH值呈显著负相关.而且,可培养细菌数及其在细胞总数中所占比值随冻土深度的增加而下降,表明深坑样...