黄土

The results indicate that the collapsibility of unsaturated loess is controlled by its microstructure and intergranular suction.

分析了非饱和黄土的物质成分及微观结构，基于非饱和土的吸力理论和黄土微结构特征，对非饱和黄土的湿陷变形机理及影响因素进行了研究。

It is essential to study collapsibility and influential factors of loess, evaluate correctly collapsible gr

为了提高公路建设质量，减轻或消除因黄土湿陷而造成的公路病害，以便指导关中地区公路的设计和施工，很有必要对黄土湿陷的特性和影响因素进行研究，准确评价黄土的湿陷等级，找出合适的防治对策。

The Necessity of water saving agriculture in the loess plateau of China is analysized,and main types of regulating soil water techniques are sumed up as follows:accumulating fertileness,crop rotation,intermittent fallowness of soil,drought resistant crop breeding, water saving ,run off agriculture and chemical methods.

分析黄土高原节水农业的必要性，总结出黄土高原农业调水技术主要有 7大类：培肥地力以肥调水，轮作倒茬调水，间隙休闲调水，抗旱育种调水，节水灌溉调水，径流农业调水，化学技术调水；指出在干旱、半干旱的黄土高原地区，利用农业调水技术是粮食增产增收的有效措施和必然趋

The results show that when the depth gradually reduces, pH values gradually increase, but conductivities and (superscript – subscript 3) content gradually reduce. There are also obvious differences between the groundwater in loess, alluvial deposit and acidity rock in the south of Chang'an, which relates to the depth, the characters of loess, the lixiviation and the evaporation. The element content of groundwater is high in the loess tableland, so it's fitter for drinking than the groundwater in the Cuihua mountains, which is of acidity and low element content.

结果表明，长安南部黄土塬随着层位的降低，pH值有逐渐增大趋势，电导率和HCO(上标–下标 3)含量有逐渐减少的趋势；黄土地下水、冲积层地下水和酸性岩石地下水的化学成分存在明显差异，这与其理深、地层性质、溶滤与蒸发作用不同有关；长安南部少陵源黄土地下水元素含量较高，比呈酸性、元素含量低的翠华山泉水更适于饮用。

In this paper, based on the triaxial test, it is discovered that the structured loess has special mechanical effect of shearing strain rate, and it is proved that the structured loess also has the phenomena of strain rate softening. The CU shear strength and cohesion c increase at first, then decrease with the increase of strain rate, and a critical rate exists; the angel of internal friction doesn't change visibly with the strain rate.

通过结构性黄土三轴试验研究，发现结构性黄土具有独特的剪应变速率力学效应，"应变速率软化"现象同样存在于结构性黄土中；其CU剪切强度和凝聚力c随剪应变率的增大而呈现先增大后减小的特征，存在临界速率现象，而内摩擦角随剪切速率的增大基本上呈线性减小的趋势。

The Loess Plateau and its adjacent regions are in the critical eco-envi-ronmental zone of China, which is from subhumid to semi-arid,from forestto steppe and from agricultural regions to animal husbandry regions. Thereare serious environmental problems such as the most extensive and serioussoil erosion in the world, desertification, water shortage for crops, flooddamage, increased soil salinity as well as increased industrial pollution.

黄土高原及其毗邻地区包括以晋、陕、甘为主体的黄土高原，面积约35.85万平方公里，及其周围与之有关联的黄土分布区，范围大致是阴山以南、秦岭以北、太行山以西及日月山和贺兰山以东的地域。J两者合计面积为62.38万平方公里。

This is not surprising, given the closer proximity of Pengyang to the Asian inland dust sources; The average content of calcium carbonateis of Pengyang section is not only higher than that of central loess plateau, but also higher the west of Chinese Loess Plateau, which reflected Pengyang loess had been deposited by near Liupanshan\'s substances that contained more calcium carbonateis; The content of diffluent element of 10m depth in the section increased fast, which indicated that the modern eluviation and the leaching depth of loess may be stronger than our guess; The soil growth index can reflect the intensity of soil forming and the climatic changes; The "abrupt chang" of glacial and interglacial period was caused by strong soil-forming processes that enlarged the discrepancy of granularity between loess and paleosol. However, the magnetic susceptibility nearly cannot reflect the existence of S_8 and the magnetic susceptibility of S_7 is highest in the whole section, which is inconsistent with other studies that S_5 has the highest magnetic susceptibility.Thin-section examination shows that the micro-texture of the soil layers is divided into both cementing texture in S_7, S_5 and S_1, and granular texture in all others.

与其它剖面相比，彭阳剖面粒度总体上要比东部的洛川、西安，甚至西部的兰州、新疆东湾要粗；CaCO_3平均含量不仅高于黄土高原中部，也高于高原西部，反映出本剖面富含碳酸盐的六盘山近源沉积起到了很重要的作用；易溶元素含量在剖面10m处快速升高，淀积特征明显，反映出黄土受现代淋溶成土作用影响较大，黄土直立、疏松、多孔特性和高温与多雨组合的气候特点，使得元素淋溶、淀积的强度和深度超出了传统的认识和判断；烧失量与其它指标相比，不仅能区分冰期、间冰期；而且能够区分出次一级的冰阶、间冰阶，有较高的分辨率；土壤发育指数、红度能够反映土壤强度差异，是反映气候波动的较好指标；然而，磁化率不能反映古土壤S_8的存在，且S_7的磁化率在全剖面中最高，这与大多剖面S_5磁化率最高的特点不一致。4。

The development of weathering crusts proves that some paleosols in the ioess belongs to the eluvial mor, and the subtropical climate in Liuhe area of Jiangsu migrates to the southeast of the Loess Plateau at that time.

是黄土高原降水丰富的气候事件的显示。风化壳的发育证明黄土中有些古土壤确属淋溶型森林土壤，当时亚热带气候至少迁移到了黄土高原东南部。

And in northwest of China, because of the poor engineering characteristic of loess, the special topography, geomorphy and climatic condition, loess landslide have become one of the most destructive disasters of loess slope, which seriously effect the safety of the local people's lives and properties.

而西北地区由于黄土的不良工程特性和特殊的地形地貌以及气候条件，黄土滑坡已成为该地区黄土边坡破坏性最大的灾害之一，严重地影响了人民生命财产的安全。

On the basis of these, the author studies the following problems and draws corresponding conclusions:(1) By demonstrating physichemical and structural character of loessial soil, the results are obtained that it is having great meaning to utilize widely distributive and profound loessial soil resources to purify sewage for protecting groundwater supplying security.

作者在论文中依次研究了如下问题，并得出了相应的结论：(1)通过论证黄土的物理化学性质与结构特性，得出利用广布而深厚的黄土地层净化污水，以保证地下水的供给安全，这在黄土地区是可行的，并具有重大意义。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。