查询词典 soil

The main factors affecting the soil-structure interface behaviors were found experimentally and theoretically, including: 1 the thickness of the interface that is five to six times the average grain size of the soil; 2 the aeolotropy of interface, which is responsible for anisotropic response of the stress-strain response of the interface; 3 two physical states, including crashing and compression of the soil near the structure surface, which govern the stress-strain response of the interface strongly; 4 two shear deformation components due to sliding and constraint of the structure surface relative to the soil respectively, which forms the deformation of the interface; 5 the volumetric strain due to dilatancy, which is found to be composed of a reversible dilatancy component and an irreversible dilatancy component. 4. A unified constitutive model of the interface, based on new elasto-plasticity damage theory, was developed. It was confirmed to be effective for the conditions considering monotonic and cyclic shearing, coupling effect of shear and volumetric strains, evolution of physical state, micro-structure aeolotropy of the soil and the resulting aeolotropy of the interface as well as the three normal boundary conditions stated above. 5. 2D and 3D finite element formulations of the present model were derived and incorporated into the FEM codes. They were applied to the evaluation of practical engineering problems with different typical interfaces between soil and structure. The new model was shown to be reasonable and effective.

确定了粗粒土与结构接触面厚度约为5～6倍的平均粒径，首次揭示了接触面的细观结构异向性以及由此所引起的宏观剪切异向性，发现了在单调和往返剪切荷载作用下土颗粒破碎和剪切压密两种物态变化机制共同支配着接触面力学性质的变化，通过细观分析证实了接触面的变形可分解为一般同时发生的土与结构交界面上的滑移变形以及结构面位移约束范围之内土体本身的剪切变形两部分，观测到接触面受剪时表现出明显的相对法向位移，并可分解为可逆性和不可逆性两个分量；(4)建立了第一个能够统一地描述单调与往返剪切特性、剪应变与体应变耦合特性、细观结构和宏观剪切异向性以及土颗粒破碎等物态变化特性的土与结构接触面弹塑性损伤本构数学模型，并采用多种法向边界条件复杂加载路径的试验成果验证了新模型的合理性和有效性；(5)提出了新模型的二、三维有限元格式并结合实际边值问题进行了应用计算分析，比较了不同接触面本构模型对计算结果的影响，证实了新模型及其有限元格式不仅能够合理地描述土与结构接触面的主要力学特性，还能够较好地反映土体与结构物在接触面处的滑移、脱开等不连续现象。

Biomass in the rain forest was far more than that in the plantation of 12 years,especially for the shrub layer.But the biomass of litterfall collected in the plantation was greater than that of the rain forest for the reason that Betula alnoidis defoliated in dry seasons.9 Four years observation found that soil bulk density tended to increase first, then decrease after planting trees;total soil porosity and non-capillary porosity tended to decrease and after few years they recovered to different degrees;the soil cation exchange capacity for all forest types increased;in the soil of 0-30cm depth,soil salt saturation tended to decrease;nutrient content in the soil of 0-60cm depth in the young stand tended to decline;soil effective P,effective K and N contents all tended to decrease.

山地雨林的总生物量远远大于10年生的西南桦人工林，其中灌木层的相对差别尤其巨大。94次的观测发现，人工林栽植后，土壤容重一般呈现一个先上升后下降的特点；而土壤非毛管孔隙度、土壤总孔隙度大多呈下降趋势，几年后有不同程度的恢复。

In this paper, the marine soft soil is mixed with 10% cement added with 0.5% NaOH and 0.5% Na2CO3 separately, which form two types of new cement-soils. Comparing with the undisturbed soil and the 20% cement-soil results in that the alkalescence additive can contribute to generate a large number of needle-like, rod-like or fibriform hydrate calcium silicate crystals. The hydrate calcium silicate crystals can inhibit the generation of calcic alum crystal which would bring expansive action. At the mean time, it can separate out hydrate calcium. The hydrate calcium silicate crystals and hydrate calcium constitute the filling and inclusions together among soil particles and on the surface of soil particles, which cut down the interstices of cement soil obviously. Therefore, the soil mass can be reinforced and the intensity can be improved.

现场试验中将海积软土与分别掺入0.5%NaOH和0.5%Na2CO3的10%水泥就地搅拌，形成两种新型水泥土，在与原状土及20%纯水泥土进行比较后，发现碱性外掺剂可以促使生成大量针状、棒状或纤维状水化硅酸钙晶体，抑制了能产生膨胀作用的钙矾石的生成，同时，有Ca2晶体析出，它们共同构成土颗粒间和土颗粒表面的充填物和包裹物，使水泥固化土的孔隙明显减小，密度和强度得到极大提高。

This paper reviewed the research on dynamic and balance of soil nutrient pool under long-term fertilization conditions,mainly about some active aspects which included dynamic variations of total nitrogen,available N,total phosphorus,available P,total potassium,available K,and organic carbon in soil; dynamic variations of ammonium N,amino acid N,amino sugar N,unknown N,non hydrolyzable N and microbiomass N in soil nutrient pool; changes of Ca2-P,Ca8-P,Al-P,Fe-P,O-P,labile organic P,moderately labile organic P,moderately stable P,highly stable P and microbiomass P in soil; changes of loosely,stably and tightly combined humus,humic and fulvic acids in soil carbon pool; effects of long-term fertilization on organic-mineral complex status in soil; nutrients cycling and balance of agricultural soil nutrients pool.

扼要地概述了国内外近年来关于长期施肥条件下土壤养分库的动态与平衡方面的研究成果。主要介绍并讨论了土壤氮、磷、钾养分全量及有效量的动态变化，土壤有机碳含量的动态变化；铵态氮、氨基酸态氮、氨基糖态氮、酸解未知态氮、非水解残渣氮及微生物体氮在土壤氮库中的动态变化；Ca2 P、Ca8 P、Al P、Fe P、闭蓄态磷，活性有机磷、中度活性有机磷、中稳性有机磷、高稳性有机磷及微生物体磷在土壤磷库中的动态变化；土壤碳库中松结态腐殖质、稳结态腐殖质、紧结态腐殖质以及富里酸和胡敏酸的动态变化；长期施肥对土壤有机无机复合状况的影响；农田土壤养分库的养分循环与养分平衡。

Results showed that:(1) soil loss from plough tillage was as much as 3~8 times that from no-tillage; the aerodynamic roughness lengths under plough and no-tillage were 0.032, 0.417, respectively.(2) No-tillage soil contained more clay and fine sand in the 0-10cm topsoil layer than the plough tillage soil. In the 0-5 and 5-10cm soil depth, the bulk density, soil hardness and soil moisture were more under no-tillage than plough tillage. Especially, the soil hardness in 0-5, 5-10 and 10-20cm under no-tillage were as much as 4.7, 2.8 and 3.8 times, respectively.

研究结果表明：翻耕农田土壤风蚀量是免耕地的3~8倍，翻耕地和免耕地的地表粗糙度分别为0.032和0.417；与翻耕地相比，免耕地表层0~10cm土壤粘粒和粉粒含量较多；免耕地土层0~5cm和5~10cm的土壤容重、坚实度和土壤水分都大于翻耕地，其中0~5cm、5~10cm和10~20cm土层土壤坚实度分别是翻耕地的4.7、2.8倍和3.8倍。

Straw returned to field played a positive role in increasing soil insect communities with the largest contribution, primarily the amounts of individuals and dominant species of macro and meso/micro soil animal, especially Neanuridae and Isotomidae animals individual amounts increased by nearly 10 times.(3) Soil nutrien had a positive correlation with soil bacteria, azotobacter, ammonifying bacteria, cellulose decomposing bacteria and denitrifying bacteria. Straw returned to field could stimulate effective microorganisms growth and population quantity in the soil. The increase of microbe community amount is 15%~44% more than that of CK.(4) Soil nutrien had a positive correlation with soil phosphatase, urease and sucrase activities, and a negative correlation with catalase.

研究发现：(1)长期配施秸秆能提高土壤速效氮、磷、钾含量，平均分别提高15%、48%和22%；(2)配施秸秆对土壤昆虫群落呈正向作用且贡献最大，主要增加了大型、中小型农田土壤动物的个体总数和优势类群数量，尤其是疣跳科和等节跳科动物个体数量增加近10倍；(3)土壤养分与土壤细菌、固氮菌、氨化细菌、纤维分解菌和反硝化细菌呈正相关，秸秆还田激发土壤有益微生物的生长和类群数量，使土壤微生物类群数量比对照增加15%~44%；(4)土壤养分与土壤磷酸酶、脲酶、蔗糖酶活性呈正相关，与过氧化氢酶呈负相关，秸秆还田增强土壤蔗糖酶、磷酸酶和脲酶活性，特别是脲酶和蔗糖酶活性平均提高26.5%。

The inoculation effectiveness of fungi varied with soil types,especially for BEG167.BEG167 performed positively on cinnamon soil,and neutral on brown soil,but negatively on red soil.Except for BEG150 all All other fungi,except BEG150,increased maize P uptake on cinnamon soil and brown soil,however,only BEG168 and BEG 141 improved P uptake significantly on acidic soil.

若以真菌的根外菌物量作为衡量AM真菌菌株土壤生态适应性的指标，BEG141和BEG167是生态适应性强的菌株，为广幅生态型菌株；菌株BEG168和BEG151次之，前者在棕壤上适应性高，后者在红壤上适应性高。

The results showed that tillage had stronger compaction effect on Red soil. By analyzing retention properties, water content was higher in the same suction for Red soil. Field capacity and wilting coefficient were higher for Red soil than those for Lou soil, but effective moisture and saturated hydraulic conductivity were lower for Red soil. For Red soil, Lateral infiltration ability was stronger, infiltration rate was greater than one number degree for Lou soil and preferential flow occurred easily.

结果表明：耕作片红壤有较强的压实作用；从持水特征分析，同一吸力下红壤的含水量较高，田间持水量和凋萎系数也高于塿土，而有效水含量略低于塿土，饱和导水率却低于塿土1个数量级；从入渗特征分析，红壤的侧渗能力很强，入渗率比塿土高1个数量级，容易发生大孔隙流。

The main contents are as follows:Firstly, starting with the general situation of soil erosion and the harms caused by it, the causes leading to the local soil erosion problem are analyzed comprehensively in the paper. And connecting with the measures taking place, sticking points towards the career of soil and water conservation are expatiated upon.Secondly, Back-Propagation Neural Network, One of Artificial Neural Network is used to set up a modal about the connection of the soil erosion modulus and seven factors impacts on it, such as, rainfall, rainfall largest intensity in 30 minutes, runoff coefficient, vegetation cover percent, rate of granule, rate of physical viscidity-clay, the rate of organic matter. Through the comparison with linear regression model, the second regression model, the Chinese Soil Loss Equation, it illustrated that BP Neural Network modal is more accurate than the other three modals in forecasting the mount of soil erosion, and the BP Neural Network will have some applicability in forecasting in soil erosion.

本文以霍山县作为皖西大别山区的典型区域，主要研究了以下内容：(1)从介绍霍山县土壤侵蚀状况以及所造成的危害入手，全面分析了导致当地土壤侵蚀发生的原因，并结合当地采取的水土保持相关措施，阐述了当地水土保持工作的症结所在；(2)结合上土市水土保持试验站多年实测资料和2005年实验资料，应用BP神经网络理论，建立了次降雨土壤侵蚀量与次降雨量、最大30min雨强、径流系数、植被覆盖度等因子之间关系的模型，并通过BP神经网络的预测模型与一次回归模型、二次回归模型、CSLE模型之间的对比分析，说明了建立的BP神经网络模型在土壤侵蚀预测可以取得较回归模型和CSLE模型更高的精度，也说明了BP神经网络理论在土壤侵蚀预报中具有一定的适用性。

Furthermore, the impact factor on runoff showed that, each stage has different impact factors, soil temperature and soil moisture above 65 cm plays a leading role in spring flood; in summer dry season, relation of soil temperature and moisture above 40 cm and runoff is negative correlation, the deeper soil temperature and soil moisture plays a leading role; temperature and precipitation plays a leading role in summer flood; in autumn dry season, the impact factors are soil temperature, soil moisture and temperature.

径流影响因子分析的结果表明：径流过程中不同时段具有不同的主导因子，春汛期主要是65cm以上的土壤温度和水分起主导作用；夏季枯水期40cm以上土壤水分与径流是负相关，深层地温和土壤水分起主导作用；夏汛期气温、降水起主导作用；秋季枯水期的影响因子依次为土壤温度、水分及气温。

I smile at your play with that little bit of a broken twig.

我微笑着看你玩那一段小小的树枝。

They may be produced for almost any shaft angle.

他们可能在制作中几乎任何一个轴角。