山东:土质调查是耕地保护“重中之重”

山东省地处中国东部沿海、黄河下游,包括半岛和内陆两部分,陆域面积15.71万平方千米,山东地势中部山地突起,东部为丘陵区,西部、北部为平原区。现有耕地762.6万公顷,山东粮食产量已保持12年连增,去年总产量达到919.32亿斤;以粮食、瓜果、蔬菜、花卉、苗木、水产养殖为代表的农业现代化取得了巨大发展。耕地保护涉及国家粮食安全,而耕地保护最核心、最本质的内容就是质量和数量的保护。自2003年国土资源部中国地质调查局和山东省人民政府签署合作协议,共同出资开展＂山东省黄河下游流域生态地球化学调查＂以来,山东一直把耕地质量调查作为耕地保护的重要内容,摆上重要议事日程,加强组织领导,强化部门协调,加大工作投入,狠抓质量监控,使土地质量调查工作全面推进。《地球》记者从山东省国土资源厅了解到,截至目前,山东省陆域范围1：25万土地质量地质调查工作已全面完成,并试点开展了章丘市、巨野县1：5万土地质量地质调查和特色农产品产地地质背景研究。

关于准高速铁路路基若干设计标准的讨论

本文介绍准高速铁路路基的设计标准问题。对路肩宽度、基床填料、压实标准,基床厚度,以及路堤地基条件等问题提出建议。

南友公路掺石灰改良膨胀土的承载比试验研究

针对在南友公路膨胀土路堤试验路采用的掺石灰改良的施工方案,进行了膨胀土的土性试验和掺灰改良土的承载比试验研究,提出以CBR值及其膨胀量作为强度和胀缩性控制指标,得到各因素对承载比特性的影响规律,确定了最佳掺灰剂量,对工程实践有一定的参考价值。

道路的冻胀破坏与防治措施

对寒冷地区出现的道路、构造物冻胀现象进行了分析,阐述了冻胀产生的原因,并提出了几项防止冻胀的措施。

现代路基施工的信息化与标准化

一、前言现代路基施工,正朝着精确化、标准化趋势发展。在施工过程中,蕴酿并逐渐形成一种薪新的方法,即应用系统分析的原理和先进的试验量测手段,在满足设计技术指标和综合经济效益的条件下,使施工中的各部环节得到科学管理和控制,使路基填筑结构层具有整体稳定,较小荷载变形,并具备规定的密度、强度的功能。

深层拌和法在软弱地基加固中的应用

近年来，深层拌和法加固软弱地基以其施工速度快、成本低、经济效益显著而在国内外得到了广泛应用。尤其是在处理已建建筑物的地基缺陷方面，本法中的高压喷射技术勿需损坏原结构，甚者可在基本保持正常使用的条件下进行施工操作。１基本方法常用的深层拌和法包括螺旋片搅...

日本造船信息

调查观测兼清扫船 三菱重工建成调查观测兼清扫船。该船长27米、宽9米、深2．8米、吃水1．2米，船体采用铝合金双体船型、喷水推进，主机功率1203千瓦，航速27节。船上设有旋臂吊车和处理装置，可进行海域水质和海底土质调查、泥层密度计测、潮流观测和垃圾回收等。

Effects of seasonal water-level fluctuation on soil pore structure in the Three Gorges Reservoir,China

Inundation of the Three Gorges Reservoir has created a 30-m water-level fluctuation zone with seasonal hydrological alternations of submergence and exposure, which may greatly affect soil properties and bank stability. The aim of this study was to investigate the response of soil pore structure to seasonal water-level fluctuation in the reservoir, and particularly, the hydrological change of wetting and drying cycles. Soil pore structure was visualized with industrial X-ray computed tomography and digital image analysis techniques. The results showed that soil total porosity(? 100 ?m), total pore number, total throat number, and mean throat surface area increased significantly under wetting and drying cycles. Soil porosity, pore number and throat numberwithin each size class increased in the course of wetting and drying cycles. The coordination number, degree of anisotropy and fractal dimension were indicating an increase. In contrast, the mean shape factor, pore-throat ratio, and Euler-Poincaré number decreased due to wetting and drying cycles. These illustrated that the wetting and drying cycles made soil pore structure become more porous, continuous, heterogeneous and complex. It can thus be deduced that the water-level fluctuation would modify soil porosity, pore size distribution, and pore morphology in the Three Gorges Reservoir, which may have profound implications for soil processes, soil functions, and bank stability.

The Influence of Earth Temperature on the Dynamic Characteristics of Frozen Soil and the Parameters of Ground Motion on Sites of Permafrost

Earth temperature is one of the most important factors influencing the mechanical properties of frozen soil. Based on the field investigation of the characteristics of ground deformation and ground failure caused by the M S8 1 earthquake in the west of the Kunlun Mountain Pass, China, the influence of temperature on the dynamic constitutive relationship, dynamic elastic modulus, damping ratio and dynamic strength of frozen soil was quantitatively studied by means of the dynamic triaxial test. Moreover, the characteristics of ground motion on a permafrost site under different temperatures were analyzed for the four profiles of permafrost along the Qinghai Xizang(Tibet) Railway using the time histories of ground motion acceleration with 3 exceedance probabilities of the Kunlun Mountains area. The influences of temperature on the seismic displacement, velocity, acceleration and response spectrum on permafrost ground were studied quantitatively. A scientific basis was presented for earthquake disaster mitigation for engineering foundations, highways and underground engineering in permafrost areas.

Geochemical characteristics of soil selenium and evaluation of Serich land resources in the central area of Guiyang City,China

Based on the results of multipurpose regional geochemical surveys of the Guizhou Province, geochemical characteristics of soil Se and Se-rich land resources in the central area of Guiyang City were studied and evaluated.Major conclusions are as follows:(1) the Se content in surface soil of the central area of Guiyang City was 0.17–2.89 mg kg^(-1), and the average was 0.78 mg kg^(-1), which were respectively 2.6 and 3.9 times of the national background value of soil and the world background value of soil.The Se content in deep soil was 0.11–1.48 mg kg^(-1), and the average was 0.44 mg kg^(-1), which were respectively 1.5 and2.2 times of the national background value of soil and the world background value of soil. The soil Se content decreased with the increase in the soil depth on the vertical profile, and the surface soil had a higher Se content.(2)Distribution of Se content was mainly affected by parent material, physicochemical properties of soil and other components, soil type, and land use type. Parent material played a key role, as the soil Se content was mainly originated from parent rock and increased with the background value of Se in parent rock, physicochemical properties of soil and other components had certain influences upon the Se content. Se was shown to have a significant linear positive correlation with S and organic carbon but no significant correlation with p H value. Se content varied with different types of soil as follows: skeleton soil > yellow soil > paddy soil > limestone soil > purple soil. Land use type also hadcertain influences upon the soil Se content as follows: dry land > construction land > garden plot > grassland =garden plot > forest land.(3) Taking 0.4 mg kg^(-1)B x(Se) <3.0 mg kg^(-1) as the standard for Se-rich soil, Se-rich soil of the study area covered an area of 2224 km^2 and 92.5% of the total area; the remaining is general soil. The study area had no Se-excess soil. Therefore, the central area of Guiyang City has a high proportion of Se-rich land, a large area of Serich land resources, and a moderate selenium enrichment strength, which have been rarely seen anywhere and provide advantageous resources for the development of Se-rich featured agriculture.

Sustainability Issues Related to the Engineering Geology of Long Linear Developments

The development of long linear structures such as roads, rail roads, tunnels, canals and pipelines often has unique engineering geology challenges. These include geological modeling, the identification of material strength and support factors, stability and risk issues, material excavation characteristics and the proposal of techniques for overcoming geotechnical problems, which are normally assessed as part of the conventional engineering geological investigation. An additional factor that is becoming increasingly important but is seldom included in investigations is the sustainability of the geotechnical inputs, in contrast to the sustainability of the project which is generally included. Sustainability issues revolve around the non-renewable nature of most construction resources and there is no doubt that the injudicious use of these construction materials and construction water is not sustainable in the long term: it is thus essential that the engineering geo-logical investigation should take cognizance of such issues and be adapted to provide the design engineer with the information that will maximize the sustainability options. This will also require a closer on-going relation-ship between the engineering geologist and the design engineer. This paper highlights significant sustainability issues (note that these differ from conventional environmental issues) and suggests some mitigating solutions. The sustainability issues discussed include primarily material and water usage, with some reference to energy conservation (mostly through alternative material usage and processing techniques and transportation).

XU Xiaohui,CHEN Hui'e and WANG Gangcheng College of Construction Engineering,Jilin University,Changchun 130026,China

On the basis of geological investigating work and experimental studies on slide zone soil of one landslide in Tibet,the authors analyzed granulometric composition,clay mineral composition and physical and mechanical properties for the soil in the slide zone.The soil samples are gravel containing fine particle.Particles larger than 2 mm occupy the main proportion with the content 51.5%--68.5%.The relative content of clay minerals is low.The clay minerals are illite smectite mixed layer and kaolinite,and their relative contents are 6%--13% and 4%-11%,respectively.The main mineral ingredient is quartz and the relative content is over 30%.Therefore,the soil’s hydrophily is poor.The cohesion and internal friction angle are high,causing preferable physical-mechanical features of slide zone soil.On the basis of the obtained data,the landslide stability is evaluated by means of limit equilibrium method.The safety factors are 3.191 and 1.92 respectively under both natural and normal water level conditions.The study results show that the landslide is stable.It can provide the appropriate basis and reference for landslide stability evaluation and landslide control in Tibet.

An improved Landsat Image Mosaic of Antarctica

A revised Landsat Image Mosaic of Antarctica （LIMA） is presented, using the 1073 multi-band scenes of the original Land- sat-7 ETM＋ LIMA image collection available at the United States Geological Survey （USGS： http：//lima.usgs.gov/）. Three improvements have been applied during the data processing： （1） DN saturation is adjusted by adopting a linear regression, which has a lower root mean square error than the ratio regression used by LIMA; （2） solar elevation angle is calculated using pixel-level latitude/longitude and the acquisition time and date of the central pixel of the scene, improving slightly upon the bi- linear interpolation of the solar elevation angles of scene comers applied in LIMA; and （3） two additional image bands, Band 5 and Band 7, are sharpened using the panchromatic band （Band 8） and a Gram-Schmidt Spectral Sharpening algorithm to more easily distinguish snow, cloud and exposed rocks. The final planetary reflectance product is stored in 16-bit bands to preserve the full radiometric content of the scenes. A comparative statistical analysis among 12 sample regions indicates that the new mosaic has enhanced visual qualities, information entropy, and information content for land cover classification relative to LIMA.

Adsorption and Desorption of Cry1Ab Proteins on Differently Textured Paddy Soils

In recent years, selected cry genes from Bacillus thuringiensis（Bt） encoding the production of Cry proteins（Bt toxins） have been engineered into crop plants（Bt-crops）. Through the cultivation of Bt crops and the application of Bt pesticides, Cry proteins could be introduced into arable soils. The interaction between the proteins and soils was analyzed in this study to investigate the affinity of Cry proteins in paddy soil ecosystems. Four Paddy soils were selected to represent different soil textures. Cry proteins were spiked in soils, and the amount of protein adsorbed was measured over 24 h. Desorption of Cry1Ab proteins from paddy soils was performed by washing with sterile Milli-Q water（H_2O_（MQ））, and subsequently extracted with an extraction buffer. The paddy soils had a strong affinity for Cry1Ab proteins. Most of the Cry1Ab proteins added（＆gt; 98%） were rapidly adsorbed on the paddy soils tested. More Cry1Ab proteins were adsorbed on non-sterile soils than on sterile soils. Less than 2% of the adsorbed Cry1Ab proteins were desorbed using H2 OMQ, while a considerable proportion of the adsorbed proteins could be desorbed with the buffer, ranging from 20% to 40%.The amount of proteins desorbed increased with the increases in the initial amount of Cry1Ab proteins added to the paddy soils. The concentration of Cry1Ab proteins desorbed from the paddy soils was higher for sterile soils than non-sterile ones. Our results indicate that Bt toxins released via the cultivation of Bt crops, the application of Bt pesticides can be adsorbed on paddy soils, and soil texture could impose an impact on the adsorption capability.