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基于岩土体膨胀性是其含水量的函数的认识，提出了岩土体吸水膨胀应力系数的概念。从膨胀应力与含水率的变化关系出发，研制出吸水膨胀应力系数试验装置；根据试验得到的膨胀应力与含水率增量的关系曲线和计算得到的岩土体吸水膨胀应力系数，对不同状态与类型重塑土样吸水膨胀应力系数的变化规律进行了深入研究。试验研究结果表明:试验装置所测土样的最终含水率误差在1.0%左右，能够较好地得到不同岩土体的吸水膨胀应力系数；由于黏土颗粒水化程度的不断增加，各岩土体的膨胀应力都随含水率的增加而增大，且膨胀应力与含水率增量呈线性关系；初始含水率15.0%条件下云南呈贡强膨胀土、成都弱膨胀土、成都粉质黏土的膨胀应力系数分别为92.2(kPa/%)、42.6(kPa/%)、0.9(kPa/%)，是由于不同类型岩土中黏粒含量的差别，导致不同类型岩土体的膨胀应力系数有较大的差别；膨胀应力系数能够有效地区分岩土体的膨胀性，可以用膨胀应力系数对岩土体的膨胀性进行分类。 相似文献
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新世纪的科技和岩土工程发展 总被引：4，自引：1，他引：4
从科技的发展谈论了人才的需求;以三峡工程、青藏铁路、西气东输、南水北调典型工程为例,论述了现代岩土工程与发展;并就21世纪岩土工程研究热点发表了自己的看法。 相似文献
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以南水北调中线工程原状强、中膨胀土/岩为研究对象,开展压力板试验与双环注水试验,结合试验结果与土-水特征曲线(SWCC),对比研究不同性质膨胀土和膨胀岩的持水性能及影响因素,计算并分析水体积变化系数的变化规律,在该基础上重点探讨渗透系数的变化特征及其与基质吸力的非线性关系,总结出膨胀土/岩的渗透特性及其规律。结果表明,膨胀土/岩的持水特性受岩土的物理性质、矿物成分与结构特征的影响,膨胀潜势强、细颗粒含量大、孔隙结构小的试样有着较低的脱水速率;渗透系数和水体积变化系数均随含水率的减小而减小,变化特征受到膨胀潜势与干密度的共同影响,并与基质吸力呈幂函数关系。研究成果可为工程建设提供计算参数及理论依据。 相似文献
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沙沟排洪渡槽是南水北调中线一期工程总干渠大型建筑物之一，场区地质条件复杂，本文阐明了场区岩土类型及岩土分布规律，分析了场区存在的工程地质问题，并提出了相应处理措施。 相似文献
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我国特殊岩土研究 总被引：1，自引：0，他引：1
顾宝和 《水文地质工程地质》1997,24(2):43-45
本文分析，总结了我国特殊岩土理论与应用研究方面的新进展，内容涉及湿陷性黄土，软土膨胀岩土，红土，软岩和特殊土的结构性，指出需要进一步研究的问题，最后对特殊土的研究方法做了阐述。 相似文献
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在大连新港油罐区的建设中,发现了一种具有高孔隙性、高含水量、高塑性、中低压缩性的特殊土。作者对这种土及其母岩的矿物学、岩石学、地球化学、物理化学和工程特性进行了系统研究,揭示了该区红粘土及其工程特性的形成机理,该区红粘土乃是蒙脱石化的粗玄岩,在中温带气候区红土花作用的产物。 相似文献
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Amer A. Al-Rawas 《Engineering Geology》1999,53(3-4):327-350
The factors controlling the expansive nature of the soils and rocks in Northern Oman were studied. Basic geotechnical data from over 40 sites were collected and using empirical relationships, swelling potentials were identified. A laboratory testing program was carried out using undisturbed samples from these swell pressures up to 3.5 MPa, and swell percent values up to 30 were measured. The clay minerals and cations of these samples were determined and Na-smectite was identified as being the main clay-mineral present. Microfabric studies showed generally dense clay matrices. However, these swelling materials exist as impersistent bands with non-swelling soils and rocks which makes prediction of the ground heave problematic. 相似文献
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Geotechnical engineering practice for collapsible soils 总被引：3，自引：0，他引：3
Sandra L. Houston William N. Houston Claudia E. Zapata Chris Lawrence 《Geotechnical and Geological Engineering》2001,19(3-4):333-355
Conditions in arid and semi-arid climates favor the formation of the most problematic collapsible soils. The mechanisms that account for almost all naturally occurring collapsible soil deposits are debris flows, rapid alluvial depositions, and wind-blown deposits (loess). Collapsible soils are moisture sensitive in that increase in moisture content is the primary triggering mechanism for the volume reduction of these soils. One result of urbanization in arid regions is an increase in soil moisture content. Therefore, the impact of development-induced changes in surface and groundwater regimes on the engineering performance of moisture sensitive arid soils, including collapsible soils, becomes a critical issue for continued sustainable population expansion into arid regions.In practicing collapsible soils engineering, geotechnical engineers are faced with (1) identification and characterization of collapsible soil sites, (2) estimation of the extent and degree of wetting, (3) estimation of collapse strains and collapse settlements, and (4) selection of design/mitigation alternatives. Estimation of the extent and degree of wetting is the most difficult of these tasks, followed by selection of the best mitigation alternative. 相似文献
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贵州喀斯特区草地生态条件下石灰(岩)土的发生特性及系统分类研究 总被引：3，自引：1，他引：2
选取贵州喀斯特区草地生态条件下5个不同区域的石灰(岩)土为研究对象,根据相应的理化性质及发生特性,探讨了影响土壤发育的因素,确定了土壤的诊断层和诊断特性。其中,供试土壤的诊断层包括:暗沃表层、雏形层和粘化层等,诊断特性包括:热性土壤温度状况、常湿润土壤水分状况、均腐殖质特性、腐殖质特性、盐基饱和、碳酸盐岩岩性、铁质特性、石灰性等,并在此基础上对其进行了土壤系统分类,结果显示:5个供试土壤分别属于中国土壤系统分类中的普通黑色岩性均腐土、腐殖钙质常湿雏形土和腐殖钙质常湿淋溶土等亚类。 相似文献
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Ian A. Navarrete Kiyoshi Tsutsuki Victor B. Asio Renzo Kondo 《Environmental Geology》2009,58(6):1257-1268
This study was conducted to evaluate the physical, chemical, and mineralogical characteristics of rain forest soils derived
from late Quaternary basaltic rocks in Leyte, Philippines. Four sites along a catena were selected at an elevation of 75–112 m
above sea level with an average annual rainfall of 3,000 mm and an average temperature of 28°C. Results indicate that the
soils are deep, clayey, and reddish in color, which is indicative of the advanced stage of soil development. They also posses
excellent physical condition (friable and highly porous) although they are plastic and sticky when wet as is usual for clayey
soils. In terms of chemical characteristics, the soils are acidic with low CEC values and generally low in organic matter
and nutrient contents. The clay mineralogy of the soils is dominated by halloysite and kaolinite with minor amounts of goethite
and hematite, and they also have generally high dithionite-extractable Fe contents confirming the advanced stage of their
development. The soils in the more stable slope positions (PL-1, PL-2, and PL-4) have generally similar characteristics and
appeared more developed than the one in the less stable position (PL-3). The most important pedogenic processes that formed
the soils appear to be weathering, loss of bases and acidification, desilification, ferrugination, clay formation and translocation,
and structure formation. The nature of the parent rock and climatic conditions prevailing in the area as well as slope position
appear to have dominant effects on the development of the soils. 相似文献
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Geological and engineering characteristics of expansive soils and rocks in northern Oman 总被引：3，自引：0，他引：3
The geology and former climate of northern Oman favoured the formation of smectite clay minerals in certain materials which are implicated in ground heave problems. Investigations have shown that the smectite content of these expansive materials was developed in Oligocene, Miocene and Pliocene times. No evidence of a significant content of smectite was found in pre Eocene strata or in Quaternary strata, except for Desert Fill. It is shown that the main types of expansive materials in northern Oman are bentonitic mudstones, marls and silty mudstones, argillaceous dolomitic limestone, altered conglomerates and the desert fill derived from these. These swelling materials exist as impersistent bands within the bedrock Tertiary conglomerates and limestones. A geotechnical testing program was carried out on undisturbed samples from Sultan Qaboos University staff housing areas where building damage had occurred, to evaluate mineralogical composition, cation content and swelling characteristics. The test results characterized these soils/rocks as highly expansive type with Na-smectite as the dominant clay mineral. 相似文献
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新疆焉耆盆地博斯腾湖东岸几种不同地貌单元中,盐渍土发育强烈。在研究区内自北至南50km的地段呈线性分布。以刻槽法分5层连续采取0～1．00m深度土壤样品,分析易溶盐含量,判断盐渍土的含盐类型。平面上,从冲洪积扇前缘的细土平原到冲积-湖积平原,盐渍化程度呈增高趋势。盐渍土的含盐类型,沙垅段主要为硫酸盐,东南岸冲积-洪积平原主要发育亚硫酸盐和硫酸盐,其余地段盐渍土类型以氯盐和亚氯盐为主。剖面上,除沙垅段外,各个地貌单元土壤盐渍化表聚性特征明显。 相似文献
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阐述了毛管水对土体强度、变形和渗流的影响。粉性土既有较高的毛管水头,又有一定的渗透性,水压传递快;毛管水对此类土的地基、基坑和堤坝等工程有明显的影响。研究的主要成果有：①根据试样浸水与否的无侧限抗压强度比较试验及理论分析,证明毛管水张力增高了土体强度,强度增高的数值,试验结果和理论分析相符;②计算分析雨季粉性土地表层毛管水张力消失和土体膨胀的过程;③借砂模试验和电拟试验,分析了毛管水对堤坝渗流流态的影响,毛管水增高了渗流量和出逸点高度;④提出了砂土和粉性土毛管水头hc和渗透系数k新的经验计算式。研究成果可应用于粉性土地基、基坑和堤坝等工程。 相似文献