谈非洲地区黑棉土地基处理

分析了非洲地区公路建设项目中黑棉土地基的形成及病害特点,并结合埃塞俄比亚高速公路工程实例具体阐述了黑棉土地基处理方案及施工控制措施,为今后海外施工企业处理同类地基提供了借鉴和参考。     

Stabilization of black cotton soil subgrade using sawdust ash and lime

This research dwells on how black cotton soil (BCS) could be stabilized and made a suitable subgrade material using sawdust, a readily and cheaply available material. Sawdust was burnt to ashes in a furnace at a temperature of 800?°C and then mixed with BCS in varying proportions of 4%, 8%, 12%, 16% and 20%. Since the trial mixes showed that the use of 16% sawdust ash gave better results, the BCS treated with optimum sawdust ash content of 16% was further stabilized with 2%, 4%, 6%, 8%, and 10% lime. Optimum reduction in liquid limit, differential free swell, plasticity index as well as optimum increase in CBR and specific gravity was achieved when BCS treated with 16% sawdust ash was stabilized with 4% lime. Scanning electron microscope images of the freshly prepared stabilized soil showed the occurrence of flocculation and agglomeration while X-ray diffraction tests on the cured stabilized soils showed the occurrence of pozzolanic reactions. It was thus concluded that treating BCS with sawdust burnt in an appropriate environment and combined with lime enhances its strength. It also offers another way to dispose of sawdust.     

Studies on geotechnical properties of Prosopis juliflora ash treated black cotton soil

Bulletin of Engineering Geology and the Environment - The pavements of the Beijing Capital International Airport (BCIA), China, where a buried fault zone lies beneath, have undergone continuous...     

渝湛高速公路击实膨胀土膨胀特性研究

以渝湛高速膨胀土为例，对击实膨胀土工程膨胀特性进行了试验研究，根据膨胀量试验的试验数据，拟台出膨胀量曲线的变化规律为指数关系；研究了有荷载情况下膨胀速度曲线的特征，利用非线性最小平方拟合法对膨胀曲线进行拟合，提出膨胀曲线的回归方程及其各参数的物理意义。     

呈贡隧道膨胀土膨胀力试验研究

选取呈贡隧道膨胀土重塑土样,通过膨胀力试验,研究了膨胀土在不同初始状态下的膨胀特性,探明了昆明膨胀土的膨胀力与初始含水量和干密度的内在联系,为昆明地区建筑物的设计与施工提供相关依据。     

圆饼状高压实膨润土膨胀力各向异性特征研究

针对作为我国缓冲/回填材料的高压实高庙子膨润土,采用自主研制的膨胀力-渗透性一体化测试仪器开展膨胀力试验,分别测定圆饼状试样的轴向膨胀力和径向膨胀力发展规律,研究试样初始干密度、初始吸力和尺寸效应对其膨胀力各向异性特征的影响。试验结果显示,轴向膨胀力和径向膨胀力均随着试样初始干密度的增加呈指数增大,膨胀力各向异性特征愈加显著。轴向膨胀力和径向膨胀力均随着试样初始吸力的增加而呈减小趋势;相同初始吸力条件下,径向膨胀力均大于轴向膨胀力,但是膨胀力各向异性系数随着初始吸力增大而不断减小。试样尺寸对膨胀力有显著影响,增加试样高度,轴向膨胀力不断增加,径向膨胀力增加到某一数值后不再随高度增加,膨胀力各向异性系数随着试样高度的增加逐渐减小。最后,基于膨润土膨胀机理、压实效应和尺寸效应,分析了膨胀力各向异性特征的形成机理。     

Influence of moisture on soil swelling

The dependence of the relative swelling of soils on their initial moisture content and yield point is examined. Physical characteristics of six types of swelling soils are determined, and results of their testing in compression devices are also described. The swelling pattern of soils with different initial moisture contents and the relation to liquid limit are demonstrated; this makes it possible to predict the uplift of the surface of a bed. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 2–5, September–October, 1997.     

Anisotropic swelling behaviour of unsaturated compacted GMZ bentonite hydrated under vertical stresses

Bulletin of Engineering Geology and the Environment - Bentonite has been considered as a potential buffer/backfill material for construction of engineering barriers in deep geological...     

石灰改良膨胀土的试验研究

对石灰改良膨胀土的基本机理进行了详细的阐述,在此基础上,结合工程实践,选取典型工段,进行了石灰改良膨胀土的试验研究,结果表明：在工程实践中,应重点控制膨胀土的含灰率均匀。     

膨胀土自由膨胀率与常规物理性质指标的关系

通过对平顶山地区典型膨胀土资料的分析、归纳，提出了两个公式，分别采用液限和塑性指数来计算自由膨胀率，指出利用这两个公式得出的计算结果较为安全、可靠，基本能够满足工程建设前期评价地基土膨胀性的要求，公式简便实用，具有较强的可操作性，能够较好的指导工程实践。     

棉浆粕黑液改性氨基磺酸系高效减水剂的研究

利用棉籽粕黑液对传统氨基磺酸系高效减水剂中进行改性,研究了其改性工艺,结果表明较佳的改性工艺条件为:n(对氨基苯磺酸钠)∶n(苯酚)∶n(甲醛)=1∶2∶5.5,棉籽粕黑液质量占对氨基苯磺酸钠与苯酚总质量百分数的10%,反应时间5 h,反应pH值9,反应温度90℃左右。改性产物的分散性能较未改性产物略有下降,但保水性能明显改善。     

南宁地区膨胀土膨胀力的现场测试

以广西南宁膨胀土为研究对象,考虑气象因素的影响,进行了现场膨胀力测试。测试场地设置桩和框锚结构,在土体中沿水平方向和垂直方向设置土压力盒,测试浅层土体水平向和竖向膨胀力,膨胀力的测试经历了一个完整的雨季。测试结果表明,土体膨胀力的变化与降雨入渗息息相关,"旱涝急转"的过程会造成土体膨胀力骤然变化,但雨季的持续又会对土体水平向和竖向膨胀力带来不同影响。现场对膨胀土竖向和水平向膨胀力的测试结果可为工程设计的优化提供参考。     

湿陷性黑土的物理力学性质

大庆南产地区分布着一种结构松散、成分复杂、对水分极度敏感的工程性质极差的土体，它兼有湿陷性土、有机土、碱土和分散土等诸多特殊土的劣性，而以湿陷性最为突出。通过对采油七厂（葡萄花）、八厂（永乐）和九厂（新站）3个典型地段样品的物理性质、力学性质、矿化成分等指标测试，经过综合分析比较，首次提出湿陷性黑土这一学术名词。     

Stabilization of maiduguri black cotton soils of Nigeria with sand

The Lake Chad Basin is an extensive Quaternary lacustrine deposit of black clay soils. Laboratory investigations show that this soil consists of abundant proportions of montmorillonite and generally poses a major problem for Civil Engineering construction due to high volume changes. Alternative soils or aggregates suitable for base construction are very difficult to obtain in these localities and hence soil stabilization is of great economic importance to the construction industry. Methods of stabilizing this soil include lime stabilization, cement stabilization, mechanical stabilization, or heat treatment. This paper is primarily concerned with sand stabilization because of the presence of large deposits of dune sands at these locations. The result indicates that sand stabilization shows promise for improving the value of black cotton clays in pavement construction and is the most economical of all the applicable methods. However the method is recommended only for improving the subgrade and as a sub-base.     

膨胀土地基的综合改良法处理试验研究

对不同起始含水率、掺入石灰率以及击实功试验条件下的大试件膨胀率进行了分析,得出了膨胀率与起始含水率为对数关系曲线,膨胀率与掺入石灰率、击实功为不同的幂函数关系曲线,研究结果为膨胀土地基的设计及膨胀土地基处理等膨胀土问题提供了重要的依据。     

Suction variations and soil fabric of swelling compacted soils

This study addresses firstly the soil fabric variations of loose and dense compacted soil samples during a single wetting/drying cycle at suctions between 0 and 287.9 MPa using mainly the mercury intrusion porosimetry（MIP） tests.Two suction techniques were employed to apply this wide suction range：the osmotic technique for suctions less than 8.5 MPa,and the vapor equilibrium or salt solution technique for suctions higher than 8.5 MPa.Secondly,the soil water retention curves（SWRCs） were predicted by the MIP test results for both loose and dense soil samples.A reasonable correspondence between MIP results and SWRCs was found on the wetting path at lower suctions close to saturation and on drying path at higher suctions.     

Effect of swelling soil on a moving retaining wall

A procedure is proposed for determining the effect of the displacement of a retaining wall on the stress-strain state of the mass swelling soil adjacent to it and the lateral pressure acting on it using the finite-element method. The results of calculations performed in accordance with the method in question and data derived from a field experiment are compared. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 14–17, September–October, 1995.     

Anisotropic elasto-plastic solutions for cavity expansion problem in saturated soil mass

On the basis of the yield criterion of Matsuoka and Nakai (1974), novel elasto-plastic solutions are obtained for the cavity expansion problem in an anisotropic medium. The solutions are formulated by employing a small-strain analysis in an elastic zone and a large-strain analysis in a plastic zone around the cavity in a soil mass. In light of the initial condition, the plastic radius and the stress in the plastic zone are derived by incorporating the large-strain analysis, the influence of stress anisotropy (K0) and the non-associated flow rule, and two fundamental solutions for the cavity expansion problem under undrained and drained conditions are presented in an anisotropic soil mass. Finally, a comparison with the previous results is performed for verification.     

公路膨胀土路堑边坡防护形式探讨

对榆林至商州高速公路洛南至岔口铺段月子岭膨胀土路堑边坡的防护形式进行了分析,并结合膨胀土的工程特性以及通车运营后边坡防护效果,提出了膨胀土边坡防护的对策,为其他膨胀土地区的路基设计积累了一定的经验,具有一定的实用价值。