水泥-废石膏加固软土的试验研究

利用废石膏和水泥配合加固软土，与单纯用水泥加固相比，可显著提高加固效果。在水泥－废石膏的水化物中，既有水泥产生的水化硅酸钙胶结松散的土颗粒，又有水泥与石膏产生的钙矾石膨胀填充孔隙。加固土孔隙水中ＣａＯ，ＯＨ－浓度决定水泥－废石膏的适用性及其增强效果。     

Influence of soil type on stabilization with cement kiln dust

A laboratory study was undertaken to evaluate the effectiveness of cement kiln dust (CKD) as a soil stabilizer. The study revealed that increases in the unconfined compressive strength (UCS) of soil occurred with the addition of CKD. Increases in UCS were inversely proportional to the plasticity index (PI) of the untreated soil. Significant PI reductions occurred with CKD treatment, particularly for high PI soils. Measurements indicate that the change in pH of soil as a function of CKD content is related to the PI of the untreated soil, and good correlation between pH response and performance of CKD treated soil was observed.     

The behaviour of organic matter in the process of soft soil stabilization using cement

In some projects where cement is used to stabilize soft soil foundations, it is found that the organic matter influences the stabilization effect. As a consequence, extra admixtures are added to accelerate the reactions of cement and improve the stabilization effect. In this study, different kinds of extra admixtures were used with cement to stabilize a soft soil with a high organic content. Direct shear and unconfined compression tests were undertaken and the mechanical indices in different conditions obtained. The total amount and components of the organic matter in every sample were also determined. The results show that the addition of extra admixtures improves the properties of cement-stabilized soils and that different extra admixtures play a different role.      

固化剂水泥稳定土基层沥青路面结构数值分析

采用路邦固化剂水泥稳定土作为某高速公路路面结构的基层材料,应用三维有限元软件计算了该路面结构在四种典型车型额定荷载、欠载、超载等荷载工况作用下的力学响应,重点分析了路面弯沉和水平、竖向应力等数据。结果表明:采用路邦固化剂水泥稳定土作为基层材料的沥青路面结构具有较强的路面承受能力,采用固化剂作基层稳定材料是可行的。     

Improvement of jet technology for soil stabilization

A geotechnology is described for soil stabilization on the basis of an improved design of jet monitor, which makes it possible to change the traditional procedural process and mix soil with grout on the surface; this makes it possible to save significantly on cementing materials, and also to completely replace the natural soil with a hardening grout or another soil. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 19–22, November–December, 1997.     

Electrochemical soil stabilization method

The writer describes an ecologically clean method of electrochemical stabilization of soils which makes it possible, without use of injection grouts, to develop anchors and piles in the soils. He presents results of laboratory investigations, full-scale tests, and experimental-industrial work for stabilization of different bases. The effectiveness of the application of the method for different engineering-technical solutions is shown.NIIOSP Institute. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 23–26, March–April, 1993.     

Chemical stabilization of scrap metal yard contaminated soil using ordinary portland cement: Strength and leachability aspects

In this study, the strength development and lechability aspects of metal-contaminated soil treated with ordinary portland cement (OPC) were investigated. The soil was collected from a scrap metal yard within the outskirts of Kuala Lumpur, Malaysia. Metal composition analysis indicated that the predominant metals present in the soil were iron (42,194 mg/kg), aluminium (8874 mg/kg), zinc (690 mg/kg), lead (428 mg/kg), copper (107 mg/kg) and chromium (52 mg/kg). The contaminated soil was treated with OPC using cement-to-dry soil (C/S_d) ratios of 0.5, 1 and 2. The effectiveness of the treatment was evaluated by performing unconfined compressive strength (UCS) as well as crushed and whole block leaching (WBL) tests on the treated soil. The treatment results were compared to the solidified waste acceptance criteria which were compiled based on the regulatory waste disposal limit at a disposal site in the United Kingdom and the maximum concentration of contaminants for toxicity characteristic of solid wastes from United States Environmental Protection Agency. Results indicated that chemical stabilization of metal-contaminated soils using OPC was effective for prevention of metal leaching from both disintegrated samples subsequent to years of weathering (crushed block) and intact samples (whole block) into the environment.     

Effective carbamide resin compositions for deep soil stabilization

Compositions of formulations based on Grade KM-2 and KM-3 carbamide resins modified by the introduction of aluminum sulfate, iron, and iron chloride salts are proposed for the chemical stabilization of soils. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 21–22, November–December, 1999.     

有机质土的固化试验

为解决传统固化剂难以有效加固含水率高、有机质含量高、孔隙比大的东南沿海地区软土的问题,以固化土7d无侧限抗压强度为评价指标,通过单掺试验和正交试验研究水泥、水玻璃、玻璃纤维、高效减水剂FDN等对有机质土的固化效果。结果表明:水泥对有机质土固化影响最为显著,水玻璃影响次之,玻璃纤维再次之,高效减水剂FDN影响最小;适用于有机质土固化剂的最优配比为水泥掺量18%,玻璃纤维掺量2%,水玻璃掺量8%,高效减水剂FDN掺量1.5%,氢氧化钠0.6%,三乙醇胺0.04%。     

水泥稳定砂砾基层的裂缝分析与防治

通过分析水泥稳定砂砾基层产生干缩、温缩及冻胀裂缝的原因,提出从材料设计、结构设计、施工控制、养生保护等四个方面加强裂缝的防治,提高基层的路用性能。     

Application of phosphogypsum in soil stabilization

This paper describes the application of phosphogypsum with cement and fly ash for soil stabilization. Atterberg limits, standard Proctor compaction and unconfined compressive strength tests were carried out on cement, fly ash and phosphogypsum stabilized soil samples. Treatment with cement, fly ash and phosphogypsum generally reduces the plasticity index. The maximum dry unit weights increase as cement and phosphogypsum contents increase, but decrease as fly ash content increases. Generally optimum moisture contents of the stabilized soil samples decrease with addition of cement, fly ash and phosphogypsum. Unconfined compressive strengths of untreated soils were in all cases lower than that for treated soils. The cement content has a significantly higher influence than the fly ash content. The use of two waste by-products, phosphogypsum and fly ash may provide an inexpensive and advantageous construction product.     

水泥粉喷桩地基加固技术在某工程中的应用

结合某工程实例，介绍了粉喷桩的施工工艺及质量控制，通过方案选择和桩基检测结果，指出该工艺处理软弱地基及居民区是比较经济、安全可靠的，对类似工程有参考意义。     

Mechanisms of metal stabilization by cement based fixation processes

The mechanism of zinc and mercury fixation by cement/silicate stabilization processes has been assessed from leaching, scanning electron microscopy, X-ray diffraction and porosimetry studies. The results of these tests correlate closely and suggest two separate mechanisms operating in the interaction between these metals and the cement/silicate system. The presence of zinc has a significant effect upon the hydration and final physical properties of cement. The chemical interaction between mercury and cement/silicate is minimal and the hydration process of cement proceeds normally. Zinc appears to be chemically stabilized by cement based fixation processes through the formation of insoluble compounds at high pH. Mercury and related metals which do not form precipitates at elevated pH levels are held in pore solution. Mobility depends largely upon physical encapsulation by the cement matrix and leachability of these materials is expected to be closely related to porosity of the final product.     

论抗裂水泥稳定碎石基层的配合比设计

通过阐述水泥稳定碎石基层的优缺点及半刚性基层设计中需解决的问题,结合实际,从级配、成型方法等方面分析了水泥稳定碎石基层的配合比设计,从而保证水泥稳定碎石路面基层满足设计要求。