Loess improvement methods

Evstatiev, Dimcho

doi:10.1016/0013-7952(88)90036-1

Cited by 50 publications

(10 citation statements)

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“…e Chinese national standards "Code for Design of Intercity Railway" (TB10623-2014) and "Code for Design of Railway Earth Structure" (TB10001-2016) stipulate that filling materials including Groups A and B should be used for filling the subgrade bed and below, but loess is classified as Group C filler [3,4]. When applied to railway subgrade engineering, it usually brings about engineering geological problems such as subgrade subsidence and serious decrease of strength and stiffness [5][6][7]. However, due to its low price and wide distribution in China, it is often used after physical or chemical stabilization to improve the strength, stiffness, and stability of loess subgrade.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Mechanical Properties of Cement‐Stabilized Loess Produced Using Different Compaction Methods

Jiang

Yuan

et al. 2020

Advances in Materials Science and Engineering

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Mechanical properties are important indexes to evaluate the improvement effect and engineering performance of cement-stabilized loess (CSL). This paper presents a comparison of the mechanical properties of CSL compacted using hammer quasi-static compaction method (QSCM) and vertical vibration compaction method (VVCM). The compaction properties, unconfined compressive strength (UCS), splitting strength (SPS), and resilient modulus (RM) of the laboratory-compacted CSL using VVCM and QSCM are tested and compared. Furthermore, the effects of compaction method, cement content, compaction coefficient, and curing time of the CSL specimens are investigated. In addition, field measurements are carried out to validate the laboratory investigations. The results show that the laboratory-compacted CSL using VVCM has a larger dry density and smaller optimum water content than that using QSCM. And the compaction method has a great influence on the mechanical strength of CSL. The UCS, SPS, and RM of the specimen produced using VVCM are averagely 1.17 times, 1.49 times, and 1.17 times that of CSL produced using QSCM, respectively, and the UCS, SPS, and RM of the specimens produced using these two methods increase linearly as the cement content and compaction coefficient increase, while the mechanical strength growth curve experiences three periods of increasing sharply, increasing slowly, and stabilizing with the curing time increased. Moreover, the results also show that the mechanical properties of laboratory-compacted CSL using VVCM have a better correlation of 83.8% with the field core samples.

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Section: Introductionmentioning

confidence: 99%

Comparison of Mechanical Properties of Cement‐Stabilized Loess Produced Using Different Compaction Methods

Jiang

Yuan

et al. 2020

Advances in Materials Science and Engineering

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“…While it may not be immediately apparent, ground improvement methods have made considerable advances since today's commonly practiced techniques began to develop in the 20th century; however, most techniques have gone through changes. Also, the purpose of the improvement techniques may be by using vertical drains, grouting, stabilization using admixtures and reinforcement to increase bearing capacity of soil and reduce its settlement, [8,3,9,11,5,12].…”

Section: Introduction and Literature Reviewmentioning

confidence: 99%

Performance of partially replaced collapsible soil – Field study

Ali

2015

Alexandria Engineering Journal

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Soil collapse occurs when increased moisture causes chemical or physical bonds between the soil particles to weaken, which allows the structure of the soil to collapse. Collapsible soils are generally low-density, fine-grained combinations of clay and sand left by mudflows that have dried, leaving tiny air pockets. When the soil is dry, the cemented materials are strong enough to bond the sand particles together. When natural soil becomes wet, moisture alters the cementation structure and the soil's strength is compromised, causing collapse or subsidence. Based on soil type and density, the potential for encountering collapsible soils throughout most of the project alignment is low. Conditions in arid and semi-arid climates like Borg El Arab, near Alexandria Egypt favor the formation of the most problematic collapsible soils. The behavior and performance of compacted sand replacement over treated collapsible soil by pre-wetting and compaction are investigated in the current study. Field investigation was performed in the form of plate loading tests conducted on compacted sand replacement over improved collapsible soil. Field plate load tests program was developed to explore the effect of compacted sand replacement thickness on collapsibility potential. Treated collapsible soil was replaced with imported cohesionless soil with variable thickness up to footing width. Results proved that the improvement of collapsible soils by sand/crushed stone replacement is possible to control/mitigate their risk potentials against sudden settlement when exposed to water. Replacement soil increases the rate and reduces the amount of footing settlement. For compacted collapsible soils, partial replacement by compacted sand/crushed stone layers decreases collapsibility potential risk. Results also, introduce the development of practical, economical and environmentally safe geochemical methods for collapsible soil stabilization and collapsible risk mitigation. ª 2015 Production and hosting by Elsevier B.V. on behalf of Faculty of Engineering, Alexandria University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/). ª 2015 Production and hosting by Elsevier B.V. on behalf of Faculty of Engineering, Alexandria University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: N.A. Ali, Performance of partially replaced collapsible soil -Field study, Alexandria Eng. J. (2015), http://dx.

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“…In the considerations regarding the reinforcement of the loess substrate, one cannot omit the work of the geologist Evstatiev, who describes eight types of techniques tested on loess soils from many areas [44]. There are two main types and four subclasses of the loess depending on their thickness and on the demonstrated collapsibility.…”

Section: Research Of Collapsibility Of European Loessmentioning

confidence: 99%

Research of the collapsibility of the European loess – review

Lal

2019

Bud-Arch

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Foundation of the buildings on the loessial soil is often associated only with difficulties resulting from the possibility of the collapse of the ground. For these reason, loess is too often unfairly disqualified as the construction subsoil in spite of its good strength and strain parameters. Thanks to continuous development of research and publications of the results, reliable data regarding loess are spread and, as a consequence, loess becomes more and more common soil used in the geotechnicalengineering.Loess collapsibility has been studied since the middle of the 20th century, nevertheless, only the computer techniques and specialist laboratory and microstructural tests, that have been developed from the end of last century, helped us to find an answer to the important questions regarding the occurrence of this phenomenon. Detailed mechanisms that cause sudden loess volumetric reduction due to humidity and load, and the elements that affects the collapsibility are still studied. Furthermore, varied technics are researched, including in-situ tests, which allow estimating the risk of collapse, as well as the methods of its elimination.The aim of this paper is to systematize the directions of current studies of European loess collapsibility and to indicate their most significant results. The review was made on the basis of the scientific publications published in the Polish and international journals as well as the Journal Citation Reports (JCR) Web of Science database.

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Loess improvement methods

Cited by 50 publications

References 1 publication

Comparison of Mechanical Properties of Cement‐Stabilized Loess Produced Using Different Compaction Methods

Comparison of Mechanical Properties of Cement‐Stabilized Loess Produced Using Different Compaction Methods

Performance of partially replaced collapsible soil – Field study

Research of the collapsibility of the European loess – review

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