Chapter 25 Treatment of metastable loess soils: Lessons from Eastern Europe

Jefferson, Ian; Rogers, C. D. F.; Evstatiev, Dimcho; Karastanev, Doncho

doi:10.1016/s1571-9960(05)80028-x

Cited by 35 publications

(10 citation statements)

References 18 publications

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“…Loess is a kind of silt-dominated Quaternary sediment, which is mostly distributed in arid and semi-arid areas in the middle latitudes of the earth [1,2]. Natural loess has the characteristics of loose structure, large porosity, rich soluble salt and slightly coherent, and often shows the metastable microstructure [3][4][5][6]. Since this special structure features, loess may collapse after wetting [7,8].…”

Section: Introductionmentioning

confidence: 99%

The Influence of Freeze-Thaw Cycles on Unconfined Compressive Strength of Lignin Fiber-Reinforced Loess

Gao¹,

Zhong²,

Wang³

et al. 2022

Journal of Renewable Materials

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In the seasonal permafrost region with loess distribution, the influence of freeze-thaw cycles on the engineering performance of reinforced loess must be paid attention to. Many studies have shown that the use of fiber materials can improve the engineering performance of soil and its ability to resist freeze-thaw cycles. At the same time, as eco-environmental protection has become the focus, which has been paid more and more attention to, it has become a trend to find new environmentally friendly improved materials that can replace traditional chemical additives. The purpose of this paper uses new environmental-friendly improved materials to reinforce the engineering performance of loess, improve the ability of loess to resist freeze-thaw cycles, and reduce the negative impact on the ecological environment. To reinforce the engineering performance of loess and improve its ability to resist freeze-thaw cycles, lignin fiber is used as a reinforcing material. Through a series of laboratory tests, the unconfined compressive strength (UCS) of lignin fiber-reinforced loess under different freeze-thaw cycles was studied. The effects of lignin fiber content and freeze-thaw cycles on the strength and deformation modulus of loess were analyzed. Combined with the microstructure features, the change mechanism of lignin fiber-reinforced loess strength under freeze-thaw cycles was discussed. The results show that lignin fiber can improve the UCS of loess under freeze-thaw cycles, but the strengthening effect no longer increases with the increase of fiber content. When the fiber content is less than 1%, the UCS growth rate of loess is the fastest under freeze-thaw cycles. And the UCS of loess with 1% fiber content is the most stable under freeze-thaw cycles. The freeze-thaw cycles increase the deformation modulus of loess with 1% fiber content, and its ability to resist deformation is obviously better than loess with 1.5%, 2% and 3% fiber content. The fiber content over 1% will weaken the strengthening effect of lignin fiber-reinforced loess, and the optimum fiber content of lignin fiber-reinforced loess under freeze-thaw cycles is 1%.

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Section: Introductionmentioning

confidence: 99%

The Influence of Freeze-Thaw Cycles on Unconfined Compressive Strength of Lignin Fiber-Reinforced Loess

Gao¹,

Zhong²,

Wang³

et al. 2022

Journal of Renewable Materials

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“…Another aspect of the collapsibility of loess was covered by Bulgarian and English researchers: namely, the impact of subsidence on construction, on the example of loess in Western Europe, particularly in Bulgaria [40]. In their work, they focused on estimating the effectiveness of strengthening the loess soil, on the example of the methods used in Bulgaria.…”

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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“…However, they are relatively common in China where thick loess mantles areas of higher and steeper relief (for example, Meng & Derbyshire 1998). Jefferson et al (2005) gave various methods for treating collapsible loessic deposits. Their suggestions are given in Table 6.17 and can be summarised as:  shallow depths 0-1.5 m: surface compaction, pre-wetting or vibroflotation;  medium depths 1.5 -10 m: vibrocompaction, dynamic compaction, explosives, compaction piles, grouting, pre-wetting, soil mixing with lime/cement, heat treatment, chemical methods;  depths greater than 10 m: as for medium depths (though some may be of limited suitability), piling.…”

Section: Geohazards Associated With Loessic Depositsmentioning

confidence: 99%

Chapter 6 Material properties and geohazards

Culshaw

Entwisle

Giles

et al. 2017

EGSP

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In engineering terms, all materials deposited as a result of glacial and periglacial processes are transported soils. Many of these deposits have engineering characteristics that differ from those of water-lain sediments. In the UK, the most extensive glacial and periglacial deposits are tills. Previously, engineering geologists have classified them geotechnically as Lodgement, Melt-out, Flow and Deformation Tills or as variants of these. However, in this book, tills have been reclassified as: subglacial traction till, glacitectonite and supraglacial mass flow diamicton/glaciogenic debris flow deposits (see Chapter 4 Sections 4.1-4.3). Because this classification is new, it is not possible to relate geotechnical properties and characteristics to the subdivisions of the new classification. Consequently, the domain/stratigraphic classification, recently developed by the British Geological Survey and others, has been used and their geotechnical properties and characteristics are discussed on this basis. The geotechnical properties and characteristics of the other main glacial and periglacial deposits are also discussed. For some of these (for example, glaciolacustrine deposits, quick clays and loess), geohazards relating to the lithology and/or fabric of the deposit are discussed along with their properties. Other geohazards that do not relate to lithology and/or fabric are discussed separately as either local geohazards or regional ones. In some cases (for example, glaciofluvial sands and gravels), the geotechnical properties and behaviour are similar to sediments deposited under different climatic conditions. Consequently, these deposits are not discussed at length. Similarly, some of the local geohazards that are found associated with glacial and periglacial deposits relate to current climatic conditions and are not discussed here. Examples include landsliding and highly compressible organic soils (peats). geographical location and description. This means that some of the data in the literature can be attributed to the new stratigraphical till units. Examples of this are discussed below. Further, it should be noted that in Chapter 4 Section 4.6 it is demonstrated how the landsystem approach can be reconciled with the domains approach of McMillan et al. (2011) and McMillan & Merritt (2012). As the geotechnical property information from the NGPD, some of which is summarised here, is classified in terms of domains, it is proposed that, in the longer term, the landsystem/domain approach should supersede the till classifications used by Trenter (1999) and Clarke (2012). 6.2.1.2 Glacial till stratigraphy 6.2.1.2.1 Glacial tills on the geological map During the desk study stage of a site investigation some of the initial geological information comes from the relevant geological map. In the UK, the geological maps used (published by the BGS) are at 1:50,000 or 1:10,000 scale. A broad overview of the national extent of glacial tills in the UK can be obtained from the engineering geology maps produced at a scale of 1:1,000...

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Chapter 25 Treatment of metastable loess soils: Lessons from Eastern Europe

Cited by 35 publications

References 18 publications

The Influence of Freeze-Thaw Cycles on Unconfined Compressive Strength of Lignin Fiber-Reinforced Loess

The Influence of Freeze-Thaw Cycles on Unconfined Compressive Strength of Lignin Fiber-Reinforced Loess

Research of the collapsibility of the European loess – review

Chapter 6 Material properties and geohazards

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