• Title/Summary/Keyword: clay swelling soil

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Using cement dust to reduce swelling of expansive soil

  • AlZubaidi, Raddi M.;AlRawi, Kawkab H.;AlFalahi, Ahmed J.
    • Geomechanics and Engineering
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    • v.5 no.6
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    • pp.565-574
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    • 2013
  • Extensive study was carried out on Clay expansive soil. This soil was silty clay and can be classified as CH. The degree of expansion was found to range from low to medium depending on the free swell and swell pressure tests. The research investigated the effect of using cement dust on swelling potential, Atterberg Limit, linear shrinkage, and mineralogical composition of expansive soil. The results showed that the swelling potential, plasticity index, linear shrinkage, and clay minerals decrease with increasing cement dust percentage. The cement dust accumulates in huge amounts as a side product in cement factories, and the disposal of this fine dust is very difficult and poses an environmental threat.

Control of phosphoric acid induced volume change in clays using fly ash

  • Chavali, Rama Vara Prasad;Reddy, P. Hari Prasad
    • Geomechanics and Engineering
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    • v.15 no.6
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    • pp.1135-1141
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    • 2018
  • Volume changes of soils induced by inorganic acids cause severe foundation and superstructure failures in industrial buildings. This study aimed to assess the potential of fly ash to control volume changes in soils under acidic environment. Two soils such as black cotton soil predominant with montmorillonite and kaolin clay predominant with kaolinite were used for the present investigation. Both soils exhibited an increase in swelling subjected to phosphoric acid contamination. Ion exchange reactions and mineralogical transformations lead to an increase in swelling and a decrease in compressibility in black cotton soil, whereas phosphate adsorption and mineral dissolution lead to an increase in swelling and compressibility in case of kaolin clay. Different percentages of Class F fly ash obtained from Ramagundam national thermal power station were used for soil treatment. Fly ash treatment leads to significant reduction in swelling and compressibility, which is attributed to the formation of aluminum phosphate cements in the presence of phosphoric acid.

Characteristics of expansive soils improved with cement and fly ash in Northern Thailand

  • Voottipruex, Panich;Jamsawang, Pitthaya
    • Geomechanics and Engineering
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    • v.6 no.5
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    • pp.437-453
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    • 2014
  • This paper studies the swelling and strength characteristics of unimproved and improved expansive soils in terms of the swell potential, swelling pressure, rate of secondary swelling, unconfined compressive strength and California bearing ratio (CBR). The admixtures used in this study are locally available cement and fly ash. The soils used in this study were taken from the Mae Moh power plant, Lampang Province, in northern Thailand. A conventional consolidation test apparatus was used to determine the swelling of the soil specimen. The optimum admixture contents are determined to efficiently reduce the swelling of unimproved soil. The rate of secondary swelling for unimproved soil is within the range of highly plastic montmorillonite clay, whereas the specimens improved with optimum admixture contents can be classified as non-swelling kaolinite. A soil type affects the swelling pressure. Expansive soil improvement with fly ash alone can reduce swelling percentage but cannot enhance the unconfined compressive strength and CBR. The strength and swelling characteristics can be predicted well by the swelling percentage in this study.

Mechanical properties and microstructures of stabilised dredged expansive soil from coal mine

  • Chompoorat, Thanakorn;Likitlersuang, Suched;Sitthiawiruth, Suwijuck;Komolvilas, Veerayut;Jamsawang, Pitthaya;Jongpradist, Pornkasem
    • Geomechanics and Engineering
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    • v.25 no.2
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    • pp.143-157
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    • 2021
  • Expansive soil is the most predominant geologic hazard which shows a large amount of shrinkage and swelling with changes in their moisture content. This study investigates the macro-mechanical and micro-structural behaviours of dredged natural expansive clay from coal mining treated with ordinary Portland cement or hydrated lime addition. The stabilised expansive soil aims for possible reuse as pavement materials. Mechanical testing determined geotechnical engineering properties, including free swelling potential, California bearing ratio, unconfined compressive strength, resilient modulus, and shear wave velocity. The microstructures of treated soils are observed by scanning electron microscopy, x-ray diffraction, and energy dispersive spectroscopy to understand the behaviour of the expansive clay blended with cement and lime. Test results confirmed that cement and lime are effective agents for improving the swelling behaviour and other engineering properties of natural expansive clay. In general, chemical treatments reduce the swelling and increase the strength and modulus of expansive clay, subjected to chemical content and curing time. Scanning electron microscopy analysis can observe the increase in formation of particle clusters with curing period, and x-ray diffraction patterns display hydration and pozzolanic products from chemical particles. The correlations of mechanical properties and microstructures for chemical stabilised expansive clay are recommended.

Time-dependent compressibility characteristics of Montmorillonite Clay using EVPS Model

  • Singh, Moirangthem Johnson;Feng, Wei-Qiang;Xu, Dong-Sheng;Borana, Lalit
    • Geomechanics and Engineering
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    • v.28 no.2
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    • pp.171-180
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    • 2022
  • Time-dependent stress-strain behaviour significantly influences the compressibility characteristics of the clayey soil. In this paper, a series of oedometer tests were conducted in two loading patterns and investigated the time-dependent compressibility characteristics of Indian Montmorillonite Clay, also known as black cotton soil (BC) soil, during loading-unloading stages. The experimental data are analyzed using a new non-linear function of the Elasto-Visco-Plastic Model considering Swelling behaviour (EVPS model). From the experimental result, it is found that BC soil exhibits significant time-dependent behaviour during creep compared to the swelling stage. Pore water entrance restriction due to consolidated overburden pressure and decrease in cation hydrations are responsible factors. Apart from it, particle sliding is also evident during creep. The time-dependent parameters like strain limit, creep coefficient and Cαe/Cc are observed to be significant during the loading stage than the swelling stage. The relationship between creep coefficients and applied stresses is found to be nonlinear. The creep coefficient increases significantly up to 630 kPa-760 kPa (during reloading), and beyond it, the creep coefficient decreases continuously. Several parameters like loading duration, the magnitude of applied stress, loading history, and loading path have also influenced secondary compressibility characteristics. The time-dependent compressibility characteristics of BC soil are presented and discussed in detail.

Hydromechanical behavior of a natural swelling soil of Boumagueur region (east of Algeria)

  • Mebarki, Mehdi;Kareche, Toufik;Derfouf, Feth-Ellah Mounir;Taibi, Said;Abou-bekr, Nabil
    • Geomechanics and Engineering
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    • v.17 no.1
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    • pp.69-79
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    • 2019
  • This work presents an experimental study of the hydromechanical behavior of a natural swelling soil taken from Boumagueur region east of Algeria. Several pathological cases due to the soil shrinkage / swelling phenomenon were detected in this area. In a first part, the hydric behavior on drying-wetting paths was made, using the osmotic technics and saturated salts solutions to control suction. In The second part, using a new osmotic oedometer, the coupled behavior as a function of applied stresses and suction was investigated. It was shown that soil compressibility parameters was influenced by suction variations that an increase in suction is followed by a decrease in the virgin compression slope. On the other hand, the unloading slope of the oedometric curves was not obviously affected by the imposed suction. The decrease in suction strongly influences the apparent preconsolidation pressure, ie during swelling of the samples after wetting.

Alkali-activated GGBS and enzyme on the swelling properties of sulfate bearing soil

  • Thomas, Ansu;Tripathia, R.K.;Yadu, L.K.
    • Geomechanics and Engineering
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    • v.19 no.1
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    • pp.21-28
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    • 2019
  • Use of cement in stabilizing the sulfate-bearing clay soils forms ettringite/ thaumasite in the presence of moisture leads to excessive swelling and causes damages to structures built on them. The development and use of non-traditional stabilisers such as alkali activated ground granulated blast-furnace slag (AGGBS) and enzyme for soil stabilisation is recommended because of its lower cost and the non detrimental effects on the environment. The objective of the study is to investigate the effectiveness of AGGBS and enzyme on improving the volume change properties of sulfate bearing soil as compared to ordinary Portland cement (OPC). The soil for present study has been collected from Tilda, Chhattisgarh, India and 5000 ppm of sodium sulfate has been added. Various dosages of the selected stabilizers have been used and the effect on plasticity index, differential swell index and swelling pressure has been evaluated. XRD, SEM and EDX were also done on the untreated and treated soil for identifying the mineralogical and microstructural changes. The tests results show that the AGGBS and enzyme treated soil reduces swelling and plasticity characteristics whereas OPC treated soil shows an increase in swelling behaviour. It is observed that the swell pressure of the OPC-treated sulfate bearing soil became 1.5 times higher than that of the OPC treated non-sulfate soil.

매립지 침출수의 효과적인 제거를 위한 반응성 차수재 개발

  • 이현주;박재우
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2003.09a
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    • pp.395-398
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    • 2003
  • Geosynthetic Clay Liners(GCLs) have been widely used as hydraulic barrier in landfills and remediation projects of contaminated sites. The aim of this research is to modify GCLs for effective removal of contaminants. We perform the free swell test, hydraulic conductivity test, and contaminants (TCE, hexavalent chromium, and nitrate) removal test on the bentonite-ZVI mixture with various ZVI content. As the ZVI content increased, contaminants removal efficiencies and swell volume increased, and hydraulic conductivity decreased.

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Characterization of Clay Minerals in Ranch Pasture

  • Kang, Sangjae;Jang, Jeonghun;Park, Nayun;Park, Junhong;Choi, Seyeong;Park, Man;Lee, Changhee;Lee, Donghoon;Zhang, Yongseon
    • Korean Journal of Soil Science and Fertilizer
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    • v.49 no.1
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    • pp.53-59
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    • 2016
  • This study deals with the distribution of the clay minerals separated from clay fractions of ranch pastures in Korea and their chemical and mineralogical properties. Crystalline phases of the clay minerals were identified by powder X-ray diffraction (XRD) pattern and FT-IR spectra, and their relative chemical compositions were also analyzed by X-ray flourescence spectrometry (XRF). Primary minerals consisted mainly of quartz and mica and chlorite and kaolinite along with a trace of swelling micas were identified as secondary clay minerals. However, the relative content of these clay minerals was different with the locations, which led to significant effects on physical and chemical properties of soils like inorganic elemental composition. In particular, $SiO_2$ content was higher in Gochang ranch pasture than in other ranch pasture. Infrared (IR) spectra did not indicate any significant differences in organic functional groups among the locations. This study clearly showed that ranch pastures had different relative content of clay minerals and chemical properties depending on the location and consequently that those properties are worthy to be taken into account for soil amendment.

A Study on the Relationship between the Physical Properties of Soil and the Compression Index of Soft Clay in Gyungnam Coastal Region (경남해안지역 연약점토의 토질특성과 압축지수와의 상관성에 관한 연구)

  • 장정욱;최성민;박춘식
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.13 no.4
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    • pp.282-289
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    • 2001
  • This study analyzed the relationship between the physical properties of soil and the compression index of the soft clay in Gyungnam coastal region. Tests of physical and mechanical properties of soil have been carried out under the undisturbed condition at 82 Gimhae, 18 Jinhae and 27 Geojespecimens. The result showed that Terzaghi & Peck's empirical equation of the compression index were not applicable. The compression index of soft clay in Gyungnam coastal region was correlated with the water contents, the liquid limit and the initial void ratio. Among these, the initial void ratio showed the highest correlation with the compression index of soft clay in Gyungnam coastal region and the relationship is shown in the following. (1) The compression index of soft clay in Gyungnam coastal region is represented as follows: $C_c=0.74(e_o-0.7$ (2) The relationship between compression index and the swelling index in Gyungnam coastal region is represented as follows: $C_s=(1/8-1/15)C_c$.

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