• Geomechanics and Engineering
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• 제37권5호
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• pp.499-510
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• 2024

In northern China, abundant summer rainfall and a higher water table can weaken the soil due to salt heave, collapsibility, and increased moisture absorption, thus the chlorine saline soil (silty clay) needs to be stabilized prior to use in road embankments. To optimize chlorine saline soil stabilizing programs, unconfined compressive strength tests were conducted on soil treated with five different stabilizers before and after soaking, followed by field compaction test and unconfined compressive strength test on a trial road embankment. In situ testing were performed with the stabilized soils in an expressway embankment, and the results demonstrated that the stabilized soil with lime and SH agent (an organic stabilizer composed of modified polyvinyl alcohol and water) is suitable for road embankments. The appropriate addition ratio of stabilized soil is 10% lime and 0.9% SH agent. SH agent wrapped soil particles, filled soil pores, and generated a silk-like web to improve the moisture stability, strength, and stress-strain performance of stabilized soil.

• Geomechanics and Engineering
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• 제28권1호
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• pp.35-48
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• 2022

The effect of discrete polypropylene fibre reinforcement on shear strength parameters, tensile properties and isotropic index of stabilized compacted residual subgrade was investigated. Composites of compacted subgrade were developed from polypropylene fibre dosage of 0%, 1%, 2.5% and 4% and 3% cement binder. Saturated compacted soil benefited from incremental fibre dosage, the mobilized friction coefficient increased to a maximum at 2.5% fibre dosage from 0.41 to 0.58 and the contribution due to further increase in fibre dosage was marginal. Binder stabilization increased the degree of isotropy for unreinforced soil at lower fibre dosage of 1% and then decreased with higher fibre dosage. Saturation of 3% binder stabilized soil decreased the soil friction angle and the degree of isotropy for both unstabilized and binder stabilized soil increased with fibre dosage. The maximum tensile stress of 3% binder stabilized fibre reinforced residual soil was 3-fold that of 3% binder stabilized unreinforced soil. The difference in computed and measured maximum tensile and tangential stress decreased with increase in fibre dosage and degree of stabilization and polypropylene fibre reinforced soil met local and international criteria for road construction subgrade.

• International Journal of Railway
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• 제7권4호
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• pp.91-93
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• 2014

In these days, use of proper soils for construction materials become more limited, but wasted soils are abundant; therefore, the method which can use wasted soil such as soft clay has been investigated. Air-foamed stabilized soil has been used widely, but never been used as a subgrade material. The aim of this study is to verify the use of air-foamed stabilized soil as the subgrade construction material. Several wasted soils such as soft clay was selected to make air-foamed stabilized soil mixtures. The air-foamed stabilized mixture design was conducted to find the optimum quantity of stabilizing agent (cement) and air-foamed, and the effect of cement quantity and air-foamed quantity on strength of air-foamed stabilized soil mixtures base on the test results of unconfined compression test was investigated. As the quantity of cement is increased, the strength is increased, but the quantity of air-foamed is increased and the strength is decreased. Elastic moduli based on unconfined compression strength were obtained to use as subgrade of railway track design.

• 한국산학기술학회논문지
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• 제15권6호
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• pp.3923-3930
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• 2014

본 연구에서는 광양 ${\bigcirc}{\bigcirc}$산업단지 공사현장내의 도로 및 구조물 시공구간 중 연구대상 3구간을 선정하여 지반의 물리 역학적 특성을 분석하고 구조물 시공조건, 고화처리 단면조건에 따라 Midas-GTS를 통해 압밀해석과 지지력 산정을 수행하였다. 도로 및 구조물이 시공되는 연약점토지반의 침하 및 지지력 개선방안으로 고화처리공법 적용 시 지반의 안정성 개선효과와 고화처리단면에 따른 침하 및 지지력 개선효과를 분석하였다. 연약점토지반에 고화처리공법을 적용 시 침하 및 지지력 개선효과가 뛰어난 것으로 나타났으며 특히, 고화처리공법 적용 후 압밀침하량이 최소 53%에서 최대 82%까지 감소하여 압밀침하 억제효과가 우수한 것으로 나타났다. 고화처리 폭이 설치 구조물 폭의 2배 이상인 경우 고화처리 폭이 증가하여도 압밀침하 억제효과는 1~7%정도로 미소한 것으로 나타났다. 또한, 고화처리 폭 6m, 심도 1m이상 적용시 고화처리 전보다 허용지지력이 2.3~3.3배정도 크게 증가한 것으로 나타나 고화처리공법을 적용하면 지지력 증대효과가 매우 우수함을 알 수 있었다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.145-149
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• 2000

We performed the geotechnical experiments of the hydraulic conductivity and compressive strength test with the stabilized soil in the laboratory, proved that it is useful to use the stabilized soil as an alternative for natural clay soil. Also, for mixing adding materials in the stabilized soil, it was determined that 1) the optimal mixing ratio of cement : bentonite : stabilizing agent was 90:60:1 of mass ratio(kg) for 1㎥ with soil, 2) it was also possible to use low quality bentonite(B\circled2) classified by swelling grade because of little difference from results of the hydraulic conductivity and compressive strength test with high quality bentonite(B\circled1). According to the results of the fixation ability of heavy metals(Pb$^{2+}$, Cu$^{2+}$, Cd$^{2+}$, Zn$^{2+}$) with soil and additives, authors can conclude that the higher pH condition had the more removal efficiency of heavy metals. B\circled1 and cement had especially high removal efficiency of heavy metals in a whole pH because of high alkalinity.alinity.

• Geomechanics and Engineering
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• 제10권2호
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• pp.247-256
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• 2016

In this paper, based on understanding the design theories on soil stabilization, a series of soil stabilizers were prepared with different kinds of industrial wastes such as calcined coal gangue (CCG), blast furnace slag (SS), steel slag (SL), carbide slag (CS), waste alkali liquor (JY), and phosphogypsum (PG). The results indicated that when the Portland cement (PC) proportion was lower than 20% in the stabilizer, for the soil sample selected from Wuhan (WT) and Beijing (BT), the unconfined compress strength (UCS) of the stabilized soil specimens could increase 4.8 times and 5.4 times respectively than that of the specimens stabilized only by PC; compared with the UCS of the specimen stabilized only by PC, the UCS of the specimen which was made from soil sample WT and stabilized by the stabilizer composed only by CCG, CS, and PG increased 1.5 times, and UCS of the specimen which was made from soil sample BT and stabilized by the stabilizer composed only by SS, JY, and PG increased 4.5 times.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.1142-1147
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• 2006

Cement-stabilized clay has widespread applications in Deep Mixing projects, whereby soft deep clay deposits are improved through the addition of cement. While much research on this subject has taken place over the past decade, the strength and deformation behaviour of cement-stabilized clay is still not well understood. An extensive laboratory program was conducted on kaolin stabilized with up to 10% cement. Water curing was employed for durations up to 112 days. To study the microstructure of raw and stabilized soil, use is made of SEM. Micrographs of selected raw and stabilized soil were obtained. These micrographs were closely analyzed for any change in the microstructure of the soil as a result of stabilization.

• Geomechanics and Engineering
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• 제16권1호
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• pp.105-112
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• 2018

This paper presents results of a compressive investigation conducted on weathered soil stabilized with ground bottom ash (GBA) and red mud (RM). The effects of water/binder ratio, RM/GBA ratio, chemical activator (NaOH and $Na_2SiO_3$) and curing time on unconfined compressive strength of stabilized soils were examined. The results show that the water/binder ratio of 1.2 is optimum ratio at which the stabilized soils have the maximum compressive strength. For 28 days of curing, the compressive strength of soils stabilized with alkali-activated GBA and RM varies between 1.5 MPa and 4.1 MPa. The addition of GBA, RM and chemical activators enhanced strength development and the rate of strength improvement was more significant at the later age than at the early age. The potential environmental impacts of stabilized soils were also assessed. The chemical property changes of leachate from stabilized soils were analyzed in terms of pH and concentrations of hazardous elements. The observation revealed that the soil mixture with ground bottom ash and red mud proved environmentally safe.

• Environmental Engineering Research
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• 제23권4호
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• pp.420-429
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• 2018

Soil stabilization is a soil remediation technique that reduces the mobility of heavy metals in soils. Although it is a well-established technique, it is nonetheless essential to perform a follow-up chemical assessment via a leaching test to evaluate the immobilization of heavy metals in the soil matrix. Unfortunately, a standard chemical assessment is not sufficient for evaluation of the biological functional state of stabilized soils slated for agricultural use. Therefore, it is useful to employ a pyrosequencing-based microbial community analysis for the purpose. In this study, a recently stabilized site in the proximity of an exhausted mine was analyzed for bacterial diversity, richness, and relative abundance as well as the effect of environmental factors. Based on the Shannon and Chao1 indices and rarefaction curves, the results showed that the stabilized layer exhibited lower bacterial diversity than control soils. The prevalence of dominant bacterial populations was examined in a hierarchical manner. Relatively high abundances of Proteobacteria and Methylobacter tundripaludum were observed in the stabilized soil. In particular, there was substantial abundance of the Methylobacter genus, which is known for its association with heavy metal contamination. The study demonstrated the efficacy of (micro)biological assessment for aiding in the understanding and post-management of stabilized soils.

• Geomechanics and Engineering
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• 제23권5호
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• pp.481-491
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• 2020

Piles installed in row(s) are used as an effective technique to improve the stability of soil slopes. The analysis of pile-stabilized slopes require a reliable prediction of lateral resistance offered by the piles. In this work, an analytical solution is developed to estimate the lateral resistance offered by the stabilizing piles in sand and c - 𝜙 soil slopes considering soil arching phenomenon. The soil arching in both horizontal direction (between the neighboring piles) and vertical direction (in the active wedge in front of the pile row) are studied and their effects are incorporated in the proposed model. The shape of soil arch is assumed to be circular and principal stress trajectories are defined separately for both modes of arching. Experimental and numerical studies found in literature were used to validate the proposed method. A detailed parametric analysis was performed to study the influence of pile diameter, center-to-center spacing, slope angle and angle of internal friction on the lateral pile resistance.