Investigation on cement-improved phyllite based on the vertical vibration compaction method

Jiang, Yingjun; Fan, Jiangtao; Yi, Yong; Tian, Tian; Yuan, Kejia

doi:10.1371/journal.pone.0247599

Cited by 8 publications

(3 citation statements)

References 28 publications

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“…Fig 1 illustrates the structure of the VVTE. The working parameters of the VVTE included a vibration frequency of 35 Hz, a nominal amplitude of 1.2 mm, and upper-and lower-system weights of 120 and 180 kg, respectively [17][18][19][20][21].…”

Section: Specimen Preparation Methodsmentioning

confidence: 99%

Deterioration characteristics of cement-improved loess under dry–wet and freeze–thaw cycles

Jiang

Sha

et al. 2021

PLoS ONE

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The effects of cement dosage, compaction coefficient, molding method (vertical vibration method and static pressure method), and dry–wet and freeze–thaw cycles on the mechanical strength of cement-improved loess (CIL) were studied to reveal its strength degradation law under dry–wet and freeze–thaw cycles. Results show that when using the vertical vibration molding method, the strength degradation effect of CIL can be improved by increasing the cement dosage and compaction coefficient; however, it is not obvious. Under the action of dry–wet cycle, damages, such as voids and cracks of CIL, develop continuously. Further, the strength deteriorates continuously and does not decrease after more than 15 dry–wet cycles. Therefore, the dry–wet cycle degradation system is selected by considering the most unfavorable conditions. In the process of freeze–thaw alternation, the pores and fissures of CIL develop and evolve continuously and the strength deteriorates continuously under the joint influence of water and low temperature. The strength tends to become stable after more than 12 freeze–thaw cycles. According to the safety principle, the deterioration coefficient of the freeze–thaw cycles is 0.3.

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Section: Specimen Preparation Methodsmentioning

confidence: 99%

Deterioration characteristics of cement-improved loess under dry–wet and freeze–thaw cycles

Jiang

Sha

et al. 2021

PLoS ONE

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“…The preliminary research and related studies have compared the VVCM with the heavy compaction method (HCM) and static compaction method (SCM), fully demonstrating that the VVCM moulding method has better field correlation than the HCM and SCM. Because of different compaction mechanisms, the mechanical strength of the VVCM-moulded specimens is also higher than those moulded by the HCM and SCM [ 30 , 31 , 32 ].…”

Section: Raw Materials and Test Plansmentioning

confidence: 99%

Research on Mechanical Properties and Influencing Factors of Cement-Graded Crushed Stone Using Vertical Vibration Compaction

et al. 2022

Self Cite

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To study the mechanical properties of cement-graded crushed stone for use in the transition sections of intercity railways, the growth laws governing unconfined compressive strength, splitting strength and resilience modulus of cement-graded crushed stone and their influencing factors were studied by the vertical vibration compaction method (VVCM). The strength growth equations of cement-graded crushed stone are proposed, and strength prediction equations are established. The research shows the unconfined compressive strength, splitting strength and resilience modulus of cement-graded crushed stone with a strong interlocked skeleton density type (VGM-30) are significantly enhanced to 20, 20 and 17% higher, respectively, than those of standard cement-graded crushed stone. The growth law of mechanical properties of cement-graded crushed stone is similar, with the fastest growth occurring before 14 days, and the rate decreasing after 28 days. The strength growth tended to be stable after 90 days, increasing with the increase in curing time, compaction coefficient and cement dosage. The correlation coefficients (R2) of the strength growth prediction models were found to be 0.99, 0.97, and 0.99, respectively. These values can be used to accurately predict the strength growth curve. This paper verifies the superiority of VGM-30 gradation through laboratory tests, providing a reference for gradation selection in the construction of intercity railway transition sections.

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“…The CBR of phyllite with 6% cement content is about twice that with 3% cement content, and when the cement content is greater than 3% it can meet the requirements of subgrade specifications. Jiang et al [15] found that for every 1% increase in cement content, the unconfined compressive strength of phyllite increased by at least 15%, and the modulus of resilience increased by at least 17%. When the cement content was 2%, the modulus of resilience of the subgrade was 64 MPa, which could meet the requirement of the "Class I Highway subgrade".…”

Section: Introductionmentioning

confidence: 99%

Synergistic Effects of Red Clay and Lime for Improving Phyllite Soil

Zhao,

Cheng

et al. 2023

Minerals

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Phyllite soil and red clay belong to the soils that negatively impact the engineering performance of railway subgrade and may cause subgrade bulges, uneven subgrade settlement, and other subgrade distresses. In order to make full use of these two soils, a collaborative improvement plan was proposed. A series of tests were conducted to analyze the synergistic effects of lime and red clay on the improvement of phyllite soil. The tests included the no loading swelling ratio, swelling pressure, consolidation, and direct shear tests. Additionally, scanning electron microscopy was used to investigate the role of lime and red clay in soil improvement. The test results show that a red clay ratio of 60% + lime content of 3% is the optimal composite improvement scheme. The scheme led to a 93% reduction in the no loading swelling ratio and an 88% reduction in swelling pressure. Additionally, cohesion, the internal friction angle, and the compression modulus increased by 345%, 73%, and 373%. Red clay and lime had weak synergistic improvement effects on the no loading swelling ratio, the swelling pressure, and the internal friction angle of phyllite soil, that is, the synergistic improvement effect of red clay and lime was less than the sum of the single improvement effect but greater than the single improvement effect. Red clay and lime had a strong synergistic improvement effect on the cohesion and the compression modulus of phyllite, that is, the synergistic improvement effect of red clay and lime was greater than the sum of the single improvement effect. The microstructure analysis test results show that red clay can fill the pores of phyllite soil and improve its immediate strength. Through hardening and cementation, lime can enhance the strength of phyllite soil as well as address the issue of the reduced engineering properties of phyllite soil and red clay when exposed to water. Red clay and lime promote each other’s reactions and have a synergistic improvement effect on phyllite soil.

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Investigation on cement-improved phyllite based on the vertical vibration compaction method

Cited by 8 publications

References 28 publications

Deterioration characteristics of cement-improved loess under dry–wet and freeze–thaw cycles

Deterioration characteristics of cement-improved loess under dry–wet and freeze–thaw cycles

Research on Mechanical Properties and Influencing Factors of Cement-Graded Crushed Stone Using Vertical Vibration Compaction

Synergistic Effects of Red Clay and Lime for Improving Phyllite Soil

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