Cement-Modified Loess Base for Intercity Railways: Mechanical Strength and Influencing Factors Based on the Vertical Vibration Compaction Method

Jiang, Yingjun; Li, Qilong; Yi, Yong; Yuan, Kejia; Deng, Changqing; Tian, Tian

doi:10.3390/ma13163643

Cited by 7 publications

(4 citation statements)

References 22 publications

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“…The compaction coefficient K of the prepared samples was controlled to be 0.93. The prepared samples were wrapped in plastic and stored in a sealed container that prevents evaporation for about 7 days before conducting tests to obtain uniform water content within samples [ 22 ].…”

Section: Methodsmentioning

confidence: 99%

“…The results show that the improvement effect of lime on loess increases with water content. Jiang et al [ 22 ] studied the influence of cement content, compaction coefficient and curing time on the mechanical strength index of cement-modified loess (CML) compacted by vertical vibration compaction (VVCM), and finally established a model to predict the growth law of strength characteristics of CML. With the general improvement of environmental protection awareness, new environmentally friendly improvement materials have been used in soil improvement [ 23 , 24 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

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Laboratory Experiments and Numerical Simulation Study of Composite-Material-Modified Loess Improving High-Speed Railway Subgrade

et al. 2022

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Construction of high-speed railway subgrade on loess soils in the Loess Plateau is risky because such soil is susceptible to differential settlements. Various soil-improvement methods have been used to enhance the mechanical properties of loess. Lime-ash soil and cement-lime soil are the most commonly used methods in the improvement of loess subgrade, while few studies have been found on loess subgrade improvement by using composite material consisting of traditional materials and new materials. A series of direct shear tests and unconfined compressive tests were conducted on the loess specimen with the addition of three kinds of composite materials: traditional material cement, new material polypropylene fiber and SCA-2 soil curing agent. The numerical simulation was conducted on loess subgrade in an actual engineering practice. The experimental results show that cement, polypropylene fiber and SCA-2 soil curing agent can effectively improve the shear strength and compressive strength of loess, and the influence degree is cement > fiber > curing agent. Additionally, based on the relative strength characteristics of the improved loess, an optimal improvement scheme for the composite-material-modified loess was obtained: 16% cement content + 0.5% fiber content + 4% curing agent content. The numerical simulation results revealed that the compressive strength index of the improved loess has a significant impact on the subgrade settlement, and the optimal improvement scheme obtained from comprehensive analysis can effectively improve the settlement of high-speed railway subgrade under vibration load.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Laboratory Experiments and Numerical Simulation Study of Composite-Material-Modified Loess Improving High-Speed Railway Subgrade

et al. 2022

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“…to control the compactness and stability of subgrade filling. At the same time, polymers, geotextiles and geogrids can be added to the subgrade fill to reduce the differential settlement deformation of the transition section [13][14][15][16][17][18] . These methods can have a significant effect on the differential settlement control of bridge-subgrade transition sections in collapsible loess areas.…”

Section: And Weiwei Wumentioning

confidence: 99%

Long-term monitoring and analysis of the longitudinal differential settlement of an expressway bridge–subgrade transition section in a loess area

Chao

et al. 2022

Sci Rep

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To solve the problem of "bridgehead bumping" in the transition section between the road and bridge of an expressway in a collapsible loess area, a lime–soil compaction pile composite foundation is used for the first time in the transition section between the road and bridge of an expressway in China; the loess subgrade is improved by adding lime, and the subgrade is arranged in a multilayer geogrid for the joint treatment of various engineering measures. At the same time, a new type of precision differential pressure settlement meter is used to monitor the long-term settlement of a bridge–subgrade transition section with a small settlement magnitude after the joint treatment, and the distribution characteristics and variation laws of the settlement along the longitudinal direction of the line are obtained. The results show that the effect is better and the differential settlement is smaller when using a lime–soil compaction pile composite foundation; lime improves the loess subgrade backfill, and the multilayer geogrid addresses the bridge–subgrade transition in the collapsible loess area. The differential settlement and settlement rate of the subgrade and abutment increase with increased monitoring time, and the differential settlement increases gradually, while the growth rate decreases gradually and finally tends to be stable. The differential settlement of the transition section is predicted and analysed by using a hyperbolic curve, exponential curve and their combination in a prediction model, and the prediction analysis shows that the combined prediction model has the best prediction effect. These research results can provide guidance and reference for the design and construction of subgrade structures similar to the wet transition section between roads and bridges.

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“…After having been compacted using VVCM and QSCM, the specimens were demolded and placed into a standard curing room with a temperature of (20 ± 2)°C and a humidity of 95%. According to the strength-growth equation of the CIL [26], the compressive strength at 28 days is 80% of the ultimate strength, and so 28 days has been taken as the curing age of the specimen in the erosion resistance test.…”

Section: Specimen Preparationmentioning

confidence: 99%

Influencing Factors and Prediction Model for the Antierosion Performance of Cement‐Improved Loess Compacted Using Different Compaction Methods

Yuan

Jiang

Cai

et al. 2021

Advances in Materials Science and Engineering

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To analyze the antierosion performance of cement-improved loess (CIL), several influencing factors have been investigated based on two different compaction methods, which include the quasi-static compaction method (QSCM) and the vertical vibration compaction method (VVCM). Then, a prediction model for the cumulative erosion mass loss (CEML) has been established. The effects of erosion on the strength deterioration of CIL were also studied. The results show that, compared with QSCM, specimens compacted using the VVCM have better antierosion performance. As the cement content and the compaction coefficient are increased by 1%, the antierosion performance is increased by 16% and 6.2%, respectively. The eroding time has a significant effect on the antierosion performance of CIL, and the CEML increases linearly with an increase in the eroding time. The compressive strength of CIL decreases significantly due to erosion, and based on the average deterioration degree of the specimens, the design criteria for strength of CIL are proposed, which can provide reference for the design of CIL.

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Cement-Modified Loess Base for Intercity Railways: Mechanical Strength and Influencing Factors Based on the Vertical Vibration Compaction Method

Cited by 7 publications

References 22 publications

Laboratory Experiments and Numerical Simulation Study of Composite-Material-Modified Loess Improving High-Speed Railway Subgrade

Laboratory Experiments and Numerical Simulation Study of Composite-Material-Modified Loess Improving High-Speed Railway Subgrade

Long-term monitoring and analysis of the longitudinal differential settlement of an expressway bridge–subgrade transition section in a loess area

Influencing Factors and Prediction Model for the Antierosion Performance of Cement‐Improved Loess Compacted Using Different Compaction Methods

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