Scale model test study on negative skin friction of piles considering the collapsibility of loess

Zhao, Zhuangfu; Ye, Shuaihua; Yan-peng, Zhu; Tao, Hui; Chen, Changliu

doi:10.1007/s11440-021-01254-1

Cited by 20 publications

(7 citation statements)

References 19 publications

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“…The single pile studied in this paper corresponds to the pile used in the tunnel section of the Heyi River Crossing Project in Quzhou City, Zhejiang Province, China. The pile length used in the project is 10 m and the pile diameter is 1 m. To simulate the in-situ pile in the model box and eliminate the scale effect 19 – 22 , a reduction factor of n = 30 was applied for the reduced scale test. The test device is made up of three parts: the model box, the loading system, and the image acquisition device.…”

Section: Lab Testsmentioning

confidence: 99%

Multi-scale study of load-bearing mechanism of uplift piles based on model tests and numerical simulations

Fang¹,

Lin

2023

Sci Rep

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The uplift pile is an anti-uplift measure in engineering widely used in practice. In order to study the mechanical parameters of the pile and the surrounding soil under the uplift load, a pile uplift model test and relevant numerical test were conducted. Image analysis technique was applied to the model test to investigate the soil displacements caused by pulling the pile. The load–displacement and pile axial force-lateral friction resistance relationships were investigated at three burial depths. Comparing the model test and numerical test results, it reveals that the pile primarily underwent four stages under the influence of uplift load: initial stage of loading, strain-hardening stage, peak of loading stage, and the strain-softening stage; the soil displacements around the pile exhibited inverted conical shape as the uplift load increases; and obvious soil arching effects could be observed near the ground surface. In addition, the development of force chains and major principal stresses indicated that the pile lateral frictional resistance first increased to its maximum value and then decreased sharply along the depth direction.

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Section: Lab Testsmentioning

confidence: 99%

Multi-scale study of load-bearing mechanism of uplift piles based on model tests and numerical simulations

Fang¹,

Lin

2023

Sci Rep

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“…Friction piles support the superstructure by friction between piles-soil, which greatly improves the foundation's bearing capacity, reduces the foundation's settlement and maintains the structure's stability [1,2]. Therefore, pile foundation is widely used in industrial and civil construction, highways, high-speed railways, ports and docks, large structures, urban municipal bridges and other projects [3,4].…”

Section: Introductionmentioning

confidence: 99%

Influence of Stratum Parameters on Bearing Characteristics of Friction Pile Reinforced by Compaction Grouting

Lv,

Wang,

Wang

et al. 2023

Advances in Transdisciplinary Engineering

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Pile-side grouting is the main method to enhance the bearing capacity of in-service pile foundation, the formation parameters have complicated influence on the grouting reinforcement effect. For the problem of inadequate bearing capacity of friction piles in service in alluvial river plains, the effect of the parameters of the complex strata of silty clay and fine sand on the bearing capacity of friction piles reinforced by extrusion grouting was investigated by model tests. When the thickness ratio of powdered clay and fine sand stratum changes from 1:3 to 3:1, the proportion of powdered clay in the stratum increases, and the bearing capacity of the pile foundation decreases by about 50∼100 N. The internal friction angle of fine sand is larger with the particle size increase, and the load transfer efficiency is higher, so the effect of pile side compaction grouting reinforcement is more pronounced. Meanwhile, the water content of powdered clay plays a negative role in the impact of pile foundation grouting reinforcement.

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“…Despite these prior studies, the special structure and water sensitivity of loess lead to the complex negative skin friction mechanism in pile foundations. It is necessary to analyze the impact of water immersion on negative skin friction through model tests [13].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Negative Skin Friction of Piles in Collapsible Loess

Chai

Chen

et al. 2023

Sustainability

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The collapsible loess is widely distributed in western China. The special structure and water sensitivity of loess lead to the complex negative skin friction mechanism in pile foundations. Previous studies mainly focused on the negative skin friction of pile foundations and treatment measures, such as casing and coating methods. However, few studies have focused on the influence of the negative skin friction on the settlement and bearing capacity of piles in collapsible loess, especially environmentally friendly methods that can reduce the negative skin friction. In this study, a series of non-immersion and immersion experiments was conducted to investigate the settlement, axial force, and side friction resistance of piles in loess soil under controlled conditions. The results showed that under the non-immersion condition, the settlement of model piles increased with the increasing pile top load. The axial force gradually decreased along the pile length for piles without casing. The axial force attenuation of the casing section of casing piles was almost negligible due to the isolating frictional resistance effect of casing. The settlement of each soil layer increased with the increase in immersion time, and the process was divided into an initial gradual stage, rapid drop stage, and later gradual stage. Both negative and positive skin friction increased with the increasing immersion time and pile top load, and there was a neutral point. The maximum axial force of piles without casing exceeded the peak load at the pile top. The presence of steel casing reduced the failure of pile foundation in collapsible loess. The research results of this paper provide theoretical support for the application of piles in loess areas.

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Scale model test study on negative skin friction of piles considering the collapsibility of loess

Cited by 20 publications

References 19 publications

Multi-scale study of load-bearing mechanism of uplift piles based on model tests and numerical simulations

Multi-scale study of load-bearing mechanism of uplift piles based on model tests and numerical simulations

Influence of Stratum Parameters on Bearing Characteristics of Friction Pile Reinforced by Compaction Grouting

Experimental Study on the Negative Skin Friction of Piles in Collapsible Loess

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