Experimental Program of Indoor Model Research about Single Pile Negative Friction

2014 ◽  
Vol 501-504 ◽  
pp. 160-165
Author(s):  
Chang Liu Chen ◽  
Song Qi Wei ◽  
Shuai Hua Ye ◽  
Yan Liu
Keyword(s):  
Skin Friction ◽  
Pile Foundation ◽  
Scale Model ◽  
Experimental Program ◽  
Engineering Practice ◽  
Negative Skin Friction ◽  
Friction Resistance ◽  
Model Research ◽  
Reduced Scale ◽  
Selection Of

This article aims to study the influence of negative skin friction resistance of waterishlogged pile foundation, through indoor scale model test of pile foundation in the loess areas. The program involved in the model similar than design, the model groove design, the selection of test materials, the design of the ground soil, the layout of measuring points and the research of load method in the test. Through the experimental study on the reduced scale model, we can deepen the understanding of the action mechanism of negative skin friction resistance of the pile, which could guide the engineering practice and design.

scholarly journals PENGARUH DIAMETER TIANG TERHADAP TAHANAN GESEK TIANG DALAM TANAH LEMPUNG

2019 ◽  
Vol 1 (3) ◽  
pp. 219-224
Author(s):  
Andikanoza Pradiptiya ◽  
A’isyah Salimah
Keyword(s):  
Pile Foundation ◽  
Structural Damage ◽  
Tensile Load ◽  
Frictional Resistance ◽  
Test Method ◽  
Scale Model ◽  
Friction Resistance ◽  
Average Value ◽  
Constant Rate ◽  
Pile Model

AbstractSome buildings impose limits on the foundation displacement that occur with relatively small values so as not to cause structural damage. The test method used was to make a model test box as a testing medium by simulating the actual model into the form of a scale model. The study was conducted using a single pile foundation with reduced scale, made of concrete with a diameter of 0.02 m, 0.03 m, 0.04 m and the length of each pile was 0.4 m. The pile model was mounted by pressing into the clay that had been compacted in the test box and then given a tensile load which refers to ASTM D3689-07 procedure E (Constant Rate of Uplift Test). Mobilization of pile friction resistance at critical displacement determined the frictional resistance of the ultimate pile units. The test results showed that the greater the diameter of the pile, the frictional resistance of the ultimate pile units would increase. The increase in frictional resistance of the ultimate pile units showed an average value of around 17.1%.Keywords : Pile foundation, Pile diameter, Friction resistance.AbstrakMeningkatnya pembangunan hunian mengakibatkan naiknya permintaan akan batako, hal ini tentunya Beberapa konstruksi bangunan memberikan batasan kepada perpindahan tiang yang terjadi dengan nilai yang relatif kecil supaya tidak menyebabkan kerusakan struktur. Metode uji yang dipakai adalah membuat box uji model sebagai media pengujian, dengan mensimulasikan model yang sebenarnya ke dalam bentuk model skala. Penelitian dilakukan menggunakan model pondasi tiang tunggal penampang lingkaran lingkaran skala tereduksi yang terbuat dari beton dengan diameter 0,02 m, 0,03 m, 0,04 m dan panjang  masing-masing tiang adalah 0,4 m. Model tiang dipasang dengan cara ditekan pada tanah lempung yang sudah dipadatkan dalam box uji kemudian diberikan beban tarik yang mengacu pada ASTM D3689-07 prosedur E (Constant Rate of Uplift Test). Mobilisasi tahanan gesek tiang pada perpindahan tiang kritis menetukan tahanan gesek satuan ultimit. Hasil uji memperlihatkan bahwa semakin besar diameter tiang, tahanan gesek satuan ultimit tiang akan bertambah. Peningkatan tahanan gesek satuan ultimit tiang menunjukkan rata-rata sekitar 17,1 %.Kata kunci : Pondasi Tiang, Diameter Tiang, Tahanan Gesek Tiang.

Skin Friction Resistance of Ships

1957 ◽  
Vol 1 (03) ◽  
pp. 3-12
Author(s):  
F. H. Todd
Keyword(s):  
Skin Friction ◽  
Present Status ◽  
Comparative Studies ◽  
Scale Model ◽  
Small Scale ◽  
Model Data ◽  
Towing Tank ◽  
Friction Resistance ◽  
Small Scale Model

The International Towing Tank Conference (ITTC) is to hold its 8th meeting in Madrid in September of this year. One of the subjects to be discussed will be the perennial one of how to estimate the resistance of a ship from that measured on a small-scale model in a towing tank. The Skin Friction Committee of the Conference was charged at the last meeting in Scandinavia in 1954, with reviewing the available data and making recommendations to the Conference in Madrid which will, it is hoped, be universally acceptable. Such a decision would remove one of the principal difficulties experienced in the use of model data in comparative studies. It is believed that a review of the present status of our knowledge in this field may be of interest to the members of the Society at this time.

Study on Negative Skin Friction of Pile Groups Considering Coupled Effect of Surface Load and Soil Consolidation

2009 ◽  
Author(s):  
Gang-qiang Kong ◽  
Qing Yang ◽  
Mao-tian Luan
Keyword(s):  
Skin Friction ◽  
Influence Factors ◽  
Pile Group ◽  
Engineering Practice ◽  
Surface Load ◽  
Soil Consolidation ◽  
Test Results ◽  
Pile Groups ◽  
Negative Skin Friction ◽  
Group Effects

The study was performed based on an analysis of model test results of 3×3 pile group and confirmed the reliability and accuracy of determining negative skin friction (NSF) using numerical modeling of fluid-soild interaction. A 3D numerical model with surface load and soil consolidation was established using FLAC3D, which focused on the mechanism of NSF and its influence factors such as friction of pile-soil interface, spacing of pile and time of consolidation. The results obtained under different cases in an engineering practice were finally compared with measured and empirical data, showing that it is necessary to consider surface load and soil consolidation when dealing with NSF. The results also indicated the analysis with surface load and soil consolidation could simulate the developing process of NSF and produce a more accurate outcome — closer to measured data. The NSF increases rapidly at beginning and then slowly down, finally stabilized at a constant as soil consolidation progresses. Due to pile group effects, the piles at the centre had a smaller downdrag and settlement than those at corner or at edges; pile group effects became more obvious when pile spacing decreased.

The Improvement on the Determining Method of the Proper Pile Length in the Collapse Loess

2013 ◽  
Vol 353-356 ◽  
pp. 725-729
Author(s):  
Gen Sheng Zhao ◽  
Wei Wei ◽  
Huan Tao Zhou ◽  
Qi Zhang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Skin Friction ◽  
Element Model ◽  
The Self ◽  
Engineering Practice ◽  
Superposition Method ◽  
Practical Application ◽  
Friction Resistance ◽  
Pile Length

In Consideration of the nonlinear of the soil and the interface between pile and soil, the spatial axisymmetry finite element model is established. Based on the model, the paper offers the Superposition Method to calculate proper pile length in the self-weight collapse loess , and gets the following deduction: when the upper and lower parts of soils skin friction has the same regularity, added pile length L has nothing to do with the skin friction distribution, but is related to ultimate friction resistance. Practical application shows that the method is effective and can be referenced in engineering practice.

scholarly journals AN ANALYSIS OF SCALING METHODS FOR STRUCTURAL COMPONENTS IN THE CONTEXT OF SIZE EFFECTS AND NONLINEAR PHENOMENA

2020 ◽  
Vol 1 ◽  
pp. 797-806
Author(s):  
O. Altun ◽  
P. Wolniak ◽  
I. Mozgova ◽  
R. Lachmayer
Keyword(s):  
Size Effects ◽  
Scale Model ◽  
Nonlinear Phenomena ◽  
Component Size ◽  
Scaling Methods ◽  
System Properties ◽  
The Impact ◽  
Reduced Scale ◽  
Selection Of ◽  
Similitude Theory

AbstractSimilitude theory helps engineers to investigate system properties and behaviour with scaling methods. The application of such methods reduces the time for product development and production of prototypes. With increasing component size, the impact of size effects and nonlinear phenomena becomes more important in reduced scale model testing. The aim of this paper is to provide an overview of the scaling methods and their applicability with regard to size effects and nonlinear phenomena as well as a procedure to support the selection of a suitable method for the scaling task of structures.

Research of Indoor Reduced Scale Model Test for Negative Friction of Pile Group

2014 ◽  
Vol 501-504 ◽  
pp. 155-159
Author(s):  
Chang Liu Chen ◽  
Yan Liu ◽  
Shuai Hua Ye ◽  
Song Qi Wei
Keyword(s):  
Model Test ◽  
Pile Group ◽  
Scale Model ◽  
Measuring Point ◽  
Loess Area ◽  
Similarity Ratio ◽  
Negative Friction ◽  
Design And Practice ◽  
Reduced Scale ◽  
Selection Of

The target of this paper is to research the change law of the negative friction for after soaking. The negative friction of pile group is measured through the indoor reduced scale model test in loess area. The similarity ratio design, the groove design of the model, the selection of test materials, the design of the ground soil, the layout of measuring point and the research of load method are involved in this test. Through the study on the reduced scale model, it will have a deeper understanding to the mechanism of pile side negative frictional resistance.It also can guide the design and practice of other engineering.

Model Test on Negative Skin Friction for Super-Long Pile under Surcharge Load Considering Time Effect

2013 ◽  
Vol 470 ◽  
pp. 1105-1108
Author(s):  
Jian Wei Zhang ◽  
Zhi Long Wang ◽  
Dong Qin Qiao
Keyword(s):  
Skin Friction ◽  
Model Test ◽  
Pile Foundation ◽  
Great Influence ◽  
Relative Displacement ◽  
Time Effect ◽  
Engineering Practice ◽  
Foundation Engineering ◽  
Tip Resistance ◽  
Negative Friction

Super-long pile bridges and high-rise buildings are commonly used in the form of pile foundation. In the flood area, due mainly silt stratum, as well as the decline in groundwater mound pile under the conditions set out in the consolidation, there will be a negative pile skin friction and negative friction obvious time effect, which bearing capacity of the pile has a great influence. Current research on negative friction for super-long pile considering time effect is relatively little. In the model box, on the base of the super-long pile silt model test, set out in a pile mound under consolidation, soil testing flour gradually over time preloading consolidation settlement, pile-soil relative displacement, so as to arrive negative friction pile variation with time, tip resistance variation with time from the pile-axial force curve deduce the location of the neutral point and changes in circumstances, the pile foundation engineering practice has a certain significance.

scholarly journals Model test study of bending moment and negative skin friction for batter rock-socketed piles under surface load

2021 ◽  
Vol 283 ◽  
pp. 01039
Author(s):  
Guo Wei ◽  
Zhuang Daokun ◽  
Ren Yuxiao ◽  
Cui Wenxi ◽  
Yue Changxi ◽  
...  
Keyword(s):  
Skin Friction ◽  
Axial Force ◽  
Soil Depth ◽  
Bending Moment ◽  
Surface Load ◽  
Negative Skin Friction ◽  
Friction Resistance ◽  
Negative Friction ◽  
Inclined Angle ◽  
Consolidation Time

Batter rock-socketed piles (BRSP) foundation is one of common foundations, such as port engineering or cross-sea bridge, while there are few studies on negative skin friction for BRSP. A series of model tests are conducted to explore negative skin friction of BRSP which are embedded in thick soft clay. The effects of the inclined angle of piles and soil consolidation time to negative friction resistance and the bending moment of BRSP are analyzed. The test results show that: the development of negative friction and bending moment BRSP have pronounced time effect; the longer the consolidation time is, the slower the axial force and bending moment intensify. The ultimate pile shaft axial force and bending moment increases nonlinearly concerning the inclined angle of piles. And the “neutral point” position and peak point of bending moment is always located at 0.9~1.0 times soil depth.

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