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Liu, Jun, Zhongwei Li, Guoliang Dai i Weiming Gong. "Field Measurement and Theoretical Analysis of Sidewall Roughness on Shaft Resistance of Rock-Socketed Piles". Journal of Marine Science and Engineering 11, nr 8 (19.08.2023): 1622. http://dx.doi.org/10.3390/jmse11081622.
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Sidewall roughness is a key factor influencing the shaft resistance of rock-socketed piles. Owing to the difficulties in onsite measuring and the inconsistency in quantitatively characterizing the roughness degree of sidewalls, existing approaches for estimating the shaft resistance of rock-socketed piles often cannot take this factor into account. Based on the measured surface curves of the 68 sockets in No. 6# and 7# group piles of the Chishi Bridge on the Ru-Chen Expressway in China, sidewall roughness is described by introducing the roughness factor (RF) based on the Horvath and Monash models, respectively, while a statistical analysis of the sidewall roughness in rock-socketed sections is also conducted. In addition, an analytical solution to the shaft resistance of rock-socketed piles with consideration of sidewall roughness and the relative settlement of the pile–rocks interface (∆s), is proposed and further compared with the field load tests. The results showed that: the RF obtained by the Horvath model is bigger than that obtained by the Monash model; the larger RF is, the bigger the mobilized shaft resistance; the analytical solution generally overestimates the mobilized shaft resistance of rock-socketed piles under the same ∆s, and the deviation is less than 15% if ∆s is larger than 3.00 mm. The Horvath model is recommended to quantitatively characterize the roughness degree of sidewalls for its good operability in practice.
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Alawneh, Ahmed Shlash, Abdallah I. Husein Malkawi i Husein Al-Deeky. "Tension tests on smooth and rough model piles in dry sand". Canadian Geotechnical Journal 36, nr 4 (22.11.1999): 746–53. http://dx.doi.org/10.1139/t98-104.
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In order to delineate the significant variables affecting the ultimate uplift shaft resistance of a pile in dry sand, a testing program comprising 64 pullout tests was conducted on open- and closed-ended rough and smooth model piles of two sizes (41 and 61 mm outside diameter). The model piles were installed in medium dense and dense sand to an embedded depth of 0.8 m using two methods of pile placement, static jacking and driving. A rigid steel box measuring 1.1 × 1.1 × 1.3 m was used as a sand container. The results obtained from this study indicated that pile placement method, initial sand condition, pile surface roughness, and pile end type are all significant variables (given in descending order) affecting the ultimate uplift shaft resistance of a single pile in dry sand. Overall, the closed-ended piles showed a 24% increase in shaft resistance compared with the open-ended piles and the average unit shaft resistance of the driven model pile was 1.33 times that of the jacked model pile in the dense sand condition and 1.52 times that of the jacked model pile in the medium dense sand condition. Depending on the test variables, the rough model piles tested in this study experienced a 12-54% increase in capacity compared with the smooth model piles. Also, the lateral earth pressure coefficient values for the rough model piles were greater than those for the smooth model piles. This suggests that part of the increase in capacity due to pile surface roughness is attributed to an increase in the radial effective stress during tensile loading.Key words: piles, shaft resistance, pile placement method, smooth pile, rough pile.
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Wang, Yan Qiang, Rui Gao i Ya Wu Zeng. "Model Test of Roughness’ Influence on Bearing Mechanism in Rock-Socketed Pile". Advanced Materials Research 243-249 (maj 2011): 3072–77. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.3072.
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The interface roughness between pile and rock in rock-socketed pile can influence its bearing mechanism largely. At present the numerical simulation, which simulates the interface roughness with changing the surface shape or interface friction coefficient, is used to study the interface roughness’ influence on pile’s bearing mechanism. It can reveal the pile bearing mechanism in some degree; however, there are some defects and limitations in simulation because of its assumptions and simplifications. Based on the pile foundation of Tian-xing-zhou Bridge, the model test is conducted to study the interface roughness’ influence on rock-socketed pile bearing mechanism. In the model test, the surface of model piles are made different ranging from smooth to rough, and the bed rock is simulated with mixture of sand and plaster, the rock-soil overlain the bed rock is simulated with silty sand, the pile is simulated with organic glass rod according to similarity principle respectively. The results show that load-settlement curves grow more gently, the ultimate bearing capacity is bigger, the proportion of point resistance is lower, and the shaft resistance is bigger which reaches more than 70% of total loading as the surface of pile is rougher. The conclusions are useful to deciding the length of pile foundation in Tian-xing-zhou Bridge.
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Subair, Aysar Hassan, i Ala Nasir Aljorany. "Shaft Resistance of Long (Flexible) Piles Considering Strength Degradation". Journal of Engineering 27, nr 3 (27.02.2021): 54–66. http://dx.doi.org/10.31026/j.eng.2021.03.04.
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Soil-structure frictional resistance is an important parameter in the design of many foundation systems. The soil-structure interface area is responsible for load transferring from the structure to the surrounding soil. The mobilized shaft resistance of axially loaded, long slender pile embedded in dense, dry sand is experimentally and numerically analyzed when subjected to pullout force. Experimental setup including an instrumented model pile while the finite element method is used as a numerical analysis tool. The hypoplasticity model is used to model the soil adjacent to and surrounding the pile by using ABAQUS FEA (6.17.1). The soil-structure interface behavior depends on many factors, but mainly on the interface soil's tendency to contract or dilate under shearing conditions. To investigate this tendency, three piles with different surface roughness and under different confining pressures are used. A dilation behavior is observed in the relation of the average shaft resistance with the axial displacement for piles with rough and medium roughness surfaces, while contraction behavior is noticed when shearing piles with smooth surfaces. A large shear strength degradation of about (10%) reduction in the shaft resistance is observed under low confining pressure compared to a lesser reduction value of about (2%) under high confining pressure. Good agreement is obtained between the experimental and the numerical results.
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Muszyński, Zbigniew, i Marek Wyjadłowski. "Assessment of surface parameters of VDW foundation piles using geodetic measurement techniques". Open Geosciences 12, nr 1 (3.08.2020): 547–67. http://dx.doi.org/10.1515/geo-2020-0042.
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AbstractThis article presents in situ research on the side surface of Vor der Wand (VDW) foundation piles using 3D laser scanning and close-range photogrammetry to assess the morphology of pile concrete surface. Contemporary analytical methods for estimation of the bearing capacity of the foundation pile surface require determination of the parameters of the concrete roughness and the model of the surface being formed, which corresponds to the pile technology used. Acquiring these data is difficult due to the formation of piles in the ground and their subsequent work as a structure buried in the ground. The VDW pile technology is one of the widespread technologies of foundation pile used in practice. These piles exhibit a specific configuration of the lateral surface, which is related to the simultaneous use of auger drilling and casing that rotates in opposite directions. Two geodetic techniques most often used to measure the geometry of buildings are terrestrial laser scanning and close-range photogrammetry. To empirically verify the suitability of these two techniques for describing the VDW pile surface parameters, a two-stage field study was performed. In the first stage, the measurements of concrete test surfaces were conducted. This surface was formed in a smooth formwork and its roughness parameters (in accordance with ISO 25178-2: 2012) were calculated and compared with the reference surface. In the second stage, measurements of the secant VDW sheet pile wall protecting the deep excavation were carried out. The roughness parameters of the pile surface were calculated for the selected areas in diverse geotechnical conditions. The original procedure for processing data (obtained using the above techniques) for assessment of roughness parameters of unique concrete surfaces was presented. The conducted research demonstrates that a pulse scanner has very limited usefulness for determination of roughness parameters for very smooth concrete surface; however, the photogrammetry techniques give acceptable results. In regard to the VDW pile surface, the results obtained from both measurement techniques give satisfactory consistency of the roughness parameters. The relative errors of calculated roughness parameters do not exceed 29% (average 12%). The proposed procedure may improve the accuracy of the assumed friction factor between pile surface and soil for assessment of the pile shaft bearing capacity for various pile technologies and soil conditions.
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Tovar-Valencia, Ruben D., Ayda Galvis-Castro, Rodrigo Salgado i Monica Prezzi. "Effect of Surface Roughness on the Shaft Resistance of Displacement Model Piles in Sand". Journal of Geotechnical and Geoenvironmental Engineering 144, nr 3 (marzec 2018): 04017120. http://dx.doi.org/10.1061/(asce)gt.1943-5606.0001828.
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Bouafia, Ali. "Étude expérimentale du chargement latéral cyclique répété des pieux isolés dans le sable en centrifugeuse". Canadian Geotechnical Journal 31, nr 5 (1.10.1994): 740–48. http://dx.doi.org/10.1139/t94-085.
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This paper presents the results of repetitive cyclic lateral loading test carried out in a centrifuge on two reduced models of single piles instrumented with strain gauges. The pile models, their instrumentation, the experimental setup, and the construction of the soil model are described. Effects of the pile surface roughness and of sand density on the pile behaviour are studied. The latest part of this paper deals with the construction of P–Y lateral reaction curves and the variation of the horizontal subgrade modulus with the number of cycles. Key words : pile, centrifuge, sand, cyclic loading, density, roughness.
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Khari, Mahdy, Khairul Anuar Kassim i Azlan Adnan. "Development ofp-yCurves of Laterally Loaded Piles in Cohesionless Soil". Scientific World Journal 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/917174.
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The research on damages of structures that are supported by deep foundations has been quite intensive in the past decade. Kinematic interaction in soil-pile interaction is evaluated based on thep-ycurve approach. Existingp-ycurves have considered the effects of relative density on soil-pile interaction in sandy soil. The roughness influence of the surface wall pile onp-ycurves has not been emphasized sufficiently. The presented study was performed to develop a series ofp-ycurves for single piles through comprehensive experimental investigations. Modification factors were studied, namely, the effects of relative density and roughness of the wall surface of pile. The model tests were subjected to lateral load in Johor Bahru sand. The newp-ycurves were evaluated based on the experimental data and were compared to the existingp-ycurves. The soil-pile reaction for various relative density (from 30% to 75%) was increased in the range of 40–95% for a smooth pile at a small displacement and 90% at a large displacement. For rough pile, the ratio of dense to loose relative density soil-pile reaction was from 2.0 to 3.0 at a small to large displacement. Direct comparison of the developedp-ycurve shows significant differences in the magnitude and shapes with the existing load-transfer curves. Good comparison with the experimental and design studies demonstrates the multidisciplinary applications of the present method.
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GALLAS, JASON A. C., i STEFAN SOKOLOWSKI. "GRAIN NON-SPHERICITY EFFECTS ON THE ANGLE OF REPOSE OF GRANULAR MATERIAL". International Journal of Modern Physics B 07, nr 09n10 (20.04.1993): 2037–46. http://dx.doi.org/10.1142/s0217979293002754.
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We use a site-site model to describe non-sphericity of particles composing a granular media. Specific effects of grain non-sphericity 011 the angle of repose are investigated. We report evidence indicating the possible existence of a shape-roughness threshold for grains: below it angles of repose are essentially the same as those obtained for spherical grains; above it there are pronounced changes 011 the angle of repose and it is possible to find rather large piles of grains.
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Aksoy, Huseyin Suha, Nichirvan Ramadhan Taher, Aykut Ozpolat, Mesut Gör i Omer Muhammad Edan. "An Experimental Study on Estimation of the Lateral Earth Pressure Coefficient (K) from Shaft Friction Resistance of Model Piles under Axial Load". Applied Sciences 13, nr 16 (17.08.2023): 9355. http://dx.doi.org/10.3390/app13169355.
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Estimating a pile shaft’s frictional capacity is challenging and has been a controversial subject among researchers. In this study, the shaft friction resistance of non-displacement (pre-installed) model piles under axial load was investigated. Four different model piles were used, including steel, timber, and two composite piles (FRP and PVC filled with concrete). The angle of interface friction (δ) between test sand, and pile materials was determined using an interface shear test (IST) at four relative densities. Axial pile load experiments were implemented in a soil tank and piles were embedded into loose to very dense sand. Model pile load tests were performed in such a way that there was no end (point) bearing capacity (only friction was generated), and lateral friction resistance between the pile material and the soil along the pile shaft formed the complete bearing capacity of the model pile. According to experimental results, it was observed that, with increasing sand relative density and surface roughness of the pile material, the shaft friction resistance of the model pile increases. A back-calculation analysis was also performed to find the values of lateral earth pressure coefficient (K) using Burland’s (1973) equation with the help of measured shaft friction capacity of the model pile load test. By performing multivariate regression analysis, an equation was obtained between the back-calculated lateral earth pressure coefficient (K) and other parameters. The obtained equation was used to calculate the K values given in other studies in the literature. It was determined that the obtained equation was in good agreement with the data in other studies. This equation can be beneficial in practice and can be advantageous for further study in the future.
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Griffiths, D. V. "Numerical studies of soil–structure interaction using a simple interface model". Canadian Geotechnical Journal 25, nr 1 (1.02.1988): 158–62. http://dx.doi.org/10.1139/t88-016.
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The effect of interface roughness in problems of soil–structure interaction is demonstrated using a simple finite element interface model. Three examples of geotechnical interest are presented to demonstrate the approach, and comparisons are made with closed-form solutions where available. Both rough and smooth extremes of interface behaviour are analysed. The smooth interface modelling is performed without the use of specialized elements, and involves uncoupling and rotation of freedoms parallel to the proposed interface direction. It is suggested that, in view of the uncertainties often associated with interface properties, a rational approach for engineering purposes is to obtain solutions for the perfectly rough and perfectly smooth cases leading to upper and lower bounds on the full range of interface behaviour. Key words: finite elements, interfaces, soil–structure interaction, foundations, lateral loads, culverts, piles.
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Xu, Hong-Fa, Ji-Xiang Zhang, Xin Liu, Han-Sheng Geng, Ke-Liang Li i Yin-Hao Yang. "Analytical Model and Back-Analysis for Pile-Soil System Behavior under Axial Loading". Mathematical Problems in Engineering 2020 (19.03.2020): 1–15. http://dx.doi.org/10.1155/2020/1369348.
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The interaction mechanism between piles and soils is very complicated. The load transfer function is generally nonlinear and is affected by factors such as pile side roughness, soil characteristics, section depth, and displacement. Therefore, it is difficult to solve the pile-soil system based on load transfer function. This paper presents a new method to study the soil-pile interaction problem with respect to axial loads. First, the shapes of the axial force-displacement curves at different depths and the displacement distribution curves along pile axis at different pile-top displacements were analyzed. A simple exponential function was taken as relationship model to express the relationship curves between two distribution functions of axial force and displacement along pile shaft obtained by using the geometric drawing method. Second, a new analytical model of the pile-soil system was established based on the basic differential equations for pile-soil load transfer theory and the relationship model and was used to derive the mathematical expressions on the distribution functions of the axial force, the lateral friction, and the displacement along pile shaft and the load transfer function of pile-side. We wrote the MATLAB program for the analytical model to analyze the influence laws of the parameters u and m on the pile-soil system characteristics. Third, the back-analysis method and steps of the pile-soil system characteristics were proposed according to the analytical model. The back-analysis results were in good agreement with the experimental results for the examples. The analysis model provides an effective way for the accurate design of piles under axial loading.
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Baca, Michal, i Jaroslaw Rybak. "First results of pipe pile static load test in small laboratory scale". MATEC Web of Conferences 251 (2018): 04038. http://dx.doi.org/10.1051/matecconf/201825104038.
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Presented laboratory testing program of tubular steel piles is a part of a bigger research program which contained static load tests in full scale and numerical simulations of conducted research. The main goal of the research is to compare static load tests with different working conditions of a shaft. The presented small scale model tests are the last part of the research. The paper contains the testing methodology description and first results of model pile axial loading. The static load tests in a small laboratory scale were conducted in a container filled with uniformly compacted medium sand (MSa). The first results of the investigation are presented in this paper, with the comparison of two pile capacities obtained for different roughness of the pile shaft (skin friction). The results are presented as load-displacement curves obtained by means of the Brinch-Hansen 80% method.
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Stelzer, D., i O. B. Andersland. "Creep Parameters for Pile Settlement Equations". Journal of Energy Resources Technology 111, nr 4 (1.12.1989): 258–63. http://dx.doi.org/10.1115/1.3231434.
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Friction pile settlement in frozen ground is tyically predicted on the basis of a creep equation relating shear stresses at the soil/pile interface to pile displacement rates. Creep parameters are used to characterize soil type, soil/ice structure, temperature, and loading conditions. Experimental tests involving model steel piles embedded in frozen sand provided data showing that change in a given test variable can alter the numerical value for some of the creep parameters. The test variables included static, incremental, and dynamic loading; pile surface roughness; soil ice content; and sand particle size. Changes observed included the apparent effect on creep rate when a small dynamic load was superimposed on the static load. A tabulation of observed creep parameter changes is included.
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Diyaljee, Vishnu. "Discussion of “Effect of Surface Roughness on the Shaft Resistance of Displacement Model Piles in Sand” by Ruben D. Tovar-Valencia, Ayda Galvis-Castro, Rodrigo Salgado, and Monica Prezzi". Journal of Geotechnical and Geoenvironmental Engineering 145, nr 4 (kwiecień 2019): 07019001. http://dx.doi.org/10.1061/(asce)gt.1943-5606.0002033.
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Tovar-Valencia, Ruben D., Ayda Galvis-Castro, Rodrigo Salgado i Monica Prezzi. "Closure to “Effect of Surface Roughness on the Shaft Resistance of Displacement Model Piles in Sand” by Ruben D. Tovar-Valencia, Ayda Galvis-Castro, Rodrigo Salgado, and Monica Prezzi". Journal of Geotechnical and Geoenvironmental Engineering 145, nr 4 (kwiecień 2019): 07019002. http://dx.doi.org/10.1061/(asce)gt.1943-5606.0002034.
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Wang, Jiang Nan, Shi Fang Tang i Chun Ma. "Numerical Simulation for Pile Group in Water Flume of 2-D Tidal Flow". Advanced Materials Research 779-780 (wrzesień 2013): 1171–75. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.1171.
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In order to study the influence on pile foundation in the numerical Simulation of 2-D tidal flow, the governing equations for numerical model of 2-D tidal flow with pile foundation have been induced, and the numerical water flume of 2-D tidal flow for pile foundation has been built. And then, with an adjusted friction coefficient and an additional roughness coefficient of the pile foundation from some physical model tests, the tidal flow field has been simulated, which was about a piled wharf of the first phase project in Yangshan deep-water Port. It indicated that the results from this numerical simulation were very close to some from water flume tests in laboratory. So some applied foundation and operational methods about the two tidal flow simulation technologies for some pile foundation have been provided.
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Prakash Arul Jose, J., P. Rajesh Prasanna i Fleming Prakash. "Technical performance of basalt fiber reinforced polymer BFRP confined RC driven piles new construction methodology". International Journal of Engineering & Technology 7, nr 3 (4.08.2018): 1685. http://dx.doi.org/10.14419/ijet.v7i3.12628.
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Pile foundations are often necessary to support large structures when the surface soil conditions are not strong enough to support the structure with shallow foundations. Pile foundation can be founded in dense sand layers at deeper, and also provide additional frictional support along their length to resist vertical loads. Load carrying capacity of Basalt FRP confined and unconfined piles were found out using the dynamic formulae and pile load test. Safe load carrying capacity of piles determined from piles load test was slightly higher than the dynamic formulae. The experimental result also shows that surface roughness of specimen is significantly changes the interface friction angle. The shear strength at the interface increases with the increase in surface roughness of the specimens.
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Boyarintsev, Andrey, Timur Sukhov i Elizaveta Tumashevskaia. "Change in surface roughness of composite piles when pressing into the ground". E3S Web of Conferences 371 (2023): 02018. http://dx.doi.org/10.1051/e3sconf/202337102018.
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The bearing capacity of piles on the ground is one of the main characteristics of pile foundations, which is responsible for its interaction with the ground. This characteristic depends on many factors: the granulometric composition of the soil, its moisture content, con-sistency, texture, as well as the type and properties of the pile material. One of the main charac-teristics of the pile material is its surface roughness. In many studies, the dependence of the angle of friction of the soil against the material of the pile on the value of the roughness of its surface was noted. At the same time, all studies focused exclusively on the dependence of the angle of friction on the roughness, not paying attention to the possibility of its variability in the process of driving the pile into the ground. This goal was set in the framework of this study. Using a standard single-plane cutter, the passage of a composite pile at a distance of 0.5m was simulated at a depth of 10 m. Before and after the test, the surface roughness parameters were measured using the Seitronic PSh8-1 SS device. The results showed that after the test, the roughness of the fiberglass plate made on the basis of polyester resin by the pultrusion method decreased by 44.4%.
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M.A, Nassar. "IMPROVEMENT OF THE HYDRAULIC JUMP FEATURES USING INCOMPLETE CIRCULAR PILES". Engineering Heritage Journal 4, nr 1 (11.06.2020): 19–22. http://dx.doi.org/10.26480/gwk.01.2020.19.22.
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The roughness elements are efficient tools to control the features of the hydraulic jump in the rectangular stilling basins. The present study suggests the use of modified elements to control the features of the free jump. The proposed tool is an incomplete circular pile. The use of piles in a one row with the different setup has been investigated. The measurements showed that the case of piles with the comparative summation areas A/∆=6.72 and the comparative distances between piles X/H1 =0.0 reduced the comparative height and length of the free jump by 11% and 24.6%, respectively. The paper detected the necessary helpful statistical formulas for the phenomenon.
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Wang, You-Bao, Chunfeng Zhao i Yue Wu. "Study on the Effects of Grouting and Roughness on the Shear Behavior of Cohesive Soil–Concrete Interfaces". Materials 13, nr 14 (8.07.2020): 3043. http://dx.doi.org/10.3390/ma13143043.
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Grouted soil–concrete interfaces exist in bored piles with post-grouting in pile tip or sides and they have a substantial influence on pile skin friction. To study the effect of grouting volume on the shearing characteristics of the interface between cohesive soil and concrete piles with different roughness, grouting equipment and a direct shear apparatus were combined to carry out a total of 48 groups of direct shear tests on cohesive soil–concrete interfaces incorporating the grouting process. The test results showed that the shear behavior of the grouted cohesive soil–concrete interface was improved mainly because increasing the grouting volume and roughness increased the interfacial apparent cohesion. In contrast, increasing the grouting volume and roughness had no obvious increasing effects on the interfacial friction angle. Interfacial grouting contributed to the transition in the grouted cohesive soil from shrinkage to dilation: as the grouting volume increased, the shrinkage became weaker and the dilation became more obvious. The shear band exhibited a parabolic distribution rather than a uniform distribution along the shearing direction and that the shear band thickness was greater in the shearing direction, and it will become thicker with increasing grouting volume or roughness. The analysis can help to understand the shear characteristics of soil–pile interface in studying the vertical bearing properties of pile with post-grouting in tip or sides.
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El Naggar, M. Hesham, i Jin Qi Wei. "Uplift behaviour of tapered piles established from model tests". Canadian Geotechnical Journal 37, nr 1 (1.02.2000): 56–74. http://dx.doi.org/10.1139/t99-090.
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Tapered piles have a substantial advantage with regard to their load-carrying capacity in the downward frictional mode. The uplift performance of tapered piles, however, has not been fully understood. This paper describes the results of an experimental investigation into the characteristics of the uplift performance of tapered piles. Three instrumented steel piles with different degrees of taper were installed in cohesionless soil and subjected to compressive and tensile load tests. The soil was contained in a steel soil chamber and pressurized using an air bladder to facilitate modelling the confining pressures pertinent to larger embedment depths. The results of this study indicated that the pile axial uplift capacity increased with an increase in the confining pressure for all piles examined in this study. The ratios of uplift to compressive load for tapered piles were less than those for straight piles of the same length and average embedded diameter. The uplift capacity of tapered piles was found to be comparable to that of straight-sided wall piles at higher confining pressure values, suggesting that the performance of actual tapered piles (with greater length) would be comparable to that of straight-sided wall piles. Also, the results indicated that residual stresses developed during the compressive loading phase and their effect were more significant on the initial uplift capacity of piles, and this effect was more pronounced for tapered piles in medium-dense sand.Key words: tapered piles, uplift, axial response, load transfer, experimental modelling.
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El Naggar, M. Hesham, i Jin Qi Wei. "Axial capacity of tapered piles established from model tests". Canadian Geotechnical Journal 36, nr 6 (1.12.1999): 1185–94. http://dx.doi.org/10.1139/t99-076.
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Tapered piles represent a more efficient distribution of pile material than uniform cross section piles in several respects. An extensive experimental research program was conducted to study the efficiency of tapered piles compared with piles of uniform cross section with the same material input. Three instrumented model steel piles with different degrees of taper were used in this program. The piles were tested in a large-scale laboratory setup under compressive and tensile loads. The pile head load and displacement and the strain along the piles were measured simultaneously. The objectives of the present paper were twofold: to examine the validity of the experimental results, and to use the unit load transfer curves established from the experimental results to predict the bearing capacity of prototype tapered piles. The shaft resistance for straight-sided wall piles established from the experimental results compared well with the theoretical predictions using the standard design procedure. The beneficial effect of pile taper was significant up to a depth of 20 pile diameters. The negative effect of the pile taper on the uplift capacity diminished quickly with depth and hence the performance of actual tapered piles (with greater length) would be comparable to that of straight-sided wall piles.
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Seidel, J. P., i B. Collingwood. "A new socket roughness factor for prediction of rock socket shaft resistance". Canadian Geotechnical Journal 38, nr 1 (1.02.2001): 138–53. http://dx.doi.org/10.1139/t00-083.
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Prediction of rock socket shaft resistance is a complex problem. Conventional methods for predicting the peak shaft resistance are typically empirically related to unconfined compressive strength through the results of pile load tests. It is shown by reference to international pile socket databases that the degree of confidence which can be applied to these empirical methods is relatively low. Research at Monash University has been directed at understanding and then modelling the complex mechanisms of shear transfer at the interface between the socketed piles and the surrounding rock. Important factors that affect the strength of pile sockets have been identified in laboratory and numerical studies. With a knowledge of the effect of these factors, the reasons for the large scatter around traditional empirical correlations can be deduced. A computer program called ROCKET has been developed which encompasses all aspects of the Monash University rock socket research. This program has been used to develop design charts for rock-socketed piles based on unconfined compressive strength and a nondimensional factor which has been designated the shaft resistance coefficient (SRC). Implementation of the SRC method in design requires an estimate of the likely socket roughness to be made. Very few researchers or practitioners have measured socket roughness, so there is little available guidance in selection of appropriate values. Although many socket load tests are described in the technical literature, the physical parameter which is regularly missing is the socket roughness. With a knowledge of the shaft resistance, and an estimate of all other relevant parameters, the authors have been able to back-calculate the apparent socket roughness using the SRC method. Based on the back-calculated roughness data, socket roughness guidelines for use in analysis and design of rock sockets have been proposed. Using these roughness guidelines, it is shown that the SRC method is able to predict the scatter observed in previously published international load test databases.Key words: rock socket, drilled shaft, shaft resistance, roughness, shaft resistance coefficient.
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Parameswaran, V. R. "Adfreezing strength of ice to model piles". Canadian Geotechnical Journal 24, nr 3 (1.08.1987): 446–52. http://dx.doi.org/10.1139/t87-055.
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Results of tests to determine the adfreezing strength of freshwater ice to piles having different surface characteristics show that adfreeze strength increases with increase in the rate of displacement and loading of the pile. Surface coatings such as creosote on wood piles and paint and silicone sealer on metallic piles drastically decrease the adfreezing strength of ice. Key words: adfreezing strength, displacement rate, ice, loading rate, model piles, surface coating.
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Lu, Yi, Hossam Abuel-Naga, Hussein A. Shaia i Zhi Shang. "Preliminary Study on the Behaviour of Fibre-Reinforced Polymer Piles in Sandy Soils". Buildings 12, nr 8 (1.08.2022): 1144. http://dx.doi.org/10.3390/buildings12081144.
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Fibre-reinforced polymer (FRP) is a type of composite material used to provide resistance to corrosion when incorporated into piles. However, there is a gap in knowledge in terms of the behaviour of FRP piles under axial or lateral loading in soils. Thus, the aim of this experimental study is to assess the factors that influence the behaviour of FRPs under axial and lateral load in sandy soil. CFRP (carbon-fibre-reinforced polymer) and GFRP (glass-fibre-reinforced polymer) piles were tested in this experiment based on a special pressure chamber. The results show that the surface roughness (Rt), confined pressure (σc), and relative density (Dr) determined the shearing resistance of the soils and subsequently affected the bearing capacity of the FRP piles under an axial load. The flexural stiffness of the FRP piles was determined by the FRP type, pile dimeter, and aging in the environment, which were affected under the lateral load. In addition, an alkaline environment was more aggressive to the FRP piles than those aged in an acidic environment. The numerical modelling results show that the sand types, in terms of the dilation angle and Young’s modulus, also had a great influence on the behaviour. This feature should be considered more carefully in future studies.
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Bisi, C., G. Chiaselotti i P. A. Oliverio. "Sand Piles Models of Signed Partitions with Piles". ISRN Combinatorics 2013 (13.01.2013): 1–7. http://dx.doi.org/10.1155/2013/615703.
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Let be nonnegative integers. In this paper we study the basic properties of a discrete dynamical model of signed integer partitions that we denote by . A generic element of this model is a signed integer partition with exactly all distinct nonzero parts, whose maximum positive summand is not exceeding and whose minimum negative summand is not less than . In particular, we determine the covering relations, the rank function, and the parallel convergence time from the bottom to the top of by using an abstract Sand Piles Model with three evolution rules. The lattice was introduced by the first two authors in order to study some combinatorial extremal sum problems.
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Zhussupbekov, A., J. S. Dhanya, A. Issakulov, A. Omarov, S. Iskakov i D. Mukhanov. "Model and field tests of drilled displacement system piles". E3S Web of Conferences 410 (2023): 03024. http://dx.doi.org/10.1051/e3sconf/202341003024.
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Drilled Displacement System (DDS) and Continuous Flight Auger (CFA) piles are two popular techniques used for building pile foundations that offer advantages over traditional pile systems, including improved load-carrying capacity, reduced installation time, and less spoil generation. This article presents laboratory-scaled model tests conducted on model piles installed using the Drilled Displacement System (DDS) and Continuous Flight Auger (CFA) technologies on a test tank setup filled with soil. Model piles considering a scaling factor of 1/20 with a diameter of 20 mm and a length of 300 mm were adopted for the study. Static loading is applied to the model piles and the corresponding displacements are measured during each loading phase. The results of the analysis were compared for load-settlement curves and ultimate bearing capacity estimates for both DDS and CFA piles. Based on the study, the DDS piles were observed to perform well in terms of load-carrying capacity compared to the CFA piles. Further, full-scale field tests under static load conditions were carried out on DDS-drilled piles of diameter 400 mm and length 6 m. The load-settlement response from the field test shows good agreement with the model tests. Overall, the results of the study provide valuable insights into the behavior and performance of DDS piles that can be used to optimize their design and installation in different soil types.
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Yang, Qing Guang, Ya Hui Wang, Feng Liu i Jie Liu. "Model Test Research on Mechanism of Close-Ended Variable Section Pipe Pile". Applied Mechanics and Materials 638-640 (wrzesień 2014): 480–84. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.480.
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Base on indoor model experiments of two constant section pipe piles and three variable section pipe piles performed in foundation pit,the load transfer mechanism of two kinds of close-ended pipe piles are studied by comparing load-settlement curves,shaft load distribution behaviors,skin resistance and resistance on pile end.Results show bearing capacity of variable section pipe piles is bigger than constant section pipe piles when settlements on pile top are equal.The bearing vertical capacity, unit volume bearing vertical capacity and availability of material of pipe pile will increase with improvement of average diameter and variable section ratio of variable section pipe piles.To variable section pipe pile, shaft load distribution suffered a sudden drop on position of variable section and shaft load distribution of small diameter pipe piles decrease quickly than constant section pipe piles.Resistance on pile end of variable section pipe piles are bigger than constant section pipe piles and resistance, ratio of resistance on pile end to bearing capacity of variable section pipe piles will increase with improvement of average diameter of variable section pipe pile. Action point of max skin resistance of variable section pipe piles are closer to pile top than constant section pipe piles .Max skin resistance will increase with decline with ratio of variable section pipe pile.If settlements on pile top are equal,force of skin resistance of variable section pipe piles are bigger than constant section pipe piles when the average diameters are same.
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Gutiérrez-Ch, J. G., S. Senent, S. Melentijevic i R. Jimenez. "A DEM-Based Factor to Design Rock-Socketed Piles Considering Socket Roughness". Rock Mechanics and Rock Engineering 54, nr 7 (10.01.2021): 3409–21. http://dx.doi.org/10.1007/s00603-020-02347-1.
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Gathimba, Naftary, Yasuo Kitane, Takeshi Yoshida i Yoshito Itoh. "Surface roughness characteristics of corroded steel pipe piles exposed to marine environment". Construction and Building Materials 203 (kwiecień 2019): 267–81. http://dx.doi.org/10.1016/j.conbuildmat.2019.01.092.
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Lei, Wen Jie, Yin Gren Zheng i Ya Kun Song. "Reinforcement Mechanism of the Deep Buried Piles by Large Scaled Model Tests". Advanced Materials Research 108-111 (maj 2010): 724–29. http://dx.doi.org/10.4028/www.scientific.net/amr.108-111.724.
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Series of large scaled model test has been carried out to examine the reinforcement mechanism of deep buried piles. Testing tools including rigid load cells, the earth pressure cells and data collecting systems are employed to measure the anti-thrust received by deep buried piles and the slope thrust of the slope on piles top. On the basis of the variation process of measured data, the time and the location of slide surface in the slope is determined, and the maximal anti-sliding force upward to the piles top could be gained by the data of earth pressure cells. Then the failure form process is analyzed with the anti-sliding length of the piles changed. The relationship between the sliding force received by the piles and that supplied by the slope on piles top is analyzed to supply scientific demonstration for the design method of slope reinforced by the deeply buried piles.
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Wang, Cheng Hua, Cheng Lin Zhang, Gan Wang i Juan Su. "The Technique for Simulation of Broken Defects in Model Pile Tests". Advanced Materials Research 790 (wrzesień 2013): 264–68. http://dx.doi.org/10.4028/www.scientific.net/amr.790.264.
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When carrying on laboratory experimental studies on broken piles, the test results depend on the technique used in simulating the model piles. Based on laboratory model tests, a complete set of making process of broken piles used in the study of the working behavior and mechanism of broken piles was presented in detail. The techniques include the pore-forming process and the simulation of the broken defects. The load vs. settlement curves for the vertically loaded broken piles obtained through the model pile tests were adopted and demonstrated the feasibility of the production process.
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Bak, Jongho, Byung-hyun Choi, Junwon Lee, Jonghwan Bae, Kicheol Lee i Dongwook Kim. "Behaviour of Single and Group Helical Piles in Sands from Model Experiments". MATEC Web of Conferences 278 (2019): 03007. http://dx.doi.org/10.1051/matecconf/201927803007.
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Mainly used foundations of oil sand plants are drilled shafts or driven piles. As environmental regulations become increasingly strict, complete removal of the foundation is becoming more important during the step of plant dismantling. However, it is difficult to remove completely drilled shafts or driven piles which are deeply installed to obtain more bearing capacity. Helical piles can be easily removed and recycled after use. This study analyses the behaviour of single and group helical piles in sands. For single helical piles, pile load tests of helical piles were conducted varying helix spacing, rotation speed and weight of axial loading during pile installation. The single pile tests determined the optimal helix spacing, rotation speed, weight of axial loading during pile installation. And then, pile load test of group helical piles was performed varying pile spacing from the centre place of upper connector based on the optimal installation conditions.
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Chan, Derek L. H., Róisín M. Buckley, Tingfa Liu i Richard J. Jardine. "Laboratory investigation of interface shearing in chalk". E3S Web of Conferences 92 (2019): 13009. http://dx.doi.org/10.1051/e3sconf/20199213009.
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Chalk, a soft fine-grained Cretaceous limestone, is encountered across northern Europe where recent offshore windfarm, oil, gas and onshore developments have called for better foundation design methods, particularly for driven piles whose shaft capacities are controlled by an effective stress Coulomb interface failure criterion. Interface type and roughness is known to affect both interface friction angles, δ′ and the magnitude of dilation required for shaft failure to develop. Site-specific interface ring-shear tests are recommended for offshore pile design in sands and clays to account for driven pile shaft materials, roughnesses and shear displacements. However, few such tests have been reported for chalks and it is also unclear whether δ′ angle changes contribute to the striking axial capacity increases, or set-up, noted over time with piles driven in chalk. This paper describes an interface shear study on low-to-medium density chalk from the St. Nicholas-at-Wade research test site in Kent, UK, where extensive field driven pile studies have been conducted [1, 2]. Direct shear and Bishop ring shear apparatus were employed to investigate the influences of interface material and surface roughness, as well as ageing under constant normal effective stresses (σn'). It is shown that the high relative roughness of the interface compared to the chalk grain size results in the ultimate interface shearing angles falling close to the chalk-chalk shearing resistance angles. The δ′ angles also increased by up to 5° over 38 days of ageing.
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Manandhar, Suman, Noriyuki Yasufuku, Kiyoshi Omine i Taizo Kobayashi. "Response of tapered piles in cohesionless soil based on model tests". Journal of Nepal Geological Society 40 (1.12.2010): 85–92. http://dx.doi.org/10.3126/jngs.v40i0.23613.
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This paper describes model tests of different types of tapered piles in cohesionless soils. Chromium plated three steel piles, one straight and two taper-shaped piles of same length and pile tip diameters have been executed for pile loading test in a downward frictional mode. Two different types of model grounds have been prepared for the test. Relative densities of 80 % and 60 % have been modeled to penetrate piles in two different types of sands to observe the effectiveness of skin frictions of different types of piles. The response of tapered piles has shown that the skin friction has increased with increasing the tapering angle at normalized settlement ratio of 0.4. High density ground yields higher skin friction when the maximum tapered pile was penetrated. Slightly increased tapering angle of the pile affects remarkably on the skin friction with compared to conventional straight cylindrical pile even at small 0.1 settlement ratios.
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Ragab, Fawzy M. "NDT Using Transmission Line Model to Identify the Defects in Pile Shaft". Applied Mechanics and Materials 105-107 (wrzesień 2011): 1580–88. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.1580.
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The behavior of piles having a single defect which may be necking, bulging or of inferior concrete is simulated by an electrical model representing an electrical transmission line. The model successively simulated defective piles embedded in homogeneous soil. Through the interpretation of response curves supported by appropriate mathematical treatment it was possible to study piles having a single defect .The type of defect can be identified from the response curve by comparing the pile head stiffness of suspect pile with that of a similar but sound pile in the same site. The location of the defect can be determined by measuring the interval between resonating peaks at higher frequencies. For the same defect location along the shaft of piles in a given site, it can be differentiated between resonating large peaks for piles with bulging and necking.,The behavior of piles having a single defect which may be necking, bulging or of inferior concrete is simulated by an electrical model representing an electrical transmission line. The model successively simulated defective piles embedded in homogeneous soil. Through the interpretation of response curves supported by appropriate mathematical treatment it was possible to study piles having a single defect .The type of defect can be identified from the response curve by comparing the pile head stiffness of suspect pile with that of a similar but sound pile in the same site. The location of the defect can be determined by measuring the interval between resonating peaks at higher frequencies. For the same defect location along the shaft of piles in a given site, it can be differentiated between resonating large peaks for piles with bulging and necking.
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Latapy, Matthieu, Roberto Mantaci, Michel Morvan i Ha Duong Phan. "Structure of some sand piles model". Theoretical Computer Science 262, nr 1-2 (lipiec 2001): 525–56. http://dx.doi.org/10.1016/s0304-3975(00)00363-7.
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Caliendo, Joseph A., Loren R. Anderson, Renέ F. Winward, Steve Dapp i Samuel C. Musser. "Instrumentation for Laterally Loaded Model Piles". Transportation Research Record: Journal of the Transportation Research Board 1548, nr 1 (styczeń 1996): 67–73. http://dx.doi.org/10.1177/0361198196154800110.
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Utah State University is involved with a research project funded by the Utah Department of Transportation and the Mountain Plains Consortium. The reaction of model piles subjected to lateral loading is the subject of ongoing research. The measured response of laterally loaded model pile is compared with predicted results. The model piles are 1524 mm (60 in.) long with approximately 1219.2 mm (48 in.) embedded in a soft clay soil. The piles consist of 1-in. Schedule 40, 33.40 mm (1.315 in.) OD aluminum tubes, with a wall thickness of 8.407 mm (0.331 in.). To measure the pile response to the lateral loads, each pile is instrumented with 14 pairs of foil strain gauges mounted at 91.875mm (3.75-in.) spacings. The gauge pairs were mounted on the inside wall of the seamless tube. A special installation tool was designed and fabricated at Utah State University for this purpose. A wedge-scissors device was used to mount the gauges to the inside wall. The strain gauges (CEA-13-250UW-120) are each wired into a ¼ Wheatstone bridge circuit with a dummy temperature gauge. The 28 two-wire leads along with linear variable deformation transform leads are routed through a multiplexer to a 21X data logger. The pile calibration and load test results are discussed. The measured moments compared favorably with those predicted by LPGSTAN and COM624P.
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Yang, Qing Guang, Yi Han Chen, Jie Tian i Jie Liu. "Model Test Research on Horizontal Bearing Characteristics of Close-Ended Valibale Section Pipe Pile". Applied Mechanics and Materials 638-640 (wrzesień 2014): 475–79. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.475.
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Base on indoor model tests of three variable section pipe piles and two constant section pipe piles performed in foundation pit,the load transfer mechanism of two kinds of close-ended pipe piles are studied by comparing horizontal load-displacement curves, critical load and bending moment of piles. Results show that horizontal load-displacement curves change slowly and horizontal bearing capacity of valiable section pipe piles will be higher than constant section pipe piles with equal average diameters.Comparing with constant section pipe piles 1# and 2# with equal average diameters, unit volume horizontal critical bearing capacity of 3# and 4# are improved 8.7% and 34.2% respectively and which have different degrees of increse with improvement of valiable section ratio. Moreover,there are two maximum bending moment to valialble section pipe piles insteard of one to constant section pipe piles.To pipe piles 3#,4# and 5#, maximum bending moment ratio of big diameter pipe to small diameter pipe of valiable section pipe pile are 3.13、2.33 and 1.89 respectively. To pipe piles 3# and 4#, maximum bending moments of big diameter pipe are improved 26.8% and 28.4%.Howeverm,maximum bending moment of small diameter pipe are improved 54.1% and 111.8%.So,it is very clear that valiable section pipe pile is more reasonable than constant section pipe pile in bearing characteristics.
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Luan, Zhao Jian, Qiang Xin i Yan Min Jia. "Analysis of Model Test Data for CFG Group Piles in Permafrost Areas". Applied Mechanics and Materials 501-504 (styczeń 2014): 16–19. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.16.
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In this paper, the author simulates geological conditions of permafrost areas, establi-shes CFG group piles indoor model, observes the pile and frozen soil temperature field, then compares the calculated results of the group piles and frozen soil temperatures under concrete hydration heat effect by using ABAQUS with the measured temperature data, thus determines the applicability of ABAQUS for analysis of CFG group piles temperature in permafrost areas, in order to analyze temperature distribution regularities of group piles and frozen soil under concrete hydration heat effect, thermal perturbation range of CFG group piles in permafrost areas, and effects of different concrete molding temperature on model temperature field.
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Wang, Cheng Hua, Juan Su i Gan Wang. "Model Test Studies of the Vertical Bearing Behavior of Bored Piles with Breakage Defects". Applied Mechanics and Materials 256-259 (grudzień 2012): 65–70. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.65.
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In order to study the vertical bearing behavior of bored piles with breakage defects, a series of methods for simulation of normal piles and broken piles in laboratory was developed and used to investigate the vertical bearing behavior of these piles. The load-settlement curves of normal piles and broken piles were measured and analyzed. The tests revealed that the upper part of a broken pile works alone as a short pile before it contact with the lower part of the pile at the end of the first sudden drop stage.The analysis of the test results showed that the position of the breakage defect has a great influence on the lost in vertical bearing capacity of the pile.
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Ge, Xin Sheng, Jiang Wei Xue i Xiao Li Zhai. "Model Test Research of Cushion Thickness on the Long-Short Piles Composite Foundation". Advanced Materials Research 168-170 (grudzień 2010): 2352–58. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.2352.
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In order to study the impact of cushion thickness on the long-short piles composite foundation,the relation between bearing capacity and settlement,distribution of the axial force and skin friction along pile,pile-soil stress ratio, load sharing ratio and the bearing mechanics of long-short-pile composite foundation with long and short piles were studied based on laboratory tests in three different conditions:zero-centimeter-thick cushion, two-centimeter-thick cushion and five-centimeter-thick cushion in this paper. Conclusions were as follows: The settlement of long-short piles composite foundation increased with the increasing of cushion thickness,Without cushion,the maximum axial force occurred in the pile top.After having paved cushion,it occurred in the neutral dot.The axial force of long and short piles decreased with the increasing of cushion thickness; Without cushion, only positive skin friction occurred. After having paved cushion,negative skin friction came into being existence.The value of long piles skin friction increased with the increasing of the cushion thickness,the value of short piles skin friction decreased with the increasing of the cushion thickness;The pile-soil stress ratio of long pile decreased with the increasing of the cushion thickness while the pile-soil stress ratio of short pile change little,The load sharing ratio of long piles were larger than that of short piles and soil.With the increasing of cushion thickness,the load sharing ratio of long and short piles became smaller while that of soil became larger.
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Gutiérrez-Ch, J. G., G. Song, C. M. Heron, A. Marshall i R. Jimenez. "Centrifuge Tests on Rock-Socketed Piles: Effect of Socket Roughness on Shaft Resistance". Journal of Geotechnical and Geoenvironmental Engineering 147, nr 11 (listopad 2021): 04021125. http://dx.doi.org/10.1061/(asce)gt.1943-5606.0002665.
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Dai, Guoliang, Rodrigo Salgado, Weiming Gong i Mingxing Zhu. "The effect of sidewall roughness on the shaft resistance of rock-socketed piles". Acta Geotechnica 12, nr 2 (13.06.2016): 429–40. http://dx.doi.org/10.1007/s11440-016-0470-8.
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Ge, Xin Sheng, Xiao Li Zhai i Jiang Wei Xue. "Model Test Research of Pile Body Modulus on the Long-Short-Pile Composite Foundation". Advanced Materials Research 243-249 (maj 2011): 2300–2303. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.2300.
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In order to study the impact of pile modulus variation on the long-short-pile composite foundation,the relation between bearing capacity and settlement, distribution of the axial force and skin friction along pile, pile-soil stress ratio, load sharing ratio and the bearing mechanics of long-short-pile composite foundation with long and short piles were studied based on laboratory tests in three different conditions: Long pile(Aluminum) with short pile (pentatricopeptide repeats, PPR), Long pile(polyvinyl chloride, PVC) with short pile (PPR), and Long pile(Aluminum) with short pile (PVC). Conclusions were as follows: The settlement of long-short-pile composite foundation decreased with the increasing of long piles modulus, meanwhile, the value of long piles axial force increased, and the value of short piles axial force decreased, and the pile-soil load sharing ratio(LSR) increased. On the other hand, there are few influence on settlement, long piles axial force, and pile-soil load sharing ratio when the modulus of short piles modulus changed, except that the value of short piles axial force and short piles modulus increased or decreased on the same direction.
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Liu, Tingfa, Haoruo Chen, Róisín M. Buckley, V. Santiago Quinteros i Richard J. Jardine. "Characterisation of sand-steel interface shearing behaviour for the interpretation of driven pile behaviour in sands". E3S Web of Conferences 92 (2019): 13001. http://dx.doi.org/10.1051/e3sconf/20199213001.
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The installation and loading of steel piles driven in sands modifies both the piles' surface topography and the characteristics of the granular materials present adjacent to the pile shaft. Large-displacement ring shear interface tests incorporating pre-conditioning stages are capable of reproducing such physical processes in the laboratory and can generate case-specific interface design parameters. This paper summarises laboratory research that characterised the interface shearing behaviour of three natural sandy soils retrieved from field test sites (Dunkirk, France; Blessington, Ireland; Larvik, SE Norway) where extensive piling studies on micro and industrial scale driven piles have been carried out. The programme examined the influences of soil characteristics (physical properties and chemical compositions), interface type (mild steel or stainless steel) and surface roughness, and highlighted the significant effects of normal effective stress level and ageing time duration. Remarkable trends of increasing interface friction angles with elevated normal effective stress levels and prolonged ageing were observed. The results from supplementary small-displacement direct shear interface tests and triaxial tests are also reported. The experiments are interpreted with reference to earlier studies to develop an overview of interface shearing characteristics between steels and sandy soils and provide important insights into the mechanisms of axial capacity increases applying to steel piles driven in sands.
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Prasad, Y. V. S. N., i S. Narasimha Rao. "Pullout behaviour of model pile and helical pile anchors Subjected to lateral cyclic loading". Canadian Geotechnical Journal 31, nr 1 (1.02.1994): 110–19. http://dx.doi.org/10.1139/t94-012.
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This paper presents the effect of lateral cyclic loading on the pullout capacity of model and helical piles in clayey soil. The tests were conducted on short rigid model piles in the laboratory in three phases, namely lateral static load tests, lateral cyclic load tests, and vertical pullout tests. From the test results it was found that the lateral cyclic loading affects the pullout capacity of piles substantially. Reduction in pullout capacity mainly depends upon the lateral deflection of the pile during cyclic loading and the embedment ratio of the pile. This reduction in the pullout capacity of model piles is presented in terms of nondimensional parameters, viz., degradation factor, lateral deflection ratio, and embedment ratio of pile. However, in the case of helical piles under similar conditions, it was found that the lateral cyclic loading has very little influence on the pullout capacity. The reasons for the better performance of helical piles over ordinary piles are explained. Key words : clay, degradation factor, helical pile, lateral cyclic loading, lateral deflection, Joading level, pile, pullout capacity.
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Sego, D. C., i L. B. Smith. "Effect of backfill properties and surface treatment on the capacity of adfreeze pipe piles". Canadian Geotechnical Journal 26, nr 4 (1.11.1989): 718–25. http://dx.doi.org/10.1139/t89-082.
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This note presents the results of a limited number of laboratory-scale pile load tests to establish those modifications to current pile construction procedures that would be most effective in increasing pile capacity. The results indicate that the properties of the backfill (ice content, salinity, and size of annulus) have a significant influence on short-term pile capacity, while the properties of the native soil are less important. The results demonstrate that the pile capacity can be maximized through the use of nonsaline sand backfill. In saline soils, the shear strength at the backfill - native soil interface may govern the design, and must be evaluated together with the adfreeze strength at the pile-backfill interface. The results also demonstrate that the roughness of the outside surface of the pile has a significant influence on adfreeze strength. Sandblasting the pile surface doubled the adfreeze strength at the pipe-backfill interface. This effect appears to be due to increased surface roughness rather than to the removal of paint from the pile surface. Key words: adfreeze strength, backfill, permafrost, piles, pile surface treatment, salinity.
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Krasiński, Adam, i Tomasz Kusio. "Comparative Model Tests of SDP and CFA Pile Groups in Non-Cohesive Soil". Studia Geotechnica et Mechanica 36, nr 4 (28.02.2015): 7–11. http://dx.doi.org/10.2478/sgem-2014-0031.
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Abstract The research topic relates to the subject of deep foundations supported on continuous flight auger (CFA) piles and screw displacement piles (SDP). The authors have decided to conduct model tests of foundations supported on the group of piles mentioned above and also the tests of the same piles working as a single. The tests are ongoing in Geotechnical Laboratory of Gdaňsk University of Technology. The description of test procedure, interpretation and analysis of the preliminary testing series results are presented in the paper.