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1
Gotman, A. L., i M. D. Gavrikov. "CALCULATION OF A LARGE-SIZE BORED PILE ON A VERTICAL LOAD". Construction and Geotechnics 12, nr 3 (15.12.2021): 72–83. http://dx.doi.org/10.15593/2224-9826/2021.3.08.
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Paper presents results of experimental and theoretical studies of vertically loaded large bored piles (length from 50 meters and more) performance. The analysis of O-cell load tests on vertically loaded large bored piles with 2m diameter, 55 and 65 meters length, in clay soils is carried out. According to the test results, features of an end and a shaft resistance (formation) were detected, and on this basis, a justification of necessity to calculate such piles according to the second limit state is given, taking into account the compressibility of the pile trunk. The kinemetic scheme of inclusion in the work of the soil base and the pile trunk as it is loaded with a vertical load is presented. A shown software research of piles based on pile tests on a real object. On this basis, a method for calculating the permissible settlement of a single pile and a method for determining the permissible load on the pile, at which the setting of the pile does not exceed the permissible settlement for the designed building, has been developed. An example of calculating a bored pile according to the developed method is given.
2
Trofymow, J. A., N. C. Coops i D. Hayhurst. "Comparison of remote sensing and ground-based methods for determining residue burn pile wood volumes and biomass". Canadian Journal of Forest Research 44, nr 3 (marzec 2014): 182–94. http://dx.doi.org/10.1139/cjfr-2013-0281.
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Following forest harvest, residues left on site are often piled and burned. Quantification of residue piles is required in many jurisdictions to estimate billable waste, harvest efficiency, smoke emissions, C budgets, and available bioenergy biomass. Piled residues and harvested wood were measured on four blocks of a second-growth Douglas-fir forest in coastal British Columbia. Pile wood volumes were determined by two ground-based methods (a Waste and Residue Survey (WRS) and a geometric equation (EEP) used for smoke emissions) and by two geospatial methods using orthophotography (GIS) and LiDAR. Eight sample piles were disassembled to determine plot densities (PD) and packing ratios (PR). Plot density did not differ between the WRS and GIS method. Packing ratios of the EEP were 50% of that of the LiDAR method. LiDAR pile bulk volume and PR were negatively correlated. Choice of LiDAR digital elevation model had no significant effect on pile bulk volumes. The WRS method underestimated pile areas by 50% and the EEP method overestimated pile bulk volumes by two times. Pile wood volumes from the WRS method (20.0 m3·ha−1 (SE 2.8)) were 30%–50% of those for all other methods (46.1–60.4 m3·ha−1). The EEP method overestimated wood volume if nonspecific PRs were used. The residues to harvest ratio for the WRS method (3.3% (SE 0.45)) was lower than for all other methods (7.5%–9.6%). Total pile wood biomass from LiDAR was 25.4 t dry mass·ha−1 (SE 5.9). Ground-based methods are still required to determine PD or PR. Since their estimation depends on the method used to determine pile area or bulk volume, and may vary with pile size and type, they remain the major source of uncertainty in determining pile wood volumes. However, use of remote sensing techniques to determine the area or bulk volume of all piles in a cutblock can improve estimates of pile wood volumes and biomass.
3
Nikitenko, M. I., i N. А. Shanshabayev. "Resistance of models of pyramidal-prismatic piles to static pulling load". BULLETIN of L.N. Gumilyov Eurasian National University. Technical Science and Technology Series 134, nr 1 (2021): 7–19. http://dx.doi.org/10.32523/2616-7263-2021-134-1-7-19.
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The article presents results of testing models of piles with different longitudinal shapes under the action of a static pulling load, performed in laboratory conditions. The article reveals resistance of the pyramidal-prismatic piles can be either more or less than the resistance of the prismatic and pyramidal piles. It was found that an increase in the length of the pyramidal part of the pile, as well as the size of its cross-section at the top, affect the resistance of the pile to pull-out load. So, the resistance of these piles is 1.28-1.85 times higher than the resistance of a prismatic pile with a section size of 20×20 cm, and 8-36% lower than the resistance of a prismatic pile with a section size of 30×30 cm and a pyramidal pile (with a top section size of 30×30 cm and at the bottom - 20×20 cm). Correlation dependencies are obtained to assess the stability of pyramidal-prismatic piles in relation to the bearing capacity of piles with traditional longitudinal section shape (prismatic and pyramidal piles).
4
LYASHENKO, P. A., V. V. DENISENKO i M. B. MARINICHEV. "DESCRIPTION OF THE BORED PILES WORK IN A GROUP WITH USING AN EXTENDED RESISTANCE CIRCUIT OF SOIL BASE". Building and reconstruction 94, nr 2 (2021): 46–55. http://dx.doi.org/10.33979/2073-7416-2021-94-2-46-55.
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The calculation of the resistance of piles in the foundation is proposed according to an extended scheme, which includes the surrounding soil, which is inextricably connected with the pile through the side surface. The implementation of the extended scheme is possible with the application of the method of testing a model pile with a constantly increasing load with continuous measurement of precipitation (CRL method), supplemented by measurements of soil deformations relative to the pile surface and displacements of deep marks near the pile. Increasing the amount of information about the state of the soil allows us to obtain the values of additional forces elastically transmitted to neighboring piles, depending on the size of the areas of plastic deformation of the soil. The assessment of the mutual influence of piles during the increase in load on the foundation makes it possible to choose the best option of its parameters, including the size of piles, their placement in the foundation, changes in resistance and settlement over time.
5
Di Laora, Raffaele, George Mylonakis i Alessandro Mandolini. "Size Limitations for Piles in Seismic Regions". Earthquake Spectra 33, nr 2 (maj 2017): 729–56. http://dx.doi.org/10.1193/032116eqs045m.
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A novel theoretical study exploring the importance of pile diameter in resisting seismic actions of both the kinematic and the inertial type is reported. With reference to a pile under a restraining cap, it is shown analytically that for any given set of design parameters, a range of admissible pile diameters exists, bounded by a minimum and a maximum value above and below which the pile will yield at the top even with highest material quality and amount of reinforcement. The critical diameters depend mainly on seismicity, soil stiffness and safety factor against gravity loading, and to a lesser extent on structural strength. This scale effect is not present at interfaces separating soil layers of different stiffness, yet it may govern design at the pile head. The work at hand deals with both steel and concrete piles embedded in soils of uniform or increasing stiffness with depth. Closed-form solutions are derived for a number of cases, while others are treated numerically. Application examples and design issues are discussed.
6
Dai, Guoliang, Rodrigo Salgado, Weiming Gong i Yanbei Zhang. "Load tests on full-scale bored pile groups". Canadian Geotechnical Journal 49, nr 11 (listopad 2012): 1293–308. http://dx.doi.org/10.1139/t2012-087.
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The interactions between closely spaced piles in a pile group are complex. Very limited experimental data are available on the loading of full-scale bored pile groups. This paper reports the results of axial static load tests of both full-scale instrumented pile groups and single piles. The load tests aimed to ascertain the influence of number, length, and spacing of the piles on pile group load response. Experiments varied in the number of piles in the group, pile spacing, type of pile groups, and pile length. All piles had a diameter of 400 mm. Two-, four-, and nine-pile groups with pile lengths of 20 and 24 m were tested. As the isolated piles and some piles in the pile groups were instrumented, the load transfer and load–settlement curves of both piles in isolation and individual instrumented piles in the groups were obtained. The interaction coefficient for each pile in the group was back-calculated from the measured data. The interaction coefficients are shown to be dependent on pile proximity, as usually assumed in elastic analyses, but also on settlement and on the size of the group.
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Qi, Jian Wen, Cui Ping Kuang, Jie Gu i Jing Huang. "Numerical Investigation of Impact of Pile Space on Flow around Two Vertical Cylindrical Piles". Applied Mechanics and Materials 212-213 (październik 2012): 1103–7. http://dx.doi.org/10.4028/www.scientific.net/amm.212-213.1103.
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The flow around two vertical cylindrical piles exposed to a steady current is studied numerically by a three-dimensional hydrodynamic model, which is closured with a k-ε turbulence model. This model is firstly validated by experimental data obtained from a labortory experiment for a steady flow through a circular pile. Then this validated model is used to study flow pattern around two cylindrical piles. Finally, four key physical factors of the size of the horseshoe vortex and lee wake vortex, the maximum current velocity and bottom shear stress are analyzed under the different pile spaces. The main conclusions are: i) the size of the horseshoe vortex increases with the increase of the two pile space, while the size of the lee wake vortex changes slightly; ii) the maximum current velocity and the maximum bottom shear stress decrease with the increase of two pile space, and reach steady after the two pile space larger than six times of cylindrical pile diameter.
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Xu, Zhijun, i Zhaoxiang Guo. "Experimental Study on Bearing Characteristics and Soil Deformation of Necking Pile with Cap Using Transparent Soils Technology". Advances in Civil Engineering 2021 (23.03.2021): 1–11. http://dx.doi.org/10.1155/2021/6625556.
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This paper will employ the transparent soil experiment technology to explore the influences of shallow necking on the vertical bearing capacity of single pile with cap. Model experiment is carried out on one intact pile and nine shallow necking piles. The load-settlement curves of all piles are obtained, which are used to study bearing characteristics of piles. The displacement fields of soil around piles are employed to investigate the reasons for the loss of vertical bearing capacity of piles with shallow necking. The vertical bearing capacity is greatly reduced which is caused by shallow necking. When the axial dimension of necking is the same, the larger the radial size is, the greater the loss of vertical bearing capacity is. When the radial dimension of necking is the same, the greater the axial size is, the greater the loss of vertical bearing capacity is. The soil near the pile shaft and under the pile cap produces a large area of vertical downward deformation, which causes the relative displacement between the pile shaft and the soil to greatly reduce. Therefore, it is easy that the necking piles with caps develop negative friction, which causes the vertical bearing capacity of piles to reduce. When the radial dimension of the shallow necking is 80% of pile diameter, the pile is easy to be damaged.
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Hou, Jin Fang, Jian Yu i Xin Wei Xu. "Research on the Large Size Loading Plate Test of Underwater Sand Compaction Pile Composite Foundation". Applied Mechanics and Materials 744-746 (marzec 2015): 574–78. http://dx.doi.org/10.4028/www.scientific.net/amm.744-746.574.
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Large size loading plate test for sand compaction pile composite foundations with the replacement ratio being up to 60% was carried out to study the deformation and bearing capacity of the sand compaction pile composite foundation. The test was carried out for 53 days with anchor pile, square loading with the side length of 5.4m, 15m-deep water and twice circulation loading mode. The compression deformation, pile-soil stress ratio and deformation modulus of the sand compaction pile composite foundation was analyzed through load test. Test results indicated that, the ultimate bearing capacity of the sand compaction pile composite foundation in this test was larger than 340kPa; sand compaction pile had a drainage consolidation effect on the soft soil between piles; under the load-keeping condition, sand compaction pile composite foundation would also has settlement; pile-soil stress ratio was 6.3 and deformation modulus was about 8kPa. The success of the test may provide experience and reference for load test of underwater sand compaction pile composite foundation carried out at open sea.
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Busse, Matt D., Carol J. Shestak i Ken R. Hubbert. "Soil heating during burning of forest slash piles and wood piles". International Journal of Wildland Fire 22, nr 6 (2013): 786. http://dx.doi.org/10.1071/wf12179.
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Pile burning of conifer slash is a common fuel reduction practice in forests of the western United States that has a direct, yet poorly quantified effect on soil heating. To address this knowledge gap, we measured the heat pulse beneath hand-built piles ranging widely in fuel composition and pile size in sandy-textured soils of the Lake Tahoe Basin. The soil heat pulse depended primarily on fuel composition, not on pile size. Burn piles dominated by large wood produced extreme temperatures in soil profile, with lethal heating lasting up to 3 days. In contrast, the heat pulse was moderate beneath piles containing a mixture of fuel sizes. Considerable spatial variability was noted, as soil temperatures were generally greatest near pile centres and decline sharply toward the pile edges. Also, saturating pile burns with water 8 h after ignition (‘mopping up’) effectively quenched the soil heat pulse while allowing near-complete fuel consumption. The findings suggest that burning of hand piles will not result in extreme or extensive soil heating except for uncommon conditions when piles are dominated by large wood and occupy a high percentage of the ground surface.
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Dhage, Amit, i S. S. Solanke. "Comparative Analysis of Raft, Pile & Piled Raft Foundation using Designing Software". IOP Conference Series: Earth and Environmental Science 1193, nr 1 (1.06.2023): 012006. http://dx.doi.org/10.1088/1755-1315/1193/1/012006.
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Abstract Raft foundations are essentially a slab that extends the entire length of the building, sustaining and dispersing its mass to the earth. A pile foundation is a collection of columns that are erected or inserted into the ground to distribute weight to the subsoil underneath. A pile is a long, cylindrical construction made made of a sturdy substance such as concrete. Building loads are transferred to hard strata, rocks, or high-bearing-capacity soil using piles. Pinned raft foundations are a combination of a pile and a raft slab. They’re frequently used for large structures and when the soil is insufficient to avoid excessive settling. As a result of this, the soil is less strained. Pile foundations are necessary in areas where buildings are large and heavy, yet the soil beneath them is weak. In areas where settlement. Deep foundations with pile rafts can help move strata Adding piles to a raft increases the effective size of the foundation and can help it sustain horizontal loads. On a G+20 residential structure, the research of raft, pile, and stacked raft foundations was conducted using structural software safe 16. For a zone factor II earthquake, a building’s seismic study is completed. The pile raft foundation has less upward soil carrying load and less settling than the raft foundation, according to a study of the G+20 structure for pile, raft, and piled raft foundations.
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Pinto, Paulo, Michael McVay, Marc Hoit i Peter Lai. "Centrifuge Testing of Plumb and Battered Pile Groups in Sand". Transportation Research Record: Journal of the Transportation Research Board 1569, nr 1 (styczeń 1997): 8–16. http://dx.doi.org/10.3141/1569-02.
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Pile groups are generally used under structures subject to heavy axial loads or large lateral forces with or without scour. The focus in this paper is only on pile groups subject to large lateral forces. Currently, little, if any, full-scale lateral load data exist on pile groups that vary pile head fixity or batter. Reported here is the summary of a series of centrifuge tests on free- and fixed-head plumb and battered pile groups. Influence of pile head constraint, pile spacing, soil density, and vertical dead load is reported for groups ranging from 3 × 3 to 3 × 7 in size. Results reveal a significant lateral resistance of fixed- over free-head pile groups; fixed-head piles develop significant axial forces; battered piles without vertical dead loads are generally no better than plumb piles; and in the case of plumb piles, the use of multipliers to represent group interaction is valid.
13
Ho, Wilson, Wylog Wong i Eric Chu. "Sheet Pile Tuned Mass Damper for Construction Noise Control". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, nr 1 (1.02.2023): 6593–600. http://dx.doi.org/10.3397/in_2022_0995.
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Sheet piles are often used for underground retaining structures. For dense geology, vibratory driven method is more cost-effective than press-in driven method, but noisier. Conventional mitigations such as noise barrier or enclosure are not applicable due to the large size of pile wall (generally >12m high and >10m width). Acoustic camera images revealed that noise radiation was dominant at 630Hz to 2000Hz and mainly came from the sheet-pile wall rather than the vibratory exciter. Vibration response measurement showed the sheet piles had two major resonance modes at 1000 and 2000Hz. An innovative noise mitigation method was developed with 14 nos. of tuned mass dampers (TMD) distributed along a 5m long aluminum tube for vibration energy dissipation at the pile wall. Specific magnetic mounts were developed for quick and easy attachment of the TMDs at the construction site. In the site test, total 6 aluminum tubes (i.e., 84 TMDs) were mounted to the 1st, 2nd and 3rd piles adjacent to the driven pile on both sides. Vibration reduction was measured ~9 to 14dB at the pile wall. Noise reduction was measured 7 to 9dB(A) at 2 noise monitoring locations (~7m and ~22m from the pile wall).
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Li, Lin, Shengli Chen i Zhongjie Zhang. "A Numerical Study on Installation Effects and Long-Term Shaft Resistance of Pre-Bored Piles in Cohesive Soils". Transportation Research Record: Journal of the Transportation Research Board 2673, nr 3 (marzec 2019): 494–505. http://dx.doi.org/10.1177/0361198119835505.
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Pre-boring is a technique widely used to facilitate large displacement pile driving in hard/dense soils, but usually at the expense of reducing the long-term shaft resistance of the pile. In the US, it is a routine practice for large displacement pile to be driven through dense cohesive soils with the ultimate capacity of pre-bored piles usually being determined based on empiricism and local experience. Understanding and quantifying the impacts of pre-boring installation on pile capacity can greatly help geotechnical design engineers to understand the interactions among the factors of pre-boring, pile size, soil conditions, and so forth and to improve the design and construction qualities of pile foundations in hard/dense soils. Due to the high cost and time involved with field instrumentation and testing on pre-bored piles, a numerical analysis study was funded by the Louisiana Department of Transportation and Development (DOTD) as a first step to exploring the impacts of pre-bore size on the long-term shaft resistance reduction of piles. This study was conducted using a practical finite element model that integrates the entire process from pile installation through subsequent consolidation to pile loading. The long-term shaft resistance was then examined after full consolidation by applying a vertical shear displacement on the soil element adjacent to the pile until the ultimate state was reached. Based on the numerical simulations, a set of reduction factor curves were then developed for a typical Louisiana soil stratum, which may provide guidelines for better design and construction of pre-bored piles in Louisiana.
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Wang, Yongjun, Xiaoming Zhang, Hemeng Zhang i Kyuro Sasaki. "Effects of temperature gradient and particle size on self-ignition temperature of low-rank coal excavated from inner Mongolia, China". Royal Society Open Science 6, nr 9 (4.09.2019): 190374. http://dx.doi.org/10.1098/rsos.190374.
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This study investigates the effects of temperature gradient and coal particle size on the critical self-ignition temperature T CSIT of a coal pile packed with low-rank coal using the wire-mesh basket test to estimate T CSIT based on the Frank–Kamenetskii equation. The values of T CSIT , the temperature gradient and the apparent activation energy of different coal pile volumes packed with coal particles of different sizes are measured. The supercriticality or subcriticality of the coal is assessed using a non-dimensional index I HR based on the temperature gradient at the temperature cross-point between coal and ambient temperatures for coal piles with various volumes and particle sizes. The critical value I HRC at the boundary between supercriticality and subcriticality is determined as a function of pile volume. The coal status of supercritical or subcritical can be separated by critical value of I HR as a function of pile volume. Quantitative effects of coal particle size on T CSIT of coal piles are measured for constant pile volume. It can be concluded that a pile packed with smaller coal particles is more likely to undergo spontaneous combustion, while the chemical activation energy is not sensitive to coal particle size. Finally, the effect of coal particle size on T CSIT is represented by the inclusion of an extra term in the equation giving T CSIT for a coal pile.
16
Ly, Chungyean, Chandoeun Eng, Muoy Yi Heng i Phanny Yos. "Concrete Pile Defect Identification: Insights from Cross-Hole Sonic Logging and High Strain Dynamic Pile Test". IOP Conference Series: Earth and Environmental Science 1117, nr 1 (1.12.2022): 012059. http://dx.doi.org/10.1088/1755-1315/1117/1/012059.
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Abstract This paper aims to identify the types of defects, location of defects, size of defects, and capacity of five concrete piles using a High strain dynamic pile test and Cross-hole sonic logging test. In this study, Cross-Hole Sonic Logging method (CSL) is a potent quality-control tool that exclusively detects much smaller flaws with high accuracy with utilizing velocity and first arrival time (FAT) from ultrasonic waves to find out the integrity of the drill shaft. From CSL test, the bearing capacity needs to be calculated manually using a waterfall diagram and soil profile. Moreover, the high strain dynamic pile test is used to identify integrity and bearing capacity of concrete pile via resistance analysis down to the pile and split of the base to shaft resistance when only pile head measurements are taken then using Case Method and CAPWAP analysis. Through this analysis, the bearing capacity can be interpreted; the Belta (damage factor) is applied to estimate location and size of the defect in the concrete pile. Based on the result of CLS test for three concrete piles, P01, P04, and P10, indicated that P01 and P04 are “Good” pile integrity with the bearing capacity of 4583kN and 6600kN, while P10 showed as “Potential defect at depth 9.25m to 10.25m” of pile integrity with bearing capacity of 6600kN. Furthermore, High strain dynamic pile test of two concrete piles, P2E and P2P, showed that the integrity category is “Ok” with bearing capacity 9896kN.
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Watford, M., J. Templeman, Z. Orazalin, H. Zhou, A. Franza i B. Sheil. "Numerical analysis of the deep soil failure mechanism for perimeter pile groups". Géotechnique Letters 12, nr 1 (marzec 2022): 27–34. http://dx.doi.org/10.1680/jgele.21.00080.
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In this paper, the lateral limiting pressure offered by the deep ‘flow-around’ soil failure mechanism for perimeter (ring) pile groups in undrained soil is explored using two-dimensional finite-element (FE) modelling. A parametric study investigates the role of group configuration, pile–soil adhesion, group size, pile spacing and load direction on group capacity and corresponding soil failure mechanisms. The FE output shows that the plan group configuration (square or circular) has a negligible influence on lateral capacity for closely spaced perimeter pile groups. When compared to ‘full’ square pile groups with the same number of piles, the present results suggest that for practical pile spacing (≳ two pile diameters), perimeter groups do not necessarily increase capacity efficiency, particularly if the piles are smooth. Nevertheless, perimeter groups are shown to be characterised by both the invariance of their capacity to the direction of loading and their highly uniform load-sharing between piles, which are beneficial features to optimise design.
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Vaziri, Hans H., i Yingcai Han. "Nonlinear vibration of pile groups under lateral loading". Canadian Geotechnical Journal 29, nr 4 (1.08.1992): 702–10. http://dx.doi.org/10.1139/t92-077.
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Dynamic response of a pile group, comprising six full-size cast-in-place reinforced concrete piles, is investigated under varying levels of lateral harmonic excitation in two directions: along a plane composed of three piles (X-direction) and along a plane normal to it composed of two piles (Y-direction). The measured response is compared with the theoretical predictions using the dynamic interaction factors approach. To account for the nonlinear response of the pile group using the theoretical model, provisions are made for yielding of soil around the piles by introducing the boundary-zone concept. It is shown that the proposed theory adequately captures the measured response of the pile group under both linear (weak excitation) and nonlinear (strong excitation) conditions. The study performed indicates that although the rocking stiffness of the pile group is strongly influenced by the number of piles along the direction of excitation, the horizontal stiffness remains virtually unaffected. The results obtained show that the stiffness and damping ratio of the pile group reduce as the excitation intensity increases. It is also found that the pile–soil–pile interaction plays a major role in the overall dynamic response of the pile group; this effect is manifested by a reduction in the stiffness and an increase in the damping of the pile group. Key words : dynamics, vibration, piles, pile group, nonlinear vibration, full-scale tests, modelling, resonance, soil separation, soil yielding.
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Bekbasarov, I. I., i N. А. Shanshabayev. "THE RESULTS OF LABORATORY STUDIES OF THE OPERATION OF MODELS OF PYRAMIDAL-PRISMATIC PILES ON THE EFFECT OF VERTICAL PULLING LOAD IN CLAY SOIL". Bulletin of Kazakh Leading Academy of Architecture and Construction 86, nr 4 (15.12.2022): 132–46. http://dx.doi.org/10.51488/1680-080x/2022.4-13.
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This paper presents the results of laboratory tests of models of pyramidal-prismatic piles on the effect of vertical pulling load. The experiments were carried out in clay soil. It is established that models of pyramidal-prismatic piles, depending on the size of the pyramidal section, can have both greater and lesser resistance compared to prismatic and pyramidal (control) piles. Thus, it was found that the resistance of pyramidal-prismatic piles to the pulling load is 1.19-1.80 times higher than the resistance of a model of a prismatic pile with a cross-section size of 20×20 mm. Compared with the model of a prismatic pile with a cross-section size of 30 ×30 mm and with the model of a pyramidal pile (with a cross-section size of 30×30 mm at the top and 20×20 mm at the bottom), the models of pyramidal-prismatic piles have less resistance (by 6-45%). An increase in the size of the upper section of the pyramidal part of the PPP has a more significant effect on increasing their resistance to pulling out than an increase in the length of their pyramidal section. Correlations have been established that can be used for a preliminary assessment of the resistance of pyramidal-prismatic piles to the pulling load relative to the resistance of traditional (prismatic and pyramidal) piles.
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Yin, Xin Sheng, Jing Wei Cai i Pang Feng Ba. "The Research for the Technology of Inner Struck Pile and the Coefficient of Pile Endpoint Resistance". Applied Mechanics and Materials 170-173 (maj 2012): 335–38. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.335.
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This document introduces a kind of new technology including testing pile, making pile, measuring pile----the technology of the inner struck pile. The mechanism for the inner struck piles and small area method for testing pile was explained. The coefficient of the pile endpoint resistance was calculated in different depth with the finite element software and it's variation was analyzed with different parameters' variation (cohesion, friction angle, elastic modulus, Poisson's ratio). The result shows that the value of the coefficients of the pile endpoint resistance reduces with the rising of the value of depth and the value is affected by the size of the pile head and the soil parameters.
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Qian, Tong Hui, Wen Cai Xia, Fang Chen i Hong Xing Ding. "Model Experimental Research on Anti-Sliding Characteristics of the Frame Anti-Sliding Piles". Applied Mechanics and Materials 90-93 (wrzesień 2011): 584–87. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.584.
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Through analysis of model test results, some of the basic sliding piles features of the frame anti-slide pile can be obtained. Under the thrust of landslide, a complex parabola and line function could be used to describe the relationship of load and lateral displacement of pile head. At the same time, there was a big crack in front of the pile. It was shown by monitoring the soil pressure that pushing force acting on the back frame pile was trapezoidal distribution and on the leading frame pile was parabola distribution. The soil pressure value was larger at back piles central and around sliding surface and smaller at the head of piles. the landslide thrust acting on the back piles more larger than the front row piles, the central of piles’ maximum soil pressure minimum 1:3 ratio of the middle pile at the before and after row, the ratio between the changes with the load. Frame pile of the inflection point after another figure appeared, at the top of the link beam and ring beam structure of the entire framework of the pile Showed a synergistic effect of spatial, compare to other forms of single row of piles and others forms, it can significantly reduce the size, to achieve the economic security landslide treatment goal, there is wide application prospect.
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Li, Hong, Hong Xia Ding i Shang Yu Han. "Effects of Shape Parameters on Deformation Characteristics of Carrier Pile". Applied Mechanics and Materials 578-579 (lipiec 2014): 546–49. http://dx.doi.org/10.4028/www.scientific.net/amm.578-579.546.
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There are many uncertainty factors which can influence the carrier pile design and construction, some of them can lead the deformation characteristic of carrier pile more complex, especially the carrier pile shape parameter. Based on the on-site testing results and the finite element simulation conclusion, the paper studied the effects of shape parameter on deformation characteristics of the carrier pile from the aspect of bottom head size, pile diameter size, gravel soil zone size, etc. The research found that increase the size of the bottom head and the size gravel soil zone can reduce the amount of deformation to a certain extent; the effect of pile diameter size increase on reducing the deformation is not obvious.
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Bei-bei, Yao, Zhao Li-ping i Pan Chun-feng. "Research on Influencing Factors of Composite Foundation Settlement with Capped Pipe Piles Based on Centrifugal Model Test". E3S Web of Conferences 198 (2020): 02001. http://dx.doi.org/10.1051/e3sconf/202019802001.
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In order to study the influence of design factors of capped pipe pile composite foundation on differential settlement of expressways, using a geotechnical centrifugal model test platform, a centrifugal model of widen roadbed has been constructed. The effects of pile length, pile spacing, pile cap and cushion thickness on differential settlement were analyzed through comparative experiments. The test results show that increasing the pile length, pile cap size and cushion thickness can effectively control the differential settlement between old and new embankments. The research results can provide a theoretical basis for the design of composite foundations with capped pipe piles.
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Chen, Guang Feng, Qing Qing Li, Hao Chun Sun i Wei Bin Wang. "Study on 2D Simulation Algorithm and Implementation for Loop Pile Tufted Carpet". Advanced Materials Research 179-180 (styczeń 2011): 651–56. http://dx.doi.org/10.4028/www.scientific.net/amr.179-180.651.
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To preview of the final appearance of tufted carpet, this paper devises a solution to simulate the color appearance of tufted carpet. The simulation adopts color blocks to represent a single loop pile in carpet surface, through resizing color block size to simulate the extrusion between loop piles. The solution starts from traversing the control pattern to get the pile height level information. Base on the current and surrounded loop piles height level to infer the size and start point of color block for current loop pile. According to patterns’ information to generate the color appearance simulation for loop pile tufted carpet. Base on the proposed simulation, devise the frame work and control logic for simulation software, and developed the simulation software with C++. Simulation test is carried out, the result shows the method can effectively generate carpet color appearance simulation for tufted carpet comprising of multicolor yarns.
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Burkovič, Kamil, Martina Smirakova i Pavlina Matečková. "Testing and Modelling of Concrete Pile Foundations". Key Engineering Materials 738 (czerwiec 2017): 287–97. http://dx.doi.org/10.4028/www.scientific.net/kem.738.287.
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Foundation of building on concrete piles is often used when it is necessary to carry the load into larger depth as by common foundation. Bearing capacity of piles or piled raft foundation is wide area to research. This paper deals with experimental load test of concrete pile and with their numerical modelling. Several types of foundation construction were tested and two kinds will be presented and compared in this paper - reinforced concrete foundation slab and raft foundation (made of reinforced concrete foundation slab supported by drilled reinforced concrete pilot). These types of foundation constructions were constructed as models, in a reduced scale, approx. 1:10. The size had to be adjusted due to limited capacity of the testing equipment and financial reasons. Except measuring of the foundation behaviour, there was also carried out measurement of the adjacent terrain.The aim of this paper is to compare the behaviour of rigid slab and the piled raft. The measurement results will be then compared with the results of numerical modelling.
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Cunha, Renato P., i Ary F. Cordeiro. "Numerical Assessment of an Imperfect Pile Group with Defective Pile both at Initial and Reinforced Conditions". Soils and Rocks 33, nr 2 (1.05.2010): 81–93. http://dx.doi.org/10.28927/sr.332081.
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The assessment of problems of imperfect, damaged, pile groups is scarce in the geotechnical literature. Besides, techniques of assessing the performance of the foundation system once a defect is found are seldom presented, as well as real examples of the behavior of large scale imperfect foundations after their remediation. Therefore, this paper has extended the design philosophy of “piled raft” foundations to predict the numerical behavior of imperfect pile group foundations at pre and post-remediated conditions. Focus will be given to the problem of groups with either defective shorter length or lower stiffness piles, caused by natural or man-made sources. The remediation of the group is considered via added reinforcement piles with either similar or dissimilar characteristics (length, diameter, stiffness) compared to the original undamaged piles. Although the results are limited, they allow preliminary generalizations of the overall group behavior at working conditions, once a pile flaw is noticed and after the remediation has taken place. Among other results the paper highlights the load sharing mechanism between foundation elements, which relates to the position and magnitude of damage of the defective pile, as well as to the overall characteristics of reinforcement one. It was concluded that a defect caused by an unwanted pile length variation can be more detrimental to the foundation system than an unexpected low structural stiffness for the constructed pile. The derived factor of safety (SF) of the system (overall value) and of its distinct components (individual values) are also influenced by aforementioned variables, leading to questions on how the reinforcement can be made in such manner to obtain well optimized SFs. As noticed throughout the analyses, defective piles share its load with system components, once a defect appears. Nevertheless, even when imperfect such piles continue to absorb some load, although to a lesser degree than the original value. The reinforcement piles tend to absorb (or retain) some of the load spread by the defective ones, in a proportion which depends to its general characteristics (size, position, stiffness). Again, questions about an optimization procedure have to be made in order to wisely and economically use this particular observed feature on the remediation design.
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Wang, Hao, Dewei Fu, Tiantian Yan, Deng Pan, Weiwei Liu i Liqun Ma. "Bearing Characteristics of Multi-Wing Pile Foundations under Lateral Loads in Dapeng Bay Silty Clay". Journal of Marine Science and Engineering 10, nr 10 (29.09.2022): 1391. http://dx.doi.org/10.3390/jmse10101391.
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This study provides a theoretical basis for reinforcement of the soil around multi-wing piles. Limit analysis was used to determine the ultimate lateral capacity (ULC) of three- and four-wing piles in Dapeng Bay silty clay. The effects of the pile–soil interaction coefficient α, wing width Bw, and lateral-load direction β on the ULC of the pile and the shear plastic zone range of the surrounding soil were analyzed. The normalized ULC of the three-wing pile decreased when the wing–diameter ratio increased. When Bw was 0.15 m and α was 0.4, the ULC of the four-wing pile was 19% higher than that of the three-wing pile. As β increased, the normalized ULC of the four-wing pile decreased, whereas that of the three-wing pile went through a minimum at 30°. The size of the soil shear plastic ring did not depend on α for either pile type; it increased around the three-wing (but not the four-wing) pile with changes in β. However, there was also a double plastic ring of broken soil around the four-wing pile. The four-wing pile had a more symmetrical influence on the soil around the pile than the three-wing pile.
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Wang, Bo, Lei Qi i Yongdong Yang. "Experimental Study on Bending Resistance of New Type Joint of Prestressed Concrete Pipe Pile". Symmetry 14, nr 9 (13.09.2022): 1920. http://dx.doi.org/10.3390/sym14091920.
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In the field of PHC pile joints, it is important that prestressed high-strength concrete pipe piles are referred to as PHC pipe piles. In conventional hoops, bamboo-like joints protrude from the pile joint position at the surface of the pile. Driving the pile in, disturbing the soil around the pile, and affecting the frictional resistance are serious issues. To address such issues, herein, a new type of clamping joint is proposed. A new method is presented to determine the size of the new joint that is flushed with the surface of the pile at the joint position. Bending resistance tests are conducted on four types of new joints for common pipe piles to study the deformation development process, bending bearing capacity, and damage characteristics of the new joints. Cracks are mainly distributed in the pure bending section and are approximately symmetrically distributed along both sides of the joint; there is no obvious cracking and damage in the joint until the pile cracks. Under the same bending moment, the deflection in the span of all specimens is greater than the deflection at the loading point.
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Meyer, Zygmunt, i Kamil Stachecki. "Static load test curve (Q–s) conversion in to pile of different size". Annals of Warsaw University of Life Sciences – SGGW. Land Reclamation 50, nr 2 (1.06.2018): 171–82. http://dx.doi.org/10.2478/sggw-2018-0014.
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Abstract In the work authors analysed possibility of obtaining static load tests curve for a pile in case of changed diameter, using load curve based on results of static load tests for given diameter. In calculation analysis authors used Meyer–Kowalów (M-K) method. A mathematical description was shown of determining new M-K curve for a pile with changed diameter, taking as a basis original M-K curve obtained from static load tests. Then an example of calculations is presented in which parameters of M-K model for a new curve were determined. Simulation calculations were carried out in the original computer program, the results of which includes load curves for piles with different diameters and relations between diameter changes, limit load capacity and settlement of a pile.
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Wang, Zezhong, Eric Tak Cho Ho i Inez Maria Zwetsloot. "Accuracy and precision of the CSLT measurement system: An experiment to defect diagnoses in bored piles". Special Issue with Awarded and Shortlisted Papers from the HKIE Outstanding Paper Award for Young Engineers/Researchers 2021 28, nr 4 (31.12.2021): 176–85. http://dx.doi.org/10.33430/v28n4thie-2021-0011.
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A new measurement system called Crosshole Sonic Logging Tomography (CSLT) provides information on the size, shape, and orientation of defects in a bored pile. The CSLT measurement system has not (yet) been accredited in Hong Kong for foundation testing. Bored piles in Hong Kong are generally wide and deep. Existing measurement accuracy studies do not consider this large type of bored piles. The objective of this research is to quantify the measurement accuracy and precision of the CSLT method for large diameter bored piles (the most common pile type for public housing projects in Hong Kong). A test pile was constructed with known defects and perform experiments with a CSLT measurement system to quantify its accuracy and precision. CSLT is found to be accurate in detecting shape, size, and location of large defects but small defects close to the tube are difficult to detect. Generally speaking, CSLT has satisfactory accuracy and precision for practical use. The use of CSLT can be considered as a feasible method in defect diagnosis of bore piles in Hong Kong.
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He, Juhua, Kenny W. K. Hui i Irene M. C. Lo. "Potential and prospects of photocatalytic disinfection: using sustainable solarenergy- driven photocatalysts". Special Issue with Awarded and Shortlisted Papers from the HKIE Outstanding Paper Award for Young Engineers/Researchers 2021 28, nr 4 (31.12.2021): 165–75. http://dx.doi.org/10.33430/v28n4thie-2021-0015.
Pełny tekst źródłaStreszczenie:
A new measurement system called Crosshole Sonic Logging Tomography (CSLT) provides information on the size, shape, and orientation of defects in a bored pile. The CSLT measurement system has not (yet) been accredited in Hong Kong for foundation testing. Bored piles in Hong Kong are generally wide and deep. Existing measurement accuracy studies do not consider this large type of bored piles. The objective of this research is to quantify the measurement accuracy and precision of the CSLT method for large diameter bored piles (the most common pile type for public housing projects in Hong Kong). A test pile was constructed with known defects and perform experiments with a CSLT measurement system to quantify its accuracy and precision. CSLT is found to be accurate in detecting shape, size, and location of large defects but small defects close to the tube are difficult to detect. Generally speaking, CSLT has satisfactory accuracy and precision for practical use. The use of CSLT can be considered as a feasible method in defect diagnosis of bore piles in Hong Kong.
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Le, Xudong, Xiuqin Cui, Mengyang Zhang, Zhijun Xu i Lin Dou. "Behavior Investigation of Necking Pile with Caps Assisted with Transparent Soil Technology". Sustainability 14, nr 14 (15.07.2022): 8681. http://dx.doi.org/10.3390/su14148681.
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Pile easily develops necking defects during construction, which can limit the exertion of shaft resistance, resulting in reducing ultimate bearing capacity and creating potential safety hazards to projects. Based on transparent soil technology, this paper took the necking located in the middle part of pile shafts as an example and carried out vertical loading experiments on one intact pile and nine necking piles with caps. Then, the influences of necking length and diameter on the vertical bearing capacity were studied. The speckle field of the soil around piles was processed using the MatPIV program to investigate soil displacement. Through comparison and analysis with the intact pile, the reasons for the reduction in bearing capacity were obtained. The results show that the bearing capacity of the piles is seriously damaged by the necking. When the necking diameter is 4 mm and the necking length is 20 mm, the loss of vertical bearing capacity was 26.6%. The vertical bearing capacity decreases with the increase in necking length or the decrease in necking diameter. Pile necking makes a significant contribution to the displacement of soil around the cap. Inclined downward displacement of soil occurs near necking, which reduces the relative displacement between pile and soil and leads to the loss of pile resistance. For the necking with a large size, the soil displacement at the necking and around the pile cap is connected, which causes the displacement range of the soil under the pile cap to increase, resulting in a weakening of the exertion of shaft resistance. Subsequently, the vertical bearing capacity of piles is reduced.
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Jun, Sanghyun, Hyungho Lee i Byungsoo Park. "Experimental and Numerical Study for Analyzing Applicability of Helical Piles". Journal of the Korean Society of Hazard Mitigation 20, nr 3 (30.06.2020): 215–23. http://dx.doi.org/10.9798/kosham.2020.20.3.215.
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A helical pile is a foundation type that can be constructed to improve the bearing capacity and pullout resistance using a spiral plate affixed to the central shaft of the pile. In the past, piles were applied in formulaic shapes, but based on recent developments of threaded joints, the specifications of a helical pile can be applied depending on the site conditions. In this study, model tests and numerical modeling were performed to analyze the bearing capacity and pullout resistance based on the number, size, and position of the helix, which were the main factors of the helical pile. The bearing capacity and pullout resistance improved as the number and diameter of the helix increased. When the helix was installed near the bottom of the pile, the helical pile showed an excellent performance. In addition, by analyzing the ratio of the increase in the bearing capacity according to the area ratio of the helix as a part of the economic analysis, it is essential to consider the installation position of the helix. Based on the analysis results, it was shown that the helical pile could be improved.
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Wang, Xiaolei, Zeyuan Wang, Changfeng Yuan i Libo Liu. "Study on the Horizontal Bearing Characteristic of a New Type of Offshore Rubber Airbag Branch Pile". Sustainability 14, nr 12 (15.06.2022): 7331. http://dx.doi.org/10.3390/su14127331.
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In this work, a new type of marine rubber airbag branch pile has been presented, and the influences of the exposed length L0 of the pile, size of rubber airbag branch and depth S0 of rubber airbag branch embedded in soil on the horizontal bearing capacity of the pile, have been investigated using numerical simulations. Simulation results were used to modify the eigenvalue equations of the horizontal bearing capacity. The results also showed that reverse displacement and the bending moment of the rubber airbag branch pile were lower in pipe piles with larger diameters, and the horizontal bearing capacity was more stable. At small horizontal displacements of the pile top, horizontal bearing capacities of large-diameter pipe piles were slightly higher, while for the pile’s top horizontal displacements of above 10 mm, horizontal bearing capacities of rubber airbag branch piles became significantly greater than those of the large-diameter pipe piles. Based on assumptions, the calculation equations of vacuum negative pressure and friction force between the rubber airbag branch and soil were derived. The equations for calculating the characteristic horizontal bearing capacities of rubber airbag branch piles were also derived and were modified based on simulation results. The calculation results confirmed the improvement in the accuracy of the modified equations.
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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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Zhuang, Xiaoxuan, Zhongling Zong, Yunhan Huang i Peipei Wang. "Analysis of the Installation Effect on the Axial Performance of Pressure-Grouted Helical Piles in Clay by Small-Scale Model Tests". Buildings 12, nr 7 (12.07.2022): 992. http://dx.doi.org/10.3390/buildings12070992.
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A pressure-grouted helical pile (PGHP) is a stiffened helical pile installed by using the simultaneous drilling and grouting technique. The formation of the soil-cement column surrounded by the helical pile is influenced by the multiple installation parameters, including helix number, helix size, and drilling speed. A series of small-scale model tests was carried out in clay to investigate the influence of installation parameters on axial behavior of PGHP and the load transfer mechanism. The model piles were pulled out after the loading tests, and the dimensions of the soil-cement columns were measured. The ultimate compressive bearing capacities of the PGHPs were 260% to 293% higher than the un-grouted helical piles. The ultimate bearing capacities of the PGHPs were proportional to the increase of the helix number and helix size and decreased with the drilling speed. The average bond diameter of the soil-cement column was 1.26 to 1.35 times the helix size. The adhesion between the soil-cement column and the surrounding clay was in the range of 0.8 to 1.2. The overall results examine the feasibility of the simultaneous drilling and grouting technique in clay and the improvement of the axial bearing performance compared to un-grouted helical piles.
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Cui, Qiang, Wen Zhi Yang, Sheng Hui Liu i Xian Long Lu. "A Study on Bearing Characteristics of Horizontally-Loaded Short Piles in 750kV Transmission Line on Loess Foundation". Applied Mechanics and Materials 256-259 (grudzień 2012): 458–62. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.458.
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For the angle tower foundation of 750kV transmission line, the overturning effect caused by wire tension is a control factor of tower foundation design. The pile foundation on loess was taken as a research object in this study, where two typical regions along 750kV Lanzhou - Tianshui - Baoji transmission line were selected to carry out the site full-size horizontal static load test. Through the arrangement of displacement sensors and earth pressure cells around piles, the load-displacement curve of pile lateral soil under horizontal loads was obtained as well as the distribution law of soil stress at different locations of the pile. Based on the "m" method, the soil stress at different locations of the pile was calculated. The results showed that the calculated results were well consistent with experimental results. This research work can provide a theoretical basis and design guidance for tower foundation selection and design optimization of 750kV transmission line.
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Setiawan, Bambang, Raden Harya Dananjaya H.I. i Muhammad Fathurrahman. "PENGARUH PERKUATAN TIANG TERHADAP STABILITAS TIMBUNAN DIATAS TANAH LUNAK MENGGUNAKAN METODE ELEMEN HINGGA". Jurnal Riset Rekayasa Sipil 3, nr 2 (1.04.2020): 54. http://dx.doi.org/10.20961/jrrs.v3i2.40953.
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<p><em>Pile strength is widely used as a solution to the problem of road pavement on soft soil, because it can reduce vertical displacement due to the load on it and increase the safety factor value. This research analyses the vertical displacement, safety factor, effective stress and bearing capacity of the embankment on soft soil using the finite element method so the results can approach the original conditions in the field.</em> <em>The pile variations used are pile size variations 20x20 cm<sup>2</sup>; 25x25 cm<sup>2</sup>; and 30x30 cm<sup>2</sup> with a square shape, variations in the distance between the piles 1,60 m; 1,80 m; 2,00 m; and 2,20 m, the depth variations 15,00 m; and 20,00 m. Loading uses truck loads based on RSNI T-14-2004 and the road classification is artery IA. The results of the analysis show that pile strength with a size 20x20 cm<sup>2</sup>, the distance between pile is 1,60 m and the depth of the piles 20 m can reduce the vertical displacement by 71,31% and increase the safety factor by 123,25%.</em></p>
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Li, Xiu Hua, Yan Yan Gao, Chen Xi Yue i Chun Qing Hu. "Horizontal Displacement of GFRP Bars and PC Strand Combination of Technology Supporting Piles". Applied Mechanics and Materials 580-583 (lipiec 2014): 420–23. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.420.
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GFRP bars and PC strand composite pile is a new supporting piles, according to the engineering field test and analysis of experimental data prove that there is a significant effect on the control aspects of the horizontal displacement of supporting piles. Principle energy method can calculate the horizontal displacement of pile foundation pit in theory, by comparing the size of the horizontal displacement of the supporting piles of ordinary reinforcement, to demonstrate the feasibility of using GFRP bars and PC strand combination of techniques to reduce the horizontal displacement of excavation, provide reference for future engineering practice.
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Firoozfar, A., A. Rostami, H. Ghaderi, H. Zamani i A. Rostamkhani. "Assessing the Effects of Length, Slope and Distance between Piles on the Bearing Capacity of a Pile Group under Axial Loading in Granular Soil". Engineering, Technology & Applied Science Research 7, nr 5 (19.10.2017): 1894–99. http://dx.doi.org/10.48084/etasr.1352.
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Piles are usually made of steel, concrete, reinforced concrete or wood, used to enhance the ground’s bearing capacity in order to enable the construction of deep foundations, also called pile foundations. However, the exact effect of the complex interaction between the piles and the surrounding soil has not adequately been investigated yet. Considering the increased application of the technique recently, further analysis is essential for achieving the highest economic and technical capacity. Using fewer piles or shorter piles and allowing greater distances between pile groups, results to reduced construction. However, other restrictions such as high groundwater level, bedrock depth and the limited size of the foundation are also to be considered. The issue of optimal pile layout is further investigated in the current paper employing Plaxis, a finite element software, for modeling purposes and considering axial loadings in granular soils. Results are shown and further discussed.
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Chen, H., Y. X. Chen, Q. S. Wei i Y. S. Shi. "Effect of Gravity on Repose Angle and Contact Forces of Particulate Pile Composed of Non-monodispersed Particles". International Journal of Aerospace Engineering 2019 (4.02.2019): 1–10. http://dx.doi.org/10.1155/2019/8513149.
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Evaluating the repose angle of granular materials under different kinds of gravitational conditions is essential for in situ resource exploration on surfaces of other Earth-like planets in the next decades. The forming process of particulate pile under different kinds of gravitational accelerations was simulated by three-dimensional discrete element method (DEM), where the particulate piles composed of normally distributed particles and lognormally distributed particles were considered, respectively. The effects of gravity on the repose angle and contact forces of the particulate pile were investigated. The results show that, for particulate pile composed of normally or lognormally distributed particles, the effect of gravity force on the repose angle is ignorable. For particles with a certain kind of size distribution, the distribution functions of normalized contact forces in the particulate pile under different gravity accelerations show to be in mutual coincidence. No obvious effect of the particle size distribution on the relation between the gravity acceleration and repose angle is observed.
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Zhang, Aobo, Jin Liao, Zhen Liu, Cuiying Zhou i Lihai Zhang. "Optimized Design of Piled Embankment Using a Multi-Effect Coupling Model on a Coastal Highway". Journal of Marine Science and Engineering 10, nr 9 (23.08.2022): 1170. http://dx.doi.org/10.3390/jmse10091170.
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This study presents a multi-effect coupling model to optimize the design of a geosynthetic-reinforced pile-supported embankment (GRPSE) considering the coupling effects of soil arching, membranes, and pile–soil interaction on a coastal highway. The developed model could optimize the design of the GRPSE to fulfill the design and construction requirements at a relatively low project cost. This was achieved by adjusting the critical factors that govern the settlement of GRPSEs, such as pile spacing, tensile stiffness of geosynthetic reinforcement (GR), arrangement of piles, pile cap size, and cushion thickness. The model predictions were validated by a series of field tests using a range of geotechnical sensors. The results show that model predictions agreed with experimental measurements reasonably well. In addition, the results indicate that in comparison to a square arrangement of piles, a triangle net arrangement can decrease the differential settlement of pile soil. Furthermore, this study demonstrates that a change in the GR’s tensile stiffness has little impact on the settlement of GRPSEs. This study can help to improve the stability of roadbeds of coastal highways.
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Lee, Won-Hyo, Soon-Goo Kwon i Tae-Hyung Kim. "A Study of Lateral Resistance of Block Breakwater Combined with Piles". Journal of Korean Society of Coastal and Ocean Engineers 34, nr 4 (31.08.2022): 100–108. http://dx.doi.org/10.9765/kscoe.2022.34.4.100.
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Three-dimensional FEM numerical analysis was performed to understand the behaviors of blocks and piles according to the horizontal load for the block breakwater combined with piles. The Modified Mohr-Coulomb model, the improved version of the Mohr-Coulomb model, was applied for the ground modeling. The cases when the pile is embedded only into the block, embedded to the riprap layer (H = 4.29 cm), and embedded to the ground down to 2H, 3H, and 4H were examined. The results of the laboratory model experiment and the numerical analysis showed similar horizontal resistance force-displacement behaviors. The pile showed rotational behavior up to the embedment depth of 1H~2H and bending behavior in the case of 3H~4H depth embedment. When the embedment depth of the pile is 3H or more, the pile shows a bending behavior, so it can be considered that the pile contributes significantly to the horizontal resistance of the block breakwater. The results of this study will be used for various numerical analyses for real-size structure design.
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SHAPOVAL, A. B., i M. G. SHNIRMAN. "HOW SIZE OF TARGET AVALANCHES INFLUENCES PREDICTION EFFICIENCY". International Journal of Modern Physics C 17, nr 12 (grudzień 2006): 1777–90. http://dx.doi.org/10.1142/s0129183106010212.
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Bak, Tang, and Wiesenfeld [Phys. Rev. Lett.59, 381 (1987)] introduced their sand-pile (BTW sand-pile) as the cellular automata coming to their critical state without tuning any inner model parameters. The main model features deal with grains falling slowly onto the two-dimensional lattice and a quick deterministic transport of the superfluous grains to the boundary. The simplest modifications of the BTW sand-pile develop a random transport mechanism instead of a deterministic one. The model transportation of the grains generates avalanches. We find that before the big avalanches the height of the pile increases and the singular grains organize themselves in special clusters. These observations lead to the formal algorithm that predicts the big avalanches in advance with a certain efficiency. However the efficiency for the BTW sand-pile is worse than that for its stochastic modifications.
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Qi, Hongliang, Guishan Chen, Wen Zou, Tiangang Yuan, Weiping Tian i Jiachun Li. "Characteristics and Mechanism of Local Scour Reduction around Pier Using Permeable Sacrificial Pile in Clear Water". Water 14, nr 24 (12.12.2022): 4051. http://dx.doi.org/10.3390/w14244051.
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To improve the local scour protection of the pier using solid sacrificial piles, a kind of permeable sacrificial pile filled with stones is put forward in this study. Four influencing factors, including the size of the filling gravel of the permeable sacrificial pile, the distance between the pile and pier, the diameter ratio D1/D (D is the diameter of the pier and D1 is the diameter of the pile.), and the submergence rate of the pile, are studied in clear water condition with indoor tests and numerical simulations. The test results show that it has the best reduction effect on the local scour of the pier when the filled gravel size is 0.2–0.25 D, the distance between the pile and pier is 3.0 D, the diameter ratio is 1.0, and the submergence rate is 0.8. Results of the numerical simulation show that the permeable sacrificial pile has a significant weakening effect on the downflow in front of the pile and the flow velocity around the pile. In the same conditions, the reduction effects of the permeable sacrificial pile and the solid sacrificial pile on the pier are similar, but the local scour around the permeable sacrificial pile is less than that around the solid one. The pressure difference outside and inside the permeable pile causes the water to flow in the direction perpendicular to the isobars. This significantly impacts the flow velocity, the vortex system, and the shear stress around the permeable sacrificial pile and pier, which leads to a huge decrease in the local scour depths. The maximum shear stress on both sides of the permeable sacrificial pile and the pier is about 1/2 and 1/4 of those around the solid sacrificial pile respectively. And the area with lower velocity and shear stress behind the permeable sacrificial pile is larger than the area behind the solid ones.
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Kostina, O. V., i T. M. Bochkareva. "STUDY OF THE NATURE OF THE WORK OF PILES WITH ROTARY ANCHORS WHEN WORKING IN AN ARRAY OF HEAVING SOILS". Construction and Geotechnics 11, nr 4 (15.12.2020): 46–57. http://dx.doi.org/10.15593/2224-9826/2020.4.04.
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A new design of horizontal pivoting pile anchors used as supports for main pipelines on heaving and watered bases is proposed. The purpose of the design is to reduce the deformability of this type of Foundation and increase its load-bearing capacity under the influence of the forces of frost heaving of the soil. Stamp tests of models of piles with rotary anchors were performed on the stand for testing Foundation models of NPP GEOTECH. Based on the test results, the effectiveness of using piles with the location of their rotary anchors at one and two levels along the trunk was compared, and the reduction in the load-bearing capacity of the pile with an unfavorable location of the anchors was determined. It is shown that according to the results of stamp tests, the rotary anchors of piles positively affect the operation of the Foundation. The use of rotary anchors in one level increases the load-bearing capacity of the pile by 16 % and reduces shrinkage by 40 % compared to a pile of the same size, but without anchors. The use of anchors in two levels increases the load-bearing capacity of the pile by 73 % and reduces the draft by 48 %. The advantage of a pile with two levels of anchors compared to its own with one level of anchors is 48 % in terms of load-bearing capacity and 11 % in terms of draft. The use of rotary pile anchors can significantly increase the reliability of the foundations of main pipelines on heaving and watered bases. This design solution is more efficient than similar metal piles with vertical anchors at equal cost levels.
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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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Wang, Yonghong, Xueying Liu, Songkui Sang, Mingyi Zhang i Peng Wang. "A Model Test for the Influence of Lateral Pressure on Vertical Bearing Characteristics in Pile Jacking Process Based on Optical Sensors". Sensors 20, nr 6 (20.03.2020): 1733. http://dx.doi.org/10.3390/s20061733.
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Photoelectric integrated testing technology was used to study precast piles during pile jacking at the pile–soil interface considering the influence of the earth and pore water pressures on its vertical bearing performance. The low temperature sensitive fiber Bragg grating (FBG) strain sensors and miniature silicon piezoresistive sensors were implanted in the model pile to test the changes of earth pressure, pore water pressure and pile axial force of the jacked pile at the pile–soil interface, and the influence of lateral pressure on pile axial force was studied. The test results showed that the nylon rod is feasible as a model pile. The FBG strain sensor had a stable performance and monitored changes in the axial force of the model pile in real time. The miniature earth and pore water pressure sensors were small enough to avoid size effects and accurately measured changes in the earth and pore water pressures during the pile jacking process. During pile jacking, the lateral earth pressure increased gradually in depth, and the lateral earth pressure at the same depth tended to decrease at greater depths. Lateral pressures caused the axial force of the pile to increases by a factor of 1–2, where the maximum was 2.7. Therefore, the influence of the lateral pressure must be considered when studying the residual pile stress.
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Lu, Ye, Yun Jiang i Xiaoyong Wang. "Investigation of soil displacements caused by the press-in process for close-ended model piles using an imaging technique". Acta Geotechnica Slovenica 17, nr 2 (2020): 2–15. http://dx.doi.org/10.18690/10.18690/actageotechslov.17.2.2-15.2020.
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In recent years, installing piles using the press-in method has gained popularity in urban areas. However, pushing piles into the ground squeezes the surrounding soils and consequently causes a disturbance or even damage to the underground structures and facilities close by. In order to investigate the squeezing effect incurred by press-in piling, a series of model tests were performed. The soil displacement field was captured using a non-contact technique called digital image correlation (DIC), and the horizontal soil stresses were measured by mini pressure cells. Analyses of the soil displacement fields showed that the pile press-in process caused different soil displacement paths at different depths and locations. The development of horizontal soil stresses correlated well with the horizontal and vertical displacements. A thin disturbance layer could be observed along the pile-soil interface and it was about 7.4-11.1 D50 in thickness (D50, median particle size). At the end, the soil displacements caused by pushing the model pile with different pile shoes were analyzed and compared, and the analyses showed that a greater shoe angle resulted in greater disturbance to the surrounding soils. However, the influence of the pile shoe angle became less substantial with the increase of the pile penetration depth.
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Wang, Yonghong, Xueying Liu, Mingyi Zhang, Xiaoyu Bai i Ben Mou. "Fiber Bragg Grating Sensors for Pile Jacking Monitoring in Clay Soil". Sensors 20, nr 18 (14.09.2020): 5239. http://dx.doi.org/10.3390/s20185239.
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The small deformation of the model pile in a pile jacking test makes its accurate measurement very difficult. Based on the installation method of clamping at both ends, a sensitized miniature fiber Bragg grating (FBG) strain sensor was developed to measure the pile strain of small-size model piles. This study investigated the working principle of the sensitized miniature FBG sensor and analyzed the strain transfer characteristics of the sensor by calibration test. The lateral resistance and the earth plug resistance of the model pile were measured accurately by the grooves embedded in the outer tube of the double-wall opening model pile and the sensors directly pasted on the surface of the inner tube. The results of this study show that the sensitized miniature FBG strain sensor has the advantages of high sensitivity, strong interference resistance, and high test accuracy. The FBG strain sensor was completely fixed on the pile by clamping supports at both ends, and the strain measured using the FBG strain sensor was found to be consistent with the pile deformation.