Lateral bearing behaviour of vibro‐ and impact‐driven large‐diameter piles in dense sand

Achmus, Martin; Schmoor, Kirill Alexander; Herwig, Volker; Matlock, Benjamin

doi:10.1002/gete.202000006

Cited by 27 publications

(9 citation statements)

References 2 publications

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“…The results of Stein et al (2020) agree with the results of another recent field test campaign conducted by Achmus et al (2020), where the lateral load behaviour of vibrated piles was compared to impact driven piles. The subsoil at the test side close to Cuxhaven (Germany) consisted mainly of fine to medium coarse silica sands with medium dense to dense initial state.…”

Section: Response Of Vibratory Driven Piles To (Cyclic) Lateral Loadingsupporting

confidence: 83%

“…It is known from experimental investigations that the pile response to loading following the installation process is influenced by the installation method (see e.g. (Dyson and Randolph, 2001;Anusic et al, 2019;Stein et al, 2020;Achmus et al, 2020;Fan et al, 2021b)).…”

Section: Introductionmentioning

confidence: 99%

“…Vibratory driving is often used in case of water-saturated soil or it is combined with impact driving in case the penetration resistance can not be overcome during the installation process. Vibratory driven piles are sometimes reported to have lower load capacity compared to impact driven or jacked piles (Grabe and Pucker, 2015;Achmus et al, 2020). In addition, vibratory driven piles are often reported to accumulate more deformation when subjected to cyclic lateral loading compared to impact driven piles (Labenski and Moormann, 2019;Stein et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

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Long-Term Response of Piles to Cyclic Lateral Loading Following Vibratory and Impact Driving in Water-Saturated Sand

Staubach

Macháček

Bienen

et al. 2022

J. Geotech. Geoenviron. Eng.

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The influence of the pile installation by vibratory or impact driving on the response to subsequent cyclic lateral loading, as faced in the offshore environment, is investigated numerically. Largedeformation analyses of the pile installation process using the Coupled Eulerian-Lagrangian method considering partially drained conditions are performed. Following the installation, one million lateral load cycles are simulated using the high-cycle accumulation (HCA) model. The lower the hydraulic conductivity of the soil during driving, the higher the accumulation of lateral deformation when the pile is subjected to high-cyclic loading. The assumption of ideally drained conditions during pile driving results in a lower accumulation, in particular for the vibratory driven pile. Compared to the influence of the drainage conditions during driving, the influence of the installation method is found to be of less importance. While the vibratory driven piles tend to give less resistance to monotonic lateral loading for most conditions, slightly lower permanent pile head rotations after one million lateral loading cycles are observed compared to the impact driven piles.

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Section: Response Of Vibratory Driven Piles To (Cyclic) Lateral Loadingsupporting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Long-Term Response of Piles to Cyclic Lateral Loading Following Vibratory and Impact Driving in Water-Saturated Sand

Staubach

Macháček

Bienen

et al. 2022

J. Geotech. Geoenviron. Eng.

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“…In all the simulations, the sand and pile were modelled by eight-node linear strain brick elements (i.e., "C3D8"). The Coulomb interface model with a friction coefficient of 0.67ϕ (ϕ is the critical state soil friction angle) was used to simulate the interface behaviour between the pile and soil (Achmus et al 2020).…”

Section: Finite-element Modellingmentioning

confidence: 99%

Ultimate soil resistance of the laterally loaded pile in uniform sand

Wang

Askarinejad

et al. 2023

Can. Geotech. J.

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Piles have been widely used as foundations to resist lateral loads. For the design of a laterally loaded pile, one of the most important inputs is the ultimate soil resistance (pult=KultDσv’, Kult is the ultimate lateral soil resistance coefficient, D is pile diameter, σv’ is the vertical effective stress). However, great discrepancy can be found in the existing design equations for piles in sand. To provide new insights and clarify the discrepancy in previous studies, this technical note performed a series of numerical simulations on piles of different configurations using the finite element model validated by centrifuge pile tests. The computed results suggest that Kult is a function of depth ratios z/D and z/L for the flexible and rigid piles, respectively (where, z is absolute depth, L is pile length) and all existing design equations failed to reproduce the magnitude and distribution of Kult. Additionally, Kult of horizontally translated fixed-head rigid piles exhibit the same pattern as flexible piles, suggesting that the difference between free-head flexible and rigid piles is caused by the change of failure modes.

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“…stricter environmental regulations in terms of underwater noise levels has motivated the development of alternatives to the conventional impact-driving method of monopile installation. One of the alternatives is the (axial) vibratory installation, which has been previously studied in field [1,2,4] and laboratory [3,5] conditions. However, there is limited knowledge on the effects of vibratory installation (and how these effects differ from those caused by impact-driving) on the lateral response of monopiles.…”

mentioning

confidence: 99%

laboratory study of the effect of installation parameters on the lateral behaviour of monopiles in sand

Peccin da Silva,

Post,

Elkadi

et al. 2023

SEG

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Monopiles are the predominant type of foundation used for offshore wind turbines. The increase in size of monopiles and the stricter environmental regulations in terms of underwater noise levels has motivated the development of alternatives to the conventional impact-driving method of monopile installation. One of the alternatives is the (axial) vibratory installation, which has been previously studied in field [1, 2, 4] and laboratory [3, 5] conditions. However, there is limited knowledge on the effects of vibratory installation (and how these effects differ from those caused by impact-driving) on the lateral response of monopiles. This extended abstract presents the results of an ongoing Join Industry Project (SIMOX – Sustainable Installation of XXL Monopiles) which aims at comparing different installation methods from the point of view of driveability, noise emissions and lateral response. The present abstract particularly focuses on the lateral response of monopiles. As a first step towards the large-scale onshore field tests to be executed in 2023, a laboratory study was conducted at the Water-Soil Flume at Deltares, in Delft (NL), which consists of a tank with 9.0 m of length, 5.5 m of width and 2.5 m of depth, with a multipurpose wagon on rails above it (Figure 1). The tank was filled with saturated Sibelco S90 sand up to a height of 2.4 m in compacted layers of 50 cm. The experimental programme consisted of 4 batches (batches 1, 2 and 3 with dense sand and batch 4 with medium-dense sand) in which piles of diameter D = 32 cm, embedded length L = 1.5 m and wall thickness t = 4 mm or 10 mm were installed and loaded laterally. While batch 1 focused on driveability aspects, in the other three batches 8 piles were installed (per batch) and subsequently subjected to lateral loading. The centre-to-centre distance between piles was 8D in the loading direction and 6.5D perpendicular to the loading direction. The distance between the piles and walls of the tank was 4.3D. All distances were larger than the minimum distances recommended in the literature [6]. The piles were installed with two different methods: vibratory-driven, using a hydraulic vibro-hammer APE-23 with an eccentric moment of 1.3 kg.m, and impact-driven, using a dropping weight impact-hammer HL750. For each method, selected installation parameters were varied, namely the vibratory frequency and lowering speed of the crane for vibrated piles, and dropping mass and fall height for the impact-driven piles. Lateral loading was applied at the pile head by means of an in-house built lateral loading device consisting of an electric motor connected to a spindle. The lateral displacements were measured by a magnetostrictive linear position sensor, independent of the lateral loading system. The loading regime consisted of an initial monotonic loading up to 25% of Hult (where Hult is defined as the load at which the pile exhibits a displacement of 0.1D at ground level – obtained from 3D FE analyses), followed by cyclic loading (1000 cycles for most piles) and a final monotonic stage up to the maximum load. The different combinations of lowering speeds of the crane (low, high) with the different frequencies of the vibro-hammer (low, high) led to different types of vibratory installation: crane controlled or free hanging. Under crane-controlled installation, the full weight of the pile-hammer system is sustained by the overhead crane, hence the crane load measured by a load cell oscillates around the static weight of the pile-hammer system. Under free-hanging conditions, on the other hand, the load taken by the crane is zero, meaning that the weight of the pile-hammer system is fully taken by the soil – both by shaft friction and tip resistance. The results in dense sand showed that the initial monotonic response of the piles is affected by the vibration mode, and not by the installation frequency or penetration speed alone. While the crane-controlled vibrated piles exhibited lateral stiffness similar (i.e. slightly lower) to the impact-driven piles, the free-hanging vibrated piles showed markedly lower lateral stiffness compared to the other piles. The softer behaviour observed for these piles could be attributed to various reasons, such as the difficulty in controlling the pile verticality during installation. For all free hanging piles, inclination was observed approximately half-way through installation, which was corrected in the final part of installation. The exact inclination during installation was not measured, which will be done in the onshore field tests. The test results showed, however, that during cyclic loading the differences in lateral stiffness decrease, i.e. the softest piles in the initial monotonic stage were the ones that exhibited the largest gain in lateral cyclic stiffness, whereas the stiffest piles in the initial loading stage were the ones with the smallest increase in stiffness during cyclic loading.

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Lateral bearing behaviour of vibro‐ and impact‐driven large‐diameter piles in dense sand

Cited by 27 publications

References 2 publications

Long-Term Response of Piles to Cyclic Lateral Loading Following Vibratory and Impact Driving in Water-Saturated Sand

Long-Term Response of Piles to Cyclic Lateral Loading Following Vibratory and Impact Driving in Water-Saturated Sand

Ultimate soil resistance of the laterally loaded pile in uniform sand

laboratory study of the effect of installation parameters on the lateral behaviour of monopiles in sand

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