The strain superposition concept, proposed for ballast study, is applied in this note to evaluate strain accumulation for laterally loaded piles in sand. It is shown that the soil properties, types of pile installation, cyclic loading types, pile embedded length, and pile/soil relative stiffness ratio are important factors that influence the pile behavior under mixed lateral loads. These factors are quantified by means of a degradation factor, t, which is derived from the results of 20 full-scale pile load tests and then verified using six additional full-scale pile load tests.

Permanent strains of piles in sand due to cyclic lateral loads. technical note

On the behavior of monopiles subjected to multiple episodes of cyclic loading and reconsolidation in cohesive soils

Pile-soil interaction under cyclic lateral load in loose sand: Experimental and numerical evaluations

Permanent accumulated rotation of offshore wind turbine monopile due to typhoon-induced cyclic loading

Optimised design is essential to reduce the cost of monopiles for offshore wind turbines. For this purpose, an in-depth understanding of the behaviour of monopile–soil interaction is required. As m...

Characteristics of cyclic undrained model SANISAND-MSu and their effects on response of monopiles for offshore wind structures

An experimental study on the parameters affecting the cyclic lateral response of monopiles for offshore wind turbines in sand

Conventional installation methods for displacement piles (i.e. impact-driving or vibratory-driving) induce vibrations and settlements in a zone close to the pile. Moreover they lead to noise pollution unfavourable especially in urban areas. A possible solution to these problems is the technology of rotary pile jacking. Thereby the pile is continuously pushed into the subsoil by a vertical force. For large pile dimensions a rotation is additionally applied to overcome high axial forces. This paper presents a new testing facility for axially loaded piles in saturated non-cohesive soils as well as the preparation procedure of the test sand. The facility is capable of installing and loading model piles by applying an axial load as well as a simultaneous rotary motion and enables model testing in different scales up to pile diameters of 101.6 mm and a maximum embedment length of 2.3 m. All test stages can be monitored and recorded with a data acquisition system, making it possible to study the influence of different installation parameters on the required installation forces and the resulting bearing behaviour. First results prove the efficiency of a rotation regarding the required axial installation force.

Dennis Frick

Papers

An experimental study on the parameters affecting the cyclic lateral response of monopiles for offshore wind turbines in sand

Model testing of rotary jacked open ended tubular piles in saturated non-cohesive soil

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