Trial Pile Research Articles

Discussion of Several Key Technologies about Offshore Wind Power

The development, structure type of foundation, trial pile experiment of the offshore wind power station is investigated and the application of foundation type is analysed for different seabed. The future development of the offshore wind power is forecasted. The documents about the trial pile experiment is collected for the guidance of the design, construction and monitoring.

Pile Foundation In Situ Test in Seaside Soil-Squeezing Backfill Zone

Design and construction of pile foundation in seaside zone face the specific geotechnical conditions. The in-situ geotechnical tests need to be conducted. The quality feature of the piles is assessed according to the results of in-situ small strain test, coring test and pile stress test. For different depth of rock and soil stratum and pile bearing layer, the trial pile stress distribution results and follow-up stress and settlement monitoring provide engineering parameters for design and pile-driving.

Pile and pile group response to tunnelling using a large diameter slurry shield – Case study in Shanghai

The study investigates the disturbance to piles and pile groups caused by multiple nearby drives of a large diameter slurry shield-driven tunnelling machine in Shanghai. The minimum distance between the slurry shield tunnel (with diameter D=15.43m) and the adjacent pile groups of Metro Line 3 and Yixian Elevated Road is 1m. The nonlinear finite element (FE) software program ABAQUS was used to analyse the movement of the pile groups caused by the process of shield tunnelling. A field investigation was conducted before the multiple crossings to study the impact (movement and excess pore water pressure) on the surrounding soil and piles caused by the tunnelling process. The field investigation is divided into two sections: (i) free-field tunnelling, and (ii) tunnelling close to trial piles pre-installed in the section. For the full-scale test, tunnelling variable, including slurry pressure and grouting pressure, are adjusted during construction to reduce the disturbance during tunnelling close to pile groups supporting two elevated bridges. The FE simulation of the multiple crossings includes two steps: (a) shield tunnelling along the south bound tunnel approaching the working shaft at the western bank of the Huangpu River, and passing separately between two adjacent pile groups of each bridge; (b) return tunnel passing again between the pile groups of the two bridges along the north bound tunnel. Three different FE models are generated: (1) free-field tunnelling process, (2) tunnelling close to trial piles, and (3) multiple tunnel passes adjacent to pile groups supporting the two elevated bridges. Most of the relevant factors in tunnelling are taken into consideration in the FE models including (a) slurry pressure, (b) grouting pressure, (c) grouting material hardening, and (d) soil-pile interaction.

Behaviour of piles subjected to passive subsoil movement due to embankment construction – A simplified 3D analysis

Two trial piles were installed at the berm section of an embankment in the later stage of its construction and one of them was fitted with an oversized casing to isolate its top 3m from the action of surrounding soil. Lateral bending behaviour these two piles subjected to passive sub soil movements were very different from each other because of the casing and is modelled in this paper using a three dimensional analysis. The effect of relative stiffness of the piles on their lateral bending behaviour is investigated. The effect of interface joint slip on the pile’s behaviour is also investigated in a later section of this paper.

Re-assessment of foundation settlements for the Burj Khalifa, Dubai

This paper deals with the re-assessment of foundation settlements for the Burj Khalifa Tower in Dubai. The foundation system for the tower is a piled raft, founded on deep deposits of calcareous rocks. Two computer programs, Geotechnical Analysis of Raft with Piles (GARP) and Non-linear Analysis of Piled Rafts (NAPRA) have been used for the settlement analyses, and the paper outlines the procedure adopted to re-assess the foundation settlements based on a careful interpretation of load tests on trial piles in which the interaction effects of the pile test set-up are allowed for. The paper then examines the influence of a series of factors on the computed settlements. In order to obtain reasonable estimates of differential settlements within the system, it is found desirable to incorporate the effects of the superstructure stiffness which act to increase the stiffness of the overall foundation system. Values of average and differential settlements for the piled raft calculated with GARP and NAPRA were found to be in reasonable agreement with measured data on settlements taken near the end of construction of the tower.

Field measurements of the stiffness of jacked piles and pile groups

INTRODUCTION This Technical Note presents a back-analysis of the axial response of some field-scale tubular displacement piles installed by jacking. This study was motivated by the recent development of large pile-jacking rigs. These rigs are sufficiently strong to offer an alternative to bored piling in urban areas where conventional dynamic methods of displacement pile installation are not permitted (White et al., 2002). The most notable feature of the axial response was the very high stiffness. Some pile jacking machines ‘walk’ along the pile wall under construction, so all piles must necessarily be installed at close centres, or indeed touching. This geometry is in contrast to conventional design guidance, which suggests that a separation of typically two or three diameters is required between piles, to prevent harmful interaction effects (BSI, 1986; GEO, 1996). Load test results from jacked piles installed closer than this recommended minimum spacing are presented. The study comprised a series of field tests carried out in Kochi, Japan. Full details are provided by Yetginer et al. (2003), and brief details are repeated below. Test piles were installed singly and in groups forming a ‘cell foundation’, comprising jacked piles at close centres around an enclosed soil block. In this Technical Note, pile group efficiency is defined as the average performance per pile (strength or stiffness) when a group is loaded in unison, divided by the performance of a single pile tested alone. Using this definition, the behaviour of trial piles installed prior to the main group can be linked to the group response. This definition is used by Vesic (1969) and Fleming et al. (1992), and is shown in equation (1) for strength and stiffness. Group strength efficiency, GROUP, is defined in equation (1a), where QSINGLE and QGROUP represent the capacity of a single (isolated) pile and the capacity of a group of n piles respectively. Group stiffness efficiency, GROUP, is defined in equation (1b), where KSINGLE and KGROUP represent the stiffness of a single (isolated) pile and the stiffness of a group of n piles respectively.

Cracked? Exploring post-construction evidence in the interpretation of trial pile data : D. S. Pennington, Proceedings - ICE: Geotechnical Engineering, 113(3), 1995, pp 132–143

There have been unique opportunities to study the performance of large diameter cast in situ piles in Bangkok. A trial piling programme for a mass transport system has included an extensive programme of construction and testing of straight-shafted trial piles. This paper presents data singled out for two particular instrumental piles. The data are used to demonstrate the influence of thermal strains on the integrity of a pile, and, in particular, seek to explore the evidence for the development of residual shaft friction and tensile cracking merely as a consequence of construction. The evidence contributes to understanding post-construction mechanisms which influence the development of shaft friction during loading. (A)

THE DESIGN, CONSTRUCTION AND LOAD TESTING OF STARSOL PILES, PERTH, SCOTLAND.

The Starsol method of pile construction had only been used on one previous occasion in the UK when the technique was chosen to construct the foundations for Hydro Electric plc's new corporate office on Dunkeld Road, Perth, in Scotland. In order to confirm that the piles could be safely constructed in the soils beneath the site, a preliminary trial pile was constructed and load tested prior to start of the main piling works. The results of the trial pile indicated that the piles could carry more load than was envisaged at design stage and, therefore, further investigation into the capacity of these piles in the soils beneath the site was justified. This paper describes the original design of the piles for the site, the construction and testing of the preliminary trial pile and investigates the potential reasons for underestimating the capacity of the piles at the design stage. (A)

CRACKED? EXPLORING POST-CONSTRUCTION EVIDENCE IN THE INTERPRETATION OF TRIAL PILE DATA.

Keywords BRISTOL UNIVERSITY, ARUP GEOTECHNICS PILES, TRIAL, DATA, POST CONSTRUCTION, EVIDENCE, PERFORMANCE, CAST IN, IN SITU, PILING, INFLUENCE, THERMAL, STRAIN, INTEGRITY, RESIDUAL, SHAFTS, FRICTION, TENSILE, CRACKING, LOADING, INSTRUMENTATION, MONITORING, BEHAVIOUR, TESTS, TESTING, CONSTRUCTION, CLAYS, BOREHOLES, GROUTING, BORES, EXCAVATION, GAUGES, INSTRUMENTS, CONCRETING, POST CONCRETING, TEMPERATURE, CONCRETE, MAGNETIC, EXTENSOMETERS, STRESS, LOADS, RAILWAYS, ROADS, MASS, TRANSPORT, CITIES, COUNTRIES, DEVELOPING BANGKOK THAILAND, ASIA... Show All

Bitumen slip coated trial piles and prototype underreamed trial pile at Angel Square, Islington : Whitworth, L J; Turner, A J; Lee, R G Ground EngngV26, N1, Jan/Feb 1993, P28–33

This paper describes the construction, testing and analysis of load tests, performed on bitumen slip-coated trial piles and a prototype underreamed trial pile at the Angel Square project, Islington, London. The project was for a seven-story office and retail building, with a two-floor basement. The foundation scheme was modified from a conventional straight-shafted pile solution, due to the proximity of forthcoming works on the upgrading of the nearby Angel Underground Station, which could severely affect the performance of the piled foundations. The ground across the site was relatively consistent London Clay and Woolwich & Reading Clay. Empirical test and finite element analyses both indicated that surface settlements of 5mm to 50mm would affect at least 50% of the site, and that the 4m to 7m deep basement excavation would cause potentially significant heave across it. A trial piling programme was carried out, to find out how effective a bitumen slip coating would be, and whether underreams would remain stable at the junctions between the two types of clay. The test results gave confidence in the bitumen slip coating's ability to reduce the negative skin friction from the London Clay. To limit heave, all the piles were constructed with slip-coated shafts.

Suitable measures against the pollution of the Rhine by chloride discharge from the Alsatian potash mines.

A great number of organic and inorganic substances pollute the water of the Rhine. The greatest concentration is formed by the chlorides, as their quantity exceeds that of the suiphates by about 50 per cent. At the German—Dutch frontier, the mean annual value of the chloride charge of the river amounts to approximately 350 kg/s C1. About 40 per cent, or 130 kg/s, of this quantity are residual salts originating from the French potash mines in Alsace. As the chloride charge of the Rhine causes considerable damage to Dutch horticulture and the public supply of both drinking water and industrial water, a solution for the problem of the salt discharges in Alsace is sought within the framework of the International Commission for the Protection of the Rhine from Pollution. By means of a separation process, KC1 is extracted from the sylvinite hauled from the mines (58 per cent NaCI, 28 per cent KC1 and 14 per cent marl), while the residual salt, about 7 million tons per year, is drained off into the Rhine. Non-realizable solutions for effecting a reduction of this discharge are: (1) Measures within the production process (2) Filling of the residual salt into the hollow spaces left by mining (3) Sale of the residual salt to soda works (4) Discharge, through a pipeline, into the sea One possible solution would be deposition in a dumping area, but this might endanger the rich ground-water resources of Alsace. At present, a two-year hydrological investigation at a 20 m high trial pile is being complemented by studies on suitable sealing, piling and transporting techniques at different locations. The possibility of transportation by ship has also been taken into consideration. For this purpose, another investigation is actually being carried out.