Tingfa LiuUniversity of Bristol | UB · Department of Civil Engineering
Tingfa Liu
Doctor of Philosophy
About
32
Publications
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359
Citations
Citations since 2017
Introduction
Additional affiliations
October 2018 - May 2020
Publications
Publications (32)
Chalk’s sensitive, variable nature poses difficulties for foundation designers. It can present as weak rock and yet be de-structured to very weak putty by dynamic or high-pressure loading. The development of multiple offshore wind farms at north European chalk sites led to the recent ALPACA Joint Industry Programme, which undertook intensive materi...
The design of large open steel piles driven at chalk sites suffers from considerable uncertainty, leading to major difficulties in many significant onshore and offshore projects. This paper describes recent instrumented driving, monotonic testing to failure and re-strike tests conducted on large open steel piles driven in primarily low- to medium-d...
Comprehensive field investigations into the axial cyclic loading behaviour of open-steel pipe piles driven and aged in low-to-medium density chalk identify the conditions under which behaviour is stable, unstable or metastable. Post-cycling monotonic tests confirmed that stable cycling enhanced pile capacity marginally, while unstable cases suffere...
This paper describes research into the poorly understood axial behaviour of piles driven in chalk. Comprehensive dynamic and monotonic axial testing on 27, mostly instrumented, piles undertaken for the ALPACA Joint Industry Projects is reported and interpreted covering: diameters between 139mm and 1.8m; lengths from 3 to 18m; different pile materia...
Experiments are described which provided the basis for advanced numerical modelling of large-scale axial and lateral pile tests undertaken chalk to assist the design of offshore wind and other projects in northern Europe. The research explored the mechanical behaviour of chalk from a UK research site under effective cell pressures up to 12.8 MPa. W...
This paper considers the axial resistances of open-ended, highly instrumented, 763 mm diameter steel pipe piles driven in sands for the EURIPIDES (EURopean Initiative on PIles in DEnse Sands) project at a well characterised research site at Eemshaven, in the northern Netherlands. It offers new analyses of previously unreported dynamic tests and con...
Monotonic and cyclic triaxial testing provides key information for a wide range of sensitive geotechnical problems. This paper assesses the potential impact on stress-strain measurements of several error sources and discusses how test quality may be improved. External volume gauges are shown to be subject to significant errors that depend on the pr...
Low-to-medium density chalk at St Nicholas at Wade, UK, is characterised by intensive testing to inform the interpretation of axial and lateral tests on driven piles. The chalk de-structures when taken to large strains, especially under dynamic loading, leading to remarkably high pore pressures beneath penetrating CPT and driven pile tips, weak put...
This paper reports the cyclic behaviour of chalk, which has yet to be studied comprehensively. Multiple undrained high-resolution cyclic triaxial experiments on low-to-medium density intact chalk, along with index and monotonic reference tests, define the conditions under which either thousands of cycles could be applied without any deleterious eff...
Low-to-medium density chalk can be de-structured to soft putty by high-pressure compression, dynamic impact or large-strain repetitive shearing. These process all occur during pile driving and affect subsequent static and cyclic load-carrying capacities. This paper reports undrained triaxial experiments on de-structured chalk, which shows distinctl...
Chalk is present under large areas of NW Europe as a low-density, porous, weak carbonate rock. Large numbers of offshore wind turbines, bridges and port facilities rely on piles driven in chalk. Current European practice assumes ultimate shaft resistances that appear low in comparison with the Chalk’s unconfined compression strength and CPT cone re...
Characterisation of shearing behaviour at soil-structure interfaces is critical in the analysis and design of a wide range of geotechnical structures. Large-displacement ring shear interface testing employing pre-shearing stages has been recognised as a robust approach for characterising interface resistance, particularly when large relative displa...
The paper presents the development of a three-dimensional finite-element model for pile tests in dense Dunkirk sand, conducted as part of the PISA project. The project was aimed at developing improved design methods for laterally loaded piles, as used in offshore wind turbine foundations. The importance of the consistent and integrated interpretati...
This paper is the first of a set of linked publications on the PISA Joint Industry Research Project, which was concerned with the development of improved design methods for monopile foundations in offshore wind applications. PISA involved large-scale pile tests in overconsolidated glacial till at Cowden, north-east England, and in dense, normally c...
The installation and loading of steel piles driven in sands modifies both the piles' surface topography and the characteristics of the granular materials present adjacent to the pile shaft. Large-displacement ring shear interface tests incorporating pre-conditioning stages are capable of reproducing such physical processes in the laboratory and can...
Chalk, a soft fine-grained Cretaceous limestone, is encountered across northern Europe where recent offshore windfarm, oil, gas and onshore developments have called for better foundation design methods, particularly for driven piles whose shaft capacities are controlled by an effective stress Coulomb interface failure criterion. Interface type and...
Compressing samples between rigid platens, as in triaxial testing, induce non-uniform specimen stress, strain and pore water distributions. Although well recognised historically, the effects of such platen restraints are often disregarded or overlooked when performing or interpreting monotonic and cyclic experiments. This paper presents an updated...
Electrical Resistivity Tomography (ERT) method has been recognised as a robust technique with unique features for achieving three-dimensional noninvasive measurements and enabling multi-scale characterisation of a range of soil or fluid properties linked to electrical resistivity. This paper introduces a research programme established to develop a...
Granular materials reach critical states upon shearing. The position and shape of a critical state line
(CSL) in the compression plane are important for constitutive models, interpretation of in situ tests
and liquefaction analysis. It is not fully clear how grain crushing may affect the identification and
uniqueness of the CSL in granular soils. D...
Offshore developments in Northern Europe often encounter chalk, a highly variable soft rock. The designers of foundation piles driven in such strata can face considerable uncertainty regarding (i) the axial resistances developed during installation, (ii) those available after consolidation and ageing and (iii) the response to cyclic axial loading....
Improved design of laterally loaded monopiles is central to the development of current and future generation offshore wind farms. Previously established design methods have demonstrable shortcomings requiring new ideas and approaches to be developed, specific for the offshore wind turbine sector. The Pile Soil Analysis (PISA) Project, established i...
In geotechnical model tests, the methods conventionally employed in measuring water content and solute transport include sensor techniques, image processing techniques and direct soil sampling methods. However, these techniques cannot fully satisfy the necessities of three-dimensional, non-destructive and real-time measurement, especially in geotec...
A one-dimensional model was developed to investigate the transport of organic acids (commonly found in landfill leachate) through a partially saturated composite liner system beneath a landfill. Specific attention was paid to the influence of water content distribution on aqueous-phase diffusion process. Composite liner system was investigated, whi...
Landfills play a key role in the disposal of large amount of waste. Imperfect contact between liner materials is inevitable during landfill construction and its effect calls for sufficient consideration. Numerical models concerning different contact conditions and leachate heads were developed and the long-term performances of two kinds of composit...
There is a huge demand for tailing ponds in China due to the vast distribution of tailing materials. The physical and mechanical properties of tailing materials are strongly affected by mineral component, treating process, depositing method and external surroundings, leading to significant difficulties in choosing the basic property index of tailin...
Anti-seepage liner plays an important role in modern landfills as the main structure preventing the landfill leachate from polluting environment. Four typical liner structures frequently used in Chinese landfills are analyzed, and three indexes, including leakage rate, mass flux and sorption capacity, are employed to evaluate the performance of lin...
Projects
Projects (4)
Interface friction angle of sands, silts, clays
Effects of effective stress, roughness, fines content, plasticity, soil type D50, etc.
The ALPACA project started in October 2017 with funding from EPSRC (£1.38m) and Industry (£390k; contributions from Atkins, Cathie Associates, DNVGL, Fugro, GCG, Iberdrola/SPR, Innogy, LEMS, ØRSTED, Siemens, Statoil) aiming to develop new driven pile design guidance for chalk sites through a comprehensive programme of high quality field tests, advanced laboratory testing, rigorous analysis and synthesis with other case history data. The Academic Work Group comprises academics and researchers from Imperial College London (project lead) and Oxford University, with the key aim to develop design procedures that overcome, for chalk, the current shortfalls in knowledge regarding pile driving, ageing, static and cyclic response under axial and lateral loading. The research has applications with offshore wind turbines and oil platforms as well as port, bridge and other works.
