| EPSRC Reference: |
EP/I031995/1 |
| Title: |
Laboratory simulation of field tube sampling using transparent soil, glass tubes and PIV (Particle Image velocimetry) |
| Principal Investigator: |
Ni, Dr Q |
| Other Investigators: |
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| Researcher Co-Investigators: |
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| Project Partners: |
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| Department: |
Sch of Engineering |
| Organisation: |
University of Warwick |
| Scheme: |
First Grant - Revised 2009 |
| Starts: |
01 July 2011 |
Ends: |
31 December 2013 |
Value (£): |
101,215
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| Panel History: |
| Panel Date | Panel Name | Outcome |
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10 Feb 2011
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Process Environment & Sustainability
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Announced
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Summary on Grant Application Form |
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In this proposed research project an innovative physical modelling system using transparent soil, glass tubes and computer based image recognition technology will be established to investigate the tube sampling disturbance to soil. Transparent soil is a mixture of amorphous silica powder with pore fluid matching its Refraction Index, which is semi-transparent and has engineering properties similar to clay. Tube sampling is the most widely used sampling technology to obtain soil specimen from the ground during site investigation.Site investigation is important because the biggest source of uncertainties and risks for the construction of civil engineering projects lies in the ground. It is observed that among projects that were delayed, nearly half of the cases were due to unforeseen ground problems and not much improvement has been made during the past three decades (Tyrell et al., 1983; NEDO, 1988; Chapman & Marcetteau, 2004). As a result, projects are often built at costs over the initial budget and it is estimated that across the European Union, about 50 billion euro is spent each year due to such problems (Chapman, 2008).Though it is of critical importance to obtain accurate and representative ground information, the task itself is very challenging for several reasons. Our knowledge of the ground mainly comes from studying soil samples, which by volume are usually less than 1/1,000,000 of the ground affected by construction (Clayton et al., 1995). Most of the time soil samples are retrieved by pushing tube samplers into the ground, a process called tube sampling. Though better sampling techniques do exist, the required technical and financial support makes them impractical for many projects, so tube sampling is still the most widely used sampling method around the world. It has long been recognized that this sampling process might cause significant disturbance to the soil, so the soil samples obtained do not truly reflect the in-situ soil state. Without understanding the tube sampling disturbances, it is impossible to interpret the laboratory test data properly and obtain the correct engineering property values. It has been a primary concern among geotechnical engineers, and though extensive research has been done, our understanding on this problem is still incomplete. Due to the practical difficulties, the real movement of soil during tube sampling has never been measured in the past.The proposed research project aims to visualize and measure the whole-field movement of soil during tube penetration for the 1st time. The process of field tube sampling will be simulated in the laboratory in ways similar to those of Santagata et al. (2006), and transparent soil and glass tubes will be used in this project. The process will be recorded using digital photography, from which the soil movement can be measured very accurately using Particle Image Velocimetry (PIV). Incremental and accumulated strain paths can be derived from the displacement data (White & Bolton, 2004). Glass tubes of various shapes will be tested in normally consolidated and over-consolidated transparent soil to investigate the effects of sampler design parameters like area ratio, cutting-shoe geometry and inside clearance. The investigation will also be extended into the post-sampling stage to include disturbances during storage and extrusion. The obtained data will provide valuable insights into the whole process from in-situ tube sampling to laboratory testing, and offer practical guidance on the design of the tube samplers, laboratory handling of soil samples, and the interpretation of laboratory tests. It will reduce the financial risks associated with the building of infrastructure, promoting the wealth of the nation and welfare for the general public.
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Key Findings |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Potential use in non-academic contexts |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Impacts |
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| Description |
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk |
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| Date Materialised |
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Sectors submitted by the Researcher |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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| Project URL: |
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| Further Information: |
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| Organisation Website: |
http://www.warwick.ac.uk |