The Experts below are selected from a list of 49212 Experts worldwide ranked by ideXlab platform

Takeshi Katsumi - One of the best experts on this subject based on the ideXlab platform.

  • evaluating the hydraulic barrier performance of soil bentonite cutoff walls using the piezocone Penetration Test
    Soils and Foundations, 2016
    Co-Authors: Atsushi Takai, Toru Inui, Takeshi Katsumi
    Abstract:

    Abstract When using cutoff walls to prevent the migration of mobile contaminants in aquifers, we should ensure that these cutoff walls maintain both low hydraulic conductivity and high homogeneity before the start of their operation. However, the on-site assessment of the properties of their main component, soil-bentonite (SB), is challenging because of the difficulty in the obtention of high-quality solid core samples after installation. This paper discusses an experimental approach for on-site quality control/quality assurance (QC/QA) immediately after installation to enhance the reliability of SB cutoff walls as containment barriers. In particular, the piezocone Penetration Test (CPTU) was conducted using a large-scale soil tank in which SB – prepared with different contents of bentonite powder – was filled to simulate vertically homogeneous or heterogeneous SB cutoff walls. The response to the Penetration Test varied according to the bentonite content, suggesting that the piezocone Penetration Test can be used for QC/QA of constructed soil-bentonite cutoff walls. Corrected cone resistance values were larger in layers prepared with lean SB mixture than in those prepared with rich SB mixture, with a difference similar to that of undrained shear strength as evaluated by triaxial compression Tests. It was also found that the hydraulic barrier performance of SB cutoff walls could be assessed via a pore pressure dissipation Test during CPTU, within one order of magnitude accuracy in a short period. A basic process for QC/QA using the piezocone Penetration Test in the field is proposed for the practical interpretation of experimental results.

Atsushi Takai - One of the best experts on this subject based on the ideXlab platform.

  • evaluating the hydraulic barrier performance of soil bentonite cutoff walls using the piezocone Penetration Test
    Soils and Foundations, 2016
    Co-Authors: Atsushi Takai, Toru Inui, Takeshi Katsumi
    Abstract:

    Abstract When using cutoff walls to prevent the migration of mobile contaminants in aquifers, we should ensure that these cutoff walls maintain both low hydraulic conductivity and high homogeneity before the start of their operation. However, the on-site assessment of the properties of their main component, soil-bentonite (SB), is challenging because of the difficulty in the obtention of high-quality solid core samples after installation. This paper discusses an experimental approach for on-site quality control/quality assurance (QC/QA) immediately after installation to enhance the reliability of SB cutoff walls as containment barriers. In particular, the piezocone Penetration Test (CPTU) was conducted using a large-scale soil tank in which SB – prepared with different contents of bentonite powder – was filled to simulate vertically homogeneous or heterogeneous SB cutoff walls. The response to the Penetration Test varied according to the bentonite content, suggesting that the piezocone Penetration Test can be used for QC/QA of constructed soil-bentonite cutoff walls. Corrected cone resistance values were larger in layers prepared with lean SB mixture than in those prepared with rich SB mixture, with a difference similar to that of undrained shear strength as evaluated by triaxial compression Tests. It was also found that the hydraulic barrier performance of SB cutoff walls could be assessed via a pore pressure dissipation Test during CPTU, within one order of magnitude accuracy in a short period. A basic process for QC/QA using the piezocone Penetration Test in the field is proposed for the practical interpretation of experimental results.

Chris R Daniel - One of the best experts on this subject based on the ideXlab platform.

  • energy transfer and grain size effects during the standard Penetration Test spt and large Penetration Test lpt
    2008
    Co-Authors: Chris R Daniel
    Abstract:

    The Standard Penetration Test (SPT) is the most widely used in-situ soil Test in the world. "Large Penetration Test" (LPT) is a term used to describe any scaled up version of the SPT. Several types of LPT have been developed around the world for the purpose of characterizing gravel deposits, as SPT blow counts are less reliable in gravels than in sands. Both Tests suffer from the lack of a reliable means of determining transferred energy. Further, the use of LPT blow counts is generally limited to calculation of equivalent SPT blow counts using correlation factors measured in sands. Variation of LPT blow counts with grain size is assumed to be negligible. This research shows that safety hammer energies can be reliably estimated from measurements of hammer impact velocity for both SPT and LPT. This approach to determining transferred energy is relatively simple, and avoids the primary limitation of existing methods, which is the inability to calibrate the instrumentation. Transferred energies and hammer impact velocities are collected from various sources. These data are used to determine the ratio between the hammer kinetic energy and the transferred energy (energy transfer ratio, ETR), which is found to follow a roughly Normal distribution for the various hammers represented. An assessment of uncertainty is used to demonstrate that an ETR based approach could be superior to existing energy measurement methods. SPT grain size effects have primarily been characterized as the variation of an empirical relative density correlation factor, (CD)SPT, with mean grain size. In this thesis, equivalent (CD)LPT data are back-calculated from measured SPT-LPT correlation factors (CS/L). Results of a numerical study suggest that SPT and LPT grain size effects should be similar and related to the ratio of the sample size to the mean grain size. Based on this observation, trend-lines with the same shape as the (CD)SPT trend-line are established for the back-calculated (CD)LPT data. A method for generating the grain size effect trend-line for LPT is then proposed. These trend lines provide a rational approach to direct interpretation of LPT data, or to improved prediction of equivalent SPT blow counts.

  • a method for correlating large Penetration Test lpt to standard Penetration Test spt blow counts
    Canadian Geotechnical Journal, 2003
    Co-Authors: Chris R Daniel, John A. Howie, A. Sy
    Abstract:

    The standard Penetration Test (SPT) split-spoon sampler is too small for investigations in gravelly soils. For this reason, several researchers have developed scaled-up versions of the SPT, commonl...

  • A method for correlating large Penetration Test (LPT) to standard Penetration Test (SPT) blow counts
    Canadian Geotechnical Journal, 2003
    Co-Authors: Chris R Daniel, John A. Howie
    Abstract:

    The standard Penetration Test (SPT) split-spoon sampler is too small for investigations in gravelly soils. For this reason, several researchers have developed scaled-up versions of the SPT, commonly referred to as "large Penetration Tests" (LPT), and attempted to correlate the measured blow counts to SPT blow counts. Several LPTs have been in use worldwide; each with different drill rods, sampler dimensions, and hammer energies; hence existing published LPT–SPT correlations differ for each system. This paper summarizes the LPT data in the literature and presents a fundamental method for predicting LPT–SPT correlations. The proposed method is based on wave equation analyses of SPT and LPT and considers variations in Test equipment, Penetration resistance, and energy. It is shown that the method provides a unified approach for assimilating the various published LPT–SPT correlations. Additional SPT and LPT data were collected at a sand research site to check the proposed method and to expand the LPT database...

Toru Inui - One of the best experts on this subject based on the ideXlab platform.

  • evaluating the hydraulic barrier performance of soil bentonite cutoff walls using the piezocone Penetration Test
    Soils and Foundations, 2016
    Co-Authors: Atsushi Takai, Toru Inui, Takeshi Katsumi
    Abstract:

    Abstract When using cutoff walls to prevent the migration of mobile contaminants in aquifers, we should ensure that these cutoff walls maintain both low hydraulic conductivity and high homogeneity before the start of their operation. However, the on-site assessment of the properties of their main component, soil-bentonite (SB), is challenging because of the difficulty in the obtention of high-quality solid core samples after installation. This paper discusses an experimental approach for on-site quality control/quality assurance (QC/QA) immediately after installation to enhance the reliability of SB cutoff walls as containment barriers. In particular, the piezocone Penetration Test (CPTU) was conducted using a large-scale soil tank in which SB – prepared with different contents of bentonite powder – was filled to simulate vertically homogeneous or heterogeneous SB cutoff walls. The response to the Penetration Test varied according to the bentonite content, suggesting that the piezocone Penetration Test can be used for QC/QA of constructed soil-bentonite cutoff walls. Corrected cone resistance values were larger in layers prepared with lean SB mixture than in those prepared with rich SB mixture, with a difference similar to that of undrained shear strength as evaluated by triaxial compression Tests. It was also found that the hydraulic barrier performance of SB cutoff walls could be assessed via a pore pressure dissipation Test during CPTU, within one order of magnitude accuracy in a short period. A basic process for QC/QA using the piezocone Penetration Test in the field is proposed for the practical interpretation of experimental results.

A Gubana - One of the best experts on this subject based on the ideXlab platform.

  • mechanical characterisation of wooden structures by means of an in situ Penetration Test
    Construction and Building Materials, 1998
    Co-Authors: P Ronca, A Gubana
    Abstract:

    Abstract The problem of evaluating wood decay and related residual strength capacity in existing wooden structures in historical buildings is particularly important when deciding on the possibility of restoration and the kind of strengthening intervention needed. The technique of the Penetration Test consists in the Penetration of a steel pin into wood with repeated and energy constant blows transmitted by a rebound hammer. This Test, based on the Penetration measurement layer after layer, makes it possible to distinguish between different degrees of decay in each layer as a function of the number of blows necessary for 1-cm Penetration. Due to the anisotropy and the different behaviour of wood with respect to moisture content, the results of the Penetration Test may be very spread. This article presents the experimental procedures, the Tests and the results obtained to point out the significance of these parameters and to find an indication of a possible correlation between the results obtained with the Penetration Test and the wood ultimate strength obtained from a usual three point bending Test on small, clear specimens. The results of Tests on spruce wood show good correlation among these data and therefore a curve — number of blows vs. bending resistance — is proposed, taking into account moisture and Penetration direction as leader parameters.