Laboratory and In Situ Tests for Long-Term Hydraulic Conductivity of a Cement-Bentonite Cutoff Wall

Joshi, K.; Kechavarzi, Cédric; Sutherland, Kenneth; Ng, Man Yin Albert; Soga, Kenichi; Tedd, P

doi:10.1061/(asce)gt.1943-5606.0000248

Cited by 51 publications

(19 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, they mention the need to publish long term performance papers on installed cutoff walls since most papers are written within a very short time of the completion of remediation. Joshi, et al (2010) looks at the long term hydraulic performance of a slag-cementbentonite cutoff wall using different in-situ and laboratory tests. Piezocone tests (CPT), packer tests, and self-boring permeameter tests were conducted in field to determine the suitability of different in-situ techniques and compare with the laboratory results.…”

Section: Long Term Performancementioning

confidence: 99%

A new approach for evaluating the ductility, volumetric stiffness and permeability of cut-off wall backfill materials

Ostrowsky

2017

DFI Journal - The Journal of the Deep Foundations Institute

View full text Add to dashboard Cite

The behavior of soil-cement and plastic-concrete cut-off walls in dams is critically affected by ductility and volumetric stiffness. Post-construction deformation of cut-off walls is common due to the differences in strength and stiffness of the wall and the surrounding embankment material and changes in loading due to changes in the seepage regime. Conventional concrete barriers crack as they deform creating regions of high permeability and concentrated flow in the cracked region. Ductile barriers, such as soil-bentonite walls will deform without cracking, but lack structural integrity. The behavior of intermediate materials, such as soil-cement and plastic concrete, are currently not well understood.A laboratory testing procedure has been developed to quantify the ductility of soil-cement and plastic-concrete relative to changes in permeability (hydraulic iii conductivity) with strain. Tests were performed on a number of soil-cement specimens having varying cement and bentonite contents. The test results show that this method is effective in illustrating and quantifying the differences in behavior of the soil-cement specimens and effectively measuring low-permeability materials (10 -6 to 10 -8 cm/s). This laboratory testing procedure can be instrumental for defining and quantifying the in-situ properties of soil-cement mixtures and plastic-concrete used for cut-off wall backfill materials.

show abstract

Section: Long Term Performancementioning

confidence: 99%

A new approach for evaluating the ductility, volumetric stiffness and permeability of cut-off wall backfill materials

Ostrowsky

2017

DFI Journal - The Journal of the Deep Foundations Institute

View full text Add to dashboard Cite

show abstract

“…Field testing methods mainly include conventional hydraulic testing methods (direct testing methods), monitoring analysis methods, and indirect testing methods. Specifically, the conventional hydraulic testing methods include the packer method [10][11][12], piezocone method [13,14], and pumping method [15]. Monitoring analysis methods can obtain the seepage indices of materials as a function of the relevant parameters of permeability of the soil and rock bodies tested using sensors [11,16].…”

Section: Introductionmentioning

confidence: 99%

Simple Fully Automatic Testing Method of Seepage Indices for Low-Permeability Materials

Shen

Wang³

2021

Water

View full text Add to dashboard Cite

In anti-seepage engineering, quality control and engineering applications are based on the accurate measurement of seepage indices for low-permeability materials. The test used to determine the seepage indices for low-permeability materials adopts an external source to produce water pressure, and the seepage flux produced during the process requires manual measurement; thus, the apparatus used is complex and difficult to operate, thereby lowering the testing efficiency and restricting its application. In this study, a built-in servo motor was used to produce high water pressure with a pressure transmitter, and it controlled and measured the seepage pressure. According to the rotation number of the electric cylinder motor, the volume change of water in the hydraulic cylinder was calculated and, thus, the seepage flux was deduced. A simple fully automatic seepage apparatus for low-permeability materials was designed with a human–computer interface. The results showed the successful calculation of seepage flux as a function of the rotation number of the servo motor through automatic measurement. Furthermore, the replacement of the external high-pressure source with the built-in servo motor enhanced the safety performance, and the human–computer interface enabled an interactive operation and simplified the measurement structure. This simple testing method can provide technical support for quality inspection and construction control of anti-seepage engineering.

show abstract

“…These requirements are fulfilled by constructing the barriers by using either soil‐bentonite or cement‐bentonite mixtures 5–7 . The site efficiency of the barrier system, however, depends not only on the properties of the mixture, but also on many other factors, such as the construction method, the presence of impurities and defects, and chemical interactions between the mixture and the pollutant 8 …”

Section: Introductionmentioning

confidence: 99%

A procedure to estimate cutoff wall transport properties from monitoring wells

Guida

Musso

Sanetti

et al. 2021

Num Anal Meth Geomechanics

View full text Add to dashboard Cite

Owing to their capability in limiting the transport of pollutants in the subsoil, cutoff walls are popular solutions for the confinement of contaminants. These barriers are often made of soil‐bentonite or cement‐bentonite mixtures, which are characterized by low hydraulic conductivity, low hydrodynamic dispersion, and long‐term durability. However, the aggressive chemical environment to which these walls are subjected might negatively impact on their performance. Assessment of their performance with time is thus a crucial issue in wall design. The use of dedicated monitoring wells, cast in place inside the wall during construction when the bentonitic mixture is still fluid, can be particularly suitable for both intercepting and detecting the fluids flowing through the barrier. In this research, the results of a numerical study aimed at providing a methodology to estimate the transport properties of the backfill material at the site scale are presented. The methodology relies on abaci and only requires (i) flow and concentration of contaminant data within a monitoring well inside the barrier and (ii) hydraulic head at inlet and outlet of the barrier to be known.

show abstract

Laboratory and In Situ Tests for Long-Term Hydraulic Conductivity of a Cement-Bentonite Cutoff Wall

Cited by 51 publications

References 8 publications

A new approach for evaluating the ductility, volumetric stiffness and permeability of cut-off wall backfill materials

A new approach for evaluating the ductility, volumetric stiffness and permeability of cut-off wall backfill materials

Simple Fully Automatic Testing Method of Seepage Indices for Low-Permeability Materials

A procedure to estimate cutoff wall transport properties from monitoring wells

Contact Info

Product

Resources

About