Field measurements of overlap reductions for two reinforced fabric-encased geosynthetic clay liners (GCLs)

2018 ◽  
Vol 55 (5) ◽  
pp. 631-639 ◽  
Author(s):  
R. Kerry Rowe ◽  
Richard W.I. Brachman ◽  
W. Andy Take
Keyword(s):  
Dominant Role ◽  
Field Measurements ◽  
Silty Sand ◽  
Geosynthetic Clay Liners ◽  
Clay Liners ◽  
Side Slope ◽  
Flat Base ◽  
Composite Liners ◽  
Hydration And Dehydration ◽  
Test Embankment

Two geosynthetic clay liners (GCLs) reported to have experienced significant shrinkage at other locations are examined on both a 3H:1V south-facing slope and a relatively flat base on a silty sand. The GCLs were overlapped by 300 mm with 400 g/m of supplemental bentonite and covered by a black 1.5 mm high-density polyethylene (HDPE) geomembrane to form a composite liner that was left exposed in a full-scale field test embankment for a period of almost 5 years. It is shown that despite the relatively uniform exposure conditions, shrinkage is highly variable with a maximum shrinkage of GCL A being 165 mm on the slope and 415 mm on the base while GCL B shrunk by up to 75 mm on the side slope and only up to 25 mm on the base. The dominant role played by variable overlap stick and heterogeneity to the locations where the overlaps are re-wetted are discussed. Based on this study of shrinkage and a related study of downslope erosion at the same site, it is concluded that neither GCLs A nor B should be left in exposed composite liners when they can be subjected to thermal cycles that can lead to hydration and dehydration of the GCL.

Insight into hydraulic conductivity testing of geosynthetic clay liners (GCLs) exhumed after 5 and 7 years in a cover

2017 ◽  
Vol 54 (8) ◽  
pp. 1118-1138 ◽  
Author(s):  
R.K. Rowe ◽  
R.W.I. Brachman ◽  
M.S. Hosney ◽  
W.A. Take ◽  
D.N. Arnepalli
Keyword(s):  
Hydraulic Conductivity ◽  
Unit Area ◽  
Divalent Cations ◽  
Hydraulic Gradient ◽  
Silty Sand ◽  
Geosynthetic Clay Liners ◽  
Clay Liners ◽  
Percentage Area ◽  
Bundle Size ◽  
Insight Into

Four geosynthetic clay liners (GCLs) serving as single liners were exhumed from below 0.7 m of silty sand on a 3:1 (horizontal:vertical) north-facing slope at the QUELTS site in Godfrey, Ontario, after 5 and 7 years. The 300 mm GCL overlaps with 0.4 kg/m supplemental bentonite were all physically intact. The exchangeable bound sodium was completely replaced with divalent cations. The GCL with the smallest needle-punched bundle size (average of 0.7 mm) and percentage area covered by bundles (4%) maintained low hydraulic conductivity (k) when tested under 0.07–1.2 m head with 10 mmol/L CaCl2 solution as the permeant. For GCLs with larger bundles (1.1–1.6 mm) and higher percentage area covered by bundles (9%–14%), k was low when the head was low (0.07 m). Once the applied head increased, k increased by 1–4 orders of magnitude depending on the (i) hydraulic gradient, (ii) size and number of the needle-punched bundles, and (iii) structure and mass of the bentonite per unit area. The results suggest that the GCLs can perform effectively as a single hydraulic barrier in covers providing that the head above the GCL is kept low (e.g., by a suitable drainage layer above the GCL).

Design for Composite Liners of Landfill under Alternating Cycles of Wetting-Drying and Freezing-Thawing

2010 ◽  
Vol 163-167 ◽  
pp. 4464-4469
Author(s):  
Hong Yu Wang
Keyword(s):  
Northwest China ◽  
Geosynthetic Clay Liners ◽  
Clay Liners ◽  
Freeze Thaw ◽  
The World ◽  
Barrier Performance ◽  
Sliding Stability ◽  
Composite Liners ◽  
Effective Design

The design conception of composite liners consisting of a geomembrane (GM), geosynthetic clay liners (GCLs) and compacted gravel soils for landfill is presented based on the climate characteristic, gravel soils material storage in abundance, and GCLs having been exported all over the world for various applications. The analyses results suggested that the capacity to resist the collapse of wetting-drying and freezing-thawing, long-term barrier performance, and the general sliding stability of barrier system are enhanced obviously by using GCLs/GM as barrier and displacing clay by gravel soils as protector in this paper. It will be plausible as effective design for the barrier system of landfill under wet-dry and freeze-thaw alternating cycles in northwest China.

scholarly journals Kaolin based protective barrier in municipal landfills against adverse chemo-mechanical loadings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Partha Das ◽  
Tadikonda Venkata Bharat
Keyword(s):  
Ionic Strength ◽  
High Ionic Strength ◽  
The Self ◽  
Design Parameters ◽  
Layered System ◽  
Geosynthetic Clay Liners ◽  
Clay Liners ◽  
Landfill Liner ◽  
First Time ◽  
Applied Stresses

AbstractIn this work, we assess the self-sealing and swelling ability of the compacted granular bentonite (GB) under an inorganic salt environment and induced overburden stresses from the landfill waste. The laboratory permeation tests with high ionic strength salt solutions reveal that the GB fails to seal and exhibits a significant mechanical collapse under different applied stresses. The applicability of GB in the form of geosynthetic clay liners as the bottom liner facilities in landfills that produce high ionic strength salt leachates, therefore, remains a serious concern. We propose an additional barrier system based on kaolin, for the first time, to address this problem. The proposed kaolin-GB layered system performs satisfactorily in terms of its sealing and swelling ability even in adverse saline conditions and low overburden stresses. The kaolin improves the osmotic efficiency of the self and also helps the underlying GB layer to seal the inter-granular voids. The estimated design parameters by through-diffusion test suggest that the kaolin-GB layered system effectively attenuates the permeant flux and suitable as a landfill liner.

scholarly journals Ground volume assessment using ’Structure from Motion’ photogrammetry with a smartphone and a compact camera

2017 ◽  
Vol 9 (1) ◽  
Author(s):  
Rafał Wróżyński ◽  
Krzysztof Pyszny ◽  
Mariusz Sojka ◽  
Czesław Przybyła ◽  
Sadżide Murat-Błażejewska
Keyword(s):  
Open Source Software ◽  
Structure From Motion ◽  
Point Cloud ◽  
Field Measurements ◽  
Video Frames ◽  
Actual Volume ◽  
Volume Assessment ◽  
Uniform Model ◽  
Free Open Source ◽  
Test Embankment

AbstractThe article describes how the Structure-from-Motion (SfM) method can be used to calculate the volume of anthropogenic microtopography. In the proposed workflow, data is obtained using mass-market devices such as a compact camera (Canon G9) and a smartphone (iPhone5). The volume is computed using free open source software (VisualSFMv0.5.23, CMPMVSv0.6.0., MeshLab) on a PCclass computer. The input data is acquired from video frames. To verify the method laboratory tests on the embankment of a known volume has been carried out. Models of the test embankment were built using two independent measurements made with those two devices. No significant differences were found between the models in a comparative analysis. The volumes of the models differed from the actual volume just by 0.7‰ and 2‰. After a successful laboratory verification, field measurements were carried out in the same way. While building the model from the data acquired with a smartphone, it was observed that a series of frames, approximately 14% of all the frames, was rejected. The missing frames caused the point cloud to be less dense in the place where they had been rejected. This affected the model’s volume differed from the volume acquired with a camera by 7%. In order to improve the homogeneity, the frame extraction frequency was increased in the place where frames have been previously missing. A uniform model was thereby obtained with point cloud density evenly distributed. There was a 1.5% difference between the embankment’s volume and the volume calculated from the camera-recorded video. The presented method permits the number of input frames to be increased and the model’s accuracy to be enhanced without making an additional measurement, which may not be possible in the case of temporary features.

Long-term shear strength of geosynthetic clay liners

2008 ◽  
Vol 26 (2) ◽  
pp. 130-144 ◽  
Author(s):  
Werner Müller ◽  
Ines Jakob ◽  
Stefan Seeger ◽  
Renate Tatzky-Gerth
Keyword(s):  
Shear Strength ◽  
Geosynthetic Clay Liners ◽  
Clay Liners

Challenges of the Filter Paper Suction Measurements in Geosynthetic Clay Liners: Effects of Method, Time, Capillarity, and Hysteresis

2021 ◽  
Vol 45 (2) ◽  
pp. 20200168
Author(s):  
A. S. Acikel ◽  
A. Bouazza ◽  
R. M. Singh ◽  
W. P. Gates ◽  
R. K. Rowe
Keyword(s):  
Filter Paper ◽  
Geosynthetic Clay Liners ◽  
Clay Liners
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