Modeling deformation behaviour of clay liners in a small centrifuge

2002 ◽  
Vol 39 (6) ◽  
pp. 1406-1418 ◽  
Author(s):  
B VS Viswanadham ◽  
K V Mahesh
Keyword(s):  
Solid Waste ◽  
Deformation Behaviour ◽  
Model Tests ◽  
Centrifuge Modeling ◽  
Waste Materials ◽  
Clay Liners ◽  
Overburden Pressure ◽  
Clay Liner ◽  
Geotechnical Centrifuge ◽  
Liner System

In modern solid waste landfills, liner systems are essential structural elements that ensure that waste materials are safely separated from the environment. Many liner systems have been developed and used over the past decade. Among impermeable layers, clay liners are regarded as one of the very significant components of liner system and are being used worldwide as a waste containment system in landfills. One of the failures associated with clay liners is the occurrence of nonuniform settlements, resulting from the sudden collapse of waste, or the decomposition of waste materials, and (or) the subgrade over which the liner is laid. This paper deals with the use of a small centrifuge to model the deformation behaviour of clay liners. Model tests were performed in a small geotechnical centrifuge to investigate the behaviour of clay liners in landfills subjected to nonuniform settlements at sharp curvatures. A parametric study was conducted to analyze the influence of parameters like thickness, consistency, and overburden on the behaviour of clay liners. The clay liner without any overburden is observed to experience severe cracking in the form of deep and wide cracks at the maximum curvature zone. The depth and width of the cracks are found to decrease with an increase in clay liner thickness. The cracking failure pattern is suppressed by shearing for a clay liner with an increase in overburden pressure. Based on model test results, the clay liner with an adequate overburden is found to be free from cracking failure even when subjected to sharp curvatures. The effective usage of a small geotechnical centrifuge to model the deformation behaviour of clay liners is demonstrated adequately.Key words: landfills, municipal solid waste, clay liners, centrifuge modeling, nonuniform settlements, model tests.

Effects of Geomembrance on the Contaminant Transport in Compacted Clay Liner System

2014 ◽  
Vol 989-994 ◽  
pp. 1208-1211 ◽  
Author(s):  
Jing Jing Fan
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Compacted Clay ◽  
Seepage Rate ◽  
Clay Liner ◽  
Compacted Clay Liner ◽  
State Process ◽  
Liner System ◽  
Municipal Solid Waste Landfills ◽  
Solid Waste Landfills

An analytical model is established to predict the seepage performance of the liner system composed of a compacted clay liner (CCL) covered by a geomembrane (GM). The contaminant of Pb2+diffusing through the geomembrane is assumed to be a steady-state process. The liner systems with low leakage performance are usually utilized in the municipal solid waste landfills to prevent the contaminants of the leachate from polluting the groundwater and soil beneath the landfill. To investigate the seepage rate of the Pb2+in the liner systems of the landfill considering the effects of the geomembrance, the influence of the geomembrance on the seepage performance of the liner system is studied. Parametric analyses are conducted to study the effects of the thickness of GM and the number of defects in the GM on the leakage performance of the liner system. In conclusion, some suggestions for the design of the municipal solid waste landfills are proposed based on the analyses results.

Earth pressures exerted on an induced trench cast-in-place double-cell rectangular box culvert

2012 ◽  
Vol 49 (11) ◽  
pp. 1267-1284 ◽  
Author(s):  
Olajide Samuel Oshati ◽  
Arun J. Valsangkar ◽  
Allison B. Schriver
Keyword(s):  
Earth Pressure ◽  
Test Results ◽  
Overburden Pressure ◽  
Centrifuge Testing ◽  
Geotechnical Centrifuge ◽  
Drag Forces ◽  
Field Instrumentation ◽  
Earth Pressures ◽  
Box Culvert ◽  
Base Contact

Earth pressure data from the field instrumentation of a cast-in-place reinforced rectangular box culvert are presented in this paper. The instrumented culvert is a 2.60 m by 3.60 m double-cell reinforced cast-in-place rectangular box buried under 25.10 m of fill constructed using the induced trench installation (ITI) method. The average earth pressure measured across the roof was 0.42 times the overburden pressure, and an average of 0.52 times the overburden pressure was measured at mid-height of the culvert on the sidewalls. Base contact pressure under the rectangular box culvert was also measured, providing field-based data demonstrating increased base pressure resulting from downward drag forces developed along the sidewalls of the box culvert. An average increase of 25% from the measured vertical earth pressures on the roof plus the culvert dead load (DL) pressure was calculated at the culvert base. A model culvert was also tested in a geotechnical centrifuge to obtain data on earth pressures at the top, sides, and base of the culvert. The data from the centrifuge testing were compared with the prototype structure, and the centrifuge test results agreed closely with the measured field prototype pressures, in spite of the fact that full similitude was not attempted in centrifuge testing.

Consolidation of cement-treated sewage sludge using vertical drains

2005 ◽  
Vol 42 (2) ◽  
pp. 528-540 ◽  
Author(s):  
J Chu ◽  
M H Goi ◽  
T T Lim
Keyword(s):  
Sewage Sludge ◽  
Land Reclamation ◽  
Model Tests ◽  
Waste Materials ◽  
Test Results ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Treated Sewage ◽  
The World

The disposal of sewage sludge and other waste materials has become a problem in many cities around the world. A study on the use of sewage sludge and other waste materials for land reclamation has been conducted. One of the methods studied is to dispose of the sludge after it has been mixed with binders or other waste materials and then to consolidate the mixture on site using surcharge and prefabricated vertical drains (PVDs). To study the consolidation behaviour of the sludge–binder mixtures around PVDs, model tests using a fully instrumented consolidation tank were conducted. Some of the test results are presented in this paper. The study shows that PVDs are effective in consolidating the sludge and binder mixtures, provided that the PVDs used can sustain large bending and resist corrosion by the chemicals in the sludge.Key words: consolidation, geoenvironmental, land reclamation, prefabricated vertical drains.

Waste management in primary healthcare centres of Iran

2009 ◽  
Vol 27 (4) ◽  
pp. 354-361 ◽  
Author(s):  
Alireza Mesdaghinia ◽  
Kazem Naddafi ◽  
Amir Hossein Mahvi ◽  
Reza Saeedi
Keyword(s):  
Waste Management ◽  
Solid Waste ◽  
Primary Healthcare ◽  
Management Practices ◽  
Waste Treatment ◽  
Field Investigation ◽  
Waste Materials ◽  
Cluster Sampling ◽  
Healthcare Waste ◽  
Waste Management Practices

The waste management practices in primary healthcare centres of Iran were investigated in the present study. A total of 120 primary healthcare centres located across the country were selected using the cluster sampling method and the current situation of healthcare waste management was determined through field investigation. The quantities of solid waste and wastewater generation per outpatient were found to be 60 g outpatient—1 day—1 and 26 L outpatient—1 day— 1, respectively. In all of the facilities, sharp objects were separated almost completely, but separation of other types of hazardous healthcare solid waste was only done in 25% of the centres. The separated hazardous solid waste materials were treated by incineration, temporary incineration and open burning methods in 32.5, 8.3 and 42.5% of the healthcare centres, respectively. In 16.7% of the centres the hazardous solid wastes were disposed of without any treatment. These results indicate that the management of waste materials in primary healthcare centres in Iran faced some problems. Staff training and awareness, separation of healthcare solid waste, establishment of the autoclave method for healthcare solid waste treatment and construction of septic tanks and disinfection units in the centres that were without access to a sewer system are the major measures that are suggested for improvement of the waste management practices.

Evaluation of Dynamic Behavior of Pile Foundations for Interim Storage Facilities Through Geotechnical Centrifuge Tests

2002 ◽  
Author(s):  
Shizuo Tsurumaki ◽  
Hiroyuki Watanabe ◽  
Akira Tateishi ◽  
Kenichi Horikoshi ◽  
Shunichi Suzuki
Keyword(s):  
Dynamic Behavior ◽  
Experimental Studies ◽  
Centrifuge Modeling ◽  
Pile Foundations ◽  
Soil Conditions ◽  
Confining Stress ◽  
Geotechnical Centrifuge ◽  
Centrifuge Tests ◽  
Interim Storage ◽  
Storage Facilities

In Japan, there is a possibility that interim storage facilities for recycled nuclear fuel resources may be constructed on quaternary layers, rather than on hard rock. In such a case, the storage facilities need to be supported by pile foundations or spread foundations to meet the required safety level. The authors have conducted a series of experimental studies on the dynamic behavior of storage facilities supported by pile foundations. A centrifuge modeling technique was used to satisfy the required similitude between the reduced size model and the prototype. The centrifuge allows a high confining stress level equivalent to prototype deep soils to be generated (which is considered necessary for examining complex pile-soil interactions) as the soil strength and the deformation are highly dependent on the confining stress. The soil conditions were set at as experimental variables, and the results are compared. Since 2000, the Nuclear Power Engineering Corporation (NUPEC) has been conducting these research tests under the auspices on the Ministry of Economy, Trade and Industry of Japan.

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