scholarly journals CLAYEY SOIL AMENDMENT BY HYDROPHILIC NANO BENTONITE FOR LANDFILL COVER BARRIER: A CASE STUDY

2020 ◽  
Vol 28 (3) ◽  
pp. 148-156
Author(s):  
Ahmad Qasaimeh ◽  
Abdulla A. Sharo ◽  
Khalid Bani-Melhem
Keyword(s):  
Hydraulic Conductivity ◽  
Clayey Soil ◽  
Transport Coefficients ◽  
Expansive Soil ◽  
Gas Diffusion ◽  
Soil Samples ◽  
Design System ◽  
Clay Material ◽  
Landfill Cover ◽  
Nano Clay

Methane and carbon dioxide are of major concern as greenhouse gases; the landfills have the problem of controlling these gases. Al Akaider in Jordan is the second biggest landfill suffers controlling gases as it lacks a cover design system. In this work, the main goal is to investigate the appropriateness of amended expansive clayey soil in Irbid as a cover barrier. The expansive soil is unwanted in construction projects, thus the modification of this expelled soil enables using it as a low cost landfill cover barrier. In this research, the effect of adding nano-clay material (Hydrophilic Nano Bentonite) on the geotechnical characteristics, hydraulic conductivity, and gas transport coefficients of the clayey soil are studied. The soil samples were obtained from Irbid city. Unconfined compressive strength and free swelling tests were performed on soil samples with different percentages of nano-clay added in the range (0.1% to 1.2%) by weight. The results indicated that the addition of nano-clay at low percentages increases the strength of expansive soil up to 315 kPa at 0.6% of nano-clay and the swelling potential decreased dramatically with the addition of nano-clay. The optimal percent of nano-clay was found to be 0.6%. The intrinsic permeability of the amended soil was 6.03×10–15 m2. The average values of fluid transport coefficients were determined at 25 °C. The hydraulic conductivity for water was about 6.5×10–10 m/s. Gas conductivity coefficients for CO2 and CH4 were 5×10–9 m/s and 2.5×10–9 m/s respectively. Gas diffusion coefficients for CO2 and CH4 were 3×10–6 m2/s and 4×10–6 m2/s respectively.

scholarly journals Characterization of Gas Transport Properties of Compacted Solid Waste Materials

Environments ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 26
Author(s):  
Muhammad Rashid Iqbal ◽  
Hiniduma Liyanage Damith Nandika ◽  
Yugo Isobe ◽  
Ken Kawamoto
Keyword(s):  
Hydraulic Conductivity ◽  
Solid Waste ◽  
Gas Transport ◽  
Bottom Ash ◽  
Gas Diffusion ◽  
Saturated Hydraulic Conductivity ◽  
Dry Density ◽  
Transport Parameters ◽  
Functional Relations ◽  
Mixed Waste

Gas transport parameters such as gas diffusivity (Dp/D0), air permeability (ka), and their dependency on void space (air-filled porosity, ε) in a waste body govern convective air and gas diffusion at solid waste dumpsites and surface emission of various gases generated by microbial processes under aerobic and anaerobic decompositions. In this study, Dp/D0(ε) and ka(ε) were measured on dumping solid waste in Japan such as incinerated bottom ash and unburnable mixed waste as well as a buried waste sample (dumped for 20 years). Sieved samples with variable adjusted moistures were compacted by a standard proctor method and used for a series of laboratory tests for measuring compressibility, saturated hydraulic conductivity, and gas transport parameters. Results showed that incinerated bottom ash and unburnable mixed waste did not give the maximum dry density and optimum moisture content. Measured compressibility and saturated hydraulic conductivity of tested samples varied widely depending on the types of materials. Based on the previously proposed Dp/D0(ε) models, the diffusion-based tortuosity (T) was analyzed and unique power functional relations were found in T(ε) and could contribute to evaluating the gas diffusion process in the waste body compacted at different moisture conditions.

scholarly journals Deep subsoiling of a subsurface-compacted typical hapludult under citrus orchard

2013 ◽  
Vol 37 (4) ◽  
pp. 911-919 ◽  
Author(s):  
João Carlos Medeiros ◽  
Getulio Coutinho Figueiredo ◽  
Álvaro Luiz Mafra ◽  
Jaqueline Dalla Rosa ◽  
Sung Won Yoon
Keyword(s):  
Hydraulic Conductivity ◽  
Management Practices ◽  
Soil Management ◽  
Penetration Resistance ◽  
Soil Bulk Density ◽  
Soil Samples ◽  
Fruit Yield ◽  
Root Depth ◽  
Citrus Orchard ◽  
Unsaturated Hydraulic Conductivity

Soil management practices which increase the root depth penetration of citrus are important to the longevity and yield maintenance of this plant, especially in regions where long periods of drought are common, even in soil conventionally subsoiled to a depth of 30-40 cm, when the orchard was first established. The objective of this study was to evaluate the efficiency of subsoiling on the physical and hydric properties of a Typical Hapludult and fruit yield in a 14-year-old citrus orchard located in Piracicaba, SP. The treatments consisted of: no-subsoiling (with no tilling of the soil after the orchard was planted); subsoiling on one side of the plant lines (SUB. 1); and subsoiling on both sides of the plant lines (SUB. 2). The subsoiling treatments were carried out 1.5 m from the plant lines and to a depth of 0.8 m. Soil samples were taken 120 days after this operation, at four depths, in order to determine physical and hydric properties. Fruit yield was evaluated 150 days after subsoiling. Subsoiling between the plant lines of an old established citrus orchard alters the physical and hydric properties of the soil, which is reflected in increased soil macroporosity and unsaturated hydraulic conductivity, and reduced soil bulk density, critical degree-of-compactness and penetration resistance. The improvements in the physical and hydric properties of the soil were related to an increase in fruit number and orchard yield.

scholarly journals The Improvement of Engineering Properties of Expansive Soil using Waste Glass Powder (WGP) and Quick Lime

2021 ◽  
Vol 9 (VI) ◽  
pp. 3598-3604
Author(s):  
Bhagwan Singh Lodha
Keyword(s):  
Glass Powder ◽  
Clayey Soil ◽  
Expansive Soil ◽  
Waste Glass ◽  
Engineering Properties ◽  
Binding Property ◽  
Unconfined Compression Test ◽  
Quick Lime ◽  
Waste Glass Powder ◽  
Consolidation Settlement

This study was carried out with an intention to observe any sign of improvement of expansive clayey soil due to the addition of Waste Glass Powder (WGP) with it. In this laboratory work clayey (BC) type soil has been chosen. The reason behind choosing clay is that it has many problems. The main problem is that it undergoes consolidation settlement due to the application of long-term loading. Another problem is it shrinks significantly if it is dried and expands significantly, if it absorbs moisture than exerts much pressure on the substructure. Quick Lime and Waste Glass powder is chosen to check the improvement because waste glass powder is cohesionless material and also contains silica, lime etc. Addition of cohesionless material to the cohesive soil means it will lesser the consolidation settlement and expansive nature of soil and Lime provides binding property. To investigate the traditional methods of analysing, the effect of additives on soil has been adopted i.e., conducting several tests of untreated soil and soil treated with waste glass and lime with varying percentage and then comparing the results obtained. The tests that were carried out in this study are Compaction test (Proctor test), Consolidation test (unconfined compression test). MDD and Unconfined compressive strength increases with the addition of glass powder and lime with oven dried expansive soil.

Characteristics of groundwater seepage with cut-off wall in gravel aquifer. I: Field observations

2015 ◽  
Vol 52 (10) ◽  
pp. 1526-1538 ◽  
Author(s):  
Yong-Xia Wu ◽  
Shui-Long Shen ◽  
Ye-Shuang Xu ◽  
Zhen-Yu Yin
Keyword(s):  
Hydraulic Conductivity ◽  
Clayey Soil ◽  
Retaining Wall ◽  
Ground Surface ◽  
Test Site ◽  
Second Phase ◽  
Confined Aquifer ◽  
Test Results ◽  
Sandy Gravel ◽  
High Hydraulic Conductivity

This paper presents a case history of the leakage behavior during dewatering tests in the gravel strata of an excavation pit of a metro station in Hangzhou, China. The groundwater system at the test site is composed of a phreatic aquifer underlain by an aquitard and a confined aquifer with coarse sand and gravel. The sandy gravel stratum has very high hydraulic conductivity. The maximum depth of the excavation is 24 m below the ground surface, which reaches the middle of the aquitard strata, where the thickness of the clayey soil is insufficient to maintain the safety of the base of the excavation. To understand the hydrological characteristics of gravel strata, single- and double-well pumping tests were conducted, where a cut-off wall was installed 43 m deep with its base penetrating 2 to 3 m into the aquifer. Test results show that this partial cut-off of the aquifer cannot effectively protect the base of the excavation from the upward seepage force of the groundwater during excavation. Therefore, a new cut-off wall (second phase) was constructed to a depth of 54 m to cut off the confined aquifer. A second pumping test was conducted after the construction of the second phase cut-off wall, and test results show that this full cut-off combined with dewatering can control groundwater effectively during excavation. This finding indicates that when a deep excavation is conducted in a confined aquifer with high hydraulic conductivity, determination of the depth of the retaining wall should be based on three factors: the stability of the base, the upward seepage stability, and settlement control.

Modified Model for Hydraulic Conductivity of Clayey Soil under Shear

2019 ◽  
Vol 19 (11) ◽  
pp. 06019015 ◽  
Author(s):  
Qianhui Liu ◽  
Yongkang Wu ◽  
Quanming Li ◽  
Yuzhen Yu ◽  
He Lv
Keyword(s):  
Hydraulic Conductivity ◽  
Clayey Soil ◽  
Modified Model

A Computer Program to Facilitate Performance Assessment of Underground Low-Level Waste Concrete Vaults

1995 ◽  
Vol 412 ◽  
Author(s):  
K. A. Snyder ◽  
J. R. Clifton ◽  
J. Pommersheim
Keyword(s):  
Hydraulic Conductivity ◽  
Service Life ◽  
Computer Program ◽  
Performance Assessment ◽  
Performance Prediction ◽  
Transport Coefficients ◽  
Reinforcement Corrosion ◽  
Low Level ◽  
Empirical Relations ◽  
Synergistic Degradation

AbstractA computer program (4SIGHT) to facilitate performance assessment of underground concrete vaults for low level waste (LLW) disposal facilities is being developed at the National Institute of Standards and Technology (NIST). Specifically, the program predicts the hydraulic conductivity and the service life of an underground concrete vault. The hydraulic conductivity estimate is based upon empirical relations. The service life is estimated from consideration of three major degradation processes: steel reinforcement corrosion, sulfate attack, and leaching. The performance prediction is based upon ion transport equations for both diffusion and advection. Most importantly, the computer program incorporates the synergistic degradation effects of all three processes, and their effect upon the transport coefficients.

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