Evaluation of Field Scale Unsaturated Soil Behavior of Landfill Cover through Geophysical Testing and Instrumentation

2019 ◽  
Author(s):  
Md. Jobair Bin Alam ◽  
Md. Sahadat Hossain ◽  
Linkan Sarkar ◽  
Naima Rahman
Keyword(s):  
Unsaturated Soil ◽  
Soil Behavior ◽  
Field Scale ◽  
Landfill Cover ◽  
Geophysical Testing

Adding Ash Methane Oxidation in Landfill Cover Soil Research

2014 ◽  
Vol 926-930 ◽  
pp. 4205-4208
Author(s):  
Yan Li Wu ◽  
Qing Feng Zhang ◽  
Ran Zhuo Zhang ◽  
Xiao Ming Mao ◽  
Xin Hua Sun
Keyword(s):  
Methane Oxidation ◽  
Chemical Properties ◽  
Soil Surface ◽  
Soil Behavior ◽  
Soil Microbial ◽  
Landfill Cover Soil ◽  
Landfill Cover ◽  
Cover Soil ◽  
Physical And Chemical ◽  
The Impact

In the past ten years, methane has a greenhouse gas, and its concentration increases by 1% per year, while an estimated worldwide annual landfill cover soil surface from escaping methane is about 20 to 70 Mtpa. Microbial methane oxidation can be carried out about 80% of global consumption of methane, the soil microbial methane oxidation can reduce methane escaping from the soil to the atmosphere. Both in domestic and foreign ash recycling in landfill cover soil behavior has performed for many years, but there is a review of domestic and foreign literature ash, mostly looks at the aspects of physical and chemical properties and heavy metals, there is no assessment of the casing methane oxidation impact. This paper mainly urban incinerator ash as a research object, and after a landfill cover soil mined to study experimentally analyze the impact of ash added methane oxidation right.

Modified state-surface approach to the study of unsaturated soil behavior. Part I: Basic concept

2009 ◽  
Vol 46 (5) ◽  
pp. 536-552 ◽  
Author(s):  
Xiong Zhang ◽  
Robert L. Lytton
Keyword(s):  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Stress Path ◽  
Complex Stress ◽  
Soil Behavior ◽  
Elastic Surface ◽  
Surface Approach ◽  
Basic Model ◽  
Plastic Hardening ◽  
Complex Stress Path

The traditional state-surface approach to the study of unsaturated soil behavior is becoming much less popular these days, as it uses unique constitutive surfaces to represent unsaturated soil behavior. This approach is essentially a nonlinear elastic formation and cannot be used to explain complex stress-path dependency for unsaturated soils. In this paper, a modified state-surface approach (MSSA) is proposed to represent unsaturated soil behavior under isotropic stress conditions in which a conventional void-ratio state surface is considered to be made up of an elastic surface and a plastic hardening surface. The plastic hardening surface remains stationary at all times, whereas the elastic surface remains unchanged when the soil experiences elastic deformation and moves downward when there is plastic hardening occurrence. Using the MSSA, the loading–collapse (LC) and the suction increase (SI) yield curves in the Barcelona basic model (BBM) are derived. The prediction of three typical cases of soils under isotropic conditions and experimental results using the proposed approach confirmed its feasibility, simplicity, and potential for the study of unsaturated soil behavior.

scholarly journals Unsaturated soils in the context of tropical soils

2021 ◽  
Vol 44 (3) ◽  
pp. 1-25
Author(s):  
José Camapum de Carvalho ◽  
Gilson Gitirana
Keyword(s):  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Structural Characteristics ◽  
Soil Formation ◽  
Soil Classification ◽  
Tropical Soils ◽  
Engineering Practice ◽  
Soil Behavior ◽  
Specific Behavior ◽  
Engineering Problems

The practice of geotechnical engineering in tropical climate regions must consider the use of unsaturated soil concepts. However, these concepts must also take into account the specific behavior traits of tropical soils, particularly those related to soil aggregation, pore structure, and mineralogy. This paper will initially present considerations on the typical properties of unsaturated tropical soils as well as fundamental concepts. Throughout the article, several engineering problems will be presented alongside reflections on the complex interaction between the numerous variables involved in the modeling and engineering practice of tropical unsaturated soil behavior. The paper addresses issues related to soil formation, chemical and mineral composition, physical properties, tropical soil classification, and structural characteristics of soils. Issues related to compaction and the influence of weathering, geomorphology and bioengineering are also addressed.

Consistent Three-Dimensional Elasto-Plastic Model to Study Unsaturated Soil Behavior with Considerations of Coupled Hydro-Mechanical Hysteresis

2021 ◽  
pp. 036119812110022
Author(s):  
Beshoy Riad ◽  
Xiong Zhang
Keyword(s):  
Unsaturated Soil ◽  
Yield Curve ◽  
Three Dimensional ◽  
Degree Of Saturation ◽  
Smooth Transition ◽  
Soil Behavior ◽  
Plastic Model ◽  
Mechanical Coupling ◽  
Mechanical Hysteresis ◽  
Characteristic Features

This paper presents a consistent three-dimensional elasto-plastic model to study unsaturated soil behavior with consideration of coupled hydro-mechanical hysteresis. The model was first formulated under isotropic conditions with special consideration to the non-linearity of the hydraulic behavior. Only one yield curve is used to represent the yielding of both mechanical and hydraulic behaviors (i.e., the occurrence of plastic water content changes and mechanical strains). Later, the model is extended to general three-dimensional stress conditions. It was formulated in a way that a smooth transition between the saturated and unsaturated soil states is guaranteed. The model provides consistent predictions for different soil phases that is considered a significant limitation in many existing models. One of the characteristic features of the proposed model is the ability to represent the hydro-mechanical coupling during shearing. Moreover, the model is able to represent the degree of saturation increase or decrease during shearing that is closely related to the soil’s contractive or dilative behavior, respectively. The model is validated through the prediction of several hydro-mechanical behavioral features. The paper also compares the model predictions with published experimental results performed under different loading conditions. The response of the model is satisfactory in relation to both mechanical and hydraulic behaviors.

Development of an Apparatus to Investigate the Stress Variables Governing Unsaturated Soil Behavior

2005 ◽  
Vol 28 (2) ◽  
pp. 11861
Author(s):  
L David Suits ◽  
TC Sheahan ◽  
A Tarantino ◽  
L Mongiovì
Keyword(s):  
Unsaturated Soil ◽  
Soil Behavior

scholarly journals A Unified Elastoplastic Model of Unsaturated Soils Considering Capillary Hysteresis

2013 ◽  
Vol 2013 ◽  
pp. 1-15
Author(s):  
Tiantian Ma ◽  
Changfu Wei ◽  
Pan Chen ◽  
Huihui Tian ◽  
De'an Sun
Keyword(s):  
Soil Water ◽  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Mechanical Response ◽  
Internal State ◽  
Degree Of Saturation ◽  
State Variables ◽  
Soil Behavior ◽  
Capillary Hysteresis ◽  
Modified Cam Clay

Unlike its saturated counterparts, the mechanical behavior of an unsaturated soil depends not only upon its stress history but also upon its hydraulic history. In this paper, a soil-water characteristic relationship which is capable of describing the effect of capillary hysteresis is introduced to characterize the influence of hydraulic history on the skeletal deformation. The capillary hysteresis is viewed as a phenomenon associated with the internal structural rearrangements in unsaturated soils, which can be characterized by using a set of internal state variables. It is shown that both capillary hysteresis and plastic deformation can be consistently addressed in a unified theoretical framework. Within this context, a constitutive model of unsaturated soils is developed by generalizing the modified Cam-Clay model. A hardening function is introduced, in which both the matric suction and the degree of saturation are explicitly included as hardening variables, so that the effect of hydraulic history on the mechanical response can be properly addressed. The proposed model is capable of capturing the main features of the unsaturated soil behavior. The new model has a hierarchical structure, and, depending upon application, it can describe the stress-strain relation and the soil-water characteristics in a coupled or uncoupled manner.

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