The mite (Acari: Oribatida, Mesostigmata) assemblages associated with Lasius flavus (Hymenoptera: Formicidae) nests and surrounding soil in an Irish grassland

2015 ◽  
Vol 115B (1) ◽  
pp. 17-28
Author(s):  
Julio Arroyo ◽  
Audrey O'Grady ◽  
Heather Vance ◽  
Thomas Bolger
Keyword(s):  
Lasius Flavus ◽  
Surrounding Soil

Geosynthetic Encased Column: comparison between numerical and experimental results

2021 ◽  
Vol 44 (4) ◽  
pp. 1-12
Author(s):  
Nima Alkhorshid ◽  
Gregório Araújo ◽  
Ennio Palmeira
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Ground Improvement ◽  
Soft Soil ◽  
Experimental Tests ◽  
High Permeability ◽  
Soft Soils ◽  
Column Comparison ◽  
Surrounding Soil ◽  
Granular Column

The use of granular column is one of the ground improvement methods used for soft soils. This method improves the foundation soils mechanical properties by displacing the soft soil with the compacted granular columns. The columns have high permeability that can accelerate the excess pore water pressure produced in soft soils and increase the undrained shear strength. When it comes to very soft soils, the use of granular columns is not of interest since these soils present no significant confinement to the columns. Here comes the encased columns that receive the confinement from the encasement materials. In this study, the influence of the column installation method on the surrounding soil and the encasement effect on the granular column performance were investigated using numerical analyses and experimental tests. The results show that numerical simulations can reasonably predict the behavior of both the encased column and the surrounding soil.

scholarly journals Effect of termite activity on soil under different land management strategies

2017 ◽  
Vol 38 (1) ◽  
pp. 143
Author(s):  
Liane Barreto Alves Pinheiro ◽  
Rodrigo Camara ◽  
Marcos Gervasio Pereira ◽  
Eduardo Lima ◽  
Maria Elizabeth Fernandes Correia ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Management Strategies ◽  
Chemical Properties ◽  
Clay Content ◽  
Exchange Capacity ◽  
Termite Mounds ◽  
Eucalyptus Plantation ◽  
Exchangeable Acidity ◽  
Calcium And Magnesium ◽  
Surrounding Soil

Mound-building termites are important agents of soil bioperturbation, but these species have not been extensively studied thus far. The present study aimed to evaluate the soil particle-size and the chemical attributes of termite mounds and the surrounding soil under different land use strategies. A one-hectare plot was defined for an unmanaged degraded pasture, planted pasture, and for a eucalyptus Corymbia citriodora plantation. In each plot, the top, center, and base sections of five Cornitermes cumulans mounds, and the surrounding soil at the depths of 0-5; 5-10; 10-20 cm, were sampled in the Pinheiral, Rio de Janeiro state. In the three areas, the center of the mounds contained higher clay content, organic carbon, phosphorous, calcium and magnesium, total bases, and cation exchangeable capacity, when compared to the top, base, and the surrounding soils. However, the center had lower values of exchangeable acidity and potassium, of the three areas. In the eucalyptus plantation, the values of pH, total bases, calcium, and magnesium were lower, whereas aluminum, exchangeable acidity, sodium, and cation exchange capacity were higher both in the mounds and in the surrounding soil, in relation to the pastures. There were no differences among the three areas in terms of organic carbon, potassium, phosphorous, and total bases, in the mounds and adjacent soil. Thus, the termite activity altered the clay content and most of the soil chemical properties in all of the studied areas, but only for the center of the mounds. However, the effect of these organisms was different in the eucalyptus plantation in relation to the pasture areas.

Pyrosequencing reveals a contrasted bacterial diversity between oak rhizosphere and surrounding soil

2010 ◽  
Vol 2 (2) ◽  
pp. 281-288 ◽  
Author(s):  
Stéphane Uroz ◽  
Marc Buée ◽  
Claude Murat ◽  
Pascale Frey-Klett ◽  
Francis Martin
Keyword(s):  
Bacterial Diversity ◽  
Surrounding Soil

scholarly journals Assessment of Mercury-Polluted Soils Adjacent to an Old Mercury-Fulminate Production Plant

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
M. Camps Arbestain ◽  
L. Rodríguez-Lado ◽  
M. Bao ◽  
F. Macías
Keyword(s):  
Surface Waters ◽  
Contaminated Soils ◽  
Flow Direction ◽  
Surface Flow ◽  
Mercury Contamination ◽  
Production Plant ◽  
Polluted Soils ◽  
Flow Through ◽  
Contamination Of Soils ◽  
Surrounding Soil

Mercury contamination of soils and vegetation close to an abandoned Hg-fulminate production plant was investigated. Maximum concentrations of Hg (>6.5 gkg−1soil) were found in the soils located in the area where the wastewater produced during the washing procedures carried out at the production plant used to be discharged. A few meters away from the discharge area, Hg concentrations decreased to levels ranging between 1 and 5 gkg−1, whereas about 0.5 ha of the surrounding soil to the NE (following the dominant surface flow direction) contained between 0.1 and 1 gkg−1. Mercury contamination of soils was attributed (in addition to spills from Hg containers) to (i) Hg volatilization with subsequent condensation in cooler areas of the production plant and in the surrounding forest stands, and (ii) movement of water either by lateral subsurface flow through the contaminated soils or by heavy runoff to surface waters.

The Research on Calculating the Low Pile Foundation According to the Limitation State Considered the Interaction between the Soil, Pile and Irrigation Structure

2011 ◽  
Vol 105-107 ◽  
pp. 1465-1469 ◽  
Author(s):  
Van Loc Nguyen ◽  
Lei Nie
Keyword(s):  
Pile Foundation ◽  
Actual Condition ◽  
Design Criteria ◽  
The North ◽  
Interaction Interaction ◽  
Pump Stations ◽  
Surrounding Soil

Low pile foundation is spacious used to process irrigation structure. In Vietnam it is effectively used to process irrigation structure in the north plains. However, when calculating load of the foundation works, it was mainly calculated to transmit to pile omitted load transmit to surrounding soil, in fact the load was transmitted to surrounding soil. So the lager number of piles were used to process foundation, it caused waste of piles and economics. Therefor calculating pile foundation, as calculated the interaction interaction between Soil, piles and irrigation structure will reduce the number of piles in the foundation, and when the irrigation structures were deformation tested by software and measured in actual condition, the results showed that the irrigation structures were guaranteed to work as the normal design criteria. Now in Vietnam some of pump stations and aqueducts are applied the interaction between Soil, piles and irrigation structure to process foundation.

scholarly journals Dye staining and excavation of a lateral preferential flow network

2009 ◽  
Vol 13 (6) ◽  
pp. 935-944 ◽  
Author(s):  
A. E. Anderson ◽  
M. Weiler ◽  
Y. Alila ◽  
R. O. Hudson
Keyword(s):  
Slope Stability ◽  
Solute Transport ◽  
Preferential Flow ◽  
Runoff Generation ◽  
Flow Paths ◽  
Soil Matrix ◽  
Preferential Flow Paths ◽  
Dye Staining ◽  
Hillslope Scale ◽  
Surrounding Soil

Abstract. Preferential flow paths have been found to be important for runoff generation, solute transport, and slope stability in many areas around the world. Although many studies have identified the particular characteristics of individual features and measured the runoff generation and solute transport within hillslopes, very few studies have determined how individual features are hydraulically connected at a hillslope scale. In this study, we used dye staining and excavation to determine the morphology and spatial pattern of a preferential flow network over a large scale (30 m). We explore the feasibility of extending small-scale dye staining techniques to the hillslope scale. We determine the lateral preferential flow paths that are active during the steady-state flow conditions and their interaction with the surrounding soil matrix. We also calculate the velocities of the flow through each cross-section of the hillslope and compare them to hillslope scale applied tracer measurements. Finally, we investigate the relationship between the contributing area and the characteristics of the preferential flow paths. The experiment revealed that larger contributing areas coincided with highly developed and hydraulically connected preferential flow paths that had flow with little interaction with the surrounding soil matrix. We found evidence of subsurface erosion and deposition of soil and organic material laterally and vertically within the soil. These results are important because they add to the understanding of the runoff generation, solute transport, and slope stability of preferential flow-dominated hillslopes.

scholarly journals Numerical Modelling of The Behavior of Tunnel in Soft Surrounding Rock. A Case Study of Djebel El-Ouahch Tunnel, Algeria.

2021 ◽  
Author(s):  
Barkane Aicha ◽  
Sami Mezhoud
Keyword(s):  
Reference Model ◽  
Soil Behavior ◽  
Tunnel Excavation ◽  
Circular Section ◽  
Geological Conditions ◽  
The Stability ◽  
Tunnel Cross Section ◽  
Calculation Code ◽  
Surrounding Soil

Abstract The response of a massif to stresses generated by tunnel excavation depends essentially on the geological conditions, the geometry of the tunnel and its underground position. The major problem related to the construction of these structures is to ensure the stability of the whole tunnel-ground, by controlling the various deformation generated during the constructionIn this context, the present paper examines the effect of these conditions on the behavior of tunnels and the surrounding soil. The study is applied to a real tunnel, in this case the tunnel of Djebel El Ouahch, Algeria was taken as a reference model. The research includes a parametric study to evaluate the effect of several parameters on the behavior of the tunnel and surrounding soil such as the tunnel anchoring depth, the tunnel-soil interface rate, and the shape of the tunnel cross section. The analysis is performed using the PLAXIS 3D TUNNEL calculation code with an elastoplastic Mohr-coulomb model for the soil behavior. The results show that the strongest and most stable position is the mid-deep tunnel with a circular section, with a non-slip interface between the tunnel and the ground. These outcomes can help to understand the effects of various influences parameters which control the stability of the tunnel in a soil with bad characteristics.

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