scholarly journals Soil compaction during harvest operations in five tropical soils with different textures under eucalyptus forests

2018 ◽  
Vol 42 (1) ◽  
pp. 58-68 ◽  
Author(s):  
Paula Cristina Caruana Martins ◽  
Moacir de Souza Dias Junior ◽  
Ayodele Ebenezer Ajayi ◽  
Ernesto Norio Takahashi ◽  
Diego Tassinari
Keyword(s):  
Bearing Capacity ◽  
Soil Compaction ◽  
Sandy Loam ◽  
Traffic Intensity ◽  
Compression Tests ◽  
Load Bearing Capacity ◽  
Undisturbed Soil ◽  
Load Bearing ◽  
Structure Degradation ◽  
Precompression Stress

ABSTRACT Traffic of farm machinery during harvest and logging operations has been identified as the main source of soil structure degradation in forestry activity. Soil susceptibility to compaction and the amount of compaction caused by each forest harvest operation differs according to a number of factors (such as soil strength, soil texture, kind of equipment, traffic intensity, among many others), what requires the adequate assessment of soil compaction under different traffic conditions. The objectives of this study were to determine the susceptibility to compaction of five soil classes with different textures under eucalyptus forests based on their load bearing capacity models; and to determine, from these models and the precompression stresses obtained after harvest operations, the effect of traffic intensity with different equipment in the occurrence of soil compaction. Undisturbed soil samples were collected before and after harvest operations, being then subjected to uniaxial compression tests to determine their precompression stress. The coarse-textured soils were less resistant and endured greater soil compaction. In the clayey LVd2, traffic intensity below four Forwarder passes limited compaction to a third of the samples, whereas in the sandy loam PVd all samples from the 0-3 cm layer were compacted regardless of traffic intensity. The Feller Buncher and the Clambunk presented a high potential to cause soil compaction even with only one or two passes. The use of soil load bearing capacity models and precompression stress determined after harvest and logging operations allowed insight into the soil compaction process in forestry soils.

scholarly journals Compaction caused by mechanized operations in a Red- Yellow Latosol cultivated with coffee over time

2012 ◽  
Vol 36 (4) ◽  
pp. 391-398 ◽  
Author(s):  
Paula Cristina Caruana Martins ◽  
Moacir de Souza Dias Junior ◽  
Maria Luiza de Carvalho Andrade ◽  
Paulo Tácito Gontijo Guimarães
Keyword(s):  
Bearing Capacity ◽  
Soil Samples ◽  
Compression Tests ◽  
Coffee Plantation ◽  
Load Bearing Capacity ◽  
Undisturbed Soil ◽  
Load Bearing ◽  
Coffee Plantations ◽  
Structure Degradation ◽  
Coffee Arabica

The main source of soil structure degradation in coffee plantation is the machinery traffic because these operations may cause soil compaction affecting the crop development. This study aimed to generate the load-bearing capacity models for a Red-Yellow Latosol and to determine through the use of these models the soil susceptibility to compaction of the coffee plantation due to the implantation time and the compaction caused by the machinery traffic on the traffic lines located at the top and bottom of the ground. This study was carried out in the EPAMIG Experimental Farm, located at Três Pontas, MG, in coffee plantations (Coffee arabica L.) with 2, 7, 18 and 33 years of establishment. To obtain the load-bearing capacity models, 12 undisturbed soil samples were randomly collected in the 0-3 cm and 15-18 cm layers in the position between the rows for each establishment time of the coffee plantation. It was also randomly collected 10 undisturbed soil samples for each establishment time of the coffee plantations along the tractor traffic lines located at the top and bottom of the ground. These undisturbed soil samples were used in the uniaxial compression tests. The use of the load-bearing capacity models allow to identify the soil susceptibility to compaction due to the implementation time of the coffee plantation and the compaction caused by the machinery traffic on the traffic lines located at the top and bottom of the ground. The percentage of compacted soil samples increases with the establishment time in the layer of 15-18 cm.

scholarly journals A Modified Pressure–Sinkage Model for Studying the Effect of a Hard Layer in Sandy Loam Soil

2021 ◽  
Vol 11 (12) ◽  
pp. 5499
Author(s):  
Nihal D. Salman ◽  
György Pillinger ◽  
Muammel M. Hanon ◽  
Péter Kiss
Keyword(s):  
Bearing Capacity ◽  
Sandy Loam ◽  
Sandy Loam Soil ◽  
High Fidelity ◽  
Load Bearing Capacity ◽  
Soil Thickness ◽  
Load Bearing ◽  
Hard Layer ◽  
Loam Soil ◽  
New Perspective

The applicability of the typical pressure–sinkage models used to characterize the soil’s bearing properties is limited to homogeneous soils (infinite thickness) that have no hard layer. At a given depth, a hard layer can have a considerable impact on the soil’s load-bearing capacity. It is thus necessary to alter the pressure–sinkage equation by taking this condition into account when assessing the load-bearing capacity. The present paper aims to determine a simple, high-fidelity model, in terms of soil characterization, that can account for the hard layer affection. To assess hard layer affection in this paper, a plate sinkage test (bevameter) was conducted on sandy loam soil. To this end, the soil was prepared by considering three bulk densities and two soil thickness levels at 7–9% moisture content levels. According to the results, this paper put forth a new perspective and related equations for characterizing bearing performance. The sinkage modulus (k) is an intrinsic soil parameter that has a determined unit of N/cm2 and is significant for managing the bearing performance. The results showed that the new modulus sinkage model incorporates the main factor of the rigid layer effect involving high fidelity that the conventional models have failed to account for.

scholarly journals Soil behaviour under load in case of finite thickness

2020 ◽  
Author(s):  
Nihal D. Salman ◽  
György Pillinger ◽  
Péter Kiss
Keyword(s):  
Moisture Content ◽  
Bearing Capacity ◽  
Sandy Loam ◽  
Finite Thickness ◽  
Initial Density ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Push Down ◽  
Soil Bin ◽  
Soil Behaviour

AbstractThis study intends to examine the soil behaviour in the case of finite thickness, represented by the hard layer under a soft layer of soil. A further aim is to define load-bearing capacity parameters (n and k). The experimental work is carried out under laboratory conditions by using hydraulic bevameter to apply the load. A circular plate with a diameter of 100 mm is used to push down the load over the targeted area with a penetration rate of about 9 cm/min for sinkage plates. The study was conducted in a soil bin (length of 200 cm, width of 100 cm and variable thickness) using a sandy loam soil. First, the study has been done with loose soil with a thickness of 11 cm, which maintained with 10% moisture content and initial density of 1.190 g/cm3. After that, a two thickness of 6 and 18 cm with 8% moisture content and initial soil density of 1.375 g/cm3 were tested to explain the effect of thickness. In each test, the bevameter plate was loaded at multiple locations, the result showed the soil was near uniform. The result suggests that it is not easy to obtain one equation for the load bearing capacity because the layer near to the surface behaves like soil with infinite thickness and the deeper layer like soil with finite thickness.

scholarly journals Structural sustainability of cambisol under different land use system

2012 ◽  
Vol 36 (6) ◽  
pp. 1724-1732 ◽  
Author(s):  
Paula Cristina Caruana Martins ◽  
Moacir de Souza Dias Junior ◽  
Ayodele Ebenezer Ajayi ◽  
Fátima Maria de Souza Moreira
Keyword(s):  
Land Use ◽  
Bearing Capacity ◽  
Soil Structure ◽  
Secondary Forest ◽  
Soil Samples ◽  
Load Bearing Capacity ◽  
Undisturbed Soil ◽  
Load Bearing ◽  
Land Use Systems ◽  
Land Use System

Incongruous management techniques have been associated with some significant loss of agricultural land to degradation in many parts of the world. Land degradation results in the alteration of physical, chemical and biological properties of the soil, thereby posing a serious threat to sustainable agricultural development. In this study, our objective is to evaluate the changes in a Cambisol structure under six land use systems using the load bearing capacity model. Sampling was conducted in Amazonas Region, Brazil, in the following land use: a) young secondary forest; b) old secondary forest; c) forest; d) pasture; e) cropping, and f) agroforestry. To obtain the load bearing capacity models the undisturbed soil samples were collected in those land use systems and subjected to the uniaxial compression test. These models were used to evaluate which land use system preserved or degraded the Cambisol structure. The results of the bulk density and total porosity of the soil samples were not adequate to quantify structural degradation in Cambisol. Using the forest topsoil level (0-0.03 m) as a reference, it was observed that pasture land use system was most severe in the degradation of the soil structure while the structure were most preserved under old secondary forest, cropping system and forest. At the subsoil level (0.10-0.13 m depth), the soil structure was most degraded in the cropping land use system while it was most preserved in young secondary forest and pasture. At the 0.20-0.23 m depth, soil structure degradation was most severe in the old secondary forest system and well preserved in young secondary forest, cropping and agroforestry.

scholarly journals Experimental and Numerical Investigation of the Fracture Behavior of Welded Aluminum Cross Joints under Axial Compression

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4310
Author(s):  
Hannes Panwitt ◽  
Horst Heyer ◽  
Manuela Sander
Keyword(s):  
Numerical Simulations ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Fracture Behavior ◽  
Stress Triaxiality ◽  
Base Material ◽  
Compression Tests ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Welded Structure

In age-hardened high-strength aluminum alloys, the area with and around a joint has a large impact on the load-bearing capacity of a welded structure. Therefore, in this study the fracture behavior of welded EN AW 6082 T6 plates is investigated experimentally and numerically. From butt joints, smooth and notched tensile specimens as well as shear specimens have been manufactured and tested for the base material (BM), heat-affected zone (HAZ) and fusion zone (FZ). With numerical simulations of these tests, the dependency of the fracture strain on the stress triaxiality is determined, and two phenomenological fracture criteria are calibrated. Whereas the one-parameter Rice–Tracey/Cockcroft–Latham (RTCL) criterion describes the behavior of the tension specimens as accurately as the two-parameter Bao–Wierzbicki (BW) criterion, the BW criterion is more accurate for shear tests. Subsequently, the material model is validated on axial compression tests of welded X-profiles. The experiments comprise tests with different plate thicknesses (8 mm, 10 mm and 12 mm) and varying strain rates (up to 1/s locally), showing the same behavior for all specimens. After crack initiation within the FZ, coalescence of cracks leads to crack growth in axial direction and a subsequent reduction of the load-bearing capacity. This behavior is reproduced well by the numerical simulations with the BW criterion, whereas simulations with the RTCL criterion predict fracture initiation at too high displacements. Overall, the results show the strong influence of the ductility of the FZ on the crushing behavior of welded X-profiles.

scholarly journals Load-bearing capacity of a red-yellow latosol cultivated with coffee plants subjected to different weed managements

2013 ◽  
Vol 37 (2) ◽  
pp. 145-151 ◽  
Author(s):  
Paula Sant'Anna Moreira Pais ◽  
Moacir de Souza Dias Junior ◽  
Adriana Cristina Dias ◽  
Piero Iori ◽  
Paulo Tácito Gontijo Guimarães ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Weed Management ◽  
Soil Samples ◽  
Coffee Plantation ◽  
Load Bearing Capacity ◽  
Undisturbed Soil ◽  
Load Bearing ◽  
Coffee Plantations ◽  
Coffee Plants ◽  
Control Post

It is essential to know the levels of pressure applied to the soil by different weed managements to adapt the management of coffee plantations in a sustainable manner. The objectives of this study were: a) to generate load-bearing capacity models of a Red-Yellow Latosol (Oxisol) submitted to different weed managements and b) to determine which weed management resulted in higher compression. The study was conducted at the Experimental Farm of EPAMIG, located near the community Farias, in Lavras-MG (latitude 21° 14' 43" S and longitude 44° 59' 59" W and altitude of 919 m). The soil is a Red-Yellow Latosol (LVA) cultivated with coffee plantation using Topazio MG 1190 coffee variety, since 2006. We evaluated five weed managements, three being through mechanical control (harrow (GD), mowing (RÇ) and brush (TC)) and two by chemical control (post-emergence herbicide (HPos) and pre emergence herbicide (HPre)). To obtain the load-bearing capacity models, 10 undisturbed soil samples were randomly collected in the 0-3, 10-13 and 25-28 cm layers between the rows. The load-bearing capacity models which indicated a higher compaction were: in the 0-3 cm layer, TC and GD; in the 10-13 cm layer, HPre, HPos and RÇ and in the 25-28 cm layer, GD. The load-bearing capacity models that indicated greater susceptibility to compaction were: in the 0-3 cm layer, HPos; in the 10-13 cm layer, GD and TC and in the 25-28 cm layer, HPre.

Experimental Research on Behavior of CFRP Circular Steel Tubular Confined Recycled Aggregate Concrete Columns under Axial Compression

2015 ◽  
Vol 744-746 ◽  
pp. 96-99
Author(s):  
Jiong Feng Liang ◽  
Ze Ping Yang ◽  
Ming Hua Hu
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Concrete Columns ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Compression Tests ◽  
Load Bearing Capacity ◽  
Aggregate Concrete ◽  
Load Bearing ◽  
Cfrp Wrapping

In order to further promote the use of recycled aggregate concrete in practice, axial compression tests were carried out for 7 CFRP circular steel tubular confined recycled aggregate concrete columns. The influence of the replace rate of recycled aggregate concrete, the wrapping method on axial compression behavior of CFRP circular steel tubular confined recycled aggregate concrete columns were analyzed. Based on the results of the tests, with the replace rate of recycled aggregate concrete increasing, the specimens have an decreasing trend in the load bearing capacity. The whole CFRP wrapping circular steel tubular confined recycled aggregate concrete columns have higher load bearing capacity than the three stripe wrapping ones.

scholarly journals Comparison of field and laboratory models of the load bearing capacity in coffee plantations

2013 ◽  
Vol 37 (2) ◽  
pp. 130-137 ◽  
Author(s):  
Piero Iori ◽  
Moacir de Souza Dias Junior ◽  
Ayodele Ebenezer Ajayi ◽  
Paulo Tácito Gontijo Guimarães ◽  
Paula Sant'Anna Moreira Pais ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Soil Structure ◽  
Homogeneity Test ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Natural Field ◽  
Moisture Contents ◽  
Precompression Stress ◽  
One Year ◽  
Laboratory Models

Precompression stress is an important property for assessment of tropical soil structure sustainability and is often determined in laboratory tests. The objective of this study was to compare the load bearing capacity models obtained with controlled moisture in laboratory and those obtained with natural field moistures determined a long one year. The evaluation of soil structural sustainability follows four distinct steps: soil sampling in the field, uniaxial compression test of the samples in the laboratory, determination of precompression stress and estimation of the load bearing capacity models. Laboratory estimates of precompression stress were obtained from moisture controlled in laboratory and from natural moisture determined in a field a long one year. In this process, the soil samples were saturated by capillarity with distilled water in laboratory, and after 48 hours, the samples were air dried to obtain the different moisture contents. Then, the precompression stress was determined for this both conditions. To verify if the load bearing capacity models obtained with controlled moisture in laboratory may represent the load bearing models obtained with natural field moisture, these models were compared using the homogeneity test procedure. It was observed that 75% of field models analyzed were similar to the laboratory models. Thus, due to the similarity on the load-bearing capacity models obtained using natural (field) or controlled (laboratory) moisture contents, the assessment of the soil structure sustainability can be done using both methods.

scholarly journals Soil compaction caused by harvest and logging operations in eucalyptus forests in coarse-textured soils from northeastern Brazil

2017 ◽  
Vol 41 (2) ◽  
pp. 191-200 ◽  
Author(s):  
Maria Luiza de Carvalho Andrade ◽  
Diego Tassinari ◽  
Moacir de Souza Dias Junior ◽  
Ricardo Previdente Martins ◽  
Wellington Willian Rocha ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Bulk Density ◽  
Soil Compaction ◽  
Bare Soil ◽  
Northeastern Brazil ◽  
Plant Residue ◽  
Planted Forests ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
The Impact

ABSTRACT Planted forests occupy more than 6.5 million ha in Brazil, where harvest and logging operations are performed with increasingly heavier machinery, increasing the risk of soil compaction. Soil compaction can be avoided if soil load bearing capacity is not exceeded, what makes it important to assess both the soil strength and the impact of different operations. The aim of this study was to evaluate the load bearing capacity of some coarse textured soils (two Hapludult and one Haplorthod) in two soil horizons (BA and B), from northeastern Brazil; and to assess the impact of harvest and logging operations performed with harvester and forwarder. Although the Haplorthod presented higher load bearing capacity in both the BA horizon (for the whole moisture range) and the B horizon (for higher water contents), it suffered the greatest soil compaction. Traffic with the harvester resulted in soil compaction in both the BA and the B horizons, but the increase in bulk density was higher on the later, reaching 18.7% in the Haplorthod. The forwarder traffic intensity and the presence of plant residue cover significantly affected the occurrence of soil compaction. In the BA horizon, the increase in soil bulk density for different forwarder traffic intensities was 3 passes ~ 6 passes < 12 passes ~ 16 passes. The increase in bulk density was higher in the Haplorthod, reaching 32% after 16 forwarder passes over bare soil. Significant linear regressions were obtained from the number of forwarder passes and the increase in bulk density.

scholarly journals Durability of concrete with CFRP wrapping

2018 ◽  
Vol 199 ◽  
pp. 09009
Author(s):  
Qian-Qian Yu ◽  
Xiang Li ◽  
Xiang-Lin Gu
Keyword(s):  
Bearing Capacity ◽  
Water Immersion ◽  
Weight Ratio ◽  
High Strength ◽  
Compression Tests ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Concrete Cylinders ◽  
Carbon Fibre Reinforced Polymer ◽  
Cfrp Wrapping

Carbon fibre-reinforced polymer (CFRP) material has a high strength-to-weight ratio and good resistance to corrosion and environmental attacks. It has been widely used in rehabilitation of aged infrastructure. However, the durability of the strengthened system has not been yet assessed thoroughly since most of the previous study was conducted based on accelerated tests while the long-term investigation was less reported. This paper investigated the effect of CFRP wrapping on the axial behaviour of concrete cylinders subjected to different environments for more than 13 years. The specimens were exposed to five different conditions, including standard curing, immersion in distilled water, immersion in saturated Na2SO4 solution, outdoor sheltered from the rain, and outdoor without shelter from the rain. Axial compression tests were performed on the wrapped concrete cylinders. The load-bearing capacity and stress-strain responses were recorded. It was found that CFRP wrapping could effectively improve the ultimate strength and ductility of the columns. Though scatter existed, no significant effect of the environmental exposure on the load-bearing capacity of the cylinder specimens was observed which indicates a good durability of the strengthening system.

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