scholarly journals The Research on a Confined Modeling Method of the Effect of Deformable Ground Soil and Crawler Board

2018 ◽  
Vol 237 ◽  
pp. 02011
Author(s):  
LV Wei ◽  
Zhong-xin LI ◽  
LOU Peng
Keyword(s):  
Maximum Stress ◽  
Ground Deformation ◽  
Soil Mechanics ◽  
Soil Surface ◽  
Physical Significance ◽  
Soil Parameters ◽  
Soil Test ◽  
Analysis Model ◽  
Soil Pressure ◽  
Vehicle Mobility

There is a great relationship between the passing capacity of vehicles on the ground deformation road and the properties of confined and shear of ground soil, so it is necessary to establish a model that can reflect the soil pressure of the deformation. Physical significance of classic soil pressure experience parameters model is indeterminate, it was generally obtained by a lot of specific soil test. In this paper a new analysis model was built though introducing the maximum stress value of the crawler board and soil surface on basis of a kind of existing analysis model. This model reveals the relations among the confined characteristics of soil, soil parameters and the geometry of confined crawler board. These soil parameters can be obtained through the conventional soil mechanics test without a large number of specific soil test. Through the contrast experiment and predictions results, this model can effectively predict the sinkage of ground soil under the load, and provide a theory basis for the prediction of vehicle mobility.

scholarly journals Laboratory study and measurement of stiffness and compaction of unsaturated clay soil by using the innovative rebound hammer

2021 ◽  
Vol 34 (02) ◽  
pp. 710-732
Author(s):  
Behrouz Halimi ◽  
Hamidreza Saba ◽  
Saeid Jafari MehrAbadi ◽  
Saeid Saeidi Jam
Keyword(s):  
Electronic Device ◽  
Soil Mechanics ◽  
Soil Surface ◽  
High Sensitivity ◽  
Soil Parameters ◽  
Soil Behavior ◽  
Rebound Hammer ◽  
Analog To Digital ◽  
Behavioral Parameters ◽  
The Impact

Defining soil behavioral parameters, which eventually results in predicting every short-term and long-term soil behavior, has continually been one of the interests of soil mechanics and has been of exceptional value. To this end, in this study, a novel method has been reviewed to determine the compressive behavior of fine-grained soils in the laboratory and the field, without sampling by the patented electronic device. In the lab, homogeneous materials of the intended soil underwent the compaction test, mechanical and physical tests, direct shear test, and impacts of the innovative rebound hammer in the horizontal and vertical directions in the test-box. The impact shear waves produce resistance and voltage output by force and dislocation sensors with high-sensitivity proportional to the pressure based on the soil surface stiffness. The obtained voltages are then converted to digital by an analog-to-digital converter and a microcontroller. Next, a number is shown on display by the "CodeVision" program. Then, by solving a quasi-dynamic equation (Viscoelastic spring-damper model) by MATLAB software and with the aid of laboratory-field results and correlation equations, a fitting connection between all effective mechanical soil parameters has been estimated to an acceptable extent. The effective mechanical parameters of the soil include the compaction percentage, specific gravity, and frequency of the system in the damped and non-damped states, the energy imposed on the soil, and the plastic stage strain in the range of less than 15% humidity. The results determine that increased hammering numbers are directly related to increased soil compaction and stiffness. In more detail, the reading of hammer numbers less than 2 corresponds to compaction of less than 75%, while the reading of hammer numbers greater than 3 in the vertical and 2.94 in the horizontal directions on clay surfaces designates compaction of 90%.

scholarly journals An Improved Method to Estimate Soil Hydrodynamic and Hydraulic Roughness Parameters by Using Easily Measurable Data During Flood Irrigation Experiments and Inverse Modelling

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1581
Author(s):  
Mohamed Alkassem Alosman ◽  
Stéphane Ruy ◽  
Samuel Buis ◽  
Patrice Lecharpentier ◽  
Jean Bader ◽  
...  
Keyword(s):  
Soil Surface ◽  
Surface Flow ◽  
Performance Criteria ◽  
Soil Parameters ◽  
Well Performance ◽  
Estimation Errors ◽  
Hydraulic Roughness ◽  
Infiltration Model ◽  
Estimation Uncertainty ◽  
Using Data

Surface irrigation is known as a highly water-consuming system and needs to be optimized to save water. Models can be used for this purpose but require soil parameters at the field scale. This paper aims to estimate effective soil parameters by combining: (i) a surface flow-infiltration model, namely CALHY; (ii) an automatic fitting algorithm based on the SIMPLEX method; and (iii) easily accessible and measurable data, some of which had never been used in such a process, thus minimizing parameter estimation errors. The validation of the proposed approach was performed through three successive steps: (1) examine the physical meaning of the fitted parameters; (2) verify the accuracy of the proposed approach using data that had not been served in the fitting process; and (3) validate using data obtained from independent irrigation events. Three parameters were estimated with a low uncertainty: the saturated hydraulic conductivity Ks, the hydraulic roughness k, and the soil water depletion ∆θ. The estimation uncertainty of the soil surface depressional storage parameter H0 was of the same order of magnitude of its value. All experimental datasets were simulated very well. Performance criteria were similar during both the fitting and validation stages.

Variation for Soil Stress on CPTU Model Test

2010 ◽  
Vol 44-47 ◽  
pp. 2597-2601
Author(s):  
Yan Chun Tang ◽  
Gao Tou Meng
Keyword(s):  
Stress Field ◽  
Maximum Stress ◽  
Clay Soil ◽  
Cell Layer ◽  
Compression Stress ◽  
Soil Pressure ◽  
Piezocone Penetration Test ◽  
Main Stress ◽  
Saturated Clay ◽  
Soil Stress

Through a series of Piezocone Penetration Test (CPTU) model tests with saturated clay soil, by CPTU probe penetrating soil stress measured by soil pressure mini-cells embedded into soil has been acquired, the variation rules of soil stress by penetrating has been analyzed, the results show that with probe close to the second cell layer, the stress measured by the cells has been increased rapidly; when probe has arrived at the position of the second cell layer, the maximum stress value has been attained; and with probe away from the second cell layer, the stress value has been decreased rapidly. Based on the achieved soil stress value, the axial and radial subsidiary stress field causing by penetrating has been acquired, the conclusions can be obtained that the main stress style of the axial subsidiary stress is compression stress, around the probe the highest stress field has been occurred; the stress style of the radial subsidiary stress is compression stress, this phenomenon shows that by penetrating the compaction effect of the soil around the probe has been created; during the course of penetrating, the radial subsidiary stress is less than the axial subsidiary stress obviously. The achieved result can provide a foundation for further study for CPTU mechanism.

scholarly journals Examination of soil parameters based on the evaluation of the spectroradiometric reflectance characteristics of the topsoil

2014 ◽  
pp. 75-80
Author(s):  
Károly Bakos ◽  
Attila Dobos ◽  
János Nagy
Keyword(s):  
Measurement Techniques ◽  
Soil Surface ◽  
Soil Parameters ◽  
Surface Reflectance ◽  
Imaging Spectrometer ◽  
Top Soil ◽  
Multiple Samples ◽  
Physical And Chemical ◽  
Landscape Formation

In this article we are presenting the methodology applied to analyse and interpret the topsoil surface reflectance parameters of multiple samples collected in the Mugello valley area in northern Italy in October 2012. The main aim of the whole project was to discover geomorphological behaviour and situation of the area ino order to improve potential for correct dating of certain archaeological artefacts found in the nearby areas. One of the crucial problem researchers are facing in the area is the lack of understanding of the underlying geological and geomorphological processes that were describing and characterizing the area and that played important role not only in the current geography and landscape formation but also in the transportation of various sediments and artefacts. In this particular research the main aim is to examine the possibility of developing a quick way to assess low level properties of the soil using hand held spectrometer and rapid analysis of cross-section using in situ measurement techniques. In this work we collected over 2000 individual samples of topsoil surface reflectance properties that we organized into a spectral library. This library is then to be used to describe physical and chemical processes in the soil. To support the analysis results were compared to analysis results from different kind of assessments in the same area. Our results show a great potential of application of hand held imaging spectrometer in soil property analysis based on the top soil surface reflectance parameters.

scholarly journals Features of optimization of model parameters for solving geotechnical problems

2018 ◽  
Vol 251 ◽  
pp. 02035
Author(s):  
Armen Ter-Martirosyan ◽  
Vitalii Sidorov ◽  
Lubov Ermoshina
Keyword(s):  
Laboratory Tests ◽  
Soft Soil ◽  
Degree Of Approximation ◽  
Creep Model ◽  
Soil Parameters ◽  
Model Parameters ◽  
Soil Test ◽  
Compression Tests ◽  
Software Complex ◽  
Input Parameters

At present, numerical methods of calculations, which are implemented in a large number of software complexes, are widely used in geotechnical practice and the definition of input parameters of the ground is very important and necessary to reflect the real work of the foundation of geotechnical structures [1-4]. There are often cases when the results obtained during laboratory tests of soils are not accepted by software complexes, errors are given, recommendations are proposed for changing the parameters in the direction of increasing or decreasing. In connection with these problems, the question arose about the need to optimize soil parameters obtained as a result of laboratory tests to compare and correct these parameters, based on the degree of approximation of model tests with laboratory tests [5]. Optimization of soil parameters can be carried out in the subroutine Soil test, incorporated in the PLAXIS geotechnical software [6]. Using the Soil test, the triaxial and compression tests are simulated based on the input parameters of the soil and the initial test data. The purpose of this study was to describe the methodology for optimizing the parameters of the Hardening Soil model and the Soft Soil Creep model using the PLAXIS 3D software geotechnical complex, as well as a comparative analysis of the results of laboratory soil tests with modeling results in software complex.

scholarly journals Laboratory development of a vertically oriented penetrometer for shallow seabed characterization

2016 ◽  
Vol 53 (1) ◽  
pp. 93-102 ◽  
Author(s):  
Fauzan Sahdi ◽  
David J. White ◽  
Christophe Gaudin ◽  
Mark F. Randolph ◽  
Noel Boylan
Keyword(s):  
Soil Surface ◽  
Site Investigation ◽  
Soil Strength ◽  
Small Scale ◽  
Soil Parameters ◽  
Embedment Depth ◽  
Fine Grained ◽  
Centrifuge Models ◽  
Measured Resistance ◽  
And Performance

Current site investigation practice for offshore pipeline design relies on soil parameters gathered from boreholes or in situ test soundings to depths of 1–2 m below the mudline. At these depths, the fine-grained seabed is very soft and possesses low undrained strength, which can be difficult to measure. This paper describes a centrifuge test programme undertaken to evaluate the feasibility and performance of a novel penetrometer designed to assess the shallow strength of soft seabed over continuous horizontal profiles. This device is termed the vertically oriented penetrometer (VOP). Tests were performed on a normally consolidated kaolin sample, with the VOP translated horizontally at velocities ranging from 1 to 30 mm/s, after embedding the VOP at 30 and 45 mm depths. All tests involved many cycles of VOP forward and backward movement to assess its potential to derive the ratio of intact to fully remoulded strength. Strength determination is achieved by dragging the VOP at a specified embedment depth along the soil surface, and deriving the soil strength from the measured resistance as if the VOP were a laterally loaded pile. The VOP is shown to yield comparable strength measurements to that of a T-bar penetrometer. The VOP is a potentially valuable addition to the range of tools used to characterize soil strength, both in small-scale centrifuge models and, following practical development, potentially also in the field.

Some investigations into soil and vegetation relationships associated with alkaline-saline soil surfaces in the Walcha area, Northern Tablelands, New South Wales

1995 ◽  
Vol 46 (1) ◽  
pp. 209 ◽  
Author(s):  
KH Kreeb ◽  
RDB Whalley ◽  
JL Charley
Keyword(s):  
Cynodon Dactylon ◽  
New South ◽  
New South Wales ◽  
Soil Surface ◽  
Tree Planting ◽  
Soil Parameters ◽  
Alkali Cations ◽  
Grazing Land ◽  
South Wales ◽  
Wide Range

The characteristics of the soil, vegetation and groundwater at a dryland salinity site on Miramoona, a property near Walcha on the Northern Tablelands of New South Wales, were investigated. Soil parameters measured at 23 points along a 200 m transect were highly correlated with the pattern of vegetation. Of overriding significance was soil pH, which varied from a high of over 10 on bare areas delineated by Critesion marinum and Cynodon dactylon to a low of less than 5 on grazing land supporting the growth of a wide range of pasture species. The bare areas were characterized by alkalinity. While they were sodic at all depths measured, they were only marginally saline and then only at the soil surface. The chemical composition of the groundwater collected from three piezometer tubes varied quite markedly over the site. It is hypothesized that the presence of alkaline bare areas on the Northern Tablelands is not a new problem, but rather the natural result of alternating wet and dry periods which have induced accumulation of carbonates and bicarbonates of the alkali cations, notably sodium. Drainage of the original perched swamps by the early landholders, tree clearing and the grazing of domestic livestock would have accelerated the process since European settlement. However, tree planting would appear unlikely to have any impact on the reclamation process in the short term. A more viable option would be the recreation of the original swamps in suitable situations, although this solution would create problems for grazing management.

FEA Analysis of Subsea Mooring Suction Anchor Under Operation Condition

2015 ◽  
Author(s):  
Shuqin Wang ◽  
Jiaping Zhang ◽  
Jim Malachowski ◽  
Jubair Hossain ◽  
James Colling
Keyword(s):  
Structural Engineering ◽  
Structural Model ◽  
Limit State ◽  
Strength Analysis ◽  
Soil Parameters ◽  
Soil Reaction ◽  
Soil Pressure ◽  
Operation Condition ◽  
Limit States ◽  
Conservative Result

The analysis of a mooring suction anchor involves both geotechnical and structural engineering. The design starts with the geotechnical analysis of a mooring suction anchor where the design loads are used to determine the size of the mooring suction anchor. Typically, a conservative estimate would be made for the soil strength and analysis would involve several layers of soil with different properties. The mooring suction anchor is then designed using the relevant soil parameters for various limit states under the combined vertical, lateral, torsional, and moment loading. Soil pressures or reactions acting on a rigid steel mooring suction anchor for each limit state are calculated. The calculation results are then provided to structural engineers to perform strength analysis to verify the integrity of the anchor. Therefore, it is important to understand how the soil reactions interact with the suction anchor in the structural model. The current analysis used the soil reaction data developed for an in-place loading condition for a mooring suction anchor. The structure of the mooring suction anchor was modelled using a 3D finite element method. Two studies were performed. The first study performed the regular mapping of the soil pressure to the suction anchor. The second study assumed that all the loads would be applied on the mooring padeye and the bottom of the suction would be fixed. It was presumed that the second study would yield a conservative result. However, the analysis results showed that the second study did not provide a conservative result. Therefore, it is recommended that the care should be taken when making such assumptions in future studies.

scholarly journals Elevated soil copper content in a Bohemian vineyard as a result of fungicide application

2012 ◽  
Vol 7 (No. 4) ◽  
pp. 151-158 ◽  
Author(s):  
C. Ash ◽  
O. Vacek ◽  
O. Jakšík ◽  
V. Tejnecký ◽  
O. Drábek
Keyword(s):  
Humus Content ◽  
Soil Surface ◽  
Parent Material ◽  
Soil Parameters ◽  
Natural Soil ◽  
High Accumulation ◽  
Distribution Maps ◽  
Guideline Value ◽  
Guideline Values ◽  
Humus Quality

A set of fifty samples were taken from soil surface layers of an anonymous vineyard in the Bohemia region of the Czech Republic. Samples were analysed for basic soil parameters including pH and humus content and quality and for potentially toxic elements Cu, Pb, Zn, Cd and Mn. When compared to soil guideline values, mean Cu exceeded the limit by 280%. Although other elements did not exceed the guideline value, Zn and Cd surpassed background concentrations by 108 and 187%, respectively. Mn did not occur in concentrations that are considered excessive with respect to common natural soil levels. A statistically significant correlation was observed for Cu and C<sub>ox</sub>, but no significant correlation could be made between Cu and humus quality, suggesting that in this case, Cu retention in surface soil is more dependent on quantity of humic substances rather than humus quality. The unnaturally high accumulation of Cu in the surface horizon is certainly of anthropogenic origin; most likely due to long term application of copper-based fungicides. High observed values of Cd are probably a result of the soils parent material and application of fertilizers which may have contained cadmium compounds. Distribution maps illustrated a common trend of potentially toxic element accumulation in the western section of the study area plot. However, many variables which were unmeasured in this study could account for the distribution and therefore more detailed study is required before conclusions can be made regarding this occurrence. An analysis of wine produced at the vineyard showed that although the end product beverage contained insignificant amounts of Cu in both red and white wines, the white wine contained 0.026&nbsp;mg/l of&nbsp;Cd; a value which could contribute considerably to exceeding the dietary allowable intake of cadmium. The investigation should be extended to analyse a wider range of wines produced from the vineyard with a focus on soil-plant-fruit-wine transfer of cadmium and/or production processes.

Soil temperature and the energy balance of vegetative mulch in the semi-arid tropics. I. Static analysis of the radiation balance

Soil Research ◽  
1985 ◽  
Vol 23 (4) ◽  
pp. 493 ◽  
Author(s):  
PJ Ross ◽  
J Williams ◽  
RL Mccown
Keyword(s):  
Surface Temperature ◽  
Soil Temperature ◽  
Soil Water ◽  
Soil Surface ◽  
Approximate Expression ◽  
Shortwave Radiation ◽  
Soil Parameters ◽  
Radiation Balance ◽  
Incoming Radiation ◽  
Soil Surface Temperature

Planting crops into chemically killed pasture protects seedlings from high soil temperature. In this paper the radiation balance and convective heat loss of such dead vegetative mulch canopies are analysed mathematically for windless conditions, and maximum soil temperatures are calculated, together with their sensitivities to mulch and soil parameters. An approximate expression for soil heat flux, and assumptions about rates of change of radiation and other inputs with time, allow calculations where actual data are unavailable. A simplified analysis regards the mulch as a radiation filter which acts independently of the soil surface. Agreement with experimental data is good. The results show that energy losses by reflection, conduction, convection, radiation and evaporative cooling are all important in balancing incoming radiation and determining soil surface temperature, so that quantitative analysis is essential for a proper understanding of the system. .Mulch can reduce soil surface temperature by up to 20�C by intercepting incoming radiation; it dissipates this intercepted energy quite efficiently by free convection without concomitant increase in the temperature of the underlying soil surface. Penetration of radiation through the mulch is its most important characteristic. Forward scattering of shortwave radiation from the mulch to the soil surface has a big effect on soil temperature, but backward scattering has little effect, hence lighter-coloured more reflective mulches may be less efficient than darker ones. Evaporation of soil water is very efficient in reducing soil temperature, and the mulch prolongs the process of slow evaporation from the soil surface. The resulting higher soil water content also decreases soil surface temperature through its effects on soil thermal properties.

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