Comparison Of Field And Laboratory Studies Results Of The Clay Soils Deformability Characteristics

2019 ◽  
pp. 40-45
Keyword(s):  
Low Cost ◽  
Field Studies ◽  
Field Conditions ◽  
Clay Soils ◽  
Saturated Soils ◽  
Natural Occurrence ◽  
Laboratory Studies ◽  
Load Tests ◽  
Definition Of ◽  
Water Saturated

Determination of the deformability characteristics of weak water-saturated soils is a complex process. Firstly, it is difficult to preserve the natural structure of the soil sample taken for the study in the laboratory. Secondly, according to the latest studies, in natural occurrence there is a constant pore pressure, which must be taken into account when determining the characteristics of deformability and strength of clay soils. During many years it was established that the compressibility characteristic of soils obtained under laboratory conditions differs sharply from the result of characterization in field conditions. It is proposed to use the characteristics of compressibility and strength of soils obtained in the course of low-cost laboratory studies, compared with the definition of these characteristics in expensive field conditions. The results of the comparison of numerous laboratory and field studies of the properties of weak water-saturated soils of the base of various regions of Russia are presented. On the basis of the data obtained, when studying the characteristics of deformability of weak water-saturated clay soils, it is recommended to use only laboratory methods and not to conduct additional field plate load tests, except in the case of construction of unique structures,

CHANGE IN STRENGTH PARAMETERS OF DISPERSED SOILS AFTER HIGH-FREQUENCY VIBRATION

2021 ◽  
Vol 12 (1) ◽  
pp. 46-56
Author(s):  
V. M Polunin ◽  
A. P Cheremhina
Keyword(s):  
High Frequency ◽  
Field Measurements ◽  
Field Studies ◽  
Clay Soils ◽  
Laboratory Studies ◽  
Strength Parameters ◽  
High Frequency Vibration ◽  
Soil Foundation ◽  
Comparison Of The Results ◽  
Water Saturated

The use of the technology of high-frequency sheet piles driving or extraction in conditions of weak, structurally unstable soils inevitably leads to a change in the structure of the soil. This is especially true for buildings which fall into the zone of influence. Often, foundation for historical buildings is water-saturated sands, spread by fluid and fluid-plastic clay soils. In the process of external dynamic action, the soil foundation is been destructing, so their strength and deformation parameters are reduced. In this case, the result of vibration effects on a dispersed water-saturated sample can be both compaction for sandy soil and decompaction of clay soils. These changes lead to additional deformations of buildings and structures of the surrounding area. Therefore, the issue of assessing the limits of applicability of vibration technology in certain conditions is relevant. The object of the study is the changes in the properties of clay soils of various consistencies after exposure to vibration. The results of laboratory studies to determine the strength parameters of dispersed soils after high-frequency vibration are presented. The results of field measurements by CPT "before", "after" vibration immersion and vibration extraction of sheet piles are considered. Comparison of the results of field and laboratory studies is carried out to identify patterns of change in the strength characteristics of weak soils under the influence of vibration loads. A tendency towards a decrease in the strength parameters of dispersed soils is shown. Currently, due to the insufficient number of laboratory and field studies to study the effect of high-frequency vibration on the change in the strength parameters of weak water-saturated clay soils, it is not possible to identify a clear dependence of the change in parameters on the time and frequency of vibration.

scholarly journals Compaction of water-saturated soil by surface vacuuming

2018 ◽  
Vol 196 ◽  
pp. 03006 ◽  
Author(s):  
Lyudmila Cherkasova
Keyword(s):  
Surface Area ◽  
Saturated Soil ◽  
Saturated Soils ◽  
Laboratory Studies ◽  
Compression Tests ◽  
The Press ◽  
Soil Venting ◽  
Similarities And Differences ◽  
Equivalent Load ◽  
Water Saturated

The results of laboratory studies of compaction of weak water-saturated soils using surface vacuuming are presented. Experiments on the compaction of water-saturated peat by the method of surface vacuuming under the screens were carried out on a special installation. The vacuum was created under round sealed screens of different sizes and stiffness. As the results of the experiments showed, the mechanism of compaction of weak water-saturated soils during vacuuming from the surface under the protection of a sealed coating is determined by the action of volumetric filtration forces. When vacuuming, in contrast to the compaction load, there is no soil venting around the perimeter of the compacted surface area, which significantly increases the efficiency of this method. And the use of flexible screens (geo-membrane) opens up opportunities for construction. A series of compression tests was carried out to identify the similarities and differences in the consolidation processes when compacting different materials by vacuuming and equivalent load created by the press.

The effect of benomyl on Gloeotinia temulenta under laboratory and field conditions

1971 ◽  
Vol 11 (53) ◽  
pp. 693 ◽  
Author(s):  
DC McGee
Keyword(s):  
Lolium Perenne ◽  
No Reduction ◽  
Field Studies ◽  
Field Conditions ◽  
Seed Infection ◽  
Laboratory Studies ◽  
Causal Organism ◽  
Infected Seed ◽  
Application Rates ◽  
Seed Crops

Laboratory studies confirmed that benomyl can completely suppress apothecial formation of Gloeotinia temulenta, the causal organism of blind seed disease in grasses. Field studies in Lolium perenne seed crops showed that benomyl, applied at 2.80 and 5.60 kg/hectare, reduced the numbers of apothecia formed by 80 and 90 per cent respectively, while no reduction was apparent at 0.56 kg/hectare. Better results were obtained when the compound was applied in November, just before flowering, than when applied in September or October. At the application rates used, benomyl did not protect plants against seed infection. However, the degree of suppression of apothecial formation possible with benomyl suggests that, in areas where reinfestation of fields with infected seed after harvest is light, the compound should control blind seed disease by limiting formation of apothecia, which are the source of ascospore inoculum, to insignificant proportions.

scholarly journals Evaluation of seismic properties of water-saturated soils for solving problems in seismic microzoning

2019 ◽  
pp. 74-81
Author(s):  
B. A. Trifonov ◽  
V. V. Sevostyanov ◽  
S. Yu. Milanovskiy ◽  
V. V. Nesynov
Keyword(s):  
Field Tests ◽  
Field Studies ◽  
Seismic Intensity ◽  
Seismic Effect ◽  
Saturated Soils ◽  
Seismic Microzoning ◽  
S Waves ◽  
Seismic Properties ◽  
Intensity Increment ◽  
Water Saturated

The experts involved in seismic microzoning (SMZ) have different opinions on whether to take into account the response of water-saturated fine soils upon the assessment of expected seismic effect. When using the method of seismic stiffness (MSS), a number of researchers consider inexpedient to apply the correction for the groundwater level (GWL). In the present paper, we analyze both the results of our own field studies and those of other researchers involved in the development of SMZ methodology. Particular attention is paid to the GWL influence on the increment of seismic intensity (ΔIGWL ) in the S.V. Medvedev’s equation upon MSS calculations by transverse s-waves. The research results provided in this paper prove that the correction for ΔIGWL should not be ignored in calculations of the seismic intensity increment. The authors appear it expedient to continue field tests in the registration of strong movements in water-saturated fine soils.

Large-Scale Enclosed Water-Column Ecosystems an Overview of Foodweb I, the Final CEPEX Experiment

1980 ◽  
Vol 60 (2) ◽  
pp. 401-414 ◽  
Author(s):  
G. D. Grice ◽  
R. P. Harris ◽  
M. R. Reeved ◽  
J. F. Heinbokel ◽  
C. O. Davis
Keyword(s):  
Large Scale ◽  
Balance Control ◽  
Hybrid Approach ◽  
Field Studies ◽  
Experimental Manipulation ◽  
Laboratory Studies ◽  
Partial Control ◽  
Larval Fishes ◽  
Natural Assemblage ◽  
Definition Of

Enclosures of various sizes and configurations have been employed to maintain natural planktonic communities and to examine their responses to pollutants (e.g. Menzel & Steele, 1978; Steele, 1979). Studies on feeding, growth, and mortality of larval fishes, at times conducted in conjunction with pollution experiments, have also been successfully conducted in large enclosures (Koeller & Parsons, 1977). Implicit in these and other comparable studies has been the expectation (or hope) that a balance could be achieved between the advantages and difficulties inherent in more traditional field and laboratory studies. Field studies offer the realism of working with the natural assemblage with its many interacting components and links, but also suffer the disadvantage associated with a turbulent and advective system, which generally makes the repetitive sampling of the same populations impossible. Laboratory studies reverse the balance; control and definition of the components are gained at the expense of realism. The use of large containers represents a hybrid approach characterized by a partial control over a moderately realistic ecosystem. In the ideal case, the use of large containers allows sufficient control to permit experimental manipulation of (and the testing of hypotheses concerning) planktonic assemblages which are sufficiently realistic to permit extension of the experimental results to the ‘real world’.

scholarly journals Soil bases modified with lime waste and polycarboxylates

2021 ◽  
Vol 2124 (1) ◽  
pp. 012023
Author(s):  
L V Zakrevskaya ◽  
K A Nikolaeva ◽  
A I Gandelsman ◽  
P A Orekhov
Keyword(s):  
Physical And Mechanical Properties ◽  
Road Construction ◽  
Clay Soils ◽  
Infrastructure Development ◽  
Laboratory Studies ◽  
The Road ◽  
Saturated Clay ◽  
Water Saturated ◽  
The Cost ◽  
Local Materials

Abstract Increasing the volume of road construction is one of the priority areas of infrastructure development in any country. When building roads, it is preferable to use local materials to reduce the cost of their transportation, therefore, it is advisable to build the roadbed on local soils. It is worth noting that clay water-saturated soils are the most common, which complicates the construction of the road due to some features of this type of soil. The object of the study is a water-saturated clay with the following characteristics: natural humidity from 25.3 % to 28.1% by weight, optimal humidity from 11.8 % to 16.7% by weight, the number of plasticity from 0.118 to 0.153. Clay soils have a number of features: waterlogged soils are difficult to compact and develop, it is quite problematic to dry them, and thixotropy is also characteristic of clay soils. In this regard, it is most advisable to use the method of complex mineral binders to optimize their physical and mechanical properties. In the course of laboratory studies, compositions of soil compositions with the addition of lime waste and superplasticizer P-17 were developed. The dependence of the strength on the consumption of mineral binders and surfactants is established: the maximum compressive strength of the soil being fixed is achieved at a lime content of 25 wt.% and at a P-17 content in the range of 0.10-0.5 wt.%.

HOUSEHOLD WATER BALANCE AND ASSESSMENT OF WATER VOLUME FOR IRRIGATION IN AGRO LANDSCAPES OF THE KYZYLSU-YUZHNAYA BASIN

2020 ◽  
pp. 102-109
Author(s):  
D.KH. DOMULLODZHANOV ◽  
◽  
R. RAHMATILLOEV
Keyword(s):  
Water Balance ◽  
River Basin ◽  
Water Use ◽  
Storage Systems ◽  
Low Cost ◽  
Field Studies ◽  
Water Volume ◽  
Land Productivity ◽  
Household Water ◽  
And Storage

The article presents the results of the field studies and observations that carried out on the territory of the hilly, low-mountain and foothill agro landscapes of the Kyzylsu-yuzhnaya (Kyzylsu-Southern) River Basin of Tajikistan. Taking into account the high-altitude location of households and the amount of precipitation in the river basin, the annual volumes of water accumulated with the use of low-cost systems of collection and storage of precipitation have been clarified. The amount of water accumulated in the precipitation collection and storage systems has been established, the volume of water used for communal and domestic needs,the watering of livestock and the amount of water that can be used to irrigate crops in the have been determined. Possible areas of irrigation of household plots depending on the different availability of precipitation have been determined. It has been established that in wet years (with precipitation of about 10%) the amount of water collected using drip irrigation will be sufficient for irrigation of 0.13 hectares, and in dry years (with 90% of precipitation) it will be possible to irrigate only 0.03 ha of the household plot. On the basis of the basin, the total area of irrigation in wet years can be 4497 ha, and in dry years only 1087 ha. Taking into account the forecasts of population growth by 2030 and an increase in the number of households, the total area of irrigation of farmlands in wet years may reach 5703 hectares,and in dry years – 1379 hectares. Growing crops on household plots under irrigation contributes to a significant increase in land productivity and increases the efficiency of water use of the Kyzylsu-yuzhnaya basin.

What’s in, what’s out? Towards a rigorous definition of the boundaries of benefit-cost analysis

2021 ◽  
pp. 1-17
Author(s):  
Daniel Acland
Keyword(s):  
Cost Analysis ◽  
Willingness To Pay ◽  
Low Cost ◽  
Consumer Sovereignty ◽  
Benefit Cost Analysis ◽  
Rigorous Definition ◽  
Pareto Criterion ◽  
Definition Of ◽  
Benefit Cost

Abstract Benefit-cost analysis (BCA) is typically defined as an implementation of the potential Pareto criterion, which requires inclusion of any impact for which individuals have willingness to pay (WTP). This definition is incompatible with the exclusion of impacts such as rights and distributional concerns, for which individuals do have WTP. I propose a new definition: BCA should include only impacts for which consumer sovereignty should govern. This is because WTP implicitly preserves consumer sovereignty, and is thus only appropriate for ‘sovereignty-warranting’ impacts. I compare the high cost of including non-sovereignty-warranting impacts to the relatively low cost of excluding sovereignty-warranting impacts.

scholarly journals An Agent-Based Crop Model Framework for Heterogeneous Soils

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 85
Author(s):  
Jorge Lopez-Jimenez ◽  
Nicanor Quijano ◽  
Alain Vande Wouwer
Keyword(s):  
Growth Models ◽  
Control Strategies ◽  
Low Cost ◽  
Soil Heterogeneity ◽  
Crop Growth ◽  
Negative Effects ◽  
Model Framework ◽  
Agent Based ◽  
Crop Growth Models ◽  
Definition Of

Climate change and the efficient use of freshwater for irrigation pose a challenge for sustainable agriculture. Traditionally, the prediction of agricultural production is carried out through crop-growth models and historical records of the climatic variables. However, one of the main flaws of these models is that they do not consider the variability of the soil throughout the cultivation area. In addition, with the availability of new information sources (i.e., aerial or satellite images) and low-cost meteorological stations, it is convenient that the models incorporate prediction capabilities to enhance the representation of production scenarios. In this work, an agent-based model (ABM) that considers the soil heterogeneity and water exchanges is proposed. Soil heterogeneity is associated to the combination of individual behaviours of uniform portions of land (agents), while water fluxes are related to the topography. Each agent is characterized by an individual dynamic model, which describes the local crop growth. Moreover, this model considers positive and negative effects of water level, i.e., drought and waterlogging, on the biomass production. The development of the global ABM is oriented to the future use of control strategies and optimal irrigation policies. The model is built bottom-up starting with the definition of agents, and the Python environment Mesa is chosen for the implementation. The validation is carried out using three topographic scenarios in Colombia. Results of potential production cases are discussed, and some practical recommendations on the implementation are presented.

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