Study of Correlation on Unconfined Compressive Strength between Different Soil

2013 ◽  
Vol 838-841 ◽  
pp. 926-929
Author(s):  
Xia Zhao
Keyword(s):  
Compressive Strength ◽  
Soil Moisture ◽  
Moisture Content ◽  
Unconfined Compressive Strength ◽  
Laboratory Tests ◽  
Soil Moisture Content ◽  
Correlation Coefficients ◽  
Friction Angle ◽  
Silty Clay ◽  
Soil Cohesion

Take the silty clay and clay as the research object, the correlation between bulk density, moisture content, cohesion, friction angle and unconfined compressive strength was analyzed using laboratory tests, and the results showed that soil cohesion, friction angle and unconfined compressive strength with good correlation, the correlation coefficients were all above 0.9, while severe and soil moisture content and unconfined compressive strength of correlation is weak, followed by the correlation formulas of the index and unconfined compressive strength were established, these formulas can used to predict the unconfined compressive strength of soil.

EFFECTS OF DIFFERENT SOIL MOISTURE TENSIONS ON FLAX AND CEREALS

1966 ◽  
Vol 46 (3) ◽  
pp. 213-216 ◽  
Author(s):  
S. J. Bourget ◽  
B. J. Finn ◽  
B. K. Dow
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Winter Wheat ◽  
Plant Species ◽  
Spring Wheat ◽  
Soil Moisture Content ◽  
Near Field ◽  
Correlation Coefficients ◽  
Field Capacity

Young seedlings of flax and cereals, grown in a greenhouse, were subjected to 0, 12.5, and 25.0 cm of soil moisture tension for periods of 7, 14, and 21 days The grain, straw, and root yields of all plant species, except barky, increased with increasing soil moisture content was maintained near field capacity during the growth of plants. The yields of oats, winter wheat, and fall rye decreased with increasing duration of flooding, whereas those of barley, flax and spring wheat were variable. Correlation coefficients between yields of tops and roots were positive.

scholarly journals Experimental Study on Shear Resistance of Carex-Root-Fibered Soil

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Feng-Chi Wang ◽  
Ming-Ze Zhao ◽  
Qi Sun
Keyword(s):  
Shear Strength ◽  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Friction Angle ◽  
Fiber Content ◽  
Soil Consolidation ◽  
And Performance ◽  
The Relationship ◽  
Root Fiber

Carex shows strong vitality, adaptability, and performance with regard to soil consolidation and slope protection but is often disregarded as a weed. This study proposes to turn this so-called weed into treasure, using its characteristics to protect the slope. We studied the interaction between the carex roots and soil and compared it to other types of grass. To understand the interaction between the carex roots and soil, this study investigated the tensile properties of the carex root fibers. The effects of fiber content, humidity, distribution, and soil moisture content on the relationship between the shear strength and vertical pressure of the soil were analyzed using a direct shear test. Furthermore, the cohesion and internal friction angle were used to evaluate the shear strength of the root-fibered soil based on Mohr–Coulomb’s law. The results showed that the smaller the diameter, the shorter the length, and the greater the quantity and the lower the humidity of the root fibers, the higher the tensile strength of root fibers. In addition, the soil strength could be improved by the joint action of the roots and the soil. With an increase in the root fiber content and humidity, the soil moisture content decreased, whereas the shear strength of the carex-root-fibered soil increased. Here, four kinds of root fiber distributions, namely, “glyph,” “herringbone,” “eccentric,” and “vertical,” were chosen to study the shear strength of the root-fibered soil. The results showed that “glyph” root fiber distribution had the highest shear strength, while the shear strength decreased for the others.

scholarly journals Studying the Effect of Implement of Two Plowing Depths and Manure Mixing with Soil on the Soil Moisture Content

2017 ◽  
Vol 30 (2) ◽  
pp. 36-44
Author(s):  
Shaker H. Adday ◽  
Kawther A. Hemeed ◽  
Murtadha A. Al-faris
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Agricultural Research ◽  
Soil Depth ◽  
Research Station ◽  
Silty Clay ◽  
Manure Application ◽  
Sunflower Crop ◽  
Moldboard Plow

A field experiment was carried out in silty clay soil at Agricultural Research Station of Garmat Ali in order to study the effect of the plowing depths and manure application on soil moisture content at different soil depths (0-10 (d1), 10-20 (d2), 20-30 (d3), 30-40 (d4), 40-50 (d5) and 50-60 cm (d6)) and two periods (after plowing and after harvesting the sunflower crop). The experiment was conducted using an implement of plowing and manure mixing with soil, which consists of two main parts (two moldboard plows and two subsoilers).The implement was designed and manufactured in the Agriculture machines and Equipment Department in 2015. The treatments used in the study were included two levels of manure application (0 and 45.5 ton ha-1) and two plowing depths of moldboard plow (M) with three plowing depths of subsoiler (S). They were 20 cm of moldboard plow with 20, 30 and 40 cm of subsoiler (M20S20, M20S30 and M20S40), and 30 cm of moldboard plow with 10, 20 and 30 cm of subsoiler (M30S10, M30S20 and M30S30). The results showed that the soil moisture content (MC) was significantly decreased with increasing the plowing depths by the moldboard plows and subsoilers especially after soil plowing. While, the MC significantly increased with increasing the soil depth after the plowing and after harvesting the crop. In contrast, mixing the manure with soil at level 45.5 ton ha-1 by the manufactured implement increased the soil moisture content by 10.73% after the plowing and by 2.33% after the harvesting the sunflower crop compared with untreated soil with manure.

Analysis on Soil Moisture Content in the Middle Reaches of the Yellow River

2011 ◽  
Vol 28 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Run-chun LI ◽  
Xiu-zhi ZHANG ◽  
Li-hua WANG ◽  
Xin-yan LV ◽  
Yuan GAO
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Yellow River ◽  
The Yellow River

Distribution of soil moisture content and its effect on the potential growth of the over-story species in North-East Chalkidiki

2001 ◽  
Vol 66 ◽  
Author(s):  
M. Aslanidou ◽  
P. Smiris
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Soil Depth ◽  
Moisture Distribution ◽  
Taxus Baccata ◽  
Mixed Stands ◽  
Potential Growth ◽  
North East ◽  
Soil Moisture Distribution

This  study deals with the soil moisture distribution and its effect on the  potential growth and    adaptation of the over-story species in north-east Chalkidiki. These  species are: Quercus    dalechampii Ten, Quercus  conferta Kit, Quercus  pubescens Willd, Castanea  sativa Mill, Fagus    moesiaca Maly-Domin and also Taxus baccata L. in mixed stands  with Fagus moesiaca.    Samples of soil, 1-2 kg per 20cm depth, were taken and the moisture content  of each sample    was measured in order to determine soil moisture distribution and its  contribution to the growth    of the forest species. The most important results are: i) available water  is influenced by the soil    depth. During the summer, at a soil depth of 10 cm a significant  restriction was observed. ii) the    large duration of the dry period in the deep soil layers has less adverse  effect on stands growth than in the case of the soil surface layers, due to the fact that the root system mainly spreads out    at a soil depth of 40 cm iii) in the beginning of the growing season, the  soil moisture content is    greater than 30 % at a soil depth of 60 cm, in beech and mixed beech-yew  stands, is 10-15 % in    the Q. pubescens  stands and it's more than 30 % at a soil depth of 60 cm in Q. dalechampii    stands.

scholarly journals Mapping barrier island soil moisture using a radiative transfer model of hyperspectral imagery from an unmanned aerial system

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rehman S. Eon ◽  
Charles M. Bachmann
Keyword(s):  
Soil Moisture ◽  
Radiative Transfer ◽  
Moisture Content ◽  
Layer Thickness ◽  
Soil Moisture Content ◽  
Hyperspectral Imagery ◽  
Barrier Island ◽  
Water Layer ◽  
Radiative Transfer Model ◽  
Transfer Model

AbstractThe advent of remote sensing from unmanned aerial systems (UAS) has opened the door to more affordable and effective methods of imaging and mapping of surface geophysical properties with many important applications in areas such as coastal zone management, ecology, agriculture, and defense. We describe a study to validate and improve soil moisture content retrieval and mapping from hyperspectral imagery collected by a UAS system. Our approach uses a recently developed model known as the multilayer radiative transfer model of soil reflectance (MARMIT). MARMIT partitions contributions due to water and the sediment surface into equivalent but separate layers and describes these layers using an equivalent slab model formalism. The model water layer thickness along with the fraction of wet surface become parameters that must be optimized in a calibration step, with extinction due to water absorption being applied in the model based on equivalent water layer thickness, while transmission and reflection coefficients follow the Fresnel formalism. In this work, we evaluate the model in both field settings, using UAS hyperspectral imagery, and laboratory settings, using hyperspectral spectra obtained with a goniometer. Sediment samples obtained from four different field sites representing disparate environmental settings comprised the laboratory analysis while field validation used hyperspectral UAS imagery and coordinated ground truth obtained on a barrier island shore during field campaigns in 2018 and 2019. Analysis of the most significant wavelengths for retrieval indicate a number of different wavelengths in the short-wave infra-red (SWIR) that provide accurate fits to measured soil moisture content in the laboratory with normalized root mean square error (NRMSE)< 0.145, while independent evaluation from sequestered test data from the hyperspectral UAS imagery obtained during the field campaign obtained an average NRMSE = 0.169 and median NRMSE = 0.152 in a bootstrap analysis.

scholarly journals Estimating Agricultural Soil Moisture Content through UAV-Based Hyperspectral Images in the Arid Region

2021 ◽  
Vol 13 (8) ◽  
pp. 1562
Author(s):  
Xiangyu Ge ◽  
Jianli Ding ◽  
Xiuliang Jin ◽  
Jingzhe Wang ◽  
Xiangyue Chen ◽  
...  
Keyword(s):  
Data Mining ◽  
Soil Moisture ◽  
Moisture Content ◽  
Hyperspectral Imaging ◽  
Fractional Order ◽  
Arid Regions ◽  
Soil Moisture Content ◽  
Order Derivative ◽  
Imaging Data ◽  
Strategy I

Unmanned aerial vehicle (UAV)-based hyperspectral remote sensing is an important monitoring technology for the soil moisture content (SMC) of agroecological systems in arid regions. This technology develops precision farming and agricultural informatization. However, hyperspectral data are generally used in data mining. In this study, UAV-based hyperspectral imaging data with a resolution o 4 cm and totaling 70 soil samples (0–10 cm) were collected from farmland (2.5 × 104 m2) near Fukang City, Xinjiang Uygur Autonomous Region, China. Four estimation strategies were tested: the original image (strategy I), first- and second-order derivative methods (strategy II), the fractional-order derivative (FOD) technique (strategy III), and the optimal fractional order combined with the optimal multiband indices (strategy IV). These strategies were based on the eXtreme Gradient Boost (XGBoost) algorithm, with the aim of building the best estimation model for agricultural SMC in arid regions. The results demonstrated that FOD technology could effectively mine information (with an absolute maximum correlation coefficient of 0.768). By comparison, strategy IV yielded the best estimates out of the methods tested (R2val = 0.921, RMSEP = 1.943, and RPD = 2.736) for the SMC. The model derived from the order of 0.4 within strategy IV worked relatively well among the different derivative methods (strategy I, II, and III). In conclusion, the combination of FOD technology and the optimal multiband indices generated a highly accurate model within the XGBoost algorithm for SMC estimation. This research provided a promising data mining approach for UAV-based hyperspectral imaging data.

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