Yield stress evaluation of Finnish clays based on analytical piezocone penetration test (CPTu) models

2020 ◽  
Vol 57 (11) ◽  
pp. 1623-1638 ◽  
Author(s):  
Bruno Di Buò ◽  
Marco D’Ignazio ◽  
Juha Selänpää ◽  
Tim Länsivaara ◽  
Paul W. Mayne
Keyword(s):  
Yield Stress ◽  
Soil Mechanics ◽  
Friction Angle ◽  
Coefficient Of Determination ◽  
Soil Conditions ◽  
Piezocone Penetration Test ◽  
Bias Factor ◽  
Constant Rate ◽  
Target Values ◽  
Spherical Cavity Expansion

A well-established analytical model based on spherical cavity expansion and critical state soil mechanics theories is applied to piezocone soundings for profiling the yield stress and overconsolidation ratio of five soft sensitive test sites located in Finland. Yield stress is related to three piezocone parameters: net cone resistance, excess porewater pressure, and effective cone resistances. Input geoparameters include the effective stress friction angle, defined at both peak strength and at maximum obliquity, and the model directly provides the operational value of the undrained rigidity index. The piezocone-evaluated profiles compare favorably with results from laboratory constant-rate-of-strain consolidation tests for all the investigated sites. Based on the obtained experimental results, simplified correlations valid for Finnish soil conditions are derived. Their validity is assessed based on the bias factor, coefficient of variation, and coefficient of determination, showing a fairly good agreement between the predicted and the target values.

Application of Neural Network in Identifying Soil Strata by CPT or CPTU Data

2012 ◽  
Vol 170-173 ◽  
pp. 945-949
Author(s):  
Jun Hai Li
Keyword(s):  
Neural Network ◽  
Ground Improvement ◽  
Thin Layers ◽  
Slope Instability ◽  
General Regression Neural Network ◽  
Excess Pore Pressure ◽  
Soil Conditions ◽  
Penetration Test ◽  
Piezocone Penetration Test ◽  
Tip Resistance

In geotechnical engineering, assessment of the depth location of stratigraphic interfaces and the depth and thickness of thin layers can be critical in the design process. For example, stratigraphic interfaces can promote anisotropic soil strength response and potentially provide preferential slip planes that create slope instability. Similarly, the presence of thin, high permeability layers can alter groundwater flow regimes and rates of consolidation, which can hinder or accelerate methods of ground improvement. The piezocone penetration test (PCPT or CPTU) is an extension of the cone penetration test (CPT) and is able to measure cone tip resistance, sleeve friction and generated pore-water pressures simultaneously. The piezocone’s functionality is through the measured excess pore pressure profile, which reflects changes in the drainage conditions, and therefore soil conditions. In this paper the relationship between CPTU parameters and soil types and strata is analyzed, and the structure of a general regression neural network (GRNN) is designed, and the application program is programmed with MATLAB language. The results, identifying soil strata by CPTU, have confirmed that GRNN can be used to carry out the automatically identifying soil strata.

Ecological Highway Slope Stability Analysis by Inversion Method

2011 ◽  
Vol 250-253 ◽  
pp. 2161-2166
Author(s):  
Jun Zhao Gao ◽  
Guo Feng Xiao ◽  
Hai Qiang Miao
Keyword(s):  
Slope Stability ◽  
Soil Mechanics ◽  
Friction Angle ◽  
Inversion Method ◽  
Time Inversion ◽  
Long Time ◽  
Main Factors ◽  
Reinforcement Design ◽  
Rock And Soil

Side slop losing stability is one of the main factors which greatly influences freeway expedite construction, especially after side slop losing stability the determination of rock and soil mechanics parameter may take a long time. Inversion method to analyze slope stability can preferably solve the problem. During the treatment of the ecological freeway landslide, we can not obtain important Parameters due to great disparity of sample Parameters of landslide. However, using inversion method to get cohesion and internal friction Angle, and anglicizing its sensitivity during calculation of stability can identify reliable Parameters. According to slope stability calculus, the ecological reinforcement design scheme come into effect.

scholarly journals Effect of nitrogen fertilization and microbial preparations on potato yielding

2014 ◽  
Vol 60 (No. 8) ◽  
pp. 379-386 ◽  
Author(s):  
M. Kołodziejczyk
Keyword(s):  
Nitrogen Fertilization ◽  
Yield Components ◽  
Field Experiments ◽  
Tuber Yield ◽  
Coefficient Of Determination ◽  
Soil Conditions ◽  
Control Analysis ◽  
Tuber Weight ◽  
Marketable Yield ◽  
Average Tuber Weight

The effect of nitrogen fertilization and microbial preparations on yielding and development of potato tuber yield components were assessed in field experiments conducted under soil conditions of Luvic Chernozem. The factors of the experiment were nitrogen fertilization levels: 0, 60, 120 and 180 kg N/ha and the following preparations: BactoFil B10, effective microorganisms and UG<sub>max</sub> soil fertilizer. Nitrogen fertilization caused a significant increase in marketable yield of potato tubers. Yield increments on individual fertilizer treatments ranged from 66% to 140%. An evident effect of this factor was also visible regarding the yield components values. Increase in the number of main stems per 1 m<sup>2</sup> under the influence of growing nitrogen doses occurred from the fertilization level 120 kg N/ha, whereas the number of tubers per 1 stem increased only to the level of 60 kg N/ha. Each nitrogen dose applied within the range to 180 kg N/ha caused a marked increase in an average tuber weight. Conducted investigations demonstrated an unfavourable effect of microbial preparations on the marketable crop yield of tubers and formation of yield components. On the objects where microbial preparations were applied, the marketable yield was lower by 1.5 to 2.3 t/ha than in the control. Analysis of linear regression revealed occurrence of significant dependencies between the total tuber yield and the values of individual yield components. The relationships were the most visible for an average tuber weight formation as evidenced by the value of coefficient of determination&nbsp;(R<sup>2</sup> = 0.983).

scholarly journals Relation between the Friction Angle of Sand at Triaxial Compression and Triaxial Extension and Plane Strain Conditions

Geosciences ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 29 ◽  
Author(s):  
Zenon Szypcio
Keyword(s):  
Plane Strain ◽  
Soil Mechanics ◽  
Triaxial Compression ◽  
Deformation Mode ◽  
Friction Angle ◽  
Failure Criteria ◽  
Compression Tests ◽  
Laboratory Test Results ◽  
Experimental Findings ◽  
Triaxial Extension

The strength of sand is usually characterized by the maximum value of the secant friction angle. The friction angle is a function of deformation mode, density, and stress level and is strongly correlated with dilatancy at failure. Most often, the friction angle is evaluated from results of conventional compression tests, and correlation between the friction angle of sand at triaxial compression and triaxial extension and plane strain conditions is a vital problem of soil mechanics. These correlations can be obtained from laboratory test results. The failure criteria for sand presented in literature also give the possibility of finding correlations between friction angles for different deformation modes. The general stress-dilatancy relationship obtained from the frictional state concept, with some additional assumptions, gives the possibility of finding theoretical relationships between the friction angle of sand at triaxial compression and triaxial extension and plane strain conditions. The theoretically obtained relationships presented in the paper are fully consistent with theoretical and experimental findings of soil mechanics.

Modelling of yields and soil nitrogen dynamics for crop rotations by HERMES under different climate and soil conditions in the Czech Republic

2013 ◽  
Vol 152 (2) ◽  
pp. 188-204 ◽  
Author(s):  
P. HLAVINKA ◽  
M. TRNKA ◽  
K. C. KERSEBAUM ◽  
P. ČERMÁK ◽  
E. POHANKOVÁ ◽  
...  
Keyword(s):  
Czech Republic ◽  
Soil Layer ◽  
Crop Rotations ◽  
Coefficient Of Determination ◽  
Soil Conditions ◽  
Good Precision ◽  
Soil Mineral ◽  
Organic C ◽  
The Czech Republic ◽  
Wide Range

SUMMARYThe crop growth model HERMES was used to model crop rotation cycles at 12 experimental sites in the Czech Republic. A wide range of crops (spring and winter barley, winter wheat, maize, potatoes, sugar beet, winter rape, oats, alfalfa and grass), cultivated between 1981 and 2009 under various soil and climatic conditions, were included. The model was able to estimate the yields of field crop rotations at a reasonable level, with an index of agreement (IA) ranging from 0·82 to 0·96 for the calibration database (the median coefficient of determination (R2) was 0·71), while IA for verification varied from 0·62 to 0·93 (median R2 was 0·78). Grass yields were also estimated at a reasonable level of accuracy. The estimates were less accurate for the above-ground biomass at harvest (the medians for IA were 0·76 and 0·72 for calibration and verification, respectively, and analogous medians of R2 were 0·50 and 0·49). The soil mineral nitrogen (N) content under the field crops was simulated with good precision, with the IA ranging from 0·49 to 0·74 for calibration and from 0·43 to 0·68 for verification. Generally, the soil mineral N was underestimated, and more accurate results were achieved at locations with intensive fertilization. Simulated yields, soil N, water and organic carbon (C) contents were compared with long-term field measurements at Němčice, located within the fertile Moravian lowland. At this station, all of the observed parameters were reproduced with a reasonable level of accuracy. In the case of the organic C content, HERMES reproduced a decrease ranging from c. 85 to 77 tonnes (t)/ha (for the 0–0·3 m soil layer) between the years 1980 and 2007. In spite of its relatively simple approach and restricted input data, HERMES was proven to be robust across various conditions, which is a precondition for its future use for both theoretical and practical purposes.

scholarly journals Peningkatan Stabilitas Lereng pada Ruas Jalan Tawaeli – Toboli dengan Vegetasi/Bioengineering

2021 ◽  
pp. 23-32
Author(s):  
S.A. Wandira ◽  
A. Rahayu
Keyword(s):  
Shear Strength ◽  
Slope Stability ◽  
Safety Factor ◽  
Friction Angle ◽  
Soil Samples ◽  
Plant Roots ◽  
Soil Conditions ◽  
Mountainous Area ◽  
Stability Calculation ◽  
The Road

Tawaeli - Toboli is one of the road that often undergo landslide. Most of these roads are in a mountainous area with high steep slopes and poor soil conditions. The road conditions worsened, especially in rainy season resulting the citizen do not know anywhere that is prone to landslides such as in Km 16 to 17. The purpose of this study was to analyze slope stability using bioengineering methods, determine the shear strength of soil without plant roots and soil with plant roots and to determine the potential for landslides that will occur. Bioengineering is used to increase the strength of the soil, and stabilize slopes and reduce erosion on slopes. The slope stability calculation using the Bishop slice method. The calculating of safety factor analyzed using the Slope / W application and manually. Soil samples were taken from 3 (three) points and the soil strength parameters,  soil cohesion and friction angle, were obtained through laboratory testing. Tests were carried out using rootless and rooted soil samples. In addition, direct field observations were made to obtain slope angles and slope heights. The results showed that the parameters of soil shear strength, cohesion and friction angle increased with the presence of plant roots. The results of the slope stability analysis show that the conditions of the slope are stable at slope 1 (Km 16) and slope 3 (Km 17) with a safety factor greater than 1.5. While slope 2 (Km 16 +300) has the potential for landslides as a safety factor of less than 1.5. The use of bioengineering increases the safety factor to be greater than 1.5. The calculation of the value of the safety factor using the Slope / W program and the Bishop manual is not much different, but the calculation time with the Slope / W program is faster

scholarly journals KARAKTERISTIK PENGERINGAN KELAPA PARUT MENGGUNAKAN ALAT PENGERING SILINDER TIPE RAK

AGROINTEK ◽  
2020 ◽  
Vol 14 (2) ◽  
pp. 286-294
Author(s):  
Hary Kurniawan ◽  
Abdul Muiz ◽  
Muhamad Ikhsan Febriyanto Mbele ◽  
Rizka Okta Dini ◽  
Zulhan Widya Baskara
Keyword(s):  
Moisture Content ◽  
Water Content ◽  
Air Temperature ◽  
Sweet Taste ◽  
Coconut Water ◽  
Coefficient Of Determination ◽  
Drying Characteristics ◽  
Constant Rate ◽  
Drying Chamber

Desiccated coconut is one of the diversification of coconut products which is cut into pieces or grated into small pieces and dried, white, sweet taste and distinctive odor. The purpose of this study was to determine the drying characteristics of desiccated coconut using a cylindrical dryer. Eight trays, each containing 350 grams of grated coconut, were arranged on a tray and measured the air temperature in the drying chamber, the temperature of the material, as well as the moisture content of the material during drying both on the top rack, middle rack and bottom rack. The results showed that the air temperature in the drying chamber and the temperature of the material were significant, and moisture content during drying of materials both on the top rack, middle rack and bottom are relatively significant. The constant rate of drying of grated coconut on the upper rack, middle rack and lower rack is 0.1306 - 1338 minutes-1. The predicted value of grated coconut water content shows that it is almost close to the observed water content value, which is marked by a coefficient of determination that is close to 1.

scholarly journals The competition between folding and faulting in the upper crust based on the maximum strength theorem

2012 ◽  
Vol 468 (2141) ◽  
pp. 1280-1303 ◽  
Author(s):  
G. Kampfer ◽  
Y. M. Leroy
Keyword(s):  
Soil Mechanics ◽  
Surface Friction ◽  
Friction Angle ◽  
Maximum Strength ◽  
Frictional Properties ◽  
Full Development ◽  
Thrust Belts ◽  
Fault Propagation Fold ◽  
Axial Surface ◽  
Kinematic Approach

It is proposed to complement the numerous geometrical constructions of fault-related folds relevant to fold-and-thrust belts by the introduction of mechanical equilibrium and of the rock limited strength to discriminate between various deformation scenarios. The theory used to support this statement is the maximum strength theorem that is related to the kinematic approach of limit analysis known in soil mechanics. The classical geometrical construction of the fault-propagation fold (FPF) is proposed for illustration of our claim. The FPF is composed of a kink fold with migrating axial surfaces ahead of the region where the ramp propagates. These surfaces are assigned frictional properties and their friction angle is found to be small compared with the usual bulk friction angle to ensure the full development of the FPF, a first scenario. For larger values of the axial surface friction angle, this development during overall shortening is arrested by the onset of fault breaking through the front limb, a second scenario. The amount of shortening at the transition from folding to break-through faulting is established.

Effects of Soil Compaction to its Shear Property

2011 ◽  
Vol 301-303 ◽  
pp. 530-533 ◽  
Author(s):  
Lin Lin Liu ◽  
Jian Qiao Li ◽  
Shi Chao Fan ◽  
Xiu Juan Li ◽  
Wen Feng Fan ◽  
...  
Keyword(s):  
Internal Friction ◽  
Bulk Density ◽  
Lunar Surface ◽  
Surface Condition ◽  
Friction Angle ◽  
Lunar Soil ◽  
Internal Friction Angle ◽  
Soil Conditions ◽  
Shear Property ◽  
Measurement Results

The survey shows that the bulk density of lunar soil increases with the depth. The compaction of lunar soil also differs in the depth. The lunar soil mechanical condition plays an important and non-negligible roll on the mobility of the rover. It is important to make research on the change of the mechanical parameters at different lunar soil conditions, and it is also important to research the trafficability of rover on different lunar surface condition. The presented paper simulates the lunar soil with different depth by means of three kinds of lunar soil simulant on different compact condition. Based on the direct shear apparatus, it was researched that the cohesion, internal friction angle, bull density of lunar soil simulant on different compaction conditions, including loose, normal, and compressed. The measurement results show that the bulk density and cohesion of the lunar soil simulant increase with the compact conditions in general. The bulk density changes within a narrow range from1.1 g/cm3 to 1.4 g/cm3. The cohesion increases, and changes significantly, which varies from 0 kPa to 0.5 kPa. The internal friction angle changes without regularity within a range from 30 deg to 40 deg. The measurement results can be used to explain the different trafficability of wheels after repeatedly passing the same lunar surface. Also it will be of significant to the evaluation of the rover mobility at different lunar soil condition.

Creep of hollow concentric tubes

1968 ◽  
Vol 3 (3) ◽  
pp. 163-169
Author(s):  
W S Blackburn
Keyword(s):  
Yield Stress ◽  
Axial Load ◽  
Axial Strain ◽  
Outer Tube ◽  
Material Parameters ◽  
Constant Rate ◽  
Swelling Rate

For a thin outer tube of non-linearly creeping material with a sharp yield stress surrounding a thick inner tube of linearly creeping material with a sharp yield stress which is swelling at a constant rate, the conditions in which each tube is plastic and in which each tube creeps have been determined for the conditions of zero axial load and zero axial strain. Equations yielding the ratios of the axial and circumferential creep rates of the outer tube to the swelling rate of the inner have been determined in terms of the material parameters for each of the above conditions and have been solved on the assumption that these ratios are small.

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