scholarly journals Consolidation Behavior and Compression Prediction Model of Coastal Cement Soil Modified by Nanoclay

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Wenjie Yu ◽  
Na Li ◽  
Mengdan Dai ◽  
Dongliang An ◽  
Biao Qian ◽  
...  
Keyword(s):  
Prediction Model ◽  
Cement Content ◽  
Exponential Model ◽  
Measured Data ◽  
Test Results ◽  
Consolidation Pressure ◽  
Improvement Effect ◽  
Linear Interval ◽  
Nanoclay Content ◽  
Cement Soil

Coastal cement soil modified by nanoclay (NCS) has particular research significance as a modification approach to improve the high compressibility of coastal cement soil (CCS). At curing ages of 7 days and 28 days, consolidation and SEM tests were performed on 6 groups of NCS samples with a nanoclay content between 0% and 10% and 6 groups of CCS samples with a cement content between 10 and 20%, and a compression prediction model was established based on the test results. Test results show that (1) there is a linear interval for the improvement effect of the increment of cement content on the compression of CCS samples. In this test, the cement content in this interval is between 12% and 18%. CCS with a cement content of 18% is preferred. (2) The improvement effect on the compression of the sample is better with a nanoclay content of 4% and 8%, but poor with a content of 2%. At a consolidation pressure between 100 kPa and 800 kPa, NCS with a nanoclay content of 4% is preferred. (3) Adhesion is better with a nanoclay content of 4%, and the filling effect is better with a content of 8%. (4) The cosine-power function-exponential model is established, and the measured data are fitted, and a prediction model for the compression amount of CCS and NCS is established.

scholarly journals Genuine and false pre-consolidation and yield pressures

2019 ◽  
Vol 92 ◽  
pp. 05001 ◽  
Author(s):  
Laurence D Wesley
Keyword(s):  
Measured Data ◽  
Soil Types ◽  
Log P ◽  
Test Results ◽  
Linear Scale ◽  
Consolidation Pressure ◽  
Oedometer Test ◽  
The Way

“It remains a mystery why the international profession still uses the awkward e-log p plots, and the incomplete and useless coefficient Cc which is not even determined from the measured data, but from a constructed line outside the measurements”. These are the words of Nilmar Janbu (1998). This paper does not solve the mystery; what it does is highlight the issue behind the mystery in the hope that the profession will face up to the defects of the log scale. An examination is made of oedometer test results when plotted to both scales. Examples are given for sedimentary and residual clays, and sands. It is shown that the e-logp plot routinely produces graphs from which pre-consolidation pressures or yield pressures can be determined. However, when plotted using an arithmetic (linear) scale, this apparent pre-consolidation or yield pressure is found, in most cases, to disappear. It is a false value created by the way the data are plotted. The paper does not deny that pre-consolidation or yield pressures exist in many soils; it gives examples for each of the soil types listed above. It is recommended that the term “yield pressure” be used in preference to “pre-consolidation pressure”, and that only the use of a linear scale will reveal whether such a pressure exists.

scholarly journals Effects of Crumb Rubber on Compressive Strength of Cement-Treated Soil

2015 ◽  
Vol 61 (4) ◽  
pp. 59-78 ◽  
Author(s):  
F. C. Wang ◽  
W. Song
Keyword(s):  
Compressive Strength ◽  
Cement Content ◽  
Rubber Particle ◽  
Crumb Rubber ◽  
Test Results ◽  
Rubber Content ◽  
Strength Tests ◽  
Strength And Stiffness ◽  
Cement Soil ◽  
Curing Age

A study was undertaken to investigate the effects of crumb rubber on the strength and mechanical behaviour of Rubberized cement soil (RCS). In the present investigation, 26 groups of soil samples were prepared at five different percentages of crumb rubber content, four different percentages of cement content and two different finenesses of crumb rubber particle. Compressive strength tests were carried out at the curing age of 7 days, 14 days, 28 days and 90 days. The test results indicated that the inclusion of crumb rubber within cement soil leads to a decrease in the compressive strength and stiffness and improves the cement soil’s brittle behaviour to a more ductile one. A reduction of up to 31% in the compressive strength happened in the 20% crumb content group. The compressive strength increases with the increase in the cement content. And the enlargement of cement content is more efficient at low cement content.

Factors affecting at-rest lateral stress in artificially cemented sands

1995 ◽  
Vol 32 (2) ◽  
pp. 195-203 ◽  
Author(s):  
Fanyu Zhu ◽  
Jack I. Clark ◽  
Michael J. Paulin
Keyword(s):  
Cement Content ◽  
Vertical Stress ◽  
Specimen Preparation ◽  
Test Results ◽  
Lateral Stress ◽  
Stress History ◽  
Cemented Sand ◽  
Vertical Loading ◽  
Cemented Sands ◽  
Dry Sand

This paper presents the results of a laboratory study on the at-rest lateral stress and Ko of two artificially cemented sands. A modified oedometer ring was used to measure the lateral stress of cemented and uncemented sands. Test materials were No. 3 Ottawa sand and a marine sand with Portland cement. The specimens were prepared using the method of undercompaction to minimize the influence of specimen preparation on test results. The cement contents were 0, 0.5, 1.0, 2.0, 4.0, and 8.0% by the weight of dry sand. The water content of the specimens was 4% of the weight of dry sand and cement. When the sands were cured under zero confining pressure, the test results indicated the following: the at-rest lateral stress in cemented sands decreases significantly with increasing cement content; the relationship between the vertical and at-rest lateral stress is nonlinear and the value of Ko increases with increasing vertical stress; and the lateral stress decreases with sand density and curing period. When the specimens were cured under vertical stress, the value of Ko during the removal of vertical loading increased with both overconsolidation ratio and cement content. Stress history has a significant influence on the behaviour of at-rest lateral stress in cement sands. Key words : cemented sand, Ko, lateral stress, overconsolidation, stress history.

Multi-day flow forecasting using the Kalman filter

1991 ◽  
Vol 18 (2) ◽  
pp. 320-327 ◽  
Author(s):  
Murray A. Fitch ◽  
Edward A. McBean
Keyword(s):  
Kalman Filter ◽  
Prediction Model ◽  
Linear Prediction ◽  
Measured Data ◽  
System Model ◽  
Parameter Estimates ◽  
Model Parameters ◽  
Forecasting Performance ◽  
Optimal Forecasting ◽  
Linear Prediction Model

A model is developed for the prediction of river flows resulting from combined snowmelt and precipitation. The model employs a Kalman filter to reflect uncertainty both in the measured data and in the system model parameters. The forecasting algorithm is used to develop multi-day forecasts for the Sturgeon River, Ontario. The algorithm is shown to develop good 1-day and 2-day ahead forecasts, but the linear prediction model is found inadequate for longer-term forecasts. Good initial parameter estimates are shown to be essential for optimal forecasting performance. Key words: Kalman filter, streamflow forecast, multi-day, streamflow, Sturgeon River, MISP algorithm.

scholarly journals Analysis of rain fade slope for terrestrial links

2020 ◽  
Vol 18 (2) ◽  
pp. 896
Author(s):  
Jalel Chebil ◽  
Al-Hareth Zyoud ◽  
Mohamed Hadi Habaebi ◽  
Islam Md. Rafiqul ◽  
Hassan Dao
Keyword(s):  
Standard Deviation ◽  
Prediction Model ◽  
Rain Attenuation ◽  
Measured Data ◽  
Rate Of Change ◽  
Tropical Regions

<p><span>Rainfall can cause severe degradation to the operation of microwave links working with frequencies above 10 GHz. Many studies have investigated this problem, and one of the factors that attract the attention of researcher is rain fade slope which is the rate of change of rain attenuation.</span><span> The focus of this study is on rain fade slope for terrestrial links and it is </span><span>based on measurement conducted in Malaysia</span><span>.</span><span> This paper investigates the characteristics of the measured rain fade slope distribution </span><span>for various attenuation levels</span><span>. Then, </span><span>the ITU-R model for rain fade slope is compared with the corresponding statistics obtained from the measured data. Significant discrepancies have been observed since the ITU-R prediction model does not fit the measured fade slope distribution for many attenuation levels. It is recommended to modify the expression of the standard deviation in the ITU-R model when implemented in tropical regions.</span></p>

scholarly journals Experimental Research on Creep Characteristics of Nansha Soft Soil

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Qingzi Luo ◽  
Xiaoping Chen
Keyword(s):  
Pearl River Delta ◽  
Soft Soil ◽  
Creep Damage ◽  
Pearl River ◽  
Test Results ◽  
Creep Failure ◽  
Consolidation Pressure ◽  
Creep Characteristics ◽  
Triaxial Creep ◽  
Shear Box

A series of tests were performed to investigate the creep characteristics of soil in interactive marine and terrestrial deposit of Pearl River Delta. The secondary consolidation test results show that the influence of consolidation pressure on coefficient of secondary consolidation is conditional, which is decided by the consolidation state. The ratio of coefficient of secondary consolidation and coefficient of compressibilityCa/Ccis almost a constant, and the value is 0.03. In the shear-box test, the direct sheer creep failure of soil is mainly controlled by shear stress rather than the accumulation of shear strain. The triaxial creep features are closely associated with the drainage conditions, and consolidation can weaken the effect of creep. When the soft soil has triaxial creep damage, the strain rate will increase sharply.

Pressure Prediction in Natural Gas Desulfurization Process Based on PCA and SVR

2014 ◽  
Vol 962-965 ◽  
pp. 564-569 ◽  
Author(s):  
Yan Chao Shao ◽  
Liang Jun Xu ◽  
Yan Zhu Hu ◽  
Xin Bo Ai
Keyword(s):  
Natural Gas ◽  
Prediction Model ◽  
Measured Data ◽  
Support Vector ◽  
Trend Prediction ◽  
Generalization Ability ◽  
Model Based ◽  
Scada System ◽  
Desulfurization Process ◽  
Natural Gas Desulfurization

Pressure monitoring is an important means to reflect the running status of the natural gas desulphurization process. By using the data mining technology, the interaction relationships between the pressure and other monitoring parameters are analyzed in this paper. A pressure trend prediction model is established to show the pressure status in the natural gas desulfurization process. Firstly, the theory of Principal Component Analysis (PCA) is used to reduce the dimensions of measured data from traditional Supervisory Control and Data Acquisition (SCADA) system. Secondly the principal components are taken as input data into the pressure trend prediction model based on multiple regression theory of Support Vector Regression (SVR). Finally the accuracy and the generalization ability of the model are tested by the measured data obtained from SCADA system. Compared with other prediction models, pressure trend prediction model based on PCA and SVR gets smaller MSE and higher correlation. The pressure trend prediction model gets better generalization ability and stronger robustness, and is an effective complement to SCADA system in the natural gas desulphurization process.

scholarly journals Prediction Model of Asphalt Content of Asphalt Mixture Based on Dielectric Properties

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yanhui Zhong ◽  
Yilong Wang ◽  
Bei Zhang ◽  
Xiaolong Li ◽  
Songtao Li ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Prediction Model ◽  
Room Temperature ◽  
Asphalt Mixture ◽  
Aggregate Size ◽  
Asphalt Pavements ◽  
Test Results ◽  
Wide Range ◽  
Asphalt Content ◽  
Ground Penetrating

The rapid detection of asphalt content in asphalt mixture is of great significance to the quality evaluation of asphalt pavement. Based on the dielectric properties of an asphalt mixture, the prediction model of asphalt content is deduced theoretically using three types of dielectric models: Lichtenecker-Rother (L-R) model, Rayleigh model, and Bottcher equation. Under the condition of laboratory mixing at room temperature (about 20–25°C), a dielectric test of asphalt mixture is conducted to verify the applicability of the model. The test results indicate that the dielectric constant of the asphalt mixture is inversely proportional to the asphalt content and directly proportional to the aggregate size of the mixture. Among the models, the Rayleigh model has a wide range of applications and exhibits a high accuracy, with an average relative error of only 1.86%. The results provide a theoretical basis for the nondestructive testing of asphalt pavements using ground-penetrating radar.

Correlation between Unconfined Compressive Strength and Penetration Index Obtained from DCP Tests for Cemented Lateritic Soils

2019 ◽  
Vol 814 ◽  
pp. 399-403
Author(s):  
Anuchit Uchaipichat
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Cement Content ◽  
Lateritic Soil ◽  
Test Results ◽  
Cone Penetration ◽  
Penetration Index ◽  
Curing Period ◽  
Cemented Soils ◽  
The Relationship

This paper presents the relationship between the dynamic cone penetration (DCP) test results and the unconfined compressive strength of lateritic cemented soils. A series of DCP tests and unconfined compressive strength was performed on lateritic cemented soil. The soils sample used in this study was lateritic soil. The test results for the DCP tests are presented in terms of penetration index. It can be observed that the penetration index decreased with increasing curing period and cement content. Moreover, the unconfined compressive strength of cemented soils increased with curing period and cement content. The relationship between unconfined compressive strength and penetration index is presented. A unique relationship for unconfined compressive strength can be obtained.

Prediction Model for Cementing Efficiency of Fly Ash Concrete by Statistical Analyses

2011 ◽  
Vol 250-253 ◽  
pp. 1293-1296 ◽  
Author(s):  
Hong Bum Cho ◽  
Nam Yong Jee
Keyword(s):  
Fly Ash ◽  
Prediction Model ◽  
Statistical Analyses ◽  
Test Results ◽  
Construction Sites ◽  
K Value ◽  
Fly Ash Concrete ◽  
Mix Proportion ◽  
Wide Range ◽  
Binder Ratio

This paper offers the model that can estimate the cementing efficiency of fly ash (k value) based on a mix proportion of concrete containing fly ash (FA). The prediction model was derived using various statistical analyses, based on a wide range of mix proportions and a number of strength test results of ready mixed concretes used in eight construction sites. The k value increases with increasing water-binder ratio. As the FA replacement ratios increase, the k value increases at FA replacement ratios of less than 15%, but decreases at ratios of 15% or more. The k values obtained from the cementing efficiency estimate model range from 0.1 to 2.1.

Sign in / Sign up

Export Citation Format

Share Document