scholarly journals Effects of Density and Moisture Variation on Dynamic Deformation Properties of Compacted Lateritic Soil

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Weizheng Liu ◽  
Shuai Qu ◽  
Zhihong Nie ◽  
Junhui Zhang
Keyword(s):  
Moisture Content ◽  
Empirical Relationship ◽  
Cyclic Stress ◽  
Lateritic Soil ◽  
Triaxial Tests ◽  
Permanent Strain ◽  
Moisture Variation ◽  
Deformation Properties ◽  
Critical Dynamic ◽  
Repeated Load Triaxial

A series of repeated load triaxial tests were conducted in this study to investigate the influences of compaction density and postcompaction moisture variation on the dynamic elastic modulus (Ed) and plastic permanent strain (PPS) of compacted lateritic soil. Specimens were compacted at optimum moisture content (OMC) and three degrees of compaction (90%, 93%, and 96%). Then the specimens were dried or wetted to different moisture contents (OMC,OMC±3%,OMC±6%, andOMC+9%) prior to testing forEdand PPS. Results show that moisture content has greater influence on theEdand PSS than compaction degree, and the increase in moisture content leads to a decrease ofEdand an increase of PPS. Furthermore, an empirical relationship betweenEdand applied cyclic stress (σd) is developed that incorporates density and moisture variations. Three different evolution types of PPS with number of load cycles, plastic stable, plastic creep, and incremental collapse, are identified as the increase of moisture content. In addition, the critical dynamic stress (σdc) separating stable and unstable deformation is determined based on the shakedown concept. The envelope curves ofσdc-moisture of lateritic soil with different degrees of compaction are also determined to provide reference for the pavement design.

scholarly journals Analysis of the resilience modulus of a subgrade soil front of humidity variations

2021 ◽  
Vol 337 ◽  
pp. 03013
Author(s):  
Camila Kern ◽  
Wai Ying Yuk Gehling ◽  
Washington Peres Núñez
Keyword(s):  
Moisture Content ◽  
Negative Impact ◽  
Statistical Significance ◽  
Great Influence ◽  
Subgrade Soil ◽  
High Statistical Significance ◽  
Moisture Variation ◽  
Repeated Load ◽  
Effect Of Moisture ◽  
Repeated Load Triaxial

The influence of the variation of moisture content in the materials that make up the pavement has a negative impact on its performance. This variation in humidity is caused by inefficient drainage, oscillation of the water table, infiltrations, which affect the resistance and increase the deformability. The objective of this article is to evaluate the effect of moisture variation on the behavior of soils used in pavement subgrade from tests of resilience module. The subgrade of the highway BR-290/RS located in the state of Rio Grande do Sul/Brazil was evaluated. The repeated load triaxial equipment was used to perform tests of the Resilience Module (MR), varying the moisture content of the specimens by ± 2% in relation to the optimum humidity. There was a 70% decrease in MR comparing specimens above the optimum humidity with the ideal humidity conditions. A new MR equation was proposed that considers the variation in humidity, which showed high statistical significance. The results presented showed a great influence of the moisture content in soils, showing that the present article can contribute to a better understanding of the behavior of soils and a greater discussion about the effect of moisture variation in the dimensioning of pavements.

Examination of moisture content variation within an operational wet deck

TAPPI Journal ◽  
2013 ◽  
Vol 12 (1) ◽  
pp. 45-50 ◽  
Author(s):  
LAURENCE SCHIMLECK ◽  
KIM LOVE-MYERS ◽  
JOE SANDERS ◽  
HEATH RAYBON ◽  
RICHARD DANIELS ◽  
...  
Keyword(s):  
Moisture Content ◽  
Southeastern United States ◽  
Forest Products ◽  
Time Domain Reflectometry ◽  
Water Application ◽  
Wood Moisture ◽  
International Paper ◽  
Content Variation ◽  
Moisture Variation

Many forest products companies in the southeastern United States store large volumes of roundwood under wet storage. Log quality depends on maintaining a high and constant wood moisture content; however, limited knowledge exists regarding moisture variation within individual logs, and within wet decks as a whole, making it impossible to recommend appropriate water application strategies. To better understand moisture variation within a wet deck, time domain reflectometry (TDR) was used to monitor the moisture variation of 30 southern pine logs over an 11-week period for a wet deck at the International Paper McBean woodyard. Three 125 mm long TDR probes were inserted into each log (before the deck was built) at 3, 4.5, and 7.5 m from the butt. The position of each log within the stack was also recorded. Mixed-effects analysis of variance (ANOVA) was used to examine moisture variation over the study period. Moisture content varied within the log, while position within the stack was generally not significant. The performance of the TDR probes was consistent throughout the study, indicating that they would be suitable for long term (e.g., 12 months) monitoring.

Repeated Load Triaxial Tests on a Dolomite Ballast

1978 ◽  
Vol 104 (7) ◽  
pp. 1013-1029
Author(s):  
Gerald Patrick Raymond ◽  
David R. Williams
Keyword(s):  
Triaxial Tests ◽  
Repeated Load ◽  
Repeated Load Triaxial

scholarly journals Experimental Study on Dynamic Resilient Modulus of Lime-Treated Expansive Soil

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Zheng Lu ◽  
Yang Zhao ◽  
Shaohua Xian ◽  
Hailin Yao
Keyword(s):  
Moisture Content ◽  
Environmental Changes ◽  
Resilient Modulus ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
The Stability ◽  
Compaction Degree

Dynamic resilient modulus is the design index of highway subgrade design code in China, which is significantly affected by the traffic loads and environmental changes. In this study, dynamic triaxial tests were conducted to investigate the influence of moisture content, compaction degree, cyclic deviator stress, and confining pressure on lime-treated expansive soil. The suitability of UT-Austin model to lime-treated expansive soils was verified. The results indicate that the dynamic resilient modulus of lime-treated expansive soils increases nonlinearly with the increase of compaction degree, while decreases nonlinearly with the increase of dynamic stress level. The dynamic resilient modulus decreases linearly with the increase of moisture content and increases linearly with the increase of confining pressure. Moreover, the moisture content has a more significant effect on the dynamic resilient modulus of lime-treated expansive soil. Therefore, it is necessary to ensure the stability of soil humidity state and its excellent mechanical properties under long-term cyclic loading for the course of subgrade filling and service. Finally, the calculated results of the UT-Austin model for dynamic resilient modulus show a good agreement with the test results.

scholarly journals New Structure for Strengthening Soil Embankments

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Fang Xu ◽  
Wuming Leng ◽  
Rusong Nie ◽  
Qishu Zhang ◽  
Qi Yang
Keyword(s):  
Shear Modulus ◽  
Large Scale ◽  
Dynamic Stress ◽  
Confining Pressure ◽  
Coarse Grained ◽  
Triaxial Tests ◽  
Additional Stress ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Critical Dynamic

A new prestressed reinforcement device (PRD) consisting of two lateral pressure plates (LPPs) and a reinforcement bar is developed to strengthen soil embankments by improving the soil confining pressure and providing lateral constraint on embankment slopes. The reinforcement effects of PRDs were demonstrated by investigating the beneficial effects of increasing confining pressure on the soil behavior via the performance of a series of large-scale static and cyclic triaxial tests on a coarse-grained embankment soil. The results show that PRDs can effectively improve the soil shear strength, bearing capacity, ability to resist elastic and plastic deformation, critical dynamic stress, and dynamic shear modulus, and empirical methods were also developed to determine the critical dynamic stress and initial dynamic shear modulus of the embankment soil. Moreover, 3D finite element analyses (FEAs) with an LPP width of 1.2 m were performed to analyze the additional stress field in a prestressed heavy-haul railway embankment. The FEAs showed that the additional stress at a given external distance from the border of an LPP first increased to a maximum value and then gradually decreased with increasing depth; the additional stress was transferred to the zones where the subgrade tends to have higher stresses with peak stress diffusion angles of 34° (slope direction) and 27° (longitudinal direction); and a continuous effective reinforcement zone with a minimum additional stress coefficient of approximately 0.2 was likely to form at the diffusion surface of the train loads, provided that the net spacing of the LPPs was 0.7 m. The reinforcement zone above the diffusion surface of the train loads can act as a protective layer for the zones that tend to have higher stresses. Finally, the advantages and application prospects of PRDs are discussed in detail. The newly developed PRDs may provide a cost-effective alternative for strengthening soil embankments.

scholarly journals Non-destructive evaluation of moisture content in wood by using Ground Penetrating Radar

2016 ◽  
Author(s):  
Hamza Reci ◽  
Tien Chinh Maï ◽  
Zoubir Mehdi Sbartaï ◽  
Lara Pajewski ◽  
Emanuela Kiri
Keyword(s):  
Moisture Content ◽  
Ground Penetrating Radar ◽  
Wood Fiber ◽  
Fiber Direction ◽  
Direct Wave ◽  
Reflected Waves ◽  
Moisture Variation ◽  
Reflection Configuration ◽  
Ground Penetrating ◽  
Non Destructive

Abstract. This paper presents the results of a series of laboratory measurements carried out to study how the Ground Penetrating Radar (GPR) signal is affected by moisture variation in wood material. The effects of the wood fiber direction, with respect to the polarisation of the electromagnetic field, are investigated. The relative permittivity of wood and the amplitude of the electric field received by the radar are measured for different humidity levels, by using the direct-wave method in Wide Angle Radar Reflection configuration, where one GPR antenna is moved while the other is kept in a fixed position. The received signal is recorded for different separations between transmitting and receiving antennas. Direct waves are compared to reflected waves: it is observed that they show a different behaviour when the moisture content varies, due to their different propagation paths.

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