| 1. |
- Erlingsson, Sigurdur, 1960-, et al.
(författare)
-
Correlating Air Freezing Index and Frost Penetration Depth : A Case Study for Sweden
- 2020
-
Ingår i: Lecture Notes in Civil Engineering. - Cham : Springer. ; , s. 847-857, s. 847-857
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The determination of frost penetration is one of the main requirements in considering environmental effects in pavement design in cold regions. At the present time, the frost depth of pavements in Sweden is estimated computationally using computer software which approximates the heat equation by finite difference. Due to the geographical positioning of Sweden, a wide range of air freezing index and frost penetration depths were observed with lower values in the south and higher values in the north. This paper introduces a simplified design chart which is obtained by empirically correlating the air freezing index estimated from temperature measurements by 44 local meteorological stations to the maximum frost penetration depth obtained by 49 RWIS Road Weather Information Station data. The results are classified depending on their location and the climatic zones defined by the Swedish pavement design codes. Nonlinear prediction intervals are implemented to provide a range of possible frost penetration depths since local site conditions are not taken into account. Further research is required to consider local on-site effects such as frost susceptibility of pavement materials, the thermal conductivity of layers, access to water and snow covering.
|
|
| 2. |
- Kuttah, Dina K, 1975-
(författare)
-
Optimizing Geotechnical Data Input Based on Light Weight Deflectometer for Road Design and Performance Analysis
- 2024
-
Ingår i: Transportation Infrastructure Geotechnology. - : Springer. - 2196-7202 .- 2196-7210.
-
Tidskriftsartikel (refereegranskat)abstract
- This study explores alternative methods for assessing critical parameters in pavement design, specifically Young’s modulus and Poisson’s ratio. While repeated load triaxial testing is traditionally used, its high cost and time requirements drive the search for more efficient methods. Falling weight deflectometer tests are also resource-intensive, leading to the investigation of light weight deflectometer tests. Utilizing EraPave software for analysis, which employs a multi-layer elastic theory back-calculation tool, the research examines material properties through laboratory tests on unbound granular material, sandy soil, silty sand soil, and sandy silty clay soil, providing data for field tests. Field LWD tests, conducted under various moisture contents and dynamic loads, provided data processed through EraPave to predict layer moduli. Results demonstrate LWD’s effectiveness in predicting layer moduli for different construction materials. Despite variations in root mean square error values, LWD data consistently align well with EraPave predictions, underscoring its reliability for pavement evaluation. Case studies illustrate LWD and EraPave’s adaptability to different moisture contents and stresses. This study advocates for LWD tests’ efficiency and highlights the importance of analytical tools like EraPave for accurate pavement assessments, contributing to optimized pavement evaluation processes and informed road construction and maintenance decisions.
|
|
| 3. |
- Kuttah, Dina K, 1975-
(författare)
-
The Next Generation of Testing with LWD to Assess the In-Situ Permanent Deformation of Geomaterials under Repeated Loading
- 2024
-
Ingår i: 7th International Conference on Geotechnical and Geophysical Site Characterization. - Barcelona, Spain : International Center for Numerical Methods in Engineering (CIMNE). ; , s. 1129-1136
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This study focuses on evaluating in-situ permanent deformation in fine-grained soils through the application of a specially designed Repeated Light Weight Deflectometer (LWD) test. The primary objective is to investigate how water content and applied stress levels influence permanent deformations in the field. Additionally, the study aims to assess the utility of LWD-derived data in predicting permanent strains. Results indicate a significant correlation between permanent deformations and key parameters, such as the number of load cycles, applied stress levels, and water content. It is observed that permanent deformations increase proportionally with these variables, particularly in cases of elevated water content and higher stress levels. The soil demonstrates an increased susceptibility to accumulating permanent deformations, persisting even after numerous LWD load applications. In response to these findings, a predictive model is presented to estimate accumulated permanent strain, exhibiting a commendable fit to data for moisture contents up to 22%, corresponding to an average water content of 19%. Ultimately, this research underscores the pivotal role of water content and applied stress levels in determining permanent deformation characteristics in fine-grained subgrade soils. The study also provides a valuable predictive model derived from repeated in-situ LWD measurements, offering critical insights into the field permanent deformation behaviour of subgrade soil. This simple and time-saving test enhances engineering practices for pavement design and construction.
|
|
| 4. |
- Olafsdottir, Elin Asta, et al.
(författare)
-
A Tool for Processing and Inversion of MASW Data and a Study of Inter-session Variability of MASW
- 2024
-
Ingår i: ASTM geotechnical testing journal. - : ASTM International. - 0149-6115 .- 1945-7545. ; 47:5
-
Tidskriftsartikel (refereegranskat)abstract
- Multichannel analysis of surface waves (MASW) is a noninvasive active-source technique for determination of near-surface shear wave velocity (VS) profiles. Here we introduce and describe MASWavesPy, an open-source Python package for processing and inverting MASW data, whose design follows an object-oriented paradigm. To assess the performance of the new tool, measurements were conducted at four benchmark sites in Norway, characterized as silt, soft clay, silty sand, and quick clay. The results show that the VS profiles obtained with MASWavesPy compare well with those obtained previously at the respective sites using invasive, noninvasive and laboratory techniques. Furthermore, the efficiency and usability of the new package is superior to previous versions developed by same authors. The software can be accessed through the Python Package Index (PyPI) at https://pypi.org/project/maswavespy/ along with sample data. This work further explores the inter-session variability of MASW measurements for civil engineering applications at soft soil sites. For this purpose, repeated measurements were conducted over a 7-year period at a silty sand site in South Iceland and the recorded time series analyzed using the newly developed tool. The inter-session variability of the analysis results is reported in terms of Rayleigh wave phase velocity, interval VS profiles, and time-averaged VS for reference depths commonly used in practice.
|
|
| 5. |
- Razouki, Sabah Said, et al.
(författare)
-
Improving Strength by Increased Compaction of Gypsum—Enriched Soil under Long-Term Soaking Conditions
- 2024
-
Ingår i: Geotechnics. - : MDPI. - 2673-7094. ; 4:2, s. 415-429
-
Tidskriftsartikel (refereegranskat)abstract
- This study investigated the effect of compaction effort and soaking time on the shear strength properties of fine-grained gypsum-containing soils. The objective was to demonstrate that increasing compaction effort increases soil strength, specifically cohesion and the angle of shear strength, when subjected to soaking in freshwater. Unconsolidated undrained triaxial tests were carried out on CBR soil samples with different soaking times. The results showed a transition from brittle to ductile failure behaviour as the soaking time increased. Mohr–Coulomb failure envelopes showed reduced cohesion and angle of shear strength with increasing soak time. Regression models were developed to establish correlations between soaked and unsoaked strength parameters. Strong relationships were found between soil strength properties, compaction effort and soaking time. Empirical equations were proposed to estimate the cohesion and angle of shear strength from compaction effort and soaking time. This study highlighted the importance of considering gypsum-rich soils in civil engineering design. Gypsum dissolution during wetting significantly affected soil strength parameters. The regression models and empirical equations provide engineers with tools to assess the influence of compaction effort and soaking time on soil strength, thus aiding decision making when designing structures on gypsum-rich soils.
|
|
| 6. |
- Salour, Farhad, 1985-, et al.
(författare)
-
Modelling Resilient Modulus Seasonal Variation of Silty Sand Subgrade Soils with Matric Suction Control
- 2014
-
Ingår i: Canadian geotechnical journal (Print). - : NRC Research Press. - 0008-3674 .- 1208-6010. ; 51:12, s. 1413-1422
-
Tidskriftsartikel (refereegranskat)abstract
- Resilient modulus of unbound materials is an important parameter in the mechanistic design of pavements. Although unbound layers are frequently in a partially saturated state, a total stress approach is conventionally used in modelling the material behaviour and therefore pore pressure effects are not considered. In fine‑grained unbound materials, the saturation state can affect their mechanical behaviour due to pore pressure effects. In this study a modified test procedure and a predictive resilient modulus model that takes into account the subgrade soil matric suction as a stress state variable is presented. Two different silty sand subgrade materials were tested in unsaturated conditions using series of repeated load triaxial tests under controlled pore suction conditions to study its influence on the resilient modulus. The test data were further used to obtain the resilient modulus model regression parameters that accounts for moisture content variations through the matric suction parameter. Generally, the prediction model could effectively capture the resilient modulus behaviour of the subgrades with respect to changes in the normal stress state and the matric suction. Given the completeness of this method, this prediction model is recommended as an improved approach in capturing the moisture content effects on the material stiffness properties.
|
|
| 7. |
- Fredriksson, Anna, 1979-, et al.
(författare)
-
Circular soil and rock masses – a public-private relational mess
- 2023
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Sweden is at EU bottom of circular soil and rock masses. The purpose of this study is to capture the relationship between the overall system and subsystems of circular soil and rock masses to identify barriers to establishing efficient circular soil and rock material flows. The main hinders are lateness of action, legislation, and lack of information sharing. This together creates a relational mess between the subsystems, leading to a lack of understanding of how to act. The relations must be clarified before public procurement will have its intended impact to increase circularity and decrease transport emissions.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Erlingsson, Sigurdur, 1960-
(författare)
-
Geotechnical challenges in Iceland
- 2019
-
Ingår i: 17th European Conference on Soil Mechanics and Geotechnical Engineering, ECSMGE 2019 - Proceedings. - : International Society for Soil Mechanics and Geotechnical Engineering. - 9789935943613 ; , s. 27-51
-
Konferensbidrag (refereegranskat)abstract
- The geotechnical challenges in Iceland are in many aspects unusual. The geological setting of the country is unique and has a great influence on the local geotechnical conditions. Iceland lies on the divergent boundary between the Eurasian plate and the North American plate formed by the Mid-Atlantic Ridge. This has created a landmass with active volcanoes, geothermal areas and zones of high seismicity. The bedrock is relatively young and mainly basaltic. It has been built up of relatively thin lava layers during eruptions. It is frequently highly jointed with irregular interlayers. The horizontal stresses in the rock mass are furthermore very low. The soil layers consist mainly of non-cohesive materials, often created in catastrophic events such as glacial floods, and are therefore often loosely packed. This paper gives a short overview of the geotechnical conditions in the country and additionally describes several geotechnical engineering projects. Some geotechnical challenges due to climate change will also be briefly discussed. © The authors and IGS: All rights reserved, 2019
|
|
