Documents published in Scipedia

• Effects of storage time on sample quality in Ballina clay

  K. Ouyang, J. Pineda*

  ISC2024.

  
  

  Abstract

  This paper explores the effects of the storage time on the engineering properties of Ballina clay, an estuarine silty clay that represents the soft soil deposits encountered along the eastern and southern Australian coastlines, which serves as foundation material for most of the country’s transport and energy infrastructure. An experimental program was carried out to evaluate the variation in soil compressibility and soil shear strength for tube specimens retrieved with an open sampler (Shelby tube) as well as an Osterberg fixed-piston sampler. Mechanical parameters obtained from tests performed immediately after sampling are compared against those measured over a period of 1 year, to assess the influence of the storage time. Results indicate that long-term storage has small influence on the quality of Ballina clay specimens in comparison with the mechanical disturbance caused during tube penetration and extraction, which is controlled by the sampler type.

  Abstract
  This paper explores the effects of the storage time on the engineering properties of Ballina clay, an estuarine silty clay that represents the soft soil deposits encountered [...]

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• Relief well identification from satelite imagery using dual kernel filter unets

  L. Zhang*, J. Tom, Z. Nick

  ISC2024.

  
  

  Abstract

  Precise identification of levee relief well locations from satellite imagery can be challenging and time-consuming. In this research, we propose a novel approach utilizing a U-Net architecture to identify relief wells along flood control levees, as a proof of concept of combining freely available imagery with machine learning techniques. The goal of this research is to develop techniques to make infrastructure asset management more efficient by automating the process. Our study highlights the crucial role of the convolution kernel size in the U-Net architecture, which significantly influences the accuracy of the results. Larger convolution kernel sizes excel in capturing extensive contextual information from the input image, potentially leading to superior outcomes. However, training with larger kernels is computationally intensive. Conversely, smaller convolution kernel sizes excel in capturing local features. To strike a balance these considerations, we introduce a Dual Kernel Filter U-Net, which combines two U-Nets with distinct convolution kernel sizes, 3x3 and 11x11. This innovative approach aims to harness the strengths of both convolution kernel sizes to improve accuracy and overall performance. The proposed Dual kernel filter U-Net was trained and evaluated on a real dataset of relief wells from Google Earth imagery. Our evaluation results demonstrate that this model achieves an accuracy rate of 99.76% with training dataset 2626 satellite images. Notably, this significant accuracy enhancement is achieved without substantially increasing computational time, making it a promising advancement in satellite image analysis for object location identification and asset, and disaster management

  Abstract
  Precise identification of levee relief well locations from satellite imagery can be challenging and time-consuming. In this research, we propose a novel approach utilizing [...]

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• Prediction of Future Settlement of Backfill at an Aggregate Mining Quarry Site in Irwindale, CA Using Numerical Method and Settlement Monitoring Data

  A. Shafiee, C. Pappo*, M. Kamalzare

  ISC2024.

  
  

  Abstract

  Future static settlement of a former aggregate mining quarry site in Irwindale, California is predicted based on the monitoring data and using numerical analyses that consider the total settlement of the deepest portion of the rockfill. The portion of quarry analyzed was backfilled with approximately 61 to 67 meters, has a volume of 2.6 million m3, and covers an area of 114,900 m2. The backfill material ranges from silty sand (SM) to silty gravel (GM) and was compacted to achieve an average relative compaction (RC) of 96%. The deepest fill area is currently being monitored with survey data to predict future 50-year settlement due to secondary compression. Settlement monument data from three different locations has been collected and made available starting from May 2009 up to now. A 3-dimensional model of the rockfill was used to determine an appropriate upper and lower bound of predicted future 50-year settlement from today in 13 stages and scenarios. The modified secondary compression index was estimated along with the modified compression index that was back calculated to match the field monitoring data. We could find good agreement between the field monitoring data and our numerical model when considering total settlement of the rockfill.

  Abstract
  Future static settlement of a former aggregate mining quarry site in Irwindale, California is predicted based on the monitoring data and using numerical analyses that consider [...]

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• How to get a good match for consolidation coefficient

  S. Peña Fernández, R. Gómez Escoubès*

  ISC2024.

  
  

  Abstract

  It is difficult to get accurate magnitudes when dealing with consolidation coefficient, decisive when clays and clayey silts, are compressing, especially if secondary consolidation is in play. This is a typical condition in harbours when new areas are to be reclaimed to get more and more loading/unloading areas. There are several approaches to assess consolidation rate. The oedometer cell is the main lab test used to get the compressibility parameters. It is accepted that 24 hours is a good time for each pressure. However, some soils consolidate slowly, and they need more time. Especially when slope is far from horizontal. On the other hand, “true” consolidation coefficient is obtained when surpassing the preconsolidation pressure. Thus, values obtained below preconsolidation pressure are usually discarded. Horizontal coefficient of consolidation can be assessed with dissipation tests from piezocones. If piezometers are installed within the consolidating layer, comparing with the theoretical isochrones we may derive the “true” consolidation coefficient. If settlements are measured, a comparison with theoretical ones can be informed on the predominant consolidation phenomenon. Much care is to be applied and not misunderstand the process in play. Dissipation tests give way to much higher consolidation values than laboratory tests. This could be due to anisotropic effects, but the main reason is that dissipation occurs in a reloading process, while oedometer tests are in primary consolidation, at least from the preconsolidation pressure and on. This paper shows some ideas to properly assess the process involving consolidation.

  Abstract
  It is difficult to get accurate magnitudes when dealing with consolidation coefficient, decisive when clays and clayey silts, are compressing, especially if secondary consolidation [...]

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• Site Characterization of a Restored Coastal Dune and Beach

  B. Harris*, J. Hubler, J. Shawler, N. Stark, P. Tereszkiewics, J. Moore, W. Caldwell, L. Provost

  ISC2024.

  
  

  Abstract

  Coastal beach and dune ecosystems are critically important for shoreline protection and significant resources have been allocated to their conservation. Dune vegetation is known to modify site response to wind, waves, and storms, but little focus has been given to understanding how belowground sediment structures enhance dune stability. A first step in addressing this knowledge gap is to determine optimal methods to measure subsurface sediment properties in onshore sandy environments. Our team performed a comparison of geotechnical and geophysical methods on a restored beach and dune system on Florida’s Atlantic coast. Methods included two types of dynamic cone penetrometer (DCP) systems, a multi-channel analysis of surface wave (MASW) system, a ground penetrating radar (GPR), soil vibracores, and grain size analyses. Two transects were investigated, a 50-meter cross-shore transect and an intersecting 20-meter along-shore transect. The transects were selected to study the gradient of sediment properties from the swash zone to the high dune. Key findings from this study were that the PANDA DCP provided a higher resolution of measurements compared to the standard DCP, which is extremely advantageous in the shallower, less consolidated soils. MASW shear wave velocity results showed similar trends to the DCP cone tip resistance and allowed for measurement of stiffer soils where the DCP reached refusal. In addition, the results from the DCP, GPR and vibracores compared well. Thus, the use of the DCP and GPR systems as minimally intrusive testing options in fragile dune systems was verified.

  Abstract
  Coastal beach and dune ecosystems are critically important for shoreline protection and significant resources have been allocated to their conservation. Dune vegetation is [...]

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• Combined Monitoring Remote Sensing Systems: Ground-Based SSR and Satellite-Based SAR

  C. Vulpe*, A. Fourie, L. Probst, H. Larkin, S. Donegan, D. Holden, G. Hanssens, A. Dianoff, E. Ronne, A. Lloyd, B. Conway-Jones

  ISC2024.

  
  

  Abstract

  A combined ground-based slope stability radar (SSR) and satellite-based (InSAR) monitoring system was trialled at a remote mine site in the Northern Hemisphere in order to investigate relative changes in displacement experienced by a mine waste storage facility. The relative changes in displacements along the InSAR line-of-sight (LoS) were compared to the relative changes in displacement provided by the ground-based SSR LoS. Although the two LoS are different, this study showed good agreement between the magnitude of relative displacements observed by both remote sensing technologies on the slope of the facility. Additionally, the study looked at the effectiveness of InSAR and SSR on capturing relatively shallow operational works undertaken on the tailings storage facility slope. Results showed that SSR is able to provide near real-time information about progressive trends in displacements and alert mine site personnel of potential areas that might need attention. InSAR could detect anomalies in surface deformations during the period when SSR did, but the radar signal was sufficiently low to not unequivocally attribute these responses to real surface deformations

  Abstract
  A combined ground-based slope stability radar (SSR) and satellite-based (InSAR) monitoring system was trialled at a remote mine site in the Northern Hemisphere in order to [...]

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• Improvement of Apparatus for Sampling and Cone Penetration Test

  R. Fujikata*, K. Tani, S. Nomura

  ISC2024.

  
  

  Abstract

  In this paper, a new innovative method of geotechnical investigation applicable to seafloor is proposed. This method is the improved version of Sampling and Cone Penetration Test (S&CPT) to evaluate geotechnical properties by Cone Penetration Test (CPT) while collecting continuous samples quickly and inexpensively for offshore geotechnical investigations. In the previous study, demonstration tests on soft cohesive soil were conducted, and some problems were found. The purpose of this study is to modify the sampler to improve penetrability, sampling performance, workability and to examine the applicability for cohesionless soils. Using the improved samplers, demonstration tests were conducted at two sand sites (loose and medium-dense) in Japan. The results of each test were used to examine: (1) sampling performance, and (2) workability. As a result, the following conclusions are drawn: 1) In loose sand, sampling of several meters is possible. In medium-dense sand, the same level of sampling may be possible by providing an appropriate shoe to prevent blockage at the sampler tip. 2) The workability of the proposed apparatus is very high compared to the conventional Cone Penetration Test and Standard Penetration Test.

  Abstract
  In this paper, a new innovative method of geotechnical investigation applicable to seafloor is proposed. This method is the improved version of Sampling and Cone Penetration [...]

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• Detection of cavities in an urban environment: Case of M’Rara region (Northeast of Algeria)

  B. Bouyahiaoui*, A. Abtout

  ISC2024.

  
  

  Abstract

  Micro-gravimetry emerges as the most appropriate geophysical technique for cavity detection in urban or industrial settings, as it remains unaffected by surrounding electromagnetic influences. The presented study investigates the occurrence of fissures, land subsidence, collapse events, and their potential association with the formation of cavities at depth. These phenomena were observed near a sealed hydraulic drilling site located in the M’Rara area within the Northeast Algerian Sahara basin. This drilling operation was sealed off due to the inflow of saline water, with a salt layer identified at a depth of 936 m according to the stratigraphic column. A gravimetric survey was conducted to image the lateral and vertical density variation. The resulting gravimetric image allows in comprehending the observed geological phenomena and their potential correlation with the presence of cavities at the salt layer.

  Abstract
  Micro-gravimetry emerges as the most appropriate geophysical technique for cavity detection in urban or industrial settings, as it remains unaffected by surrounding electromagnetic [...]

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• A Cylindrical Cavity Expansion Test on Sand

  S. Nachum*, M. Talesnick, M. Ghafghazi

  ISC2024.

  
  

  Abstract

  Cylindrical cavity expansion is one of the fundamental boundary value problems in geotechnical engineering used as a simplified analogue to the pressuremeter test, pile driving and the Cone Penetration Test. Much of the popularity of cavity expansion comes from the simplicity of modelling it numerically. All numerical models require verification and validation, but doing so for cavity expansion has been limited due the relatively small amount of physical modelling of the problem. Past cavity expansion tests in calibration chambers have often been limited in range of strains, diameter to length ratio, and the amount and type of measurements made. This paper describes a calibration chamber set up used to perform cylindrical cavity expansion tests in a dry fine sand. Instead of attempting to replicate a specific application (e.g., pressuremeter test), the goal was to create a near-perfect cylindrical cavity expansion model, with in-soil measurement of stresses and strains, to serve as baseline data for validation of numerical models. The experimental set up is described, the material properties are summarized, and results of a cavity expansion tests are presented and discussed.

  Abstract
  Cylindrical cavity expansion is one of the fundamental boundary value problems in geotechnical engineering used as a simplified analogue to the pressuremeter test, pile driving [...]

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• How much does the spatial variability of CPTu measurements affect the hydro-mechanical variables' estimation?

  G. Vessia*, D. Di Curzio, W. Pula

  ISC2024.

  
  

  Abstract

  Using CPTu profiles for subsoil characterisation, transformation equations must be used to obtain the hydro-mechanical properties for structures and infrastructure designing. Additionally, the uncertainty and the spatial variability of measured parameters must be taken into account for a reliable geotechnical design. In this work, we used a Stochastic Simulation approach to define reliable 3D models of two geotechnical designing variables for granular soils (friction angle–’ and the Darcy permeability coefficient–k) from tip resistance (qc), sleeve friction (fs), and pore pressure (u2) profiles. The selected method – the Sequential Gaussian Co-Simulation (SGCS) – provided reliable optimized 3D models of the spatial distribution of the variables of interest and allowed quantifying the propagation of the estimation uncertainty associated with the raw measurement models through the transformation equations. Overestimation (OE) and Underestimation (UE) percentages for a confidence interval of 68% were calculated throughout the 3D model: granular soils showed a larger uncertainty than fine soils concerning the measured variables (qc, fs, and u2). In granular soils, the measured variable uncertainty varies up to 100% but the derived variables show different behavior: ’ shows UE and OE less than 25% while k reaches 100%. These differences in the propagated uncertainties depend on the transformation equations and the measured variable dependence.

  Abstract
  Using CPTu profiles for subsoil characterisation, transformation equations must be used to obtain the hydro-mechanical properties for structures and infrastructure designing. [...]

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