Geotechnical Survey Research Articles

Geotechnical engineering surveys and soil testing in the construction of buildings and structures

The article suggests a way to increase the efficiency of geotechnical engineering surveys through the rational use of fast approximate methods of soil testing (“express methods”). Such tests are recommended to be carried out in large volume and considered as a means of assessing the geotechnical structure of the site as a whole. In this paper, these issues are considered by the example of determining the bearing capacity of piles according to static sounding data and static tests of full-scale piles. A mathematical model for assessing the information content of the test complex based on the concepts of information theory is proposed. Calculations based on this model show that the informativeness of a large number of approximate tests may (due to the heterogeneity of the soil) exceed the informativeness of a small number of accurate tests.

Clarifying baseline seismicity for a geotechnical survey site at Gross mining and processing plant

Clarifying baseline seismicity for a geotechnical survey site at Gross mining and processing plant

Numerical modeling of site response at large strains with simplified nonlinear models: Application to Lotung seismic array

Abstract Site response analyses at large strains are routinely carried out neglecting the shear strength of soil and the stiffness degradation due to the increase in pore pressures, leading to unrealistic predictions of the seismic response of soil deposits. The study investigates the performance of a simplified nonlinear (NL) approach, implemented in the Deepsoil code, constituted by coupling a hyperbolic model incorporating shear strength with a strain-based semi-empirical pore pressure generation model. The first part of the study, based on a large one-dimensional parametric study, shows that above a shear strain of 0.1%, it is necessary to include shear strength in the site response modelling to get more realistic results. Then, the approach has been evaluated with reference to the well-known downhole Large-Scale Seismic Test array located in Lotung (Taiwan): numerical results have been compared with recordings in terms of acceleration response spectra and pore water pressure time histories at different depths along the soil profiles. The comparison shows that the NL simplified model is characterized by an accuracy comparable with more sophisticated advanced elasto-plastic NL analyses adopting essentially the same input data of the traditional equivalent linear approaches(shear modulus and damping curves) and simple physical-mechanical properties routinely determined during geotechnical surveys (i.e., shear strength, relative density, fine content). This approach is therefore recommended for site response analyses reaching large strains (i.e., soft soil deposits and moderate-to-high input motions).

Automated Photogrammetric Tool for Landslide Recognition and Volume Calculation Using Time-Lapse Imagery

Digital photogrammetry has attracted widespread attention in the field of geotechnical and geological surveys due to its low-cost, ease of use, and contactless mode. In this work, with the purpose of studying the progressive block surficial detachments of a landslide, we developed a monitoring system based on fixed multi-view time-lapse cameras. Thanks to a newly developed photogrammetric algorithm based on the comparison of photo sequences through a structural similarity metric and the computation of the disparity map of two convergent views, we can quickly detect the occurrence of collapse events, determine their location, and calculate the collapse volume. With the field data obtained at the Perarolo landslide site (Belluno Province, Italy), we conducted preliminary tests of the effectiveness of the algorithm and its accuracy in the volume calculation. The method of quickly and automatically obtaining the collapse information proposed in this paper can extend the potential of landslide monitoring systems based on videos or photo sequence and it will be of great significance for further research on the link between the frequency of collapse events and the driving factors.

Predicting Mechanical Properties of Carbonate Rocks Using Spectroscopy Across 0.4–12 μm

Determining the mechanical characteristics of rocks is crucial in various civil engineering sectors. Traditionally, the mechanical properties of rocks are determined through on-site and laboratory tests carried out during geotechnical surveys. However, these extensive surveys require considerable time and resources. In contrast, hyperspectral remote sensing techniques offer a rapid and simple means to determine the mineral composition and crystallographic structure of rocks. These features, in turn, influence the rocks' mechanical properties. This study focuses on characterizing the mechanical properties of carbonate rocks in a laboratory setting, using hyperspectral sensors. Approximately 150 cylindrical carbonate rock samples, spanning a wide strength range, were collected from diverse Israeli rock outcrops. Employing a point spectrometer (0.4 to 2.5 µm) and a spectral image sensor (8.0 to 12.0 µm), we captured samples' light reflections and spectral emissivity. Mechanical attributes, including density, porosity, water absorption, and uniaxial compressive strength (UCS), were measured. Advanced data mining techniques identified statistical correlations between hyperspectral signatures and mechanical properties, pinpointing key wavelengths for prediction. The developed models exhibited excellent predictability for the specified properties, attributing accuracy to discernible mineralogy and internal crystalline structure through spectroscopy. However, predicting UCS showed slightly weaker results due to influences from internal flaws not entirely reflected in spectroscopic data. Nonetheless, outcomes regarding rock UCS were deemed satisfactory. These findings open avenues for non-destructive tools in assessing the mechanical properties of rocks in quarrying operations.

Modelowanie cyfrowe w celu przewidywania zagrożenia osuwania się gruntu na wybranym obszarze; Przypadek testowy Ponzano (Włochy)

Creating a digital model is one of the aims of the geotechnical engineers, to predict the land sliding hazard which occur in different regions in the world. In February 2017, an extensive landslide occurred in the hamlet of Ponzano as a sloped area in the Abruzzo region in Italy. In this regard, predicting the land sliding hazard is one of the important issues to prevent hazard to the civilizations. In this project we created a model in the 3D dimension through the Plaxis 3D numerical solution software from the data based of the region Abruzzo in 2007 to evaluate the land sliding hazard before happened and then compare the results with the data from the drone data surveyed recently in the 2022. In this regard, the data from the Abruzzo resources from 2007 imported into the QGIS as the open-source cross-platform software to analysis the geospatial data and then imported into the Recap software to work on the point cloud data and then imported into the Civil 3D software to create a solid surface from the TIN surface and finally since the solid surface contains a large number of irrelative details, they were imported into the Rhinoceros software to create a NURBS surface to be smoothed for better performance in the analysis. The NURBS surface imported into the Plaxis and all of the geometry and geotechnical engineering parameters by considering the investigated geotechnical survey that was conducted in parallel in the area, defined for the model. The “Hardening Soil” model considered for the 1st layer as the “clay and lime” and the “Hoek-Brown” model defined for the 2nd layer as the “marl-flysch”. A fine mesh elements distribution assessed also for the model. The phases defined as the “gravity” to define the unit weight of the soil layers, the “plastic” phase to calculate the instant deformations and the “consolidation” to analyze the plastic deformations in the sloped area of the model. In parallel, the drone data achieved in 2022, were imported into the CloudCompare as the 3D point cloud processing software and different methods such as the “segment”, “statistical outlier Filter”, “CSF filter”, “noise filter”, “cross section” etc. were performed to clean the data and then imported into the Recap software to work on data and then imported into the Civil 3D software to create solid surface of the current data after the land sliding. In this regard, to evaluate the displacement occurred from the year 2007 toward the 2022, a TIN volume surface as the colored map created through the Civil 3D software to show the displacements in the z direction and all of the results were compared with the Plaxis 3D numerical solution software. The results showed that the colored map with the displacement in the positive and negative direction of the z is the same of the analyzed model and the values match each other’s and we created a digital model of the selected area to predict the land sliding hazard in the region in the following.

Study on automatic lithology identification based on convolutional neural network and deep transfer learning

Automatic and fast rock classification identification is an important part of geotechnical intelligent survey system. Image based supervised deep learning analysis, especially for convolutional neural networks (CNN), has potential in optimizing lithologic classification and interpretation using borehole core images. However, the accuracy and efficiency of lithology identification models are low at present. In this work, a systematic and enormous rock data framework based on the geological rock classification system is firstly established to provide rock learning datasets. The dataset is composed of approximately 150,000 images of rock samples, which covers igneous rocks, sedimentary rocks, and metamorphic rocks. Secondly, based on CNN-deep transfer learning algorithm, an end-to-end, image-to-label rock lithology identification is established. Finally, the generalization of the proposed model and the field drilling core verification test show that the constructed intelligent rock recognition model has an ability to identify rocks quickly and accurately, and the recognition accuracy of 12 kinds of common engineering rocks is more than 95%. The proposed rock intelligent classification model provides a convenient and fast tool for field geologists and scientific researchers.

The influence of soils of selected sites of Addis Ababa on predicted earthquake ground motions

One-dimensional nonlinear ground response analyses were conducted on selected sites of Addis Ababa. The sites were characterized based on the results of seismic and geotechnical surveys. Input motions were selected from the Pacific Earthquake Engineering Research Center (PEER) ground motion database. The results of the analyses show that the selected sites have a potential amplification significantly higher than the current seismic code specifications. In particular, the average PSA obtained at the ground surface is more than double the code values in the lower period range of up to 1.3 s. Considering that most buildings lie within this range, this calls for a revisiting of the code provisions for such sites of seismic prone areas in the region in general.

Studying Hydrogeological Conditions for the Purpose of Developing Methods of Drying the Walls of Zhairem Deposit Dalnezapadny Site

The mining and geological characteristics of the Zhairem deposit that consists of the Zapadny and Dalnezapadny pits, are considered. The hydrogeological surveys carried out at the site are described. The site for hydrogeological testing includes the area around the Zapadny and Dalnezapadny pits, as well as test pumping and testing with the use of a downhole flowmeter. In the course of studies, theoretical and empirical methods were used; there were studied and applied archival historical data. Conducting geotechnical surveys made it possible to compose a conceptual characterization of the hydrogeological system around the mine and to obtain high-quality initial data for predicting the flow of groundwater. The final stage was the development of recommendations in order to prepare for the pumping of water from the Dalnezapadny 1-2 pit and future expected inflows, in order to carry out high-quality drainage of the Dalnezapadny 1-2 site walls

Investigation of the subsurface structure at the target site in Kumamoto, Japan, and the distributed data of the blind prediction exercise: report for the experiments for the 6th international symposium on effects of surface geology on seismic motion

This technical report explains details on the results of the investigation to build a subsurface structural model and a selection of earthquake data at the target site of the blind prediction exercise for “The 6th International Association of Seismology and Physics of the Earth’s Interior/International Association of Earthquake Engineering International Symposium on the Effect of Surface Geology on Seismic Motion (ESG6).” The selection process of the target site in the Kumamoto Plain, Japan, in ESG6 was explained with a historical review of the blind prediction tests in the previous ESG conferences. We have collected existing subsurface structural and earthquake data and conducted geophysical and geotechnical surveys in and around the target site to generate important velocity structure and the earthquake data used in the blind test. Microtremor data were obtained in triangular arrays ranging in side lengths from 1 to 962 m, and active surface wave data were derived along a 36-m line at the site. These data were provided for the prediction of a subsurface structural model in the first step of the blind prediction exercise. We also conducted a velocity logging in a borehole to a bottom depth of 39 m at the site and laboratory tests of soil samples from the borehole. We constructed a velocity profile of the shallow and deep sedimentary layers from a combination of the geophysical and geotechnical data at the site, and validated it by comparing the characteristics of the ground motion data from the moderate event. This “preferred velocity model” was provided as a standard model to the participants in the second and third steps of the blind prediction test to predict the earthquake ground motions of a moderate event and the mainshock of the 2016 Kumamoto earthquake.Graphical

Characterization of the Ngouache Landslide by Geotechnical Survey (Bafoussam, Cameroon)

The heavy rainfall during the night of October 28-29, 2019, caused a landslide in the Ngouache 4 neighborhood in Bafoussam in the West Cameroon region. This landslide caused 43 deaths, several missing persons and the destruction of several houses and plantations. The present investigation attempts to find the causesof this landslide. First, the landslide area was identified and heavy dynamic penetrometer surveys were conducted. Next, intact and reworked samples were taken and, finally, slopes were measured on the slide area to determine the soil parameters. The results of the heavy dynamic penetrometer showed the presence of altered clay layers which, when saturated, exert hydrostatic pressure and unbalance the soil. The granulometric analysis noted a soil with more than 50% of grains of ϕ>80µm with liquidity limits between (50-65.3%), a consistency index between (1.01-1.24), a low cohesion between (0.22-0.30 bars) for a high internal friction angle (20.72°-23.86°), slopes between 48° and 56° and a degree of saturation Sr between (80.5° and 139.9°). These characteristics associated with the large water columns of the night of October 28 to 29, 2019 demonstrated that the water had exerted a hydrostatic pressure having made the clay material reach the limit of plasticity to the creep and raised the level of the water table. Thistherefore promoted the saturation of the substrate yet the increase in the water content reduces the cohesion of the materials and that triggered the saturation at the origin of this deadly slide. The results of the present research may help the public authorities in the decision making regarding the characterization and the securing of risk zones.

Passive seismic tomography for 3D imaging of the subsurface in a tunnel area

This study aims to provide decision support for future measures to be taken regarding 2 tunnels using high-resolution 3D imaging of the subsurface. This project involves a more comprehensive risk analysis than localized tests, such as geotechnical surveys, and a more precise characterization of the subsoil at the tunnel entrance for approximately 200 meters. To address this issue, a 3D passive seismic tomography was conducted using a network installed on the surface of the study area and another in the tunnels to better analyze the subsurface beneath the tunnels. The 3D shear wave velocity model allowed the identification and delineation of risk zones and the estimation of risk levels based on the analysis of Vs (shear wave velocity) contrasts and their correlation with borehole data.

Toward the use of an intermediate value of the modulus of deformation of soils in geotechnical design

This study presents the results of a critical analysis of the existing methods of selecting the values of ground deformation modulus used in calculating the settlement of designed foundations. The importance of improving the reliability of the determination of the modulus of deformation for ensuring the reliability, economic efficiency and safety of structures is highlighted. It is revealed that the determination of the deformation modulus is not performed at the full depth of soil samples, which can lead to the risk of accidents at facilities. To increase the reliability of deformation modulus determination, a method of interpolation of values based on data from nearby wells is proposed. A new model for determining intermediate values of the deformation modulus is presented, which can be used in calculating the settlement of designed buildings. The results of test problems confirm the high efficiency of the proposed method not only for the calculation of foundation settlement using the values of ground deformation modulus, but also for the control determination of refined values of ground deformation modulus at the stage of geotechnical engineering surveys.

Evaluation of Open Geotechnical Knowledge in Urban Environments for 3D Modelling of the City of Seville (Spain)

The need for sustainable urban growth management and preventive conservation of built elements constitute the key factors in today’s increasing demand for the better understanding of subsoil. This information, mainly available from geotechnical surveys, can be integrated into spatial databases to produce operational models. Aiming to generate strategies that enable the visualisation of underground properties in highly anthropised environments, the following four-phase methodology has been proposed: (a) Gathering of geotechnical data; (b) Spatial and statistical analysis; (c) Database design; (d) Generation of 2D and 3D models. Following the aforementioned criteria and using open sources, a spatial dataset of 650 points located within the historical centre of Seville (Spain) has been developed. This urban area is characterised by the heterogeneous distribution of its soil layers and their geotechnical properties. The results show that the application of this method enables a prompt and efficient display of the distribution of geotechnical layers in urban and metropolitan environments, by considering the variations in their mechanical properties. This simplified approach therefore establishes a new starting point for the development of predictive strategies based on approaches of a more complex nature that facilitate the analysis of the interactions between subsoil, buildings, and infrastructures.

Geotechnical conditions of in-field road design in northern territories of Yamalo-Nenets Autonomous Okrug (Tomsk)

The Yamal-Nenets Autonomous District is the largest hydrocarbon resource base, supplying up to 300–330 billion m3/year of gas and up to 10–15 million t/year of liquid hydrocarbons. Mineral extraction is accompanied by the development of engineering infrastructure, namely: cluster pads, oil storage tanks, pumping stations and automobile roads that link both within and between sites. The area is unique in terms of complexity of geotechnical conditions due to permafrost soils in particular in the upper open-cast. The assessment of geotechnical conditions of the field development as well as adverse processes, hazards, risks and impacts on designed, constructed and operating roads to the cluster pads is undoubtedly relevant.Purpose: The evaluation of geotechnical conditions of design, construction and operation of in-field roads in the Severo-Komsomolsk field.Methodology/approach: The analysis and generalisation of materials of geotechnical surveys for design and construction documentation of the cluster pad 11 in the Severo-Komsomolsk oilfield, performed by AO "TomskNIPIneft". Determination of composition and physical properties of undisturbed soils taken when equipping observation posts, performed in the Laboratory of Ground Science and Soil Engineering, TSUAB.Research findings: Natural and geotechnical conditions of the Yamal-Nenets Autonomous District includes areas with hard frozen soil and areas with complete or partial absence of permafrost soils. In the first case, the subgrade design envisages that the upper permafrost horizon is not lower than the embankment bottom and remains at this level during the entire period of the road operation. In the second case, the design implies preliminary thawing of frozen soil lenses and road drainage prior to the subgrade construction. In the first case, the position of perennially frozen soils is evaluated by the appropriate embankment height, when non-cemented road-building materials are used, and by arranging heat-insulating layers (peat, polystyrene foam, hard frozen soil) with their thermotechnical calculation. The first principle implies the subgrade construction only in winter. To prevent deformation of embankment slopes, it is recommended to build peat benches fixed with a geosynthetic material. Land reclamation in the road construction zone should be avoided to prevent erosion of the soil cover.

Robust quantitative estimation of the seismic attenuation from shallow geotechnical borehole VSP data

Estimating seismic attenuation from shallow geotechnical borehole surveys can be a delicate task. Measured data are often collected within the source near-field domain and the classic inverse-distance correction of the geometric spreading (GS) is inappropriate at this scale. We develop a novel approach based on a 3D full-waveform modeling to substitute the inverse-distance correction. It consists of scaling the picked amplitudes using their counterparts obtained from an elastic simulation carried out under conditions mimicking the data acquisition. The seismic attenuation may be inferred from the corrected amplitudes using either a piecewise regression or a ray-based inversion. Numerical experiments involving P- and S-wave synthetic data indicate that our correction better compensates for the GS effect than the inverse-distance correction. For a synthetic example with 5% noise, the Q-factor values derived from amplitude corrected via the proposed approach have a relative error of approximately 10% compared with 40% for the traditional correction. We investigate the effect of the velocity and density uncertainty upon the calculated correction terms and show that our approach is unbiased and stable. Finally, the robustness of our workflow is assessed on a real case study involving a P-wave data set acquired in a geotechnical borehole.

Study and evaluation of the effects of vegetation cover destruction on soil degradation in Middle Guinea through the application of remote sensing and and geotechnics

Soil degradation in Middle Guinea is increasing over the years. While it's good to have precautions to deal with it, it's even more important to go back to the source of the scourge in order to lessen its effects over time, or even eradicate it. At the center of the factors that are often mentioned is the destruction of the vegetation cover, and the aim of this study is to clear it (in all its forms: trees, grass, savannah, etc.) by following its variation in time [1982 and 2021] and in space. The present study was conducted by combining the remote sensing and GIS results, developed with data from geotechnical survey data and laboratory tests. On the Mali Labé Linsan axis, between [1982 and 1992], 63 % of the territory explored was occupied by fresh vegetation cover, compared to 13 % of dry vegetation, as well as 12 % of sterile soil and 12 % of sand mineral soil. For the periods [1992–2002] and [2002–2012], these same parameters increased to: 67 %; 11 %; 11 % and 11 %. The period [2012–2021] was marked by changes of 73 %; 10 %; 9 % and 9 %, respectively. The bearing capacity of soils varies from one point to another. In all six boreholes presented, their maximum values are greater than or equal to 400 Kpa (≥400 Kpa). The minimum values calculated for 2.1 ≤ B(m)≤7.3 fluctuate between 291 Kpa and 806 Kpa. The investigations carried out on this subject show that the overall movement of the positive variation of the vegetation cover in time (63 % < 67 % < 73 %) and very contrasted in space, would not be responsible for the degradations (which are local and mainly caused by erosion: wind and water). In addition, they open up to a (geoscientific and geotechnical) approach of a deep analysis, the purpose of which suggests the adoption of slab/concrete/grating foundations (depth of anchorage specific to each soil analyzed).

Verification of the Design Parameters Based on the Control Diagnostic of the Deformation Resistance of the Sub-Ballast Upper Surface

Abstract Based on the quality control diagnostics of the used base layers on the interstation railway section Palárikovo - Nové Zámky, the article analyzes the achieved results of static load tests that were carried out on the plane of the sub-ballast upper surface. The verification of the values is based on the project documentation, in which, on the basis of a previously performed geotechnical survey, the designer proposed a suitable type of structural sub-ballast layers. The design of the structural sub-ballast layers reflects the expected deformation resistance of the subgrade surface, its water regime, the railway line characteristic (speed zone), the type of construction work (reconstruction) and also takes into account the principle of conservation of natural resources (recycling of recovered ballast bed material).

Integration of GIS with the Generalized Reciprocal Method (GRM) for Determining Foundation Bearing Capacity: A Case Study in Opolo, Yenagoa Bayelsa State, Nigeria

This study addresses the pressing need to assess foundation bearing capacity in Opolo, Yenagoa, Bayelsa State, Nigeria. The significance lies in the dearth of comprehensive geotechnical data for construction planning in the region. Past research is limited and this study contributes valuable insights by integrating Geographic Information System (GIS) with the Generalized Reciprocal Method (GRM). To collect data, near-surface seismic refraction surveys were conducted along three designated lines, utilizing ABEM Terraloc Mark 6 equipment, Easy Refract, and ArcGIS 10.4.1 software. This methodology allowed for the determination of key geotechnical parameters essential for soil characterization at potential foundation sites. The results revealed three distinct geoseismic layers. The uppermost layer, within a depth of 0.89 to 1.50 meters, exhibited inadequate compressional and shear wave velocities and low values for oedometric modulus, shear modulus, N-value, ultimate bearing capacity, and allowable bearing capacity. This indicates the presence of unsuitable, soft, and weak alluvial deposits for substantial structural loads. In contrast, the second layer (1.52 to 3.84 m depth) displayed favorable geotechnical parameters, making it suitable for various construction loads. The third layer (15.00 to 26.05 m depth) exhibited varying characteristics. The GIS analysis highlighted the unsuitability of the uppermost layer for construction, while the second and third layers were found to be fairly competent and suitable for shallow footing and foundation design. In summary, this study highlights the importance of geotechnical surveys in Opolo’s construction planning. It offers vital information for informed choices, addresses issues in the initial layer, and suggests secure, sustainable construction options.

Wind resource assessment and potential development of wind farms along the entire coast of South Korea using public data from the Korea meteorological administration

The feasibility of a wind farm locations should be evaluated on a thorough analysis and assessment of the available wind resources which necessitates wind data measurement for a minimum period of one year. Nevertheless, several limitations arise during this process, including challenges related to the site selection, cost considerations such as the installation of meteorological masts subsequent to marine physical and geotechnical surveys, and the requirement for ongoing maintenance. Therefore, several studies have been carried out to determine wind energy potential using reanalysis data. However, in areas with distinct terrain characteristics, such as maritime and coastal areas, uncertainties exist in the use of reanalysis data. Therefore, an analysis of wind resources based on measurement data is necessary in such areas. In this study, wind data measured by the Korea Meteorological Administration's automatic weather system and light house automatic weather system for 56 points along the Korean coast is obtained and analyzed. Additionally, the expected annual energy production and capacity factor were predicted when offshore wind turbines are installed using the power curve of a reference model of large offshore wind turbines in the 15–20 MW class. As a results, five points at which a capacity factor of over 35% is predicted as promising sites for future wind farm development. These public data from the Korea Meteorological Administration are also limited in their ability to provide accurate wind resource analysis for wind power generation due to the wind speed measurement instrument's height being lower than that of the wind turbine hub and environmental influences. However, these results can be useful in identifying possible candidate sites for wind farms in South Korea.