<abstract><title style='display:none'>Abstract</title>The article is a review of the current problems of the foundation pile capacity calculations. The article considers the main principles of pile capacity calculations presented in Eurocode 7 and other methods with adequate explanations. Two main methods are presented: <italic>α</italic> – method used to calculate the short-term load capacity of piles in cohesive soils and <italic>β</italic> – method used to calculate the long-term load capacity of piles in both cohesive and cohesionless soils. Moreover, methods based on cone CPTu result are presented as well as the pile capacity problem based on static tests.</abstract>

Pile Load Capacity – Calculation Methods

<abstract><title style='display:none'>Abstract</title> The paper presents the results of a triaxial test conducted on stiff, consolidated clays. The standard TXCIU procedure (isotropic consolidation and undrained shearing) was applied in the laboratory soil tests. The undrained elastic modulus Eu50 was determined from each test.The Eu50 values were determined for soil samples cut out from different depths and tested under different confining pressures. There was a significant scatter of values with depth, and no relationships between Eu50 modules or other geotechnical parameters (e.g., cu) were observed.This work presents the concept of normalization of Eu50 modulus values using modified normalization SHANSEP (Stress History And Normalized Soil Engineering Properties). This method was first proposed for estimating the value of the undrained shear strength cu normalizing the parameter relative to the in situ effective vertical stress σ′vo and loading history (overconsolidation stress σ′p and overconsolidation ratio OCR) of the soil.The study demonstrated that the concept of normalization of soil properties can also be used for testing elastic modulus Eu50 of consolidated natural clays and normalized values of geotechnical parameters taking into account the state of stress and load history can be correlated with the value of the overburden pressure. </abstract>

The elastic undrained modulus Eu50 for stiff consolidated clays related to the concept of stress history and normalized soil properties

<abstract>
<title style='display:none'>Abstract</title>
The paper concerns the characteristic parameters of the selected isotropic failure criteria, i.e. Mohr–Coulomb, Drucker–Prager, Matsuoka–Nakai and Lade–Duncan. The parameters are determined directly from the failure criteria and stress measurements or by semi-theoretical approach, assuming that the soil obeys the associated flow rule and using the plane strain condition. In the latter case, the parameters can be expressed as functions of the plane strain internal friction angle, which is determined from measurements. The principal stress tensor components, corresponding to the soil peak strength and necessary to obtain the failure criteria parameters, are measured in a series of true triaxial, plane strain tests, on coarse Skarpa sand samples of different initial relative density, subjected to various confining pressures.
</abstract>

Characteristic parameters of soil failure criteria for plane strain conditions – experimental and semi-theoretical study

<abstract><title style='display:none'>Abstract</title>Numerical simulations of air blast loading in the near-field acting on the ground have been performed. A simplified blast model based on empirical blast loading data representing spherical and hemispherical explosive shapes has been simulated. Conwep is an implementation of the empirical blast models presented by Kingery and Bulmash, which is also implemented in the commercial code LS-DYNA based on work done by Rahnders-Pehrson and Bannister. This makes it possible to simulate blast loads acting on structures representing spherical and hemispherical explosive shapes of TNT with reasonable computational effort as an alternative to the SPH and Eulerian model. The CPU time for the simplified blast model is however considerably shorter and may still be useful in time consuming concept studies. Reasonable numerical results using reasonable model sizes can be achieved not only for modelling near-field explosions in air but most areas of geotechnical. Calculation was compared with blast SPH and Eulerian model.</abstract>

Numerical Simulations of Blast Loads from Near-Field Ground Explosions in Air

<abstract><title style='display:none'>Abstract</title>The paper deals with the methodology of performing and interpretation of seismic cone penetration test (SCPT). This type of test is used to determine velocity of the seismic wave in the soil medium. This study is focused on shear wave. The wave is triggered on the ground surface by hitting an anvil with a sledgehammer. Then, vibrations induced at different depths are measured. Based on recorded measurements wave velocity (Vs) and thus also small strain shear modulus Gmax may be calculated. An interpretation of exemplary seismic test results is presented. Crossover and cross-correlation methods are discussed and another, more adequate one is featured and then applied in the interpretation example. Conditions for correct test performance and interpretation are discussed.</abstract>

Wrocław University of Technology, Faculty of Civil Engineering, Wrocław, Poland

On the interpretation of seismic cone penetration test (SCPT) results

<abstract><title style='display:none'>Abstract</title>Results of investigations of shearing resistance and compressibility of fine-grained cohesive soil from the southern part of the wielkopolskie voivodeship in relation to the increasing moisture content are presented. The analysis of two series of samples, using soil paste for the consistency index of 0.9 and 0.4–0.3 was carried out. The results imply that the increasing moisture content causes a decrease in the angle of shearing resistance and cohesion and is also reflected in the higher compressibility of the soil. It was observed that regardless of the soil consistency, the angle of shearing resistance decreases and the cohesion value and the oedometric modulus of primary (consolidation) and secondary compressibility grows with the increase in the clay fraction.</abstract>

Moisture Content Impact on Mechanical Properties of Selected Cohesive Soils from the Wielkopolskie Voivodeship Southern Part

<abstract>
<title style='display:none'>Abstract</title>
The article proposes a method of combining CloudCompare, RHINO, and FLAC3D software, aimed at building numerical models of underground objects of natural or engineering origin, based on the results of measurements made using terrestrial laser scanning technology. This technology is one of the most advanced in mine survey as it enables accurate mapping of even the most complex geometries of underground facilities. This opens wide possibilities in the construction of more accurate numerical models of the behavior of the rock mass around such underground objects. The results of simulation of the behavior of the rock mass around the analyzed excavations, obtained by performing numerical calculations, allow predicting unfavorable phenomena that may occur as a result of the destruction of the rock mass and which may threaten the safety of users of underground facilities, for example, caves, tunnels, and mining excavations.
In this work, we carried out measurements using a terrestrial laser scanner and obtained a “point cloud” that reproduced the geometry of the underground facility. An example is a fragment of the adit St. Johannes, which is part of the underground tourist route “Geopark” St. Johannes Mine in Krobica in Lower Silesia in Poland in the neighborhood of Gierczyn and Przecznica. In the next step, the measurement results were processed, so that it was possible to import the generated geometry into the FLAC3D software and use it to build a numerical model of the adit, based on “brick” zones.
The aim of the article is to present in detail the methodology of geometrization of numerical models of underground objects with complex geometry. The author wanted the method to be as easy to use as possible, give full control over the surface structure, and not require many numerical modeling programs.
</abstract>

Geometrization of a 3D numerical model of an underground facility based on the results of terrestrial laser scanning

<abstract>
<title style='display:none'>Abstract</title>
This article presents a study on the stiffness of mixtures of anthropogenic materials derived from construction or demolition waste, specifically fine recycled concrete aggregates (fRCAs) with different fine fraction (FF) contents. The study investigated small-strain shear moduli via various signal interpretation methods, examining, above all, the time domain approaches and considering the influence of FF content. However, the inconclusive results from the bender element (BE) tests highlight the complexity of factors affecting shear wave velocity, which requires further research to refine the methodology and assess long-term performance in geotechnical applications.
Selecting the correct test frequency and interpretation method is crucial to obtain accurate results. The BE test method should consider all relevant factors. At low input frequencies (≤5 kHz), the near-field effect affected the received signal for fRCA mixtures. At higher frequencies (around 14 kHz), the noise levels increased, thereby interfering with the S-wave travel time determination. Intermediate input frequencies (10.0 and 12.5 kHz) provided the representative shear modulus (<italic>G</italic>) values. The small-strain shear modulus (<italic>G</italic>max) of the fRCA compounds from the resonant column and BE tests was found to be in good agreement, despite differences in the test procedures themselves.
</abstract>

Small-strain stiffness of selected anthropogenic aggregates from bender element tests

<abstract>
<title style='display:none'>Abstract</title>
The correct investigation of the foundation soil is essential for the optimal and efficient design of any structure. The interaction of a structure with the foundation soil can only be evaluated through the physical and mechanical characteristics of the intercepted geotechnical layers on the entire zone of influence. For this reason, the role of technical documentation that includes and summarizes field investigations and laboratory tests is particularly important. An important and sometimes complicated component in providing useful design information is the division into geotechnical or computational layers. This can be done at different levels, starting from the physical characteristics such as color, grain size distribution, plasticity and consistency and can continue with the evaluation of the mechanical characteristics of compressibility and shear strength. The aim of the paper is to create a graphical representation of the geotechnical parameters using a spatial interpolation technique (Kriging method). The creation of 2D maps using SURFER software assists geotechnical engineers in the correct interpretation of the geotechnical parameters. This interpolation technique for division into layers is also useful in quarries and borrows pits, when soil is used as construction material.
</abstract>

The Role of Spatial Distribution of Geotechnical Soil Parameters in Site Investigation

<abstract>
<title style='display:none'>Abstract</title>
It is proved analytically that the complex growth rate <italic>n</italic> = <italic>nr</italic> + <italic>ini</italic> (<italic>nr</italic> and <italic>ni</italic> are the real and imaginary parts of <italic>n</italic> , respectively) of an arbitrary neutral or unstable oscillatory disturbance of growing amplitude in rotatory electrothermoconvection in a dielectric fluid layer saturating a sparsely distributed porous medium heated from below, for the case of free boundaries, is located inside a semicircle in the right half of the <italic>nrni</italic> − plane, whose centre is at the origin and radius = 
<inline-formula>
<alternatives>
<inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/j_sgem-2024-0008_ineq_001.png"/>
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msqrt><mml:mrow><mml:mo>max</mml:mo><mml:mfenced><mml:mrow><mml:msub><mml:mi>T</mml:mi><mml:mi>a</mml:mi></mml:msub><mml:msubsup><mml:mi>P</mml:mi><mml:mi>r</mml:mi><mml:mn>2</mml:mn></mml:msubsup><mml:mo>,</mml:mo><mml:mfrac><mml:mrow><mml:msub><mml:mi>R</mml:mi><mml:mrow><mml:mi mathvariant="italic">ea</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi>P</mml:mi><mml:mi>r</mml:mi></mml:msub></mml:mrow><mml:mi>A</mml:mi></mml:mfrac></mml:mrow></mml:mfenced></mml:mrow></mml:msqrt></mml:mrow></mml:math>
<tex-math>\sqrt {\max \left( {{T_a}P_r^2,{{{R_{ea}}{P_r}} \over A}} \right)} </tex-math>
</alternatives>
</inline-formula>
, where <italic>Ta</italic> is the modified Taylor’s number, <italic>Pr</italic> is the modified Prandtl number, <italic>Rea</italic> is electric Rayleigh number and <italic>A</italic> is the ratio of heat capacities. The upper limits for the case of rigid boundaries are derived separately. Furthermore, similar results are also derived for the same configuration when heated from above.
</abstract>

On the upper limits for complex growth rate in rotatory electrothermoconvection in a dielectric fluid layer saturating a sparsely distributed porous medium

<abstract>
<title style='display:none'>Abstract</title>
For more than a dozen or so years now, there has been growing interest in the use of modern laser scanning measurement methods in numerous mining operations engaged in underground excavation. However, the simple possession of a scanner does not guarantee satisfactory measurement results. This study sets out the results of scanning mine excavations in an active mine and describes the current guidelines on various aspects of the measurement process. These guidelines were developed on the basis of several hundred measurements carried out over the last dozen or so years.
This study also outlines the typical measurements errors observed over the course of many years. These errors, resulting partly from hardware limitations and partly from human error when planning or actually performing measurements, were an important factor behind the introduction of standards regulating underground measurements.
This study discusses in detail not only scanning that utilises traditional stationary laser scanners but also scanning based on mobile scanners. It also presents possible areas of future technological development in line with global trends.
</abstract>

Practical Aspects of Using Modern Laser Scanning Techniques for Measuring Mine Excavations

<abstract>
<title style='display:none'>Abstract</title>
This study highlights the possibility of determining the shear stress distribution along the skin of a pile, which represents skin resistance. Geotechnical engineering is plagued by the challenge of designing appropriate piles as a sufficient foundation construction while being economically justified solution. Static load testing facilitates verification if the pile satisfies these requirements. In most cases, the pile skin resistance is undervalued. This study first introduces the general approach based on static load test results using an appropriate mathematical approach in the presence of linear, vertical shear stress distribution boundary conditions as well as phenomena such as pile shortening and Kirchhoff's principle. Moreover, a scientific approach for pile compression and shear stress distribution is presented. Further, the study expands upon previous work by applying mathematical calculus to displacement piles. The promising results indicate that further work on greater number of piles may lead to a better understanding of pile–soil interaction and a more accurate design process.
</abstract>

Pile–Soil Interaction during Static Load Test

<abstract><title style='display:none'>Abstract</title>The purpose of the present study was to compare the prediction performances of three statistical methods, namely, information value (IV), weight of evidence (WoE) and frequency ratio (FR), for landslide susceptibility mapping (LSM) at the east of Constantine region. A detailed landslide inventory of the study area with a total of 81 landslide locations was compiled from aerial photographs, satellite images and field surveys. This landslide inventory was randomly split into a testing dataset (70%) for training the models, and the remaining (30%) was used for validation purpose. Nine landslide-related factors such as slope gradient, slope aspect, elevation, distance to streams, lithology, distance to lineaments, precipitation, Normalized Difference Vegetation Index (NDVI) and stream density were used in the landslide susceptibility analyses. The inventory was adopted to analyse the spatial relationship between these landslide factors and landslide occurrences. Based on IV, WoE and FR approaches, three landslide susceptibility zonation maps were categorized, namely, “very high, high, moderate, low, and very low”. The results were compared and validated by computing area under Road the receiver operating characteristic (ROC) curve (AUC). From the statistics, it is noted that prediction scores of the FR, IV and WoE models are relatively similar with 73.32%, 73.95% and 79.07%, respectively. However, the map, obtained using the WoE technique, was experienced to be more suitable for the study area. Based on the results, the produced LSM can serve as a reference for planning and decision-making regarding the general use of the land.</abstract>

Landslide Susceptibility Assessment in Constantine Region (NE Algeria) By Means of Statistical Models

<abstract><title style='display:none'>Abstract</title>The constant development of geotechnical technologies imposes the necessity of monitoring techniques to provide a proper quality and the safe execution of geotechnical works. Several monitoring methods enable the preliminary design of work process and current control of hydrotechnical works (pile driving, sheet piling, ground improvement methods). Wave parameter measurements and/or continuous histogram recording of shocks and vibrations and its dynamic impact on engineering structures in the close vicinity of the building site enable the modification of the technology parameters, such as vibrator frequency or hammer drop height. Many examples of practical applications have already been published and provide a basis for the formulation of guidelines, for work on the following sites. In the current work the author’s experience gained during sheet piling works for the reconstruction of City Channel in Wrocław (Poland) was presented. The examples chosen describe ways of proceedings in the case of new and old residential buildings where the concrete or masonry walls were exposed to vibrations and in the case of the hydrotechnical structures (sluices, bridges).</abstract>

Methodology of Dynamic Monitoring of Structures in the Vicinity of Hydrotechnical Works – Selected Case Studies

<abstract><title style='display:none'>Abstract</title> An unconventional subdivision of volumetric strains, the newly formulated frictional and critical frictional states and some of energetic and stress condition assumptions result in new stress-plastic dilatancy relationships. These new stress-plastic dilatancy relationships are functions of the deformation mode and drainage conditions. The critical frictional state presented in this paper is a special case of the classical critical state.</abstract>

Stress-Dilatancy for Soils. Part I: The Frictional State Theory

<abstract><title style='display:none'>Abstract</title> Crashed or dimensional rocks have been used as natural construction material, decoration stone or as material for artistic sculptures. Especially old historical towns not only in Slovakia have had experiences with use of stones for construction purposes for centuries. The whole buildings were made from dimensional stone, like sandstone, limestone or rhyolite. Pavements were made especially from basalt, andesite, rhyolite or granite. Also the most common modern construction material - concrete includes large amounts of crashed rock, especially limestone, dolostone and andesite. However, rock as any other material if exposed to exogenous processes starts to deteriorate. Especially mechanical weathering can be very intensive if rock with unsuitable rock properties is used. For long it had been believed that repeated freezing and thawing in relation to high absorption is the main reason of the rock deterioration. In Slovakia for many years the high water absorption was set as exclusion criterion for use of rocks and stones in building industry. Only after 1989 the absorption was accepted as merely informational rock property and not exclusion. The reason of the change was not the understanding of the relationship between the porosity and rock deterioration, but more or less good experiences with some high porous rocks used in constructions exposed to severe weather conditions and proving a lack of relationship between rock freeze-thaw resistivity and water absorption. Results of the recent worldwide research suggest that understanding a resistivity of rocks against deterioration is hidden not in the absorption but in the structure of rock pores in relation to thermodynamic properties of pore water and tensile strength of rocks and rock minerals. Also this article presents some results of research on rock deterioration and pore structure performed on 88 rock samples. The results divide the rocks tested into two groups - group N in which the pore water does not freeze even when the temperature decreases to -20 ºC, and the second group F in which the pore water freezes. It has been found that the rocks from group N contain critical portion of adsorbed water in pores which prevents freezing of the pore water. The presence of adsorbed water enables thermodynamic processes related to osmosis which are dominantly responsible for deterioration of rocks from group N. A high correlation (R = 0.81) between content of adsorbed water and freeze-thaw loss was proved and can be used as durability estimator of rocks from group N. The rock deterioration of group F is caused not only by osmosis, but also by some other processes and influences, such as hydraulic pressure, permeability, grain size, rock and mineral tensile strength, degree of saturation, etc., and the deterioration cannot be predicted yet without the freeze-thaw test. Since the contents of absorbed water and ratio between adsorbed and bulk water (of which the absorbed water consists) is controlled by the porosity and pore structure, it can be concluded that the deterioration of some rocks is strongly related to rock pore structure.</abstract>

Rock Pore Structure as Main Reason of Rock Deterioration

<abstract><title style='display:none'>Abstract</title> The basic type of rock mass reinforcement method for both preparatory and operational workings in underground metal ore mines, both in Poland and in different countries across the world, is the expansion shell or adhesive-bonded rock bolt. The article discusses results of static loading test of the expansion shell rock bolts equipped with originally developed deformable component. This component consists of two profiled rock bolt washers, two disk springs, and three guide bars. The disk spring and disk washer material differs in stiffness. The construction materials ensure that at first the springs under loading are partially compressed, and then the rock bolt washer is plastically deformed. The rock bolts tested were installed in blocks simulating a rock mass with rock compressive strength of 80 MPa. The rock bolt was loaded statically until its ultimate loading capacity was exceeded. The study presents the results obtained under laboratory conditions in the test rig allowing testing of the rock bolts at their natural size, as used in underground metal ore mines. The stress-strain/displacement characteristics of the expansion shell rock bolt with the deformable component were determined experimentally. The relationships between the geometric parameters and specific strains or displacements of the bolt rod were described, and the percentage contribution of those values in total displacements, resulting from the deformation of rock bolt support components (washer, thread) and the expansion shell head displacements, were estimated. The stiffness of the yielded and stiff bolts was empirically determined, including stiffness parameters of every individual part (deformable component, steel rod). There were two phases of displacement observed during the static tension of the rock bolt which differed in their intensity.</abstract>

Reinforcement of Underground Excavation with Expansion Shell Rock Bolt Equipped with Deformable Component

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Studia Geotechnica et Mechanica

The Journal of Wrocław University of Science and Technology

and AGH University of Science and Technology

 An international journal ‘Studia Geotechnica et Mechanica’ covers new developments in the broad areas of geomechanics as well as structural mechanics. The journal welcomes...

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 An international journal ‘Studia Geotechnica et Mechanica’ covers new developments in the broad areas of geomechanics as well as structural...

Studia Geotechnica et Mechanica

The Journal of Wrocław University of Science and Technology and AGH University of Science and Technology

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