<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 procedure of building a quasi-3D geometry of a numerical model of an underground post-mining facility is presented in the article. For this purpose, measurements were made, based on the terrestrial laser scanning (TLS) technology, of a fragment of St. John adit, which is part of the underground tourist route “Geopark” St. Johannes Mine in Krobica in Lower Silesia in Poland, in the neighborhood of Krobica, Gierczyn and Przecznica – the places located in the vicinity of the well-known health resort Świeradów Zdrój. TLS, as one of the most advanced mining surveying technologies, enables accurate mapping of even the most complex geometries of underground mining facilities. This opens wide possibilities in the construction of more accurate numerical models of the behavior of the rock mass around such underground objects. As a result, more reliable calculation results are obtained, which are the basis for designing mining support protection, for example, with rock bolting. This translates into an improvement in the safety of underground excavations, in the conditions of exploitation in mining as well as in historical post-mining excavations made available to tourists.
In the construction of the geometry of numerical model, software such as Trimble RealWorks was used to orientate individual “point clouds” from measurement stations. CloudCompare software was also used to generate cross sections to the adit axis, and AutoCad software was used for processing and spatial orientation of a selected characteristic cross section. Using the latest version of the FLAC 3D v.9.0 software, the excavation cross-section geometry obtained from measurements was mapped to and discretized (i.e., meshed), giving it a third dimension at the same time.
</abstract>

Terrestrial laser scanning in the construction of a numerical model geometry related to underground post-mining facility

<abstract>
<title style='display:none'>Abstract</title>
The relationship between the soil water characteristic curve (SWCC) and the mechanical behavior of unsaturated soil is imperative and has been well investigated. However, the correlation between elastic wave velocity along the wetting and drying paths of SWCC is largely unknown due to the nonavailability of a standard experimental setup for such a purpose. An ordinary triaxial apparatus has been modified for laboratory assessment of SWCCs under different Ko stresses, along with the measurement of shear and compression wave velocities in due course. The main aim of the study is to draw SWCC, wave velocity characteristic curve (WVCC), and a Poisson’s ratio characteristic curve (PRCC) and to establish the phenomenon that these curves possess hysteresis. The Poisson’s ratio was obtained indirectly by measuring Vp and Vs. Three soil samples with relative densities of 85%, 56%, and 39% were prepared and placed in a modified triaxial test apparatus under wetting and drying cycles. The test results showed that the newly developed apparatus is accurately capable of measuring SWCC. Owing to the similarity in the shape of wave velocity and Poisson’s ratio, response to SWCC, WVCC, and PRCC are drawn. The phenomenon of stress history and the effective stress of the soil affected the behavior during wetting and drying paths.
</abstract>

Development of Wetting-Drying Curves from Elastic Wave Velocities Using a Novel Triaxial Test Apparatus

<abstract>
<title style='display:none'>Abstract</title>
Composite dowels opened new possibilities for engineers designing composite structures. The fundamental and most important characteristic of composite dowels is the shape of the cutting pattern (called line). It is important to understand why only one particular shape of the cutting line, the modified clothoidal (MCL) shape, is being used in bridge engineering, while so many different shapes have been investigated by many researchers. The essential part of the process of developing composite dowels – the development of shape of the cutting line – is presented in this paper. The investigation, development, and evolution of the MCL shape, which is the final form of composite dowels for bridges and has been widely introduced in bridge engineering, are presented. The results of comparative tests of different shapes under cyclic loads are discussed. The background for the design formulas for the steel part and the fabrication aspects are highlighted.
</abstract>

Development of the modified clothoidal (MCL) shape of composite dowels against the background of fatigue and technological issues

<abstract>
<title style='display:none'>Abstract</title>
This paper presents a quantitative characterisation of the fracture openings obtained in triaxial shear tests on several cement mortar samples. The comparison was carried out on three samples with various apertures using different methods of semi-destructive and non-destructive characterisation: optical microscopy, scanning electron microscopy, X-ray computed tomography, digital volume correlation and the 14C-polymethylmethacrylate method. The fracture aperture distribution results are in good agreement between the different methods. Although the opening results obtained are comparable, the most advantageous method was considered to be XRCT profile analysis based on the size of the target area studied and the specific characteristics of each technique.
</abstract>

Comparing fracture openings in mortar using different imaging techniques

<abstract>
<title style='display:none'>Abstract</title>
This study evaluates various methods for estimating soil permeability using microtomography-derived data and compares them to the conventional laboratory approaches. Different methods, including measurement in custom-designed permeameter at micro-CT-compatible scale, empirical equations, simulated sifting, semi-theoretical equations, pore-network modeling, and lattice-Boltzmann simulations, were applied to samples of sandy soils with distinct microstructural properties. The empirical equations showed varied results, highly dependent on the method chosen. The simulated sifting method was able to adequately estimate the granulometric properties of the soil, allowing the use of empirical permeability formulations for substantially small samples. Semi-theoretical equations based on the microstructural properties presented reasonable agreement for some samples. The pore-network modeling approach demonstrated computational efficiency but lacked accuracy. The lattice-Boltzmann method required significant computational resources but did not provide substantially closer alignment with the measured hydraulic properties of some samples. None of the simulations was able to properly determine the permeability of silty and organically contaminated sand. The study highlights the complexity of permeability estimation, emphasizing the need for choosing volumes of interest, resolution of micro-CT scans, and methods that match specific soil characteristics and available computational resources.
</abstract>

Insights Into Estimation of Sand Permeability: From Empirical Relations to Microstructure-based Methods

<abstract>
<title style='display:none'>Abstract</title>
Rafts are frequently used to design foundations on soft soils to minimize the overall and differential settlements of structures built on them. In many cases, the raft alone can offer sufficient bearing capacity and all that is needed to restrict foundation settlements to a predetermined level with a few widely spaced piles. Granular piles (GPs) can be used due to their several advantages over steel or concrete piles. An annular raft foundation is generally provided for overhead water tanks, chimneys, etc. The provision of granular piles underneath the annular raft foundation not only increases the capacity of the foundation but also minimizes the settlement to an acceptable level. The present study deals with a rigorous analysis of annular raft foundation supported by GPs based on the continuum approach. A new numerical method is developed with geometric considerations for excluding the loaded pile portion from the region of the raft area by considering two distinct zones. This article introduces a novel approach, the annular raft over granular piles, which represents an innovative solution in geotechnical engineering. This innovation has the potential to improve the efficiency and effectiveness of foundation design in various construction projects. The response of annular raft foundation with GPs is evaluated in terms of settlement influence factor (SIF), load shared by granular piles (in %), and normalized shear stress variation along the GP–soil interface. The present study reveals that the presence of the pile influences the stress distribution locally. The stiffness of GP, relative length of GP, relative size of the raft influence the settlement and load sharing of annular raft with GPs.
</abstract>

An Analytical Study of Annular Raft on Granular Piles

<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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