Abstract Efforts to recycle marble processing waste (MPW), a by-product of dimensional marble production, are essential in mitigating environmental impacts but face challenges such as composition variability, low inclusion rates, and preprocessing requirements in current practices. This study evaluates the feasibility of utilising MPW as a sustainable structural fill material in Reinforced Soil Structures (RSS), an inevitable part of transportation infrastructure. Comprehensive characterisation of MPW—including particle gradation, plasticity, hydraulic conductivity, electrochemical properties, morphology, mineralogical composition, and shear strength—demonstrates its suitability as a structural fill material, comparable to Local Soil (LS). Although MPW exhibits slightly lower interaction characteristics with geogrids compared to LS, as evidenced by interaction coefficients (R i ) and interface apparent coefficients (µ s/GSY ) obtained from interface shear and pullout tests, the differences are minimal. For the MPW-geogrid interface, R i and µ s/GSY values ranged between 0.70–0.85 and 0.25–1.38, respectively. Being non-hazardous and environmentally safe, along with offering environmental benefits and approximately 51% cost savings in fill material, MPW establishes itself as a viable and sustainable alternative to natural soil. This addresses the dual challenges of MPW disposal while meeting the growing demand for structural fill, contributing to natural soil conservation efforts.

Abstract Non-contact surveying strategies such as terrestrial laser scanning (TLS) and digital close-range photogrammetry (DCRP), have recently become popular as surveying techniques due to their rapid deployment and high accuracy. The critical issue that researchers typically face is the limited number of LVDTs or dial gauges available in laboratories, and occasionally it might be physically challenging to install several gauges in the testing facilities. Consequently, the primary objective of this paper is to examine the present viability and benefits of employing TLS and DCRP techniques in monitoring geotechnical applications. Calibration of these methods was performed through two laboratory tests: (1) monitoring of secant pile walls (SPW) as well as the soil movements; and (2) axial compression tests on SPW. The findings reveal that the discrepancy between traditional measurement methods and the TLS approach is less than 3.0%, whereas the difference between traditional methods and DCRP is under 1.8%. Furthermore, both DCRP and TLS techniques are capable of precisely tracking initial deformations, geometric irregularities, deficiencies in the samples (including pre-buckling phenomena), and deformations of the soil tank at each stage of loading. In conclusion, TLS and DCRP methods were found to offer accurate and advantageous alternatives for geotechnical monitoring, notably their capacity for the automatic collection and analysis of an unlimited number of measurement points.

Abstract The mechanical behavior of rock masses in longwall mining is critically influenced by spatial correlation among material properties, yet conventional deterministic models often overlook this variability. Conventional deterministic models often overlook this spatial variability, leading to potentially misleading assessments of rock strength and stability. This research addresses the critical need for a nuanced understanding of rock mass behavior by investigating the effects of spatial correlation on stress distribution and failure mechanisms in coal seams. The primary objective is to evaluate how incorporating spatially correlated random properties can enhance the accuracy of predictions in mining operations. The study uses a three-dimensional numerical model to contrast deterministic approaches with a stochastic framework that integrates spatial correlation factors. The methodology involves generating a realistic random field database based on the Extreme Value stochastic model, which is then applied to simulate stress responses in the rock mass under various loading conditions. This 40% reduction in peak stress estimates translates to substantially different safety assessments and mining strategy recommendations compared to traditional deterministic approaches. This research underscores the necessity of adopting stochastic approaches in rock mass evaluations, as they provide a more accurate representation of real-world conditions. The insights gained from this study are essential for developing safer and more effective longwall mining strategies, highlighting the importance of considering spatial variability in rock mechanics. The findings contribute to the advancement of mining engineering by integrating advanced statistical techniques with practical applications, ultimately enhancing operational efficiency and safety in mining practices.

In the present investigation an attempt is made to study the axial and oblique pullout capacity of monopile and belled pile embedded in geogrid reinforced sand beds by conducting tests on model piles. A model tank of size 1.2mX0.75mX1.5 m is used to study the behaviour of an aluminium model pile under axial and oblique pull-out loads in geogrid reinforced sand bed of relative density 30%. A comparative study was made between monopile and belled piles by varying parameters such as embedment ratios (L/Ds) of 5, 7.5, and 10 respectively and diameter ratios (Db/Ds) of 1.5 & 2 with bell angles of 30°, 45°, and 60° under axial and oblique inclination angle of 30˚& 45˚.The use of the optimum size of the geogrid reinforcement placed at the bottom of the short pile and at a spacing of 4.5Ds from top in case of intermediate and long pile significantly enhanced the pullout and oblique pullout capacities of both monopile and belled piles. In the case of a monopile, the pull-out capacity increases with an increase in the load inclination angle from 0˚ to 45°, whereas in the case of the belled pile, the pullout capacity decreased with an increase in the load inclination angle. A non-dimensional parameter called the Uplift Improvement Ratio was evaluated, and the results revealed that the efficiency of the geogrid reinforcement was independent of the load inclination, bell angle, Db/Ds ratio, and L/Ds ratio when the optimum size of the geogrid was placed at optimum position of the belled pile foundation. It was also found that the obtained breakout factor increases with an increase in the L/Ds ratio and load inclination angle but the influence of the bell angle on the breakout factor was found to be marginal.The obtained values of the breakout factor were compared with the existing limit equilibrium theory, and it was found that the results of the breakout factor were in good agreement with the Meyerhof and Adam theory for both unreinforced and geogrid-reinforced sand beds.

Improving problematic soils using economical and appropriate methods is a major focus in geotechnical research. Recently, nanoparticles such as nanoclay have gained attention as a cost-effective and eco-friendly solution for enhancing soil quality. Nanoclay’s high specific surface area and ion exchange capacity make it economically viable, while its environmental friendliness comes from its derivation from bentonite minerals. This case study aims to improve a local sandy soil with low shear strength in an earthquake-prone region south of Qom City, Iran. The study uses nanoclay stabilization and compares its effectiveness on improving the local soil under both static and dynamic loading conditions, providing a novel approach. Thus, a series of direct shear and simple shear tests were performed to accomplish this specified task. After adding nanoclay to the soil, the sandy soil pores were filled with a cohesive mixture, increasing its agglomeration, which ultimately led to the following results. The results showed that incorporating nanoclay significantly increased the cohesion (c) value by an average of 12 times and raised the internal friction angle (Φ) by 15% compared to the untreated soil. Furthermore, the shear modulus (G) increased 1.4 times on average, while the damping ratio (D) decreased by 25% relative to the original soil. Overall, the use of montmorillonite nanoclay proved to be highly effective in enhancing the strength of non-cohesive sandy soils, especially under static loading. Additionally, the method of stabilizing soil with nanoclay was found to be economical for improving its strength in both static and dynamic conditions.

Accurately predicting the performance of Earth Pressure Balance Tunnel Boring Machines (EPB-TBMs) in soft ground conditions is crucial yet challenging due to the complex interaction of geological and operational factors. This study investigates Mashhad Metro Line 3, where a TBM was employed to excavate a 1831-m section through variable soil compositions, including significant cobble and boulder content, presenting unique challenges to performance prediction. To address these complexities, several machine learning models—Multiple Linear Regression (MLR), Decision Trees (DT), and Multi-Layer Perceptron (MLP) neural networks—were applied to predict TBM penetration rates and assess model efficacy. Beginning with a dataset of 438,960 rows, rigorous feature selection and data processing yielded a final dataset of 1833 rows. Among the models, MLR achieved an R2 score of 0.991, closely matching the more complex MLP model, which reached an R2 score of 0.988. In contrast, the Decision Tree model demonstrated a lower R2 score of 0.923, suggesting a tendency to overfit. While MLR provided an effective, straightforward approach, MLP proved valuable for capturing non-linear patterns that could improve predictive accuracy in more variable tunneling conditions. These findings underscore the practical applications of both simple and complex machine learning models in enhancing TBM performance prediction.

Existing anchor solutions are limited in their applicability to the floating offshore wind industry, which demands prolonged load endurance in extreme weather conditions and varied seabed soils. This limitation restricts project feasibility and increases costs. In order to address these challenges, the Deeply Embedded Ring Anchor (DERA) is proposed to achieve substantial reductions in anchor costs through efficiency enhancements. Ensuring the long-term safety and reliability of the DERA, especially considering a minimum operational period of 25 years, necessitates a comprehensive understanding of fatigue damage. Induced by repetitive loading below material yield strength, fatigue poses a significant threat to structures exposed to waves and currents. Anchors, vital for station keeping, are susceptible to fatigue damage, particularly in the padeye area. This paper conducts a fatigue analysis, focusing on factors such as the wall thickness of the ring anchor, inner stiffeners, and stiffener thickness, to evaluate the performance of DERA in this context. The results showed that the stiffener significantly affects the elongation of the total life of the anchor. In conclusion, this paper focuses on advancing innovations like DERA, enabling the efficient utilization of offshore wind resources, and addressing safety concerns through meticulous fatigue analysis.

This study contributes to the quantitative understanding of kaolinite reactions with lime over two years. Unconfined Compressive Strength (UCS) increased linearly with time, doubling within one year, followed by a 14% decrease. Spectroscopic analysis of the system was performed at ten curing times (0, 7, 28, 90, 120, 180, 270, 360, 540 and 720 days) using Thermogravimetric Analysis (TGA), X-Ray Diffraction (XRD) and 2Nuclear Magnetic Resonance (NMR). Both TGA and XRD showed decrease of portlandite up to 180 days; complete consumption appears to have occurred by 270 days. TGA curves indicated an increase in hydration products in the first 360 days which followed a linear trend with UCS increase. No hydration products were observable by either XRD or NMR during that timeframe and no detectable changes in the kaolinite content either. After 360 days, growth in the hydrates in TGA slowed, and XRD, NMR showed a rapid increase of stratlingite (Ca2Al2SiO7∙8H2O) up to 720 days along with a decrease in the kaolinite signal. Collectively, these results point to two phases in kaolinite dissolution: the first phase, up to about 360 days, is incongruent, characterized by preferential release of Si or Al and portlandite consumption, leading to amorphous Calcium Silicate Hydrate (CSH) or an Afm phase, calcium monosulphoaluminate hydrate (CAH) formation. The second phase involves congruent dissolution and formation of Calcium Alumino Silicate Hydrate (CASH). It is hypothesized that CSH or CAH to CASH transformation occurs in the second stage, causing a disturbance in the cementitious matrix and loss in strength.

In this study, analysis of complicated underground structure of Horemheb tomb (KV57) at Luxor, Egypt by using the software PLAXIS 3D is adopted and the deformation that occurs in the body of the underground structure after applied the failure load detected; the failure loads are obtained from the series of laboratory tests. Then, the structure is modelled by using finite element code to perform accurate three-dimensional analysis of deformation and stability in complex geotechnical engineering and rock mechanics. These underground monumental structures have been analyzed by finite element method FEM to obtain the deformation that accrued into the structure and so beneath of the surface and calculated the effective stress, shear stress and horizontal displacements. In order to modeling requires the soil parameters obtained from laboratorial tests. In the analysis elastic–plastic Mohr–Coulomb model is used as material model. It involves five parameters namely, Young’s Modulus (E) and poison’s ratio (ν) for soil elasticity, friction angle (φ) and cohesion (c) for soil plasticity. To set up the boundary condition, the standard fixities option is used. As a result a full fixity at the base and free condition at the horizontal side of geometry are generated. Numerical Engineering analysis for Horemheb tomb (KV57) in the valley of kings at the west bank of Luxor was carried out through the following four main steps: (1) Evaluation of surrounding rocks (marl limestone and marl shale) by experimental research and Roclab program to obtain the Hoek Brown and Mohr- Coulomb fit classification criterion and rock mass standards in particular the global strength and deformation coefficient. Also to specify the main characteristics of the Esna Shale using different methods such as swelling test, swelling potential, swelling pressure, in addition, discussion of the role of the expansive Esna Shale in the deterioration of archaeological buildings and sites. (2) Quantitative and qualitative estimates of the relevant factors affecting the stability of the tomb, especially overloading, fixed, geographic, and dynamic. (3) Integrated 3D geotechnical modeling of the cemetery environment for stress and displacement analysis and identification of volumetric strains and plastic points using advanced symbols and programs such as PLAXIS 3D. (4) The rapeutic and retrofit policies and techniques and the fixed monitoring and control systems needed to strengthen and stabilize the cemetery, where the rock mass classification refers to the rock mass where KV57 is excavated and it is poor rocks. The mechanical behavior of the rocks is simulated by assuming a foundational model to soften the elastic stress of the flexible plastic that captures fragile failure and the mechanisms of progressive substrate failure. In addition, rock pillar treatments and ground support strategies are discussed. This article represents the second phase of the numerical analysis of KV57 using PLAXIS 3D.

Representative elementary volume (REV) is defined as the usual size of a rock mass structure beyond which its mechanical properties are homogenous and isotropic, and its behavior can be modeled using the equivalent continuum approach. Determination of REV is a complex problem in rock engineering due to its definition ambiguity and application area. This study is one of the first attempts to define a REV for jointed rock masses using the equivalent continuum approach. It is aimed to numerically search a ratio between the characteristic size of an engineering structure and pre-existing joint spacing, which are the two most important contributing elements in assessing REV. For this purpose, four hypothetical engineering cases were investigated using the RS2 (Phase2 v. 9.0) finite element (FE) analysis program. An underground circular opening with a constant diameter, an open-pit mine with varying bench heights, a single bench with a constant height, and an underground powerhouse cavern with a known dimension were executed for possible changes in the safety factor and total displacement measurements under several joint spacing values. Different cut-off REVs were calculated for FE models depending on the type of excavation and measurement method. An average REV size of 19.0, ranging between a minimum of 2 for tunnels and a maximum of 48 for slopes, was found in numerical analysis. The calculated sizes of REV were significantly larger than the range of values (5 to 10) commonly reported in the relevant geotechnical literature.