Deep Pit Research Articles

Numerical Simulation and Deformation Prediction of Deep Pit Based on PSO-BP Neural Network Inversion of Soil Parameters.

The finite element numerical simulation results of deep pit deformation are greatly influenced by soil layer parameters, which are crucial in determining the accuracy of deformation prediction results. This study employs the orthogonal experimental design to determine the combinations of various soil layer parameters in deep pits. Displacement values at specific measurement points were calculated using PLAXIS 3D under these varying parameter combinations to generate training samples. The nonlinear mapping ability of the Back Propagation (BP) neural network and Particle Swarm Optimization (PSO) were used for sample global optimization. Combining these with actual onsite measurements, we inversely calculate soil layer parameter values to update the input parameters for PLAXIS 3D. This allows us to conduct dynamic deformation prediction studies throughout the entire excavation process of deep pits. The results indicate that the use of the PSO-BP neural network for inverting soil layer parameters effectively enhances the convergence speed of the BP neural network model and avoids the issue of easily falling into local optimal solutions. The use of PLAXIS 3D to simulate the excavation process of the pit accurately reflects the dynamic changes in the displacement of the retaining structure, and the numerical simulation results show good agreement with the measured values. By updating the model parameters in real-time and calculating the pile displacement under different working conditions, the absolute errors between the measured and simulated values of pile top vertical displacement and pile body maximum horizontal displacement can be effectively reduced. This suggests that inverting soil layer parameters using measured values from working conditions is a feasible method for dynamically predicting the excavation process of the pit. The research results have some reference value for the selection of soil layer parameters in similar areas.

Residual stress and crystallite size analysis of SMAT on AA7075-T6

The study examines how SMAT influences the microstructure, dislocation density, and residual stress of AA7075-T6 alloy. SMAT involves the repeated impact of shots on a material surface within a vibration chamber, inducing severe plastic deformation and grain refinement. The study explores the interplay between vibration-induced shot effects and their impact on surface properties, emphasizing the importance of optimizing process parameters for improved material performance. Experimental analyses, including surface and subsurface microstructure examinations, X-ray diffraction (XRD) characterization, and residual stress evaluations, are conducted to elucidate the underlying mechanisms of SMAT. Results indicate that SMAT leads to significant plastic deformation, grain size reduction, increased dislocation density, and microstrain. The treatment produces a nanocrystallite layer, enhancing material properties. Residual stress measurements reveal a surface stress of −245 MPa, increasing to −360 MPa at 50 µm depth. The proposed multiple impact model accurately predicts deformation behavior, highlighting the deep pit regions formed during SMAT. This comprehensive investigation provides insights into the dynamic nature of SMAT and its potential for enhancing material properties. By integrating experimental findings with numerical modeling approaches, the study advances our understanding of SMAT-induced plastic deformation mechanisms and residual stress profiles.

A new metatherian (Mammalia) from the Itaboraí basin (Early Eocene), Brazil: Implications to trophic niche partitioning between large-sized “didelphoid-like” metatherians

The Itaboraí Basin, municipality of Itaboraí, Rio de Janeiro state, Brazil, preserved an Early Eocene vertebrate assemblage. Among its representatives, Metatheria comprises its most diverse clade, with a minimum of 29 genera and 43 species. Considering this diversity, large-sized taxa (based on didelphid standards, i.e., between 1 kg and 3.3 kg) are represented by Didelphopsis, Protodidelphis and Patene, each considered to have explored different trophic niches. However, the discovery of a new large-sized metatherian from this locality, here named Xenocynus crypticus gen. et sp. nov., indicates that the trophic complexity of Itaboraí’s metatherians could not be so well-defined. Xenocynus crypticus gen. et sp. nov. is identified by the presence of its reduced StD, long postmetacrista, short protocone, talonid's area much smaller than the one of trigonid, spaced paraconid and metaconid (bases are not in contact), molar series increasing in size from m1 to m4, deep maxillary pits between upper molars, and robust symphysis. We included Itaboraidelphys camposi, X. crypticus gen. et sp. nov. and other large-sized taxa in two PCA analyses, the first considering morphometric measurements and the second considering some morphofunctional indexes, to test their placement in morphospace. Our analyses indicated that these taxa exhibit distinctive morphometric and morphofunctional patterns, suggesting low trophic niches overlapping between them. The results indicate that X. crypticus gen. et sp. nov. was a generalized carnivore (insectivory-carnivory), more specialized than the insectivorous/omnivorous Itaboraidelphys camposi, but less specialized than the larger Patene simpsoni, a carnivorous taxon.

Improving mechanical property and corrosion resistance of high electrical conductivity Al-Ce-Sc-Y and Al-Mg-Si-Ce-Sc-Y alloys by laser shock peening

The high electrical conductivity Al-Ce-Sc-Y and Al-Mg-Si-Ce-Sc-Y alloys were used to study the effects of laser shock peening on their mechanical property, pitting and intergranular corrosion resistance. The strength and elongation of the alloys were improved simultaneously at the expense of very low electrical conductivity after laser shock peening due to the gradient structure and residual compressive stress. After two side laser shock peening, the strength and elongation of Al-Ce-Sc-Y and Al-Mg-Si-Ce-Sc-Y alloys increased to 231 ± 3 MPa/16.2 ± 0.2 % and 359 ± 3 MPa/17.1 ± 0.3 %, respectively. The samples with two surface states were used to study the corrosion behaviors. The number and depth of corrosion pits can be significantly reduced by laser shock peening and the crystallographic corrosion morphology exists in the corrosion pits. After two side laser shock peening with polished surface, the intergranular corrosion depth of Al-Mg-Si-Ce-Sc-Y alloy can reach the minimum and the intergranular corrosion cracks are much finer at the same depth. The Al-Ce-Sc-Y alloy had no tendency of intergranular corrosion, but the unpolished surface was prone to form the deep corrosion pits rather than occurred uniform corrosion. According to the microstructure analysis, the corrosion mechanism of pitting and intergranular corrosion was revealed.

Dark tourism goes underground: ghostly materialities of Japanese occupation in Datong, China

In north China, memorial museums are often associated with the suffering of victims of the Japanese occupation during the Second Sino-Japanese War (1931-1945). The Datong Coal Mine Massacre Site Memorial Hall affords visitors opportunity to bear witness to atrocities at the hands of the occupiers. At the 10,000 men pit (wanrenkeng), where over 60,000 miners perished, visitors gaze at the corpses of dead miners in two deep pits, at harrowing photographs of excavated remains and at unnamed spirit tablets in the memorial hall and on the hillside above. The research brings together the spectrality of absent presence with the Chinese tradition of hungry ghosts as social actors. Referencing the newly available North China Railway Archive of photographs taken by the Japanese of everyday life on the Datong coalfields, read through a lens inspired by Georges Didi-Huberman, we aim to enrich the state-authorised narrative of victimization and humiliation with narratives of individual people. The photographs summon the survival, or afterlife, of those depicted, sometimes smiling into the camera. We suggest that the photographic archive may afford identification of miners, enabling their lives to be honoured as well as mourned and their ghosts to be appeased. Collaborative development of a traditional Hungry Ghost festival could fold memorial sites together with intangible cultural heritage to offer visitors opportunity to commemorate both death and life through integrating history with culture.

Characteristics of the non-uniform corrosion of the steel bars extracted from the marine transportation infrastructures

This paper investigates the spatial morphological characteristics of non-uniform corrosion of reinforced concrete in coastal areas. A series of naturally corroded reinforced concrete specimens were retrieved from marine transportation infrastructure. Non-destructive tests were conducted by X-ray computed tomography (CT). The morphological propagations of the corrosion pits were explored, and the spatial distribution of non-uniform corrosion of the steel bars was analyzed in both longitudinal and circumferential directions. The results show that the non-uniformity of corrosion is related to both the corrosion degree and the morphology of corrosion pits. When the morphology of corrosion pits is similar, non-uniformity decreases exponentially with the corrosion degree of the steel bars. The morphologies of corrosion pits can be divided into two main categories: surficial corrosion pits and deep corrosion pits. The morphologies are related to the non-uniformity of the concrete surrounding the steel bar. When the corrosion degrees are similar, deep corrosion pits are more significant than surficial corrosion pits for the non-uniformity of the corrosion. The eccentricity was adopted to quantify the corrosion non-uniformity of bars with high corrosion degrees. These results provide a new perspective for evaluation on the non-uniform corrosion of steel bar in the marine transportation infrastructures.

Model Adaptation and Validation for Estimating Methane and Ammonia Emissions from Fattening Pig Houses: Effect of Manure Management System.

This paper describes a model for the prediction of methane and ammonia emissions from fattening pig houses. This model was validated with continuous and discrete measurements using a reference method from two manure management systems (MMS): long storage (LS) in deep pits and short storage (SS) by daily flushing of a shallow pit with sloped walls and partial manure dilution. The average calculated methane and ammonia emissions corresponded well with the measured values. Based on the calculated and measured results, the average calculated CH4 emission (18.5 and 4.3 kg yr-1 per pig place) was in between the means from the continuous data from sensors (15.9 and 5.6 kg yr-1 per pig place) and the means from the discrete measurements using the reference method (22.0 and 3.1 kg yr-1 per pig place) for the LS and SS systems, respectively. The average calculated NH3 emission (2.6 and 1.4 kg yr-1 per pig place) corresponded well with the continuous data (2.6 and 1.2 kg yr-1 per pig place) and the discrete measurements using the reference method (2.7 and 1.0 kg yr-1 per pig place) from LS and SS, respectively. This model was able to predict the reduction potential for methane and ammonia emissions by the application of mitigation options. Furthermore, this model can be utilized as a predictive tool, enabling timely actions to be taken based on the emission prediction. The upgraded model with robust calculation rules, extensive validations, and a simplified interface can be a useful tool to assess the current situation and the impact of mitigation measures at the farm level.

Изменение подхода к проектированию горнотехнических систем при открытой разработке месторождений на базе совершенствования принципов управления качеством горной массы

The main effect in transition of deep open pits to the In Pit Crushing and Conveying (IPCC) system of rock mass transportation is achieved through cutting the costs of rock mass hauling. Independence of the transportation system throughput from the haulage distance makes it possible to increase the boundary stripping ratio and extend the service life of the open pit. Transition from the cyclic to the In Pit Crushing and Conveying (IPCC) system of rock mass hauling still leaves insufficiently studied the issues related to assessment of the minimum commercial and cut-off grades of valuable components and contaminants in ores, the permissible thickness of the ore bodies when justifying the feasibility study of conditions, as well as management of the rock mass flow quality, optimization of the rock mass reduction ratio at the stage of its preparation for conveyor hauling from the open pit to the ore stockpiles and, further, to the ore hoppers of the processing plants, and many other challenges. The paper systematizes the results of other research by the authors as well as other data and it shows that the placing the crushing equipment and the belt conveyors within the boundaries of the open pit offers additional opportunities to manage the quality of rock mass flows, i.e. the ore mass and the overburden due to variations in the logistic and hauling schemes of the open pit due to transition to the In Pit Crushing and Conveying (IPCC) system. The above approaches to implementation of the rock mass haulage system in open pits remove the boundaries between mining and processing of minerals, expand the possibilities of targeted formation of technogenic deposits, and potentially expand the range of marketable products of the mining company. In fact, the mining and processing facility is considered as a unified technological process of the complete production cycle carried out in a single technological environment. Implementation of the proposed technological schemes will require changes in the regulatory and legal framework.

Ground-penetrating radar investigation of regolith thickness on a periglacial alpine summit flat, Uinta Mountains, Utah, USA

ABSTRACT Summit flats are low-relief, gently sloping landforms common in periglacial mountain environments. Apart from at their edges where summit flats are truncated by glacial headwalls and at their crests where isolated tors are occasionally present, bedrock is typically mantled on a summit flat by a continuous layer of regolith. This study applied ground-penetrating radar (GPR) to survey the thickness of regolith on a summit flat in the Uinta Mountains (Utah, USA). More than 500 m of GPR data were collected along transects extending from the edge of the summit flat to the crest, as well as adjacent to a deep soil pit. Results indicate that the regolith thickness is quite variable, with a mean of 91 ± 38 cm when calculated with an appropriate radar velocity. Because the ground surface of the summit flat is notably smooth, the variability in thickness is a consequence of irregularities in the bedrock surface at depth, which is significantly rougher. Recognition that regolith thickness can vary considerably beneath an alpine summit flat has implications for soil formation, carbon storage, and the transmission and storage of shallow groundwater, as well as evolutionary models for periglacial mountain landscapes.

The effects of trait and state anxiety on gait in healthy young adults.

Stable, personality-based (trait), and fluctuating, situational (state) anxiety have both been shown to consume attentional resources and reduce functional cognitive capacity, which may play a role in gait control. However, the role of attention in the relationship between trait and state anxiety has not yet been investigated formally. This study used a virtual reality-threat environment to evaluate whether changes in attention mediate the effects of state and trait anxiety on gait. Thirty adults aged 19-28 completed five walking trials in four conditions: (i) low threat-walking across a virtual plank (0.5m wide) on flat ground; (ii) low threat + dual task (auditory digit monitoring); (iii) high threat-walking across a virtual plank elevated above a deep pit; and (iv) high threat + dual task. Trait anxiety levels were determined by the State-Trait Anxiety Inventory, while state anxiety was captured using self-assessment manikins. Higher trait anxiety predicted slower gait velocity and longer time in double support in the high-threat condition compared to low-threat condition (i vs iii), but not when dual tasking, compared to single-task walking, in the absence of threat (ii vs i). Additionally, higher trait anxiety predicted increased step length variability in the high compared to low-threat dual-task condition. Overall, trait anxiety predicts a slower, more cautious gait pattern during threatening conditions while dual tasking during the threat.

Synergistic effects of melamine functionalized graphene oxide and imidazolium ionic liquid on the tribological performance and thermal stability of polyalphaolefin based hybrid nanolubricants

Tribological and thermophysical characteristics of a new hybrid nanolubricant that incorporates melamine functionalized graphene oxide (mGO) and imidazolium cation based ionic liquid (IL) in a polyalphaolefin (PAO-6) base oil have been investigated. Different formulations of nanolubricants with 0.05 wt%, 0.1 wt% nanosheets and 1 wt% ionic liquid were studied to examine the synergistic effects of surface functionalization and ionic liquid addition on the antifriction and antiwear properties of the PAO-6 base oil. Thermal stability studies involved Thermogravimetric analysis to analyze the oxidation onset and decomposition temperature of different formulatons at varying weight concentrations of nanoadditives. Anti-friction performance was quantified by the coefficient of friction (COF) reduction compared to neat lubricant. The highest reduction in COF was observed for 0.05 wt% mGO + 1 wt% IL with an outstanding 73.33% reduction followed by 0.05 wt% mGO and 0.05 wt% GO with 73% and 67% reduction respectively. Post-wear analysis of the wear scars was performed using 3D optical profiler, SEM micrographs, EDX elemental composition and Raman spectra. The highest reduction in wear depth was observed in the case of PAO-6 + 0.05% mGO with a value of 46.3% followed by a 39.9% reduction in the case of PAO-6 + 0.05% GO. The morphologies of samples containing both ionic liquid and nanosheets exhibited a much smoother surface with the absence of deep grooves and pits which was attributed to the formation of a strongly bonded tribofilm owing to the chemical interactions between ionic liquid capped nanosheets and metal substrate. Strong interfacial interactions also induced a significant increase in the thermal stability of the nanofluids. The maximum shift observed in the oxidation onset temperature compared to neat PAO-6 was 68◦C while the decomposition temperature increased by 61◦C. Due to their excellent friction, wear, and thermal properties, these hybrid nanofluids could be applied in various highly demanding industrial sectors such as automotive, machining operations, aerospace, thermal power plants and micro/nano-electromechanical systems.

Sustainable golden nanoflowers grafted food-waste derived biotemplate for the direct SERS-detection of carcinogenic herbicides from agro-farms

Surface Enhanced Raman Scattering (SERS) is emerging as a potent analytical tool for the detection of various pollutants in complex environments due to its distinctive vibrational fingerprint ability and pronounced detection sensitivity. Precautious of adverse blue-green economies and ecological impacts, sustainable generation of SERS active substrates and analyte casting matrices are getting prioritized. Herein, gold nanoflowers (AuNFs) of ∼75 ± 15 nm were initially biofabricated using an expended cell culture medium as a one-step synthesis cum stabilization strategy. Then the heavy architecture of multi-faceted AuNFs with deep pits and edges, that acted as hotspots for enhancing the localized electromagnetic fields, was utilized for the direct SERS detection of commonly used carcinogenic herbicides collected from agro-farms at nanomolar regimes with 0.44 ppm and 0.27 ppm for Glyphosate and amino methyl phosphonic acid, respectively. Such a low level detection is superior by 8.33% when compared to the reported values. Computational finite-difference time-domain (FDTD) simulations affirmed the enhanced SERS effect from the multi-faceted nanostructure of AuNFs with structural heterogeneities that provide numerous hotspots to amplify the localized electromagnetic field. More eminently, fish scale derived biotemplate through AuNF-analyte drop casting contributed to the exceptional intensities, attributed to the naturally grooved hierarchically porous hydrophilic lamellar structures contact angle of 73°. Overall, the adapted bioengineering of SERS substrate is safe, robust, affordable and reproducible, fostered by bioderived durable biomatrix offering potent sustainable SERS detection of various biomedically and environmentally relevant molecules.

Comparative Analysis of Techniques for Pit and Fissure Sealant Application to Reduce Microleakage.

Introduction In modern dentistry, the focus is more on preventing caries than on treating it, which helps preserve the tooth structure. Pit and fissure sealants (PFS) are the most effective methods for providing a mechanical barrier and avoiding the accumulation of dental plaque in deep pits and fissures, thereby preventing occlusal caries. The present study was conducted to compare the efficiency of dentin bonding agents (DBA) with or without fissurotomy in reducing microleakage before PFS placement. Materials and methods A total of 48 freshly extracted premolars were randomly divided into four groups as follows: Group 1, the conventional technique of PFS (Clinpro, 3M ESPE sealant); Group 2, fissurotomy performed before PFS placement; Group 3, Scotchbond Universal Adhesive (3M ESPE DBA) applied before PFS placement; and Group 4, fissurotomy along with DBA was used before PFS placement. The teeth were subjected to thermocycling followed by dye penetration using a 1% solution of methylene blue for 24 hours. All teeth were then assessed for microleakage by a qualitative method using a stereomicroscope at 40X and depth of dye penetration by image analysis. The Kruskal-Wallis test followed by Dunn's test was used for intergroup comparisons of microleakage scores, and ANOVAfollowed by Tukey's test was used for intergroup comparisons of the depth of dye penetration. These analyses were conducted using statistical software (SPSS version 22, Chicago, IL, USA). Results Statistically significant differences were observed between the groups in terms of the microleakage scores and depth of dye penetration (p<0.05). The group 4 showed a minimum microleakage score (0.50±0.52), and maximum scores were observed in Group 1 (2.16±0.71). Group 2 showed insignificant differences with groups 3 and 4 for depth of dye penetration (p>0.05). Statistically significant differences were observed between groups 1 and 2, groups 1 and 4, and groups 3 and 4 for the microleakage score (p<0.05). Conclusion Fissurotomy with or without DBA significantly reduced microleakage before the PFS placement. Prior use of fourth-generation DBA significantly reduced microleakage compared with PFS placement without the use of DBA.

Behaviour of redox-sensitive elements (Ti, As, V and Fe) in clay pit samples with and without Al normalization

Natural clay minerals, because of their physical and chemical characteristics are good adsorbents of metals. Among metals, heavy metals are often investigated, but redox-sensitive metals are increasingly getting attention. Redox-sensitive elements were measured in clay pit samples from a clay mine in Bosnia and Herzegovina. For the purpose of analysis, a 23 m deep clay pit core sample was taken, and it was randomly subsampled to give 45 clay pit samples from different depths. The pH, electrical conductivity (EC), oxidation–reduction potential (ORP) and redox-sensitive elements contents were measured. Amounts of redox-sensitive metals and aluminium were measured with an inductively coupled plasma optical emission spectrophotometry instrument. For statistical evaluation, maximum, minimum, average, median, Pearson's prior correlation, correlation applying Al normalization and centred log-ratio (clr) transformation were calculated. When justified, principal component analysis (PCA) was also performed. The results show acidic pH and oxidative ORP. EC varied significantly through the sediment. The element concentrations lie in the sequence: Fe &gt; Ti &gt; V &gt; As. There is a significant change in correlations with and without Al normalization. The highest difference was found for Ti and V (coefficient of correlation ( r ) value ranging from −0.553 to 0.835). Correlations and PCA after clr transformation showed mainly strong negative correlations, meaning that redox-sensitive elements behave differently in clay samples. Supplementary material: Graphical abstract is available at https://doi.org/10.6084/m9.figshare.c.7014329

River Gem Mining, its Impacts and Mitigation: A Case from Kumbukkan Oya, Monaragala Divisional Secretariat Area

Gem mining is one of the oldest industries and a major source of income in Sri Lanka. Both traditional and recent mechanical gem mining methods are currently being practiced. However excessive, uncontrolled and illegal gem mining activities have caused many adverse impacts. This study was carried out to analyze the environmental impacts of river gem mining and to propose suitable remedial and mitigatiory measures, with more emphasis on existing legal framework. Study was conducted along a 15 km stretch of Kumbukkan Oya in Monaragala Divisional Secretariat area, where both legal and illegal gem mining activities are taking place at a high intensity. Data were collected by spatial surveys, field surveys and interviews with mine-owners, government officials and general public. All observed mining sites were within the 60m area on both sides of riverbanks. More than 80.00% of the localities from 36 observed sites were unlicensed mines. Natural vegetation had been removed and banks were collapsed due to uncontrolled mining, destructing riverine and aquatic ecosystems. Deep pits were observed in riverbeds at 12 locations. Removed trees and debris were accumulated at the middle of the river, causing flow direction changes. Washing out of damaged banks and disturbances to the riverbed had increased river turbidity and siltation. High number of unlicensed mines, negligence of miners for license conditions, poor monitoring by relevant authorities, lack of cohesion in gem mining policies and laws and the lack of awareness have triggered these issues. Immediate cancellation of condition-violated mining licenses and initiation of legal actions against illegitimate mining activities are important in preventing unregulated mining activities. Systematic rehabilitation of damaged riverine vegetation and riverbanks shall be conducted. Issuance of mining licenses in compliance with the National Environmental (Prohibition of the use of equipment for exploration, mining and extraction of sand and gem) Regulations No.01 of 2006 in Gazette Extraordinary No.1454/4 dated 17.07.2006, demarcation of the ―Reservation Limit‖ of the river mentioned in the said Gazette Notification and obtaining Environmental Recommendations from Central Environmental Authority prior to issuing the license are important to avoid conflicts between the provisions of National Environmental Act and National Gem and Jewellary Authority Act. Issuance of licenses only subject to an acceptable rehabilitation plan submitted by the mine owners, continuous monitoring by relevant authorities and raising awareness among all the stakeholders shall be implemented. More comprehensive studies can be carried out to find the ability of implementing modern environmentally friendly mining technologies. &#x0D; Keywords: River gem mining, Impacts, Mitigation, Kumbukkan Oya

Effect of multiple factors on sediment erosion characteristics of hydro turbine materials

Hydraulic turbines on sediment-laden rivers suffer from cavitation-silt erosion. This study conducted cavitation-silt erosion tests on three materials (06Cr16Ni5Mo, Q355B, 06Cr20Ni11) with different sediment concentrations and impact velocities using a rotating disk facility, and used a scanning electron microscope (SEM) to observe the cavitation-silt erosion characteristics of the materials. The results show that the cumulative weight loss of all materials continuously increases with the sediment concentration and impact velocity rises. The weight loss of 06Cr16Ni5Mo is the lowest, and 06Cr20Ni11 is the highest. As the impact velocity rises, the cumulative weight loss increases exponentially. As the sediment concentration rises, there are obvious scour marks and fatigue spalling on the material surface. As the impact velocity rises, the size and depth of micro-cutting marks and cavitation pits increases. Due to the lower surface hardness of 06Cr20Ni11, the deep platelet pits appear on the material surface.

Study of the Mechanical Behavior of Retaining Structures and Adjacent Buildings during the Excavation of Deep and Long Pits

Excavation of deep and long pits can cause strata deformation and settlement of adjacent buildings. The excavation of a deep foundation pit of a nearby building in Zhengzhou City, China, is taken as the research object. The foundation of the foundation pit is an independent foundation under the column, the depth of the foundation pit is 24.5∼26.3 m, and the support form of an underground continuous wall and four internal supports is adopted. The stress and deformation characteristics of retaining structures during the construction of deep and long pits and their impact on the deformation of nearby buildings were studied through on‐site monitoring and finite element simulation. The analysis focuses on the effects of different excavation stages on adjacent structures, with the main conclusions as follows. After excavation, the underground continuous wall far from the building undergoes a “rotating‐kick” displacement, while the underground continuous wall on the side near the building only shows a “kick” displacement. Adjacent buildings have little influence on the distribution of shear force and bending moment of the underground continuous wall of the foundation pit. The first horizontal strut experiences pressure, gradually shifting to tension as excavation continues, with the maximum stress reaching 3.6 × 103 kN. The second, third, and fourth horizontal struts mainly bear compressive forces, increasing with the depth of the struts. The building primarily undergoes settlement in the early stages of deep and long pit excavation. As the excavation progresses, the building points near the pit begin to bulge, but the building corners far from the pit continue to show settlement. During the excavation of the deep and long pit, the differential settlement of the long side of the nearby building first decreases and then increases, and the differential settlement of the short side changes from a slight decrease to a significant increase. The settlement evolution of the building is as follows: overall settlement ⟶ overall uplift ⟶ uplift of the side of the building near the pit ⟶ outward tilting away from the pit. The findings may provide references for designing, constructing, and operating deep and large foundation pits.

Multi-criteria analysis of deep pits sustainable development strategy

Relevance. Long periods of development of steeply dipping deposits necessitate multiple adjustments of mining and technical system throughout an open pit life cycle. The decisions made determine the development strategy of a mining enterprise for a long period. The complexity of making such strategic decisions depends on numerous influencing parameters. These parameters have a different impact, have a variety of units of measurement, target values, and are not only quantitative but also qualitative. There is a need for new approaches to the choice of development strategy of the mining and technical system of an open pit, as well as its main subsystem – the opening-up of an opencast system. It is proposed to base these approaches on multi-criteria decision-making methods that consider many influencing parameters. Aim. Development of a methodology for choosing a strategy for sustainable development of the deep open pit mining and technical system based on multi-criteria decision-making methods and assessment of the opening system parameters. Objects. Mining enterprise, mining and technical systems, opening system. Methods. Literature review, system analysis, multi-criteria decision making. Results. The authors have determined the main strategies for development of the mining and technical system for deep open pits. These strategies aim at achieving the sustainable development of the mining and technical system: adjustment of the current stage mining parameters; transition to a new stage of mining; transition to a combined open-underground mining; mine closure. The key role of the opening system in the structure of the mining and technical system is substantiated to ensure its sustainable development. The authors systematized the main parameters for evaluating the pit opening system and set target values for each parameter. A review of the main multi-criteria decision-making methods used to solve various problems in the mining industry is made. A rank coefficient is proposed for choosing the mining and technical system development strategy. The calculation of this coefficient is based on a combination of the fuzzy AHP and CRADIS multi-criteria methods. A method was developed for selecting a strategy for sustainable development of the mining and technical system of deep open pits. A case study was conducted on the conditions of the Maly Kuibas open pit. The obtained results strongly suggest that the best strategy with the highest ranking is the transition to the combined development method.

Методика планирования экскаваторных работ в карьере на основе компьютерного моделирования

Introduction. In-pit excavators, which provide removal and loading of muck piles, are one of the main process links in the system of complex mechanization of open-pit mines. The level of mining operation intensity is determined by the arrangement of excavators in the open pit. Research objective. The research aims to develop a method of automated positioning of excavators at the production benches of the open pit mine. Methodology. Arrangement of in-pit excavators excavators at the production benches of the open pit mine is based on calculations, computer modeling and ia made with account of technical and operational parameters of the excavators, as well as estimation of the active front of mining operations. The main stage of solving the formulated problem is the construction of block models of the ore body, modeling of mining operations, and building a model of the open pit mine by the stages of the deposit development. Based on the results of block modeling, the optimal length of the excavator block at the production bench for the selected model of the face excavator is determined. Results. The article proposes a methodology for planning excavator operations in the open pit mine and positioning of the face excavators based on computer modeling of the mining operations progress with due account of the volume of rock mass handling on the open pit bench, the length of the active front, the mineral grade, the given rate of development, the accepted models of excavators and other attributive computer data. Based on the block model, the excavators are positioned on the production benches of the open pit mine. The proposed approach allows a prompt consideration of many options to arrange face excavators in the open pit ore mine in a semi-automatic mode and select the best option to increase the mining efficiency. Conclusions. The proposed methodology allows to promptly solve in a semi-automatic mode the issues of opening the lower levels of deep pits, to consider many options for placing face excavators in the ore pit and choose the best option, contributes to minimizing the operational risks in the development of complex-structured deposits and complex extraction of raw materials.

Research on the Applicability of Integrated Earth Lifting Machine for 500KV Transmission and Substation Project in Highland Area

In the power construction project, the tower foundation deep pit operation is a fundamental and important process, because of its operation point of the geological foundation structure complex and changeable, large amount of work, many dangerous factors and difficult to observe and identify, the construction is easy to cause safety accidents. State Grid Gansu Power Company has developed a set of intelligent equipment for deep foundation pit operation which is easy to operate, safe, reliable and complete in function, relying on the equipment to actively and timely discover the danger and early warning, and automatically take effective measures to strengthen the protection of personnel, crack the problem of safe operation of deep foundation pit and prevent the occurrence of infrastructure safety accidents. Since this project is located in the plateau area of Tibet, it is intended to study the applicability of the integrated deep foundation pit operation intelligent machine in the plateau area through this project. This project adopts "integrated deep pit operation intelligent machine"; this equipment is specially designed for a series of problems encountered in deep pits and other limited spaces, it integrates a number of practical functions: electric lifting, real-time gas detection, intelligent air supply, automatic sound and light alarm, emergency rescue, differential hanging point, soft ladder hanging point, lighting power, etc. It aims to protect the lives of construction personnel, improve the safety and reliability of construction, enhance construction efficiency, and is a kind of equipment with convenient transportation, installation and operation, diversified and integrated functions and intelligent control.