Engineering Conditions Research Articles

Determining the Stabilised Subfoudation Soil Deformation Modulus According to the Plate Load Tests and Geotechnical Monitoring Data

Introduction. The subsiding soils, which are widely spread in the south of Russia, create a number of problems and hazards due to the high probability of subfoundations subsidence in case of exceeding the values of initial soil moisture and initial pressure for subsidence. This is an important phenomenon to be considered at all life cycle stages of a building or structure, especially at the stage of design, when the scientifically justified design and technological solutions must be developed to ensure the reliable operation of facilities in the complicated engineering and geological conditions being studied hereby. The present article analyses the acting federal and regional regulatory and technical documentation in the field of buildings and structures design on the subsiding soils. Based on the numerical experiment, the incorrectness of the results sometimes received upon following the normative methodology is shown. A new calculating methodology based on determining the stabilised subfoudation soil deformation modulus according to the plate load tests and geotechnical monitoring data is proposed.Materials and Methods. The research comprised:– analysis of the existing approaches and methodologies for the subfoundations and foundations design on the subsiding soils;– numerical experiments, including calculations according to the normative methodology, which implied variation of the original data of both the initial properties of soils and technological parameters of stabilisation, as well as statistical processing of the results;– analysis of the carried out earlier by the authors geotechnical monitoring results of the buildings built on the stabilized soils and experimental study of the deformation properties using a patented device;– determining the main factors having influence on the design solutions for the subfoudation soils and building foundations strengthening under a complicated set of operational loads and establishing a new dependence of the stabilised soil deformation modulus on the initial soil deformation modulus and percentage of soil reinforcement.Research results. It has been established that the existing methodologies for calculating the stabilised subfoudation soils are not enough precise for determining the forecastable subsidence of buildings and structures, and the obtained design values do not always correspond to the factual deformations of subfoundations and foundations. The dependence of the stabilised subfoudation soil deformation modulus on the initial soil deformation modulus and percentage of soil reinforcement with the cement-sand mortar has been traced. A new calculating methodology has been developed based on determining the stabilised subgrade soil deformation modulus according to the data of the plate load tests using a patented device and geotechnical monitoring.Discussion and conclusion. It has been established that the deformation modulus of the soil mass stabilised by the cementation method depends non-linearly on percentage of soil reinforcement with the cement-sand mortar and the initial soil deformation modulus, and this dependence is described by a second-order surface equation of a general form. It is recommended to apply the discovered dependencies for designing the technological parameters of the subsiding soils stabilisation in the Rostov region conditions.

INCREASING THE BEARING CAPACITY OF SOFT WATER-SATURATED CLAY SUBGRADES ROADS

Problem statement. The restoration and development of Ukraine's infrastructure, the elimination of the consequences of the destruction caused by hostilities, and the post-war reconstruction of the country require, first and foremost, the restoration of the road and aerodrome networks in Ukraine, as well as civil and industrial facilities. For the smooth operation of infrastructure facilities located in difficult engineering and geological conditions, it is necessary to increase the bearing capacity of the foundations on which the restoration, reconstruction, construction or overhaul of these facilities is planned. Increasing the bearing capacity of soft, water-saturated clay soils is performed by traditional methods such as the use of geosynthetic materials or lime, as well as new alternative methods such as the addition of biopolymers. The purpose of the article is to analyze foreign experience in the use of effective and environmentally safe materials for consolidating and increasing the bearing capacity of soft water-saturated clay soils and justification of the feasibility of their use in Ukraine based on laboratory studies of soils with the addition of lime and a biopolymer, xanthan gum. Conclusion. An analysis of foreign methods for the use of lime and biopolymers to consolidate and increase the bearing capacity of soft water-saturated clay soils was performed. Studies on the selection of the concentration of lime and biopolymers in the soil mixture were analyzed. Laboratory experimental studies were conducted on soft water-saturated clay soils with varying soil liquidity index and lime content of 2−4 % and xanthan gum content of 2−4 %. The research results showed a significant reduction in deformations of soft soils when they are fixed with biopolymer.

Carrying Out Engineering and Geological Surveys for the Construction of an Access Road to the Taiynsha Station

The object of engineering-geological surveys, indicates the goals and methods of research are considered. The hydrogeological conditions of the site were studied. Exploration and field work, laboratory tests of the physical and mechanical properties of the soil were carried out. It was noted that engineering surveys were carried out taking into account the requirements of regulatory documents in force on the territory of the Republic of Kazakhstan. Conclusions are drawn. Engineering and geological surveys were carried out to obtain a comprehensive assessment of the engineering and geological conditions of the projected construction site, taking into account the specifics of the designed facilities

Применение искусственного интеллекта для обнаружения дефектов в строительных конструкциях

Monitoring the technical condition of structures is the most important task aimed at improving the reliability and safety of buildings and structures. During the survey, a set of tasks arises to assess visible defects and damages, the solution of which requires the experience and attention of structural survey specialists. Often the omission of visible defects is the most common mistake when examining the engineering and technical condition of a building. Technical vision, as a method of classifying objects in images, can significantly improve the efficiency of visual inspection and reduce the number of errors on the object. In this paper, an algorithm for detecting damage to reinforced concrete structures based on a convolutional neural network model created in the Python programming language is investigated. The neural network was trained and tested on real defects of a monolithic reinforced concrete building. According to the results of the work, the high efficiency of artificial intelligence in determining defects and damages in the framework of the survey of the engineering and technical condition of monolithic reinforced concrete structures of a building under construction was revealed. Automation of works on visual inspection of building structures is a promising direction for the development of artificial intelligence.

Construction practice of water conveyance tunnel among complex geotechnical conditions: a case study

The construction practice of water conveyance tunnels often encounters various complex geotechnical engineering conditions, which bring huge challenges to the design and construction of water conveyance tunnels. Based on the theory of rock elastic–plastic mechanics and finite element analysis technology, this article carried out investigations of engineering geological features, geological formations and hydrological conditions establishes a calculation model for the 3# water conveyance tunnel of the Fenhe River Diversion Project, and analyzes the variation law of surrounding rock stress and displacement during TBM excavation of the tunnel. The results indicate that the dominant direction of the rock mass principal stress measured by the hydraulic fracturing method is NE84°, and the maximum horizontal principal stress, minimum horizontal principal stress, and vertical stress decrease sequentially, analyzing the characteristics of shield TBM construction technology, it is applied to the construction of water transfer tunnels. The numerical simulation of TBM construction using FLAC3D software shows that as the excavation surface advances, the subsidence value of the tunnel roof first slowly increases, then rapidly increases, and then tends to stabilize. The horizontal displacement of the surrounding rock is increasing. The maximum principal stress of the surrounding rock gradually increases. The final surrounding rock stress is 35 MPa. The TBM shield machine with mud water balance driven by indirectly controlled frequency conversion motor is selected for TBM construction of the tunnel. The study offers statistical information to support tunneling technology for water conveyance in the geotechnical engineering practice.

Generative Artificial Intelligence GPT-4 Accelerates Knowledge Mining and Machine Learning for Synthetic Biology.

Knowledge mining from synthetic biology journal articles for machine learning (ML) applications is a labor-intensive process. The development of natural language processing (NLP) tools, such as GPT-4, can accelerate the extraction of published information related to microbial performance under complex strain engineering and bioreactor conditions. As a proof of concept, we proposed prompt engineering for a GPT-4 workflow pipeline to extract knowledge from 176 publications on two oleaginous yeasts (Yarrowia lipolytica and Rhodosporidium toruloides). After human intervention, the pipeline obtained a total of 2037 data instances. The structured data sets and feature selections enabled ML approaches (e.g., a random forest model) to predict Yarrowia fermentation titers with decent accuracy (R2 of 0.86 for unseen test data). Via transfer learning, the trained model could assess the production potential of the engineered nonconventional yeast, R. toruloides, for which there are fewer published reports. This work demonstrated the potential of generative artificial intelligence to streamline information extraction from research articles, thereby facilitating fermentation predictions and biomanufacturing development.

ANALYSIS OF DOMESTIC AND WORLD STANDARDS REGARDING THE CRITERIA OF THE BOUNDARY STATES FOR THE STEEL SILOS FOUNDATIONS

In the process of operation the structures of steel silos undergo various failures associated with natural and climatic loads and influences, the insufficient study of engineering and geological conditions, as well as some errors during operation. Damage to the above-ground structures of steel silos is mainly caused by roof structures and silo shells failures. Whilst operating silos, various types of raw material flow are distinguished during unloading. Possible scenarios of the operating technology violations can lead to deviations from the approved flow regime during unloading and they quite often become factors of an emergency situation. The conditions of loading and operation of silos have been compared pursuant to their presentation in the domestic and the foreign regulatory documents. A significant number of industrial accidents are associated with operation failures of reinforced concrete foundations, their insufficient load-bearing capacity and their deformability. It should be noted that the construction of the foundation affects its "flexibility", which may cause uneven settlement of the foundations and their base. Sometimes this leads to extra-design loads on the upper structure of the silo. In the domestic practice of increased diameters silos construction, the foundations with an underground gallery are the most common. For the construction areas having a high level of groundwater, the foundations with an above-ground under-silo storey are used. For the silos with an above-ground discharge funnel, the type of outflow influences the load pattern of the foundation. Whilst operating normally, the loads are uniform, and when the storage material hangs on the walls, the loads are uneven, which can lead to the destruction of the above-ground structure or a foundation tilting. The type of funnel significantly determines the shape of the outflow, which affects the distribution of internal forces in the silo and the load on the foundation. In this work, a brief analysis of the failure factors of steel silos has been carried out, and a comparative analysis of modern domestic and international design standards has been suggested concerning the criteria for the occurrence of boundary states of steel silos foundations during designing. There has also been analyzed the special operational features taking into account specific technological loads on silo shells and foundations, the certain features of engineering and geological conditions of construction sites. Conclusions have been made that the main criteria for foundations designing and calculating are the deformation criteria for limiting settlement and tilting. It should be noted that the foreign regulations place the issue of limiting maximum settlements within the scope of a designer's competence. Keywords: reinforced concrete foundation, steel silo, failure, boundary state, design norms.

Engineering and geological aspects in the museumification of architectural and archaeological monuments

Background. Tourism is an important economic sector, attracting a large amount of people to historical sites, including architectural and archaeological monuments. At present, the question of their museumification is resolved by considering their historical value and economic expediency. At the same time, the possibility of physically preserving the structures and materials of extant monuments is frequently ignored. Aim. To substantiate the need to study the engineering and geological conditions during museumification of architectural and archaeological monuments to predict their sustainable functioning. Materials and methods. The results of the authors’ long-term field and desktop research into the impact of engineering and geological conditions on the preservation of architectural and archaeological monuments during museumification were generalized and analyzed. Results. Two different scenarios were formulated for carrying out an engineering and geological assessment of the state of not only already museumified monuments, but also those that are supposed to be museumified in order to ensure their long-term, safe and manageable functioning as museums. Conclusion. The need to involve geologists in solving the question of museumification of architectural and archaeological monuments is substantiated. Examples of successful implementation of such a practice, which allowed emergency situations to be avoided, are provided.

Synchronized tracking control for dynamic positioning vessel

AbstractThis article addresses the time‐synchronized control problem for a floating liquefied natural gas (FLNG) vessel and a liquefied natural gas carrier (LNGC) in side‐by‐side offloading operation. For such a problem, the existing finite‐time control approaches available are essentially only designed to ensure that the system state‐variables converge within a certain time. Specifically how each state‐variable converges is typically not considered in the design process. Along this line, the approach of time‐synchronized design in this paper attains the more comprehensive and desirable outcome of having the marine vessels' state‐variables arrive at the sliding mode surface in a fixed time. Also additionally, the state‐variables converge at the same moment. This approach thus can attain synchronous tracking of the LNGC to the FLNG vessel. All these desirable properties and outcomes of control system convergence are rigorously proved in the work here via the methods of Lyapunov‐type theorems and associated stability analysis. Furthermore, in order to ensure that the approaches developed here are suitably applicable in real‐world engineering conditions (with system uncertainties and external disturbances), robustness extensions are also incorporated. In the presented work, the analytical issues and the methodologies in the designed control system solution under the conditions of the disturbed systems are discussed in detail. The numerical simulations conducted verify the merits of the proposed algorithm. Comparative numerical simulations on the developed scheme, and on traditional control, are carried out to demonstrate the important and improved outcomes attained with the time‐synchronized features.

Mathematical modeling of the geomechanical stateof a manufactured rock mass under the conditionsof seismic loading

The aim of the study is to predict the geomechanical stability of the bottom slope of the operating tailing dump PJSC ArcelorMittal Kryvyi Rihunder the conditions of the main and emergency load combination. Research methods. The geomechanical stability of the tailing dump bottom slope under seismic loading was assessed based on the results of numerical modeling of hydrodynamic and geomechanical processes using the Phase2 software package implemented on the basis of the finite element method for two-dimensional analysis of the stress-strain state of loaded rock masses. Research results. Based on the analysis and synthesis of data on geological, hydrogeological, engineering, geological and technical conditions of the tailings slope, a predictive assessment of the hydrodynamic regime of the tailings slope was performed in accordance with the adopted scheme of its expansion and the geomechanical stability of the tailings slope under the action of the main and emergency combination of loads was determined. Based on the results of the calculations, the measures and technical solutions aimed at ensuring the normalized stability of the tailing dump are substantiated. Scientific novelty. The dependence of the geomechanical stability of the hydraulic structure on the physical condition of the rocks stored in the tailings dump and the nature of their watering under seismic loading was established, which made it possible to substantiate measures to ensure the stability of the tailings dump's lower slope, which consist in organizing the efficient operation of individual structures and elements of the drainage system, as well as excluding the storage of rock material with reduced filtration permeability in the contour zone of the upper part of the tailings dump slope. Practical significance. The results of the performed research form the basis for substantiating technical solutions to ensure the stability of hydraulic structures under seismic loading.

Computational Modeling of Photo-Electrochemical Reduction of CO2 Utilizing Concentrated Light

Solar energy conversion of water and CO2 into H2/CO by an integrated photo-electrochemical (IPEC) cell and utilizing concentrated solar light allows for high power density and, if carefully designed, delivers high solar-to-fuel efficiency [1], [2]. In such devices, light absorption, charge generation/separation/transport, electrochemical reactions, and mass and ionic transport are required to occur simultaneously. Managing the coupled photon, charge, mass, and heat transport is central to a functioning and stable device. If not carefully designed, challenging operating conditions (high irradiation fluxes, critical thermal management) can induce irreversible damage to the IPEC cell and impact its performance. Thus, the optimal design of a high-performance device is conditioned by the development of a multi-dimensional and multi-physics computational model capable of estimating experimentally inaccessible quantities in complex porous geometries [3]. While such models have already been developed for water splitting, computational modeling of CO2 reduction under concentrated light is still missing.We present an IPEC cell computational model operating under highly concentrated radiation that accounts for both water splitting and CO2 reduction in a zero-gap gas diffusion electrode configuration. The continuum modeling is based on the solution of the coupled conservation and transport equations: species conservation and transport with electrochemical reactions, mass and momentum conservation, conservation and transport of electron and holes in the semiconductors, and Maxwell’s equations for the light propagation and absorption. We quantify spatially resolved non-uniform fields (local temperature, partial current densities, molar species fractions, etc.), inhomogeneities (e.g., local hotspots that could damage sealing), and CO2 conversion rates to demonstrate how such simulations can help to address engineering and operating conditions challenges. Finally, we show that the data obtained in experiments of an IPEC device operating under concentrated light are in agreement with our computational findings.Our simulations reveal that critical thermal management is required to improve IPEC cell efficiency. We provide evidence that challenging operating conditions (high solar irradiation concentration, low mass flow rate) can affect the CO partial current density, favor the competing hydrogen evolution reaction, lead to quartz window failure and decrease the photo-absorber efficiency.Overall, this work provides a validated multi-physics computational model of an IPEC cell operating with concentrated radiation that can be used to conduct feasibility studies and provide design guidelines for such thermally integrated IPEC devices for CO2 reduction at large solar irradiation concentrations. Keywords : Solar fuel, simulation, concentrated light, high power[1] S. Tembhurne, F. Nandjou, S. Haussener, A thermally synergistic photo-electrochemical hydrogen generator operating under concentrated solar irradiation, Nat. Energy. 4 (2019) 399–407. https://doi.org/10.1038/s41560-019-0373-7.[2] E. Boutin, M. Patel, E. Kecsenovity, S. Suter, C. Janáky, S. Haussener, Photo-Electrochemical Conversion of CO2 Under Concentrated Sunlight Enables Combination of High Reaction Rate and Efficiency, Adv. Energy Mater. 12 (2022). https://doi.org/10.1002/aenm.202200585.[3] S. Tembhurne, S. Haussener, Integrated Photo-Electrochemical Solar Fuel Generators under Concentrated Irradiation, J. Electrochem. Soc. 163 (2016) H999–H1007. https://doi.org/10.1149/2.0321610jes.

Mechanisms for Charge Selectivity on Semiconducting Photocatalyst Particles

Overall-water splitting on photocatalysts provides a direct-unassisted path in the conversion of solar energy to chemical energy. Optoelectronic properties (absorbing incident light with long excited state lifetimes) and carrier selective contacts (transporting and transferring the desired electronic carrier to the targeted redox active species) are two key parameters that govern photocatalyst behavior. However, the advantageous small geometry of the highest achieving photocatalysts makes measurement of their carrier selective contacts difficult. Additionally, several mechanisms that enable high energy-conversion efficiencies and large gradients in free energy manifest only at the nanoscale at individual nanoparticle sites. SrTiO3 has been extensively studied and shown to split water with high quantum yields when decorated with HER and OER catalysts. SrTiO3 is used, in this work, as a model system to study mechanisms for charge selectivity on overall-water splitting photocatalyst particles.Here, we use three sample geometries to measure local, facet, and catalyst-dependent, electrochemical driving forces and their synergistic enhancement of carrier selectivity, (single crystal planar (b), single crystal co-facet exposed planar (a), facetted nanoparticles (c) loaded with OER and HER catalysts [{Pt/CrO3, Rh/CrO3} and CoOOH respectively]). We use ex-situ conductive atomic force microscopy to individually interrogate the electrical properties of nano-scale catalyst/semiconductor junctions decorated on facet-engineered surfaces of SrTiO3. Supporting experiments of SECM and Operando AP-XPS will be used to measure the charge carrier selectivity when an electrolyte is present and connect the ex-situ characterization observations to operando conditions. In summary, these findings demonstrate the underlying mechanisms and the degree that they play, enabling directed research of photocatalyst systems under the two dominant engineering conditions, high optoelectronic properties and charge selective contacts. Figure 1

Study of the stress-deformation state of the soil base and foundations for equipment under significant horizontal loads

The study of the possibility of calculating foundations for stability against displacement along the sole and overturning under significant horizontal loads was carried out by the LIRA-SAPR computer software complex.
 The study was carried out by analyzing the amount of horizontal (sliding) and vertical (overturning) displacement of the foundation under the shunting winch under two variants of the engineering and geological conditions of the construction site.
 Through "manual" calculation, it was found that the stability of the foundation is ensured in the first variant of geological conditions, but not in the second one. Therefore, such geological conditions are illustrative for the study of calculation possibilities using the software complex.
 The foundation with width b=1.8 m, length l=4.2 m and height h=2.35 m is modeled by volume finite elements. The bottom layer, which is in contact with the soil base, is modeled by quadrilateral finite elements of the slab (slab on an elastic base).
 Friction under the footing is modeled by finite stiffness links (single-node finite elements) that are added at each node of the slab that models the bottom layer of the foundation.
 The stiffness of such finite elements in the direction of the global axis X and axis Y is determined automatically in the "GRUNT" system according to the methodology of SNiP 2.02.05-87.
 Summarizing the conducted research, we can say that the advanced capabilities of the LIRA-SAPR PC, in particular, the implementation of the algorithm for determining the stiffness coefficients of the base according to the SNiP 2.02.05-87 method, allow calculating foundations for resistance against displacement along the sole and overturning by numerical methods. This allows, firstly, to completely automate the calculation of the foundations, and secondly, during the automated calculation, the negative influence of the neighboring foundations is additionally taken into account, which is relevant, since the foundations for machines and mechanisms are mainly subjected to significant horizontal loads.
 In addition, the conducted research revealed the absence of a kinematic criterion for assessing the stability of the foundation. In manual calculation, the criterion for ensuring the stability of the foundation against displacement is the condition of static equilibrium. When calculating by the method of finite elements, implemented in PC "LIRA" and similar, displacements are decisive, so it is considered promising to study the issue of the criterion of stability of the foundation by displacements.

Comparison of experimental pile penetration force and calculated by regulatory documents

The paper studies the pile penetration force in engineering and geological conditions of Tomsk. The pile penetration method allows piles to be penetrated in urban conditions with a large number of historical buildings, which makes this work extremely relevant for Tomsk and other cities.The paper presents experimental data and theoretical calculations of the pile penetration in various districts of Tomsk. Theoretical calculations are based on several regulatory documents. Research results allow assessing the applicability of the proposed methods to engineering and geological conditions of Tomsk as well as identifying factors reducing the reliability this method. Recommendations are given for selecting methods to determine the pile penetration force, depending on the soil conditions at the construction site.

ASSESSMENT OF KARST-SUFFUSION HAZARD OF THE CHAYANDA–ESPO OIL PIPELINE IN YAKUTIA

Link for citation: Nechaev D.A., Strokova L.A. Assessment of karst-suffusion hazard of the Chayanda–ESPO oil pipeline in Yakutia. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 7, рр. 78-92. In Rus. The study is relevant due to the need to identify dangerous sections of oil and gas pipelines located in underdeveloped and sparsely populated areas, due to the development of dangerous geological processes. This study aims to assess the intensity and forecast the development of karst-suffusion processes within the pipeline route located in southern Yakutia, and to determine the most significant factors that activate this process. Methods: processing engineering and geological survey data, digitization of geological maps and decoding satellite images to build factor maps that affect the activation of the karst process: geological structure of the route; curvature, slope, surface exposure; map of surface drainage density and density of total tectonic fracturing. We created a map of the density of karst occurrences along the route according to the route survey and data from engineering and geological surveys during construction. We compiled a map of the susceptibility of the route territory to the development of karst-suffusion processes based on the Frequency Ratio method. Results. We carried out a description of the engineering and geological conditions of the pipeline route. To assess the karst-suffusion hazard of the pipeline route, calculations were made of the expected sizes of sinkholes in the base of structures using the method of G.M. Shakhunyants. Using the method of the ratio of particulars, the correlations between factors and foci of karst occurrences along the pipeline route were obtained. The susceptibility map developed on the basis of these results makes it possible to determine specific site boundaries for determining solutions for monitoring the development of the exogenous process and optimizing the pipeline operation processes. Therefore, the application of such methodology can be applied to other extended gas and oil pipelines located in difficult geological conditions.

Forecasting the Costs for Adapting the Housing Stock to Changing Permafrost Conditions (the Case of Norilsk)

The problem of predicting the socio-economic consequences of permafrost degradation due to climate change is an important area of modern scientific research. At the moment, there are no unified approaches and methods for assessing this type of natural risk, respectively, there is no reliable idea of the scale of possible consequences, which in turn is manifested in the poor elaboration of the issue in strategic planning documents for permafrost areas. The city of Norilsk (Krasnoyarsk krai) is an example of an Arctic city in Russia, located in the permafrost zone, where active work has begun on the housing stock renovation, including due to problems associated with the degradation of permafrost under the influence of anthropogenic and climatic factors. An analysis of legal documents related to the socioeconomic development of the city, renovation plans and documents aimed at solving the problem of replacing the deformed housing stock showed that the scale of measures does not fully correspond to the severity of the problem. A comparison of the key characteristics of the Norilsk housing stock, taking into account its current state and plans for transformation, with a long-term forecast of changes in engineering and cryological conditions until 2050, made it possible to estimate the total costs of adaptation, which can reach 1.6 trillion rubles in 2023 prices. In addition, a rating of Russian Arctic municipalities was compiled, based on the ratio of indicators characterizing internal adaptive capabilities to changing geocryological conditions and the amount of expected damage to the buildings and structures. It was found that, in general, the scale of the likely consequences significantly exceeds the available resources, and the most negative situation is already developing in the most depressed areas.

Fault Diagnosis With Robustness and Lightweight Synergy Under Noisy Environment

Over the years, deep learning-based fault diagnosis approaches have made remarkable progress. However, the diagnosis accuracy has been on a steady decline because of the noise interference in industrial applications. Additionally, the accuracy improvement is often accompanied by an increase in computational cost, which makes it difficult to achieve engineering-embedded deployment. To find the balance between robustness and complexity, a new intelligent fault diagnosis framework named lightweight multi-scale dilated causal convolutional attention network (Li-MDCCAN) is proposed. Based on dual fusion mechanisms, the proposed network realizes high robustness by adopting multi-scale strategy and attention modules, which explore multi-scale and multi-dimensional features along three parallel paths. Furthermore, lightweight convolutional blocks are introduced to reduce the network’s complexity. The performance of Li-MDCCAN is verified with six different datasets and compared with those of four advanced fault diagnosis networks. The experimental results indicate the effectiveness and superiority of Li-MDCCAN in increasing robustness and decreasing complexity. Moreover, prior sensor placement is discussed to guide applications under limited engineering conditions.

On Design and Assessment of Tail Void Grouting Material in Mechanized Tunneling: A Review

AbstractThe utilization of tail void grout as a stabilizing and sealing agent in mechanized tunneling procedures is of paramount significance, given the geological and engineering conditions inherent to tunneling projects. Prior to its application within a tunnel, a detailed evaluation of the fresh-state characteristics of the grout, as well as the time-dependent evolution of its hydro-mechanical properties, becomes imperative. This review paper aims to provide a comprehensive introduction to the various types of tail void grouting materials used in mechanized tunneling. The potential for behavior enhancement of the grout through the utilization of different additives, considering diverse mixing ratios in varying ground conditions, is discussed. Moreover, an in-depth analysis of the fresh- and hardened-state properties of different grout types, along with the cross-effects induced by additives in the grout mixture, is presented and reviewed. The paper also delves into the testing methodologies and property investigations employed to assess different grout types using experimental approaches. Additionally, a detailed overview of the numerical simulation of mechanized tunneling is provided, with a particular emphasis on the role of grout. Finally, the coupled hydro-mechanical effects of typical grout additives are explored, and the applicability of various grouting material according to the ground conditions is presented and discussed.

Floodwater utilization potential assessment of China based on improved conceptual model and multi-reservoir basin assessment method

Floodwater resource utilization is an important way to alleviate the water resources shortage in China. The quantitative assessment of the floodwater utilization potential under the current engineering conditions is vital for implementation of floodwater resource utilization. However, the imperfect conceptual model of floodwater utilization potential, the limited availability of reservoir engineering data, and the lack of universal assessment method that directly considers the reservoirs regulation capacity pose a major challenge to assessment of floodwater utilization potential in China. This study improves the universality of the previous conceptual model of floodwater utilization potential by analyzing the differences and connections of floodwater resources potentials under different states of utilization. The floodwater utilization potential assessment method for river basin with multi-reservoir was also proposed based on our previous assessment method for single reservoir controlled basin. The assessment method was used to evaluate the floodwater utilization potential of the first- and second-level water resources regions in China based on the reanalyzed monthly runoff data (1902 ∼ 2014) and large and medium-sized reservoirs data (as of 2015). Results indicate that the annual average total floodwater utilization potential of China was calculated as 668.62 billion m3 under the current reservoir regulation capacity, accounting for 34.05% of the total floodwater water resources in China. The study demonstrated that the frequency curve of floodwater utilization potential can provide a better understanding of the states of floodwater utilization, and the assessment method. Strategies for long-term floodwater utilization and flood control planning in different regions of China were also provided to government in our study.

Shear behaviour of anchored jointed rock mass under different engineering conditions considering damage and joint surface morphology

According to different geological conditions and engineering disturbance, three dimensional numerical models of anchored jointed rock mass with two kinds of boundary conditions of constant normal load (CNL) and constant normal stiffness (CNS) were constructed considering the ductility damage of rockbolt, the stiffness degradation of grouting layer and the joint surface roughness. The effects of anchorage angle, joint surface morphology, and boundary conditions on the shear performance of anchorage system were analyzed, and the failure characteristics under different working conditions were revealed. Finally, the analytical solution of shear strength of anchored system was established. Results show that the larger the anchorage angle is, the more serious the necking phenomenon of rockbolt will be. The damage degree of the bonding layer and the horizontal displacement of the bedding rock mass decrease with the increase of the joint surface roughness. The CNL condition is to instantaneously apply high normal stress, and the CNS condition is to gradually form a high normal stress environment through the superposition of increment on the basis of the initial value, which can resist greater transverse load. This is equivalent to enhancing the ductility of the rockbolt. The shear strength of the system increases with the increase of normal stress and normal stiffness. Ignoring the normal stiffness will underestimate the shear strength.