•Proposing a network theory for geotechnical structure deformations in 2D condition.•Accumulated errors of three relative nodes are less than 6% in calibration tests.•Recommending the rubber gasket ...as the point connection in practical applications.
The Brillouin optical time domain analysis (BOTDA) technology is gaining immense popularity and increasingly being utilised to measure strains in geotechnical structures. The deformations are usually determined by recording strains of selected points, from which the precaution and early warning of instability can be obtained. The errors of the measured strains using BOTDA are related to uncertainties in different connection methods and accumulated errors of the network in the monitoring zone. In this study, a network theory was derived first to measure the deformations of a geotechnical structure in two-dimensional (2D) condition. Next, two physical models (one with four nodes and the other with eight nodes) were established. The performance of the calculated deformations using the network theory based on the measured strains from BOTDA was examined and analysed by comparing the preset displacements from micrometres. From the test results, it is found that the stress concentration at the connection, which has a direct impact on the measured data, can be effectively reduced when using the rubber gasket. There is a good agreement between the calculated deformations and the preset displacements. The accumulated errors are less than 6% for three groups of relative stable nodes, which demonstrates that the proposed network theory can be well utilised in various fields and practical applications that require high precision.
Geomaterials comprise naturally formed materials through geological processes, such as soils and rocks, or artificially processed materials, including mineral waste and geosynthetics. These materials ...find extensive use in geotechnical structures, such as slopes, dams, and pavements, among others. However, two issues commonly arise in earthworks: the materials available in the region do not meet the minimum engineering requirements, resulting in high transportation costs, and the exploitation of new deposits increases environmental impacts. Consequently, there is a need to develop stabilization and reinforcement techniques aimed at creating new geomaterials (NGs) to expand the range of local material applications. In this context, the present study evaluates the key success factors (KSFs) related to the application of NGs in geotechnical structures. The Delphi method was employed through a structured questionnaire developed after an extensive literature review. Brazilian experts from the public, private, and academic sectors were selected to identify the obstacles and potential pathways for the practical application of NGs. The outcomes of the study indicated that the lack of standardization, the complex behavior of geomaterials under varying conditions, as well as technical and economic limitations serve as barriers impeding the widespread adoption of NGs. Finally, a roadmap proposal was devised, encompassing a series of actions intended to facilitate the broader utilization of NGs.
Effective grounding is the most important aspect in every electrical installation because it can ensure efficient equipment operation in the event of electrical faults. Measurement data of soil ...resistivity is used to assess the suitability of the soil for grounding purpose and also to evaluate the structures of the soil. However, the limitation of soil resistivity measurement is various investigations on two‐layer soil structures cannot be performed due to the variation of natural soil structures is limited. Therefore, in this work, modelling of soil resistivity of two‐layer soil structures was proposed using finite element analysis method to estimate the depth of upper layer of non‐homogeneous soil based on the measurement results from Wenner and Schlumberger methods. Also, using the proposed method, the effect of soil resistivity of each layer on the overall two‐layer soil resistivity was investigated. To validate the results obtained from the proposed method, comparison between the FEA results and measured field data was made. It was found that the average error between both results is <3%. From the model that has been developed, the soil properties can be varied, which enhances the information that can be obtained from two‐layer soil structures.
Evaluating the seismic security of enormous structures is extremely vital, and this concern has continually motivated the trends of refined numerical simulations for years. However, the ability to ...perform a concurrent global refinement analysis of large-scale projects with complex spatial geometries and spanning huge scales has remained a formidable challenge in settings such as high concrete-faced rockfill dams. In this paper, a global concurrent cross-scale nonlinear analysis approach (GCCNA) benefitting from an efficient hybrid octree-based discretization technique is presented. Significantly, a polygon interface is constructed to automatically connect the cross-scale element and solve the interactions between the concrete-faced rockfill and foundation. A viscoelasticity polygonal artificial boundary element is subsequently developed to render the influence of radiation damping on an infinite foundation so that the travelling wave effect on the dynamic response and stabilization can be captured. A high-efficiency and economically time-consuming solution strategy is adopted, wherein the scaled boundary finite element is introduced to manage the minority polyhedrons in the generated octree model, and the numerous hexahedrons are assigned to the isoparametric element. The features of rapid discretization, high flexibility, extraordinary grid reconstruction and coupling with the conventional finite element are contained perfectly, which are demonstrated via the comprehensive elasto-plastic dynamic simulation of an extremely complicated practical constructed highest rockfill dam. The proposed approach has attractive potential and practicability for the efficient refinement analysis of complicated enormous engineering structures and can be readily extended to subterranean structures, nuclear plants, and architectural and aviation structures.
•A Global Concurrent Cross-scale Nonlinear Analysis approach (GCCNA) is presented.•Concurrently meticulous mesh is generated automatically fastly for mega projects.•Versatile polygon interface and viscoelasticity artificial boundary are explored.•High efficiency and economic time-consuming SBPFE-FEM solution strategy.
This paper aims to develop an efficient geotechnical reliability-based design (RBD) approach using Monte Carlo simulation (MCS). The proposed approach combines a recently developed MCS-based RBD ...approach, namely expanded RBD approach, with an advanced MCS method called “Subset Simulation (SS)” to improve the computation efficiency at small probability levels that are often concerned in geotechnical design practice. To facilitate the integration of SS and expanded RBD, a generalized surrogate response f is proposed to define the driving variable, which is a key parameter in SS, for expanded RBD of geotechnical structures (e.g., soil retaining structures and foundations). With the aid of the proposed surrogate response, failure probabilities of all the possible designs in a prescribed design space are calculated from a single run of SS. Equations are derived for integration of the surrogate response-aided SS and expanded RBD, and are illustrated using an embedded sheet pile wall design example and two drilled shaft design examples. Results show that the proposed approach provides reasonable estimates of failure probabilities of different designs using a single run of the surrogate response-aided SS, and significantly improves the computational efficiency at small probabilities levels in comparison with direct MCS-based expanded RBD. The surrogate response-aided SS is able to, simultaneously, approach the failure domains of all the possible designs in the design space by a single run of simulation and to generate more complete design information, which subsequently yields feasible designs with a wide range of combinations of design parameters. This is mainly attributed to the strong correlation between the surrogate response and target response (e.g., factor of safety) of different designs concerned in geotechnical RBD.
With increasing awareness about environmental sustainability issues, the geotechnical engineering community is in search of sustainable materials, innovative applications and ground improvement ...technologies which are resilient to climate change, involve low carbon emissions, are ecologically friendly and affordable, yet effective. As such, this reprint brings together 18 novel contributions providing the state-of-the-art in “Sustainable Geotechnics” with special focus on the reuse and recycling of waste materials in geotechnical applications as well as sustainable design, construction, and monitoring of the performance of geostructures. This reprint may be of particular interest to geotechnical professional engineers and researchers who are facing the challenging task of increasing the sustainability and resiliency of geotechnical assets and infrastructures.
Road Tunnels are an important part of the current road transportation infrastructure. As the main form of tunnel lining diseases, cracks are easy to interact with other areas, which seriously affects ...the safe operation of the tunnel. Due to the similarity of brightness and linearity between surface cracks and lining cracks, the existing crack detection algorithms can not extract cracks accurately and quickly. An algorithm of lining seam crack elimination with rectangular mark is proposed here. First, the line segments in the image are detected by the Line Segment Detector algorithm based on the coarse percolation detection of the crack. Second, the distribution directions are calculated, and cracks from the lining seams are distinguished by the adaptive threshold judgment method. Third, by using the distribution characteristics of pixels, the line segments are extended to form rectangular marks perpendicular to the direction of lining seams. Finally, the marking information is used to remove the lining joints and obtain the real surface cracks of tunnel lining. Experimental results show that the algorithm can quickly and effectively remove any shape distribution of lining seam. The algorithm fills in the blank of concrete tunnel lining surface crack detection technology.
Scale modelling should be a very useful strategy for the design of lunar structures. Preventing structural damages in the lunar environment is crucial and scale models are helpful to achieve this ...aim. The size of these models must be scaled to take into account the different gravitational levels. Since the lunar gravity acceleration is about one-sixth of the terrestrial one, it follows that the models on Earth will be very smaller than the prototype to be realized on the Moon. This strategy will represent an opportunity for engineers working on lunar structure design, provided that the errors, both computational and experimental, related to the change of scale are quantified, allowing reliable extension of the physical scale modelling results to the prototype. In this work, a three-dimensional finite element analysis of walls retaining lunar regolith backfill is described and discussed, in order to provide preliminary results, which can guide a future experimental investigation based on physical scale-modelling. In particular, computational errors related to the scale effects are assessed, with respect to a virtual prototype of the lunar geotechnical structure, and compared with errors from other sources of discrepancy, like the adopted constitutive model, the variability of the geotechnical parameters and the calculation section used in the 3D analysis. The results seem to suggest the soundness of this strategy of modelling and are likely to encourage new research, both numerical and experimental, supporting the structure serviceability assessment.
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