Displacement Patterns Research Articles

Quantification of immiscible displacement in a rough-walled fracture through direct visualization

Subsurface substance migration in the fractured rock aquifer is mainly controlled by fractures, and immiscible fluid-fluid displacement in fractures is important to many geophysical processes and engineering activities. Using a fracture-visualization system, we present the qualitative and quantitative assessment of fracture geometry associated with fluid movement and distribution in the rough fracture. Based on fracture geometry and statistical analysis, we first conducted a quantitative study of fracture surface roughness and aperture distribution. Then, fractal dimensions of displacement front and residual oil distribution were determined by image processing procedures. Influenced by wettability and micro-scale roughness, at the end of the displacement, residual oil saturation of molded sample is lower (6.45%–25.74%), and displacement pattern is more uniform, indicating that displacement effect is better. Due to smaller differences in residual oil saturation (9.08%) under different injection directions, the impact of wettability on the displacement process is greater than that of anisotropic roughness. Additionally, the fractal dimension of the displacement front increased under low injection rates initially but decreased when the rate was increased later. Overall, visualized temporal monitoring of experimental images enabled us to provide a preliminary assessment of the impact of anisotropic roughness and the material constituting the fracture wall on invading fluid saturation and the fractal dimension of the displacement front under various injection rates.

Networks of persistence: A new framework for protracted displacement from a Georgian lens

AbstractMillions of internally displaced people are living in their own countries in a temporary status called ‘protracted displacement’, a term not without its debates. We use a social network analysis database to assess how social interactions and demographic characteristics, including the relative location of resettlement, may contribute to IDP integration during the first 2 years of displacement. Our analysis of information from 57 internally displaced individuals in the aftermath of the 2008 Russo‐Georgian War, finds that networks of persistence, rather than survival or integration, characterize patterns of protracted displacement within 2 years of displacement. This suggests a need for rethinking the mainstream definitions to ensure vital resources are provided to displaced populations to promote timely integration.

Evolution of structural safety for tunnel arch crown linings under the coupled influence of void and insufficient thickness

The existence of voids behind tunnel linings constitutes a recognized inherent defect in tunnel engineering. Void and insufficient thickness can significantly compromise structural safety, especially at the tunnel arch crown. In this study, we employed similar model tests and numerical analysis methods to examine how the coupling of voids and insufficient thickness affects the structural performance of arch crown linings. Key findings reveal that the coupling of arch crown voids and insufficient thickness causes notable shifts in displacement patterns and internal force distribution. The displacement pattern of the arch shifts from the inner side to the outer side of the tunnel, resulting in the concrete stress state on the inner side of the arch crown changing to compression. Spatial distribution characteristics of voids and insufficient thickness defects were analyzed to assess their impact on structural degradation, with quantitative analysis using the safety factor index. Geometric parameters of voids and insufficient thickness (longitudinal length, thickness, circumferential range) were chosen based on analysis under various conditions to predict the structural safety factor using a Wide Neural Network regression model with 98 % accuracy. This method offers a new approach for rapidly predicting the safety status of lining structures. These findings are crucial for comprehending the effects of arch crown voids and insufficient thickness defects and for devising effective strategies to address tunnel lining defects.

Complex fault system associated with the Molucca Sea Divergent double subduction zone revealed by the 2019 Mw 6.9 and Mw 7.1 Earthquakes

GNSS (Global Navigation Satellite System) data in northern Sulawesi and western Halmahera reveals a pattern of coseismic displacement that was caused by the 7 July 2019 (Mw 6.9) and 14 November 2019 (Mw 7.1) Molucca Sea earthquakes. The coseismic slip of these earthquakes are obtained via inversion on rectangular fault planes of surface GNSS coseismic deformation offsets. The 7 July 2019 earthquake ruptured on an east-dipping fault with a maximum slip of ∼35 cm located at ∼4 km depth and ∼ 100 km north-west of the epicenter. The 14 November 2019 earthquake also ruptured on an east-dipping fault, which has a maximum slip of ∼64 cm located at ∼22 km depth and ∼ 20 km south-west of the epicenter. The coseismic slip distribution of the 14 November earthquake is spatially aligned to that of an earthquake of similar magnitude that took place on 15 November 2014 in the same region. This observation points to the possibility of synchronization, thus raising the prospect of a future earthquake exceeding magnitude 7. If the stress was completely released during the 2014 event, it would have been necessary to reload that portion of the fault at a rate significantly larger than the observed convergence rate of ∼5.8 cm/yr. This suggests that partial ruptures are likely controlling the recurrence time of large earthquakes in the region.

Photomonitoring as a Tool for Monitoring Landslides: A Technology within Everyone’s Reach

Landslides pose significant threats to human lives and infrastructure, making accurate monitoring essential for understanding and preventing these events. Photomonitoring, utilizing optical/multispectral sensors and digital image processing techniques, has emerged as a valuable tool for studying and monitoring landslide deformation processes. This article explores the application of photomonitoring in landslide studies, presenting three diverse case studies showcasing its efficacy and versatility. The technique allows for continuous, automated, and real-time monitoring of landslide events, providing valuable insights into displacement patterns and deformation trends. To enhance its usability, the software IRIS was developed to analyze data acquired from various platforms and sensors. This innovative solution promises to improve landslide management, contributing to better comprehension, prevention, and mitigation strategies, ultimately ensuring the safety of communities and infrastructure in landslide-prone regions.

Periosteum response to static forces stimulates cortical drifting: A new orthopedic target

The mechanism of cortical bone adaptation to static forces is not well understood. This is an important process because static forces are applied to the cortical bone in response to the growth of soft tissues and during Orthodontic and Orthopedic corrections. The aim of this study was to investigate the cortical bone response to expanding forces applied to the maxilla. Overall, 375 adult Sprague-Dawley rats were divided into three groups: 1) static force group, 2) static force plus stimulation group, and 3) sham group. In addition to static force across the maxilla, some animals were exposed to anti-inflammatory medication. Samples were collected at different time points and evaluated by micro-computed tomography, fluorescence microscopy, immunohistochemistry, and gene and protein analyses. The application of expansion forces to the maxilla increased inflammation in the periosteum and activated osteoclasts on the surface of the cortical plate. This activation was independent of the magnitude of tooth movement but followed the pattern of skeletal displacement. Bone formation on the surface of the cortical plate occurred at a later stage and resulted in the relocation of the cortical boundary of the maxilla and cortical drifting. This study demonstrates that cortical bone adaptation to static forces originates from the periosteum, and it is an inflammatory-based phenomenon that can be manipulated by the clinician. Our findings support a new theory for cortical adaptation to static forces and an innovative clinical approach to promote cortical drifting through periosteal stimulation. Being able to control cortical drift can have a significant impact on clinical orthodontic and dentofacial orthopedics by allowing corrections of severe deformities without the need for maxillofacial surgery.

The Role of Bone and Root Resorption on the Biomechanical Behavior of Mandibular Anterior Teeth Subjected to Orthodontic Forces: A Finite Element Approach.

This study was conducted to systematically evaluate the biomechanical impact of varying degrees of root and bone resorption resulting from periodontitis and orthodontic tooth movement (OTM) on the mandibular anterior teeth. The objective was to determine whether these distinct resorption patterns exert a specific influence on tooth displacement and strain patterns. A finite element (FE) model of an idealized anterior mandible from the first premolar in the third to the fourth quadrant was developed without bone or root resorption and a constant periodontal ligament (PDL) thickness of 0.2 mm. Variations included three root resorption levels (0%, 20%, 50%) and three bone resorption types (circular 50%, circular 80%, vestibular 80%). Models ranged from 200,000 to 440,000 elements and 55,000 to 130,000 nodes. Orthodontic forces, namely root torque (5 Nmm), intrusion (0.2 N), and distalization (0.5 N) were applied for subsequent crown displacement and PDL strain analysis. A total of 180 simulations were performed. Simulations showed that displacement was similar across different bone resorption conditions, irrespective of modeled root resorptions. Circumferential bone resorption increased tooth displacement, regardless of root resorption status. Vestibular bone resorption exhibited less increase in tooth displacement. However, when accompanied by root resorption, the combination exacerbated tooth displacement. Strains in the PDL clearly increased with a circumferential bone resorption of 80%. This study highlights the critical role of bone resorption in tooth displacement during OTM, particularly the challenges associated with circumferential resorption. Clinicians must consider both bone and root resorption for personalized medicine treatment of patients with severe periodontitis, in favor of low-force application strategies to optimize outcomes and minimize complications linked to excessive tooth displacement.

Insights into Afikpo Synclinorium structures: Subsurface analysis and intrusion outlining from airborne magnetic data

The airborne magnetic data over Afikpo Synclinorium were used to highlight subsurface structures and establish the orientations of tectonic features and their influence on the hydrocarbon play of the area. The characteristic trends of the lineaments were achieved through the center for exploration targeting of grid data analysis. The results of the TMI, residual magnetic field, first vertical, horizontal derivative, Analytic signal, and Tilt angle derivative classified the area into regions of high magnetic intensity observed around the northeastern, southwestern, and central portions of the study area. These areas characterized by anomalous signatures of short magnetic wavelengths delineate shallow magnetic sources. Conversely, regions with medium to low magnetic intensities are characterized by long magnetic wavelengths which indicates deep-seated magnetic source(s) and prospect for hydrocarbon (if other play concepts are emplace); due the thick sediment cover at the southern portion of the area (around, southern part of Nguzu, Ohafia, Biakpan, Abriba and Bende areas). The sediment thickness decreases towards north, west, North-east and north-west (dominated by Benue Trough deposit). Depth to the anomaly sources is of two categories, namely, shallow <1.0 km (dominated by NE trending structures) and deep ≥2.5 km. Ground-truthing confirmed the anomalous zone of high magnetic sources in the northeastern and central regions as Tertiary related tectonic-magmatic intrusion. The most prominent intrusion cuts across Amangwu Edda in Afikpo South through Amaeta-Oziza to Cross River State in a fissure form. This intrusion occurrence conformed to the high magnetic signature identified as a dolerite sill within the Afikpo Sub-basin. It stretches over 16 km in length with an average width of about 1.2 km, having its widest part in the northern parts of Mata Hospital Afikpo. The subsurface topographic model indicated that no fewer than 50% of the study area is characterized by sporadically distributed intrusive rocks. The result revealed several structural lineaments with high lineament density at the northcentral corner of the area trending NE-SW with fault lines (slip fault) perpendicular to it, offsetting the Akpoha, Ibii, Amasiri. and Ozara-ukwu ridges. The major drainage systems across the area followed major structural trends perpendicular to the identified major lineaments, passing through the major regional structural displacement pattern of the Basin. The emplacement of these intrusions might have impacted the hydrocarbon potential of the basin.

Tectonic geomorphology and paleoseismology of the Angelochori fault segment of the Anthemountas extensional detachment fault, Central Macedonia, Greece: Paleoseismic evidence from the 1677 CE earthquake

This study presents the results of a geomorphological and paleoseismological investigation on the Angelochori normal fault. This fault controls the southern boundary of the Anthemountas basin and constitutes the western segment of the Anthemountas extensional detachment fault (AEDF), a ∼48 km-long, E-W-trending, north-dipping low-angle normal fault in Central Macedonia, Greece. To assess the relative tectonic activity of the Angelochori fault and to determine the number, timing, and displacement of surface-faulting earthquakes, we conducted detailed field mapping and paleoseismological investigations. Our approach involved utilizing geomorphic indices, analyzing stratigraphic and structural relations, considering luminescence ages, and employing OxCal modeling techniques. The acquired data reveal, for the first time, the Middle-Late Holocene activity of the Anghelochori fault, providing constraints on the age of three strong (M > 6) surface-rupturing earthquakes over the last ∼7.7 ka. The youngest of these events aligns with the historical earthquake of the Anthemountas basin in 1677 CE. The observed minimum displacement per event ranges from 0.48 m to 0.65 m, consistent with a fault length estimated at about 24–28 km, suggesting an earthquake magnitude on the order of 6.6. The cumulative slip rate over the recorded period averages 0.21 ± 0.02 mm/a, with an average open recurrence interval of 2.6 ± 0.2 ka. Nonetheless, the displacement pattern displays alternating intervals of rapid slip at 0.60 ± 0.16 mm/a and slower slip at 0.08 ± 0.01 mm/a. Classified as Class 1, the Angelochori fault signifies an active tectonic structure posing a significant seismic hazard for the Thessaloniki metropolitan area.

Causal discovery reveals complex patterns of drought-induced displacement

The increasing frequency and severity of droughts present a significant risk to vulnerable regions of the globe, potentially leading to substantial human displacement in extreme situations. Drought-induced displacement is a complex and multifaceted issue that can perpetuate cycles of poverty, exacerbate food and water scarcity, and reinforce socio-economic inequalities. However, our understanding of human mobility in drought scenarios is currently limited, inhibiting accurate predictions and effective policy responses. Drought-induced displacement is driven by numerous factors and identifying its key drivers, causal-effect lags, and consequential effects is often challenging, typically relying on mechanistic models and qualitative assumptions. This paper presents a novel, data-driven methodology, grounded in causal discovery, to retrieve the drivers of drought-induced displacement within Somalia from 2016 to 2023. Our model exposes the intertwined vulnerabilities and the leading times that connect drought impacts, water and food security systems along with episodes of violent conflict, emphasizing that causal mechanisms change across districts. These findings pave the way for the development of algorithms with the ability to learn from human mobility data, enhancing anticipatory action, policy formulation, and humanitarian aid.

Radial displacement patterns of shear-thinning fluids considering the effect of deformation

Radial injection of shear-thinning fluids into rock fractures is ubiquitous in subsurface engineering practices, including drilling, hydraulic fracturing, and rock grouting. Yet, the effect of injection-induced fracture deformation on radial displacement behavior of shear-thinning fluids remains unclear. Through radial injection experiments of shear-thinning fluids displacing an immiscible Newtonian fluid in a Hele–Shaw cell, we investigate the fracture deformation behavior during injection and the fluid–fluid displacement patterns under this impact. A mixed displacement pattern is observed where the invasion front gradually evolves from unstable (viscous fingering) to stable (compact displacement) as the injection proceeds. We demonstrate that the combined effect of shear-thinning property and radial flow geometry plays a controlling role in the evolution of the patterns. At high flow rates, the fracture dilation induced by high injection pressure tends to reduce the displacement efficiency in stages. Based on linear stability analysis, we propose a theoretical criterion for the transition of interfacial stability considering the viscosity of injected fluids and fracture deformation, which agrees well with the experimental observations. This research underscores the importance of rock deformation on two-phase flow dynamics in fractured media.

Collapse Pattern in Gypseous Soil using Particle Image Velocimetry

Abstract Gypseous soil is prevalent in arid and semi-arid areas, is from collapsible soil, which contains the mineral gypsum, and has variable properties, including moisture-induced volume changes and solubility. Construction on these soils necessitates meticulous assessment and unique designs due to the possibility of foundation damage from soil collapse. The stability and durability of structures situated on gypseous soils necessitate close collaboration with specialists and careful, methodical preparation. It had not been done to find the pattern of failure in the micromechanical behavior of gypseous sandy soil through particle image velocity (PIV) analysis. This adopted recently in geotechnical engineering to track the motion of soil grains and using tracer particles by applying digital particle image analysis. It has also been used to study the displacement distribution in some cases of granular materials. Therefore, the goal of this study is to find out how gypseous sand medium moves when in contact with a rigid strip foundation that is under static stress and plane strain conditions. The experimental model would focus on two common types of wetting, namely water table rise and dry conditions. The PIV showed that the collapse pattern under the footing is of the type of punching shear failure. The predominant mechanism of soil deformation was the vertical compression of the gypseous granular soil. The results showed that understanding gypseous sandy grain displacement and failure patterns at the local scale is crucial for enhancing the design of foundations under static stress conditions.

Force and Deformation Characteristics of Large-Scale Zoning Excavation in Soft Soil: A Case Study in Hangzhou

The zoning excavation method is fully employed to control the deformation of foundation pits constructed in urban soft soil areas. However, the similarities and differences in forces and deformations between foundation pits excavated by the zonal method and those excavated by the conventional method still need to be further explored. In this study, the deformation was monitored and analyzed by taking the zonal excavation of a foundation pit of the ‘New World’ project in Hangzhou City as the research object. The measured results showed that the pre-built diaphragm wall for the first excavated foundation pit restricted the deformation of the first excavated diaphragm wall. The presence of extensive construction and unloading activities also changed the deformation pattern of the soil. Further, finite element simulations were carried out. The simulation results revealed that excavating the foundation pit first caused displacements in the pre-built diaphragm wall. The displacements transmitted by non-adjacent pits through the pre-built diaphragm wall were small and were concentrated at the junction of the two sub-pits. Adjacent foundation pits caused large displacements of the pre-built diaphragm wall with similar displacement patterns. The results of the study can provide effective guidance for foundation pit excavation in soft soil areas in the future.

Exploring Factors Influencing the Internal Displacement Decisions Amidst Natural Disasters in Bangladesh

Bangladesh, a densely populated country in the world’s largest coastal delta, is seriously threatened by the ongoing onslaught of major natural disasters brought on by climate change. The main perpetrators, cyclonic storms and floods cause millions of displaced people each year and increase the vulnerability of communities already facing devastation from the environment and poverty due to these disasters. This study explores the complex patterns of internal displacement brought on by cyclonic storms and floods in Bangladesh from 2008 to 2022. The study identifies the patterns, trends, vulnerable districts, and influencing factors of displacement by analysing data from multiple sources. Every year, an average of 6.14 million people are displaced by floods, a persistent problem. Gaibandha is the district most at risk, having seen 13 floods in the previous 15 years. Throughout the study period, Bhola experienced eight strikes from cyclonic storms that decimated the southern coast. These natural disasters force people to move from environmentally susceptible to safe areas. The disaster’s intensity or frequency and some economic, social, and political factors influence this decision to displace. The study also identifies factors that influence displacement decisions after catastrophic disasters. Additionally, it emphasises the importance of understanding displacement patterns and influencing factors to make informed decisions about displacement in such situations.

Analysis of the Flow of Offenders to the Metropolitan Region of Chile

This study, based on data from 2015 to 2019 on the movement of offenders to the Metropolitan Region of Chile, uses Poisson and Negative Binomial models to analyze the flow of offenders from other Chilean regions. It confirms that factors such as gender, educational level, location of crime, and type of crime significantly motivate displacement. The profile of the typical offender is an educated man who commits crimes against property on public roads, coming mainly from neighboring and populated regions. These findings have implications for crime prevention, suggesting that strategies to prevent crime should take this into account. Future research at the commune level is proposed for a more detailed understanding of offender displacement patterns and to inform local crime-prevention strategies.

Damage analysis and mechanical performance evaluation of frame structures in recycling

Research on the recycling of space frame structures is beneficial to reduce the waste of resources and has important engineering application prospects. Repeated disassembly tests were carried out on a full size space frame structure with bolt-ball joints. The maximum number of cycles was 3. The test results showed that with the increase of the number of cycles, the damage of joints and tubes gradually increased, the phenomenon of false tightening increased, and the construction efficiency decreased. After three cycles, the damage of high-strength bolts accounted for 16.56 % and the damage of steel tubes accounted for 5 %. Due to the component damage and construction deviation, the deformation and stress of the structure after unloading could not be restored to that before loading. However, within three cycles, the overall displacement and stress of the frame structure under general roof loads were almost not affected by component damage and construction deviation. Furthermore, the distribution pattern of displacement and stress was independent of the number of cycles. The maximum mid-span displacement of the structure was about 80 mm and the maximum difference of the overall stress level was within 10 MPa. Finally, according to the test results, the relevant engineering suggestions for the recycling of space frame structures were put forward.

Detection and Mechanical Interpretation of Surface Displacement by Volcanic and Anthropogenic Interactions around Bandung Basin, through Multi Temporal Interferometric SAR (MT-InSAR) Technique

Abstract This study aims to evaluate capability of MT-InSAR (Multi Temporal interferometric synthetic aperture radar) technique for measuring the surface displacement caused by tectonic, volcanic, and anthropogenic activity around the Bandung Basin, West Java, Indonesia. For this, persistent scatterer (PS), small baseline subset (SBAS), and combined PS and SBAS techniques are adopted. The results reveal different displacement patterns within two areas anthropogenic-caused subsidence in the middle Bandung city and geothermal production field, and volcanic-caused uplift in the northern area around the Tangkuban Parahu volcano. In addition, each InSAR tehnique shows unique spatial deformation. A significant pattern is located around the Wayang Windu geothermal field that large displacements has been occurred around injection, production wells. Those detected displacements are crucial for mitigating geological hazards as well as geothermal production monitoring.

Detailed analysis based on vertical and longitudinal deformations estimated from InSAR displacement by data assimilation

Application of a SAR satellite to Structural Health Monitoring (SHM) has attracted much attention due to its high efficiency. SHM using a SAR satellite doesn’t require installation of sensors and has the capability of monitoring wide area. However, the displacement obtained by a single SAR satellite is line-of-sight displacement which is not either vertical or longitudinal displacement. Thus, it is not easy to interpret line-of-sight displacement. This paper aims to solve this problem. The objective of this paper is to estimate longitudinal and vertical displacement from line-of-sight displacement and to analyze in detail a fallen water pipe bridge. For estimation of longitudinal and vertical displacement, data assimilation is employed. As a result of data assimilation, successfully observed line-of-sight displacement is reproduced. Negative correlations between displacements at piers and temperature are observed. A year prior to the bridge collapse, anomalous displacement pattern is observed at the centre of the span. In addition, deformation caused by damage is observed.

RC wall building structures: Comparison of first and second generation Eurocode 8 seismic design and detailing strategies

This study provides a thorough comparative analysis of structural design strategies across different ductility classes and seismic action levels, as outlined in Eurocode 8 provisions. The analysis is carried out for 5- and 10-storey building examples. The research highlights key findings regarding base shear demand, storey displacements, sensitivity coefficients, and other crucial structural performance parameters. Those findings indicate that while buildings designed for DCM and DC3 ductility classes generally exhibit similar base shear values and roof displacements, exceptions arise, particularly in the lower-storey buildings where DC2 demonstrates significantly lower roof displacements. The influence of strut inclination on design bending moments is also noted, underscoring its significance in structural behaviour. Moreover, the study delves into interstorey drift ratio (IDR) demands from analysis, revealing consistent displacement patterns across various structures with notable implications for deflection and stability. Additionally, insights into chord rotation control, sensitivity coefficients, and reinforcement quantities shed light on their behaviour under diverse seismic conditions, aiding in optimising structural design strategies.

Effects of different tooth movement patterns and aligner thicknesses on maxillary arch expansion with clear aligners: a three-dimensional finite element study.

The objective of this study was to investigate the biomechanical effects of different tooth movement patterns and aligner thicknesses on teeth and periodontal tissues during maxillary arch expansion with clear aligners, to facilitate more precise and efficient clinical orthodontic treatments. Three-dimensional models including teeth, maxilla, periodontal ligament, and aligner were constructed and subjected to finite element analysis. Tooth displacement trends and periodontal ligament stresses were measured for seven tooth displacement patterns (divided into three categories including overall movement of premolars and molars with gradually increasing molar expansion in each step; distributed movement of premolars and molars; and alternating movement between premolars and molars at intervals) and two aligner thicknesses (0.5mm and 0.75mm) during maxillary arch expansion with clear aligners. When expanding the maxillary arch with clear aligners, the effective expansion of the target teeth mainly showed a tilting movement trend. Increasing the amount of molar expansion increased the buccal displacement of the first molar but decreased the buccal displacement of the premolars. The mean buccal displacement of the target teeth was greater in the posterior teeth interval alternating movement group (0.026mm) than in the premolar/molar distributed movement group (0.016mm) and the overall movement group (0.015mm). Increasing aligner thickness resulted in greater buccal displacement of the crowns and increased stress on the periodontal ligaments. Increasing the amount of molar expansion reduces the efficiency of premolar expansion. Alternating movement of premolars and molars at intervals achieves a higher arch expansion efficiency, but attention should be paid to the anchorage of adjacent teeth. Increasing the thickness of the aligner increases the expansion efficiency but may also increase the burden on the periodontal tissues.