Joint Sets Research Articles

System reliability analysis of foundation stability of gravity dams considering anisotropic seepage and multiple sliding surfaces

PurposeFor gravity dams built on foundations with directional joint sets, the seepage in the foundation possesses anisotropic characteristics and may have adverse effects on the foundation stability. A methodology for system reliability analysis of gravity dam foundations considering anisotropic seepage and multiple sliding surfaces is proposed in this paper.Design/methodology/approachAnisotropic seepages in dam foundations are simulated using finite element method (FEM) with the equivalent continuum model (ECM), and their effect on dam foundation stability is involved by uplift pressures acting on the potential sliding surfaces. The system failure probability of the dam foundation is efficiently estimated using Monte Carlo method (MCM) combined with response surface method (RSM).FindingsThe case study shows that it is necessary to consider the possibly adverse effect of anisotropic seepage on foundation stability of gravity dams and the deterministic analysis of the foundation stability may be misleading. The system reliability analysis of the dam foundation is justified, as the uncertainties in shear strength parameters of the foundation rocks and joint sets as well as aperture, connectivity and spacing of the joint sets are quantified and the system effect of the multiple potential sliding surfaces on the foundation reliability is reasonably considered.Originality/value(1) A methodology is proposed for efficient system reliability analysis of foundation stability of gravity dams considering anisotropic seepage and multiple sliding surfaces (2) The influence of anisotropic seepage on the stability of gravity dam foundation is revealed (3) The influence of estimation errors of RSMs on the system reliability assessment of dam foundation is investigated.

Performance of exterior beam-column connections with innovative bar anchorage schemes: Numerical investigation

Proper detailing of the joint reinforcement is essential for achieving an optimum framing action of the connected members. The ACI 352R-02, ACI 318–19 and EC-8 codes specify minimum requirements for the components of the standard 90-degrees hook; horizontal part, bend, and vertical tail as a reliable detailing alternative for achieving satisfactory performance of the joint. This numerical study aims to investigate the optimum tail length needed for ensuring adequate performance of the exterior joint and to develop a measure for the joint shear strength under various vertical tail length conditions, utilizing two experimentally tested joints with different reinforcement details as reference. The impact of a wide range of vertical tail lengths on the joint’s ultimate strength has been evaluated. It has been found that the provided tail length governs the joint's ultimate shear strength, where providing a vertical tail length of thirty times the bar diameter or greater achieves the superior performance, which is attributed to the improved confinement to the joint and the better bond condition in the joint region. However, the available column depth determines how the vertical tail length affects the joint strength, where the influence is more significant for joints with narrow depth columns. Thus, this study reveals that the dependence on increased vertical tail length, as a non-conventional alternative, can be safely considered to ensure sufficient joint shear strength, especially in joints with narrow depth columns. Hence, the limits of tail length given by several international codes; e.g., ACI 352R-02, ACI 318–19, and EC-8, are inadequate. Furthermore, an accurate equation for predicting the joint shear strength has been developed based on an extensive parametric study on various sets of exterior joints, taking into account the tail length under various conditions of column depths, joint aspect ratio, column axial stress, and the concrete strength.

Caves in clastic rocks (Muğla, SW Türkiye)

Caves evolution is controlled by lithological properties, discontinuities, water, climate, and physico-mechanical properties of soluble rocks, vegetation and human impact. This study investigates the cave formation in Upper Miocene-Pliocene clastic rock in Menteşe town of Muğla. The lithology, physico-mechanical properties and hydrogeologic factors of host rocks and morphology of the caves in Asar Hill and Damlam stream valley were examined. The caves are 1.47-9.71 m long, 2.24-19.36 m wide and 1.38-27 m high. Four joint sets and bedding planes affect the clastics in the Asar Hill area. Mudstones (low plasticity clay, sandy clay) are in soft-very soft rock, while conglomerate is in moderate-hard rock class. The mudstone removal has started the formation of the caves. The vegetation roots act as groundwater circulation paths in the Damlam stream area. Water has eroded mudstone and muddy matrix of conglomerate following cracks and led to the formation of the caves. Water infiltration may have led to stalactite, flowstone and travertine formation in Damlam stream caves. Possible cave collapse could threaten life and property in the Asar Hill area, and may cause the destruction of internal structures of the caves in the Damlam stream. Thus, precautionary measures such as continuous monitoring and protection must be taken in both cave areas.

Influence of Longitudinal Joint Setting and Synchronous Cooling Zone on High Altitude Region’s Dam Construction

The crack problem in mass concrete is a difficult problem to thoroughly solve, especially for the crack of dam construction in high-altitude regions. High altitude regions have the fundamental features of a dry climate and strong solar radiation. When dam construction is performed under these special climate conditions, temperature control and crack prevention become more difficult problems. Based on the high altitude region’s dam construction conditions, the existing temperature control measures were optimized by combining the three-dimensional finite element method. The synchronous cooling zone’s temperature control technique is adopted to lower the temperature gradient in the dam’s height direction, coordinate the deformation of the upper and lower layers, and reduce mutual constraints between the upper and lower layers to further reduce the temperature stress. Calculation results show that the adoption of synchronous cooling zones and the set of longitudinal joints can effectively reduce mutual constraints, increase the safety factor, and prevent cracks. This method can be considered an important reference to dam projects in high-altitude regions.

Morphology of Dome- and Tepee-Like Landforms Generated by Expansive Hydration of Weathering Anhydrite: A Case Study at Dingwall, Nova Scotia, Canada

The gypsum-anhydrite rocks in the abandoned quarry at Dingwall (Nova Scotia, Canada) are subjected to physical and chemical weathering, including hydration of the anhydrite, i.e., its transformation into secondary gypsum under the influence of water. This process is known to lead to the localized volume increase of the rock and the formation of spectacular hydration landforms: domes, tepees and ridges. Cavities appearing in the interior of these domes are often unique hydration caves (Quellungshöhlen in German). For the first time, this paper gives detailed geomorphometric characteristics of the 77 dome- and tepee-like hydration landforms growing today at Dingwall based on their digital surface models and orthophotomaps, made with the method of photogrammetry integrated with direct measurements. The length of hydration landforms varies from 1.86 to 23.05 m and the relative height varies from 0.33 to 2.09 m. Their approximate shape in a plan view varies from nearly circular, through oval, to elongated with a length-to-width ratio rarely exceeding 5:2. Length, width and relative height are characterized by moderate mutual correlation with proportional relations expressed by linear equations, testifying that the hydration landforms generally preserve the same or very similar shape independent of their sizes. The averaged thickness of the detached rock layer ranges from 6 to 46 cm. The size of the forms seems to depend on this thickness—the forms larger in extent (longer) generally have a thicker detached rock layer. Master (and other) joints and, to a lesser extent, layering in the bedrock influence the development of hydration landforms, particularly by controlling the place where the entrances are open to internal cavities or caves. Three structural types of the bedrock influencing the growth of hydration forms were recognized: with master joints, with layering and with both of them. The latter type of bedrock has the most complex impact on the morphology of hydration landforms because it depends on the number of master joint sets and the mutual orientation of joints and layering, which are changeable across the quarry. The durability of the hydration forms over time depends, among others, on the density of fractures in the detached rock layer.

Gravity-based patterning of osteogenic factors to preserve bone structure after osteochondral injury in a large animal model

Chondral and osteochondral repair strategies are limited by adverse bony changes that occur after injury. Bone resorption can cause entire scaffolds, engineered tissues, or even endogenous repair tissues to subside below the cartilage surface. To address this translational issue, we fabricated thick-shelled poly(D,L-lactide-co-glycolide) microcapsules containing the pro-osteogenic agents triiodothyronine and β-glycerophosphate, and delivered these microcapsules in a large animal model of osteochondral injury to preserve bone structure. We demonstrate that the developed microcapsules ruptured in vitro under increasing mechanical loads, and readily sink within a liquid solution, enabling gravity-based patterning along the osteochondral surface. In a large animal, these mechanically-activated microcapsules (MAMCs) were assessed through two different delivery strategies. Intra-articular injection of control MAMCs enabled fluorescent quantification of MAMC rupture and cargo release in a synovial joint setting over time in vivo. This joint-wide injection also confirmed that the MAMCs do not elicit an inflammatory response. In the contralateral hindlimbs, chondral defects were created, MAMCs were patterned in situ, and nanofracture (Nfx), a clinically utilized method to promote cartilage repair, was performed. The Nfx holes enabled marrow-derived stromal cells to enter the defect area and served as repeatable bone injury sites to monitor over time. Animals were evaluated one and two weeks after injection and surgery. Analysis of injected MAMCs showed that bioactive cargo was released in a controlled fashion over two weeks. A bone fluorochrome label injected at the time of surgery displayed maintenance of mineral labeling in the therapeutic group, but resorption in both control groups. Alkaline phosphatase (AP) staining at the osteochondral interface revealed higher AP activity in defects treated with therapeutic MAMCs. Overall, this study develops a gravity-based approach to pattern bioactive factors along the osteochondral interface, and applies this novel biofabrication strategy to preserve bone structure after osteochondral injury.

“Hyperfeedback” as a Tool to Assess and Induce Interpersonal Synchrony: The Role of Applied Social Neurosciences for Research, Training, and Clinical Practice

In the last 25 years, the field of neuroscience has seen exponential growth due to technological advances, which have not only allowed for collecting more accurate data, but also for addressing a variety of innovative studies for human development understanding. Neurofeedback (NF), and particularly Brain–Computer Interfaces (BCI) applications, are among the most promising methods, since they enable individuals to interact with a computer by using their brain activity to learn implicitly and train some specific cognitive and affective functions. These applications proved to be suitable for many different fields, from research to clinical practice. However, NF was used only in individual settings, with participants interacting with a computer, while more ecological and complex phenomena could be better explored in interactive contexts. In the present work, we propose that the future of BCI provided NF may lie in the development of interactive settings where two or more participants can be informed about their inter-brain synchrony to train and reinforce them towards enhanced joint interactions and promote learning and empowerment. We propose that BCI methods should move to brain-X-brain-computer interfaces (B2CI). In this new protocol, that we called “hyperfeedback,” brain signals coming from two people involved in a joint setting are processed so to provide a compound feedback. The possible applications of such a paradigm are discussed.

Cosmogenic age constraints on rock avalanches in the Qinling Range associated with paleoearthquake activity, central China

Although it is generally assumed that understanding the trigger factor leading to the transition from a progressive rock failure toward sudden and rapid events is better to risk management, the ability to identify triggering factors responsible for prehistoric catastrophic rock avalanches is still debated. Here we describe two rock avalanches (Ganqiu and Shuiqiu) in the Cuihua Mountain area of the Qinling Range, China, providing new mapping of rock avalanche source areas and deposits and absolute age constraint from cosmogenic 10Be surface exposure dating. Results reveal that the Ganqiu rock avalanche is controlled by three sets of joints, causing the 380 m high ridge to collapse. Debris filled roughly the entire V-shaped valley and has a width ranging from 250 to 470 m, extending ~1260 m from the base of the cliff. The Shuiqiu rock avalanche was sourced near the summit of Cuihua Mountain from a cliff above 60° that is mainly controlled by inherited fault and joints. The rock mass fell ~250 m as a giant blocky stream across the width of the valley floor, with the deposit extending ~300 m from the base of the cliff. Both events caused the large-scale collapse of ridge crests and developed into high-mobility rock avalanches with long runout. Cosmogenic 10Be surface exposure dating from seven different parts of the deposits revealed nearly coincident ages for both rock avalanches, 10.0 ± 0.9 ka for the Ganqiu rock avalanche and 9.5 ± 1.2 ka for the Shuiqiu rock avalanche. Because this region was not affected by valley glaciation, rock avalanches triggering by paraglacial stress release can be excluded. Moreover, without clear evidence for specific climatic conditions in the Qinling area circa 9–10 ka, a climatic trigger for the Cuihua Mountain rock avalanches is equivocal. Instead, we find coincidence between the concurrent exposure ages and paleoseismic records from the nearby Qinling North Piedmont fault (QNF). This coincidence of ages, combined with the fact that the Mw 8.0 1556 CE Huaxian earthquake triggered numerous large rock falls in the Huashan Mountains at the eastern end of the Qinling Range, suggest that a large-magnitude earthquake centered in the middle-east section of QNF at ca. 8–11 ka may have triggered the Ganqiu and Shuiqiu rock avalanches.

The morphology and sedimentology of the Walai rock avalanche in southern China, with implications for confined rock avalanches

The Walai rock avalanche (H/L ratio = 0.32), which was laterally and frontally confined occurred in the high mountainous areas of the eastern Tibetan Plateau. According to the field investigation and optically stimulated dating, the initial rock slope failure was determined to be a wedge failure controlled by bedding and two joint sets at approximately 38 ka ago. Based on the topography reconstruction, the deposited volume of this rock avalanche was estimated at 5.2 × 107m3, which was 1.24 times the mass detached from the source area. We observed and mapped trimlines, longitudinal ridges, arched ridges, and lateral ridges associated with the rock avalanche. We also observed well-developed sedimentary features, including carapace facies, body facies, stratified structures, jigsaw fractures, directional arrangements, shear-damaged rock clasts, and interior folds. Measured grain size distributions indicated that the Walai rock avalanche fragmented within a relatively short travel distance after detachment from the source area, with no progressive reduction of grain sizes during the subsequent movement. Based on the morphological and sedimentary features, the emplacement process of the Walai rock avalanche was determined to be controlled by the local terrain and could be divided into four stages: an initiation stage (detachment), an accelerating stage (fragmentation), a longitudinal compression stage (momentum transfer), and a spreading stage (shearing).

Determinants and Clinical Significance of Musculoskeletal Symptoms in Patients With Chronic Graft-Versus-Host Disease.

Musculoskeletal symptoms in chronic graft-versus-host disease (cGVHD) are rare manifestations contributing to disease burden. This study assesses the frequency of muscle cramps, joint and muscle aches, and muscle weakness in a cohort of patients severely affected by cGVHD. Three hundred thirty-four patients participated in the NCI natural history study of cGVHD (NCT00092235) from October 2004 to March 2017. Five-point Lee cGVHD Symptom Scale was dichotomized (less symptom bother—0, 1, 2; severe symptom bother—3, 4) and tested for associations with: Short Form 36 (SF36), 2-minute walk test, grip strength, joint range of motion, and human activity profile, clinical and laboratory data. Seventy-five point four percent of patients reported joint and muscle aches (36.8% severe, Lee Symptom Scale score 3–4), 74.3% muscle cramps (33.5% severe), and 82.34% muscle weakness (45.51% severe), which were associated with reduced functional capacity (SF36 Physical Component Scale, P < 0.0001). Muscle cramps were associated with limited joint movement (P < 0.0001) and skin manifestations (skin thickening, P = 0.0008; itchy skin, P = 0.0003). Muscle cramps did not show association with potential causative agents, such as concomitant calcineurin inhibitors therapy, statins, or use of antidiabetic drugs. Joint and muscle aches showed associations with multiple variables (including strong associations with mood symptoms and fatigue, P < 0.0001). Muscle weakness was not associated with steroid dose, but was significantly associated with depression (P < 0.0001) and anxiety (P = 0.0009). This study documents a high frequency of musculoskeletal symptoms in a cohort of adult patients with cGVHD. The multivariable logistic regression models showed that a joint set of factors were moderately well associated with musculoskeletal symptoms in this study.

OP0294 REDUCED JOINT SYNOVITIS ASSESSMENT VERSUS THE GLOBAL EULAR OMERACT SYNOVITIS SCORE (GLOESS) TO PREDICT THE RESPONSE TO SECUKINUMAB IN PATIENTS WITH ACTIVE PSORIATIC ARTHRITIS AND INADEQUATE RESPONSE TO CONVENTIONAL DISEASE-MODIFYING ANTI-RHEUMATIC DRUGS: EXPLORATORY RESULTS FROM THE ULTIMATE TRIAL

BackgroundThe combined use of B-mode ultrasound (US) and Power Doppler (PD; combination termed as PDUS) allows visualisation of morphological and pathophysiological changes of the synovium. ULTIMATE (NCT02662985) was the first large, randomised, double-blind, placebo-controlled PDUS phase IIIb study in psoriatic arthritis (PsA), to demonstrate that Global OMERACT EULAR Synovitis Score (GLOESS), a US score at patient level, was sensitive to detect the early and continuous decrease in synovitis in a multicenter setting using different US devices and examiners.1 However, the US assessment for GLOESS was time-consuming owing to the number of joints assessed.ObjectivesTo investigate the value of various reduced joint sets to predict the validated GLOESS score.MethodsULTIMATE was a 52-week study with a 12-week double-blind, placebo-controlled period followed by 12-week open-label (OL) treatment and 6-month OL extension period.1 In the ULTIMATE trial, GLOESS for the 24 paired joints was calculated, with a potential score ranging between 0 to 144.1 A Spearman’s rank correlation matrix and a Cluster Image Map were constructed to identify highly correlated joint clusters based on the composite PDUS scores. Based on the different approaches (best correlation, model optimization, etc.), representative joints were then selected from each group, which yielded several corresponding combinations of joints. Linear models were developed with these reduced joint sets as predictors of GLOESS, using data from 60% of patients randomly selected from the ULTIMATE study. The remaining 40% data were used for model validation and diagnostics.ResultsFive models were established with reduced pairs of joint sets (9–13 pairs). The joints included in each linear model are summarized in Table 1. All five models of reduced joint sets showed high correlation with GLOESS score of R2 ~ 0.95. Figure 1 depicts all the 5 models of reduced joint sets for PDUS-detected synovitis versus the actual GLOESS in secukinumab and placebo-secukinumab groups, with modified GLOESS scores using reduced PDUS joint sets demonstrating changes very close to that of validated GLOESS.Table 1.Joints included across five linear models, indicated by green shadingJoint pairsModel 1 (N=9)Model 2 (N=9)Model 3 (N=9)Model 4 (N=13)Model 5 (N=12)ElbowKneeMTP2WristMCP1DIP4MTP4MCP2MCP4MCP5PIP3PIP4PIP1, PIP5DIP2DIP3, DIP5MTP1MTP5ShoulderTibiotalarN, number of joint pairs used in model. DIP, distal interphalangeal; MCP, metacarpophalangeal; MTP, metatarsophalangeal;PIP, proximal interphalangealFigure 1.Reduced set of joints synovitis score vs GLOESS scoreConclusionAll models of reduced joint sets for PDUS-detected synovitis predicted GLOESS well. The next steps will be to document responsiveness and ability to discriminate between active and placebo treatment.

Incipient karst generation in jointed layered carbonates: Insights from three-dimensional hydro-chemical simulations

We develop a hydro-chemical model to simulate incipient karst generation in three-dimensional (3D) jointed layered carbonates. The discrete fracture networks consist of fractures that are represented by two-dimensional (2D) planes. The numerical model couples the important physical processes of fluid flow, reactive transport, and dissolutional growth of fracture aperture. We represent the typical layered joint systems by the synthetic fracture networks composed of two jointed layers separated by a horizontal bedding plane. By considering a wide range of initial flow rates and aperture distributions of the joints and bedding plane, the combined effects of the penetration length and the flow localization on karst evolution are systematically investigated. The simulation results confirm that different flow regimes (i.e. joint-dominated, transitional, and bedding plane-dominated) may induce distinct features of incipient karst morphologies observed in nature (i.e. pipe-like, stripe-like and sheet-like), which is attributed to the flow reorganization and the scale alteration of effective flow region. We further found the diversity of morphologies also depends on the initial penetration length, which plays a primary role in controlling dissolution patterns in joint-dominated systems. In addition, introducing the second joint set results in distinct 3D flow structure and dissolutional behavior comparing to single joint system. Our findings highlight the importance of 3D hydro-chemical modeling for realistic engineering applications as the structural complexity of 3D fractured rocks may be underrepresented by the previous studies using simplified conduit networks.

Impact of Groundwater Table Fluctuation on Stability of Jointed Rock Slopes and Landslides

Groundwater level plays an important role in triggering landslides. In this paper, Distinct Element Method is used to investigate the impact of groundwater table fluctuation on the stability of jointed rock slopes. For this purpose, 110 cases including different number of joint sets, joint friction angles, joint spacings, and joint angles are considered and the influence of changing groundwater level on the stability of a jointed rock slope is investigated through a series of parametric studies. This study shows that the factor of safety for slopes can decrease significantly with increasing the groundwater level, and the impact is more significant on slopes with steeper joints. Furthermore, as the spacing of the joints decreases, the impact decreases. However, as the joint spacing increases, the groundwater table should rise to a higher elevation to be able to have an impact. Moreover, the impact on the factor of safety is similar for different joint friction angles when the groundwater level elevation is high. This study provides a better understanding of the impact of groundwater table fluctuation on the stability of jointed rock slopes.

An analysis of the degree of circularity of the wood products industry in Europe

AbstractBy developing products derived from materials included in what is nowadays called bioeconomy, the wood products industry is today receiving considerable attention for its potential to provide more environment‐friendly materials. At the same time, this and other industries are transforming to obtain more circular production systems. This study aims to analyze circularity in this type of industry at a European Union level, by establishing a ranking of countries based on their performance in an aggregate circularity index. This task has been set up by taking an initial joint set of indicators for all countries and covering a time horizon of up to 19 years. After proceeding to normalize those indicators and applying an analysis of correlation, a biannual ranking (from 2008 to 2018) was made, using for this purpose a multicriteria decision‐making model that includes three different types of solutions. Next, a statistical model that helped to explain the rankings previously obtained was proposed, in which a set of 15 explanatory variables were defined. The results showed that Sweden, and to a lesser extent Portugal, are the countries presenting a more circular wood products industry, whereas the Benelux countries give the worst result. Moreover, the statistical models showed that the variables related to trade had a negative relationship with circularity, but some of them exerted a strong effect, such as the ratio “production/exports.” Global competitiveness also tended to diminish wood circularity. Other variables, like those related to research and development, had a strong effect positively linked to circularity.

Research on Zonal Disintegration Characteristics and Failure Mechanisms of Deep Tunnel in Jointed Rock Mass with Strength Reduction Method

To understand the fracture features of zonal disintegration and reveal the failure mechanisms of circle tunnels excavated in deep jointed rock masses, a series of three-dimensional heterogeneous models considering varying joint dip angles are established. The strength reduction method is embedded in the RFPA method to achieve the gradual fracture process, macro failure mode and safety factor, and to reproduce the characteristic fracture phenomenon of deep rock masses, i.e., zonal disintegration. The mechanical mechanisms and acoustic emission energy of surrounding rocks during the different stages of the whole formation process of zonal disintegration affected by different-dip-angle joints and randomly distributed joints are further discussed. The results demonstrate that the zonal disintegration process is induced by the stress redistribution, which is significantly different from the formation mechanism of traditional surrounding rock loose zone; the dip angle of joint set has a great influence on the stress buildup, stress shadow and stress transfer as well as the failure mode of surrounding rock mass; the existence of parallel and random joints lead the newly formed cracks near the tunnel surface to developing along their strikes; the random joints make the zonal disintegration pattern much more complex and affected by the regional joint composition. These will greatly improve our understanding of the zonal disintegration in deep engineering.

Evaluation of polymeric 3D printed adhesively bonded joints: effect of joint morphology and mechanical interlocking

PurposeThe purpose of this paper is to evaluate and exploit the combination of additive manufacturing polymeric technology and structural adhesives. The main advantage is to expand the maximum dimension of the 3D printed parts, which is typically limited, by joining the parts with structural adhesive, without losing strength and stiffness and keeping the major asset of polymeric 3 D printing: freedom of shape of the system and low cost of parts.Design/methodology/approachThe materials used in the paper are the following. The adhesive considered is a commercial inexpensive acrylic, quite similar to superglue, applicable with almost no surface preparation and fast curing, as time constraint is one of the key problems that affects industrial adhesive applications. The 3D printed parts were in acrylonitrile butadiene styrene (ABS), obtained with a Fortus 250mc FDM machine, from Stratasys. The work first compares flat overlap joint with joints designed to permit mechanical interlocking of the adherends and then to a monolithic component with the same geometry. Single lap, joggle lap and double lap joints are the configurations experimentally characterized following a design of experiment approach.FindingsThe results show a failure in the substrate, due to the low strength of the polymeric adherends for the first batch of typical bonded configurations, single lap, joggle lap and double lap. The central bonded area, with an increased global thickness, never does fail, and the adhesive is able to transfer the load both with and without mechanical interlocking. An additional set of scarf joints was also tested to promote adhesive failure as well as to retrieve the adhesive strength in this application. The results shows that bonding of polymeric AM parts is able to express its full potential compared with a monolithic solution even though the joint fails prematurely in the adherend due to the bending stresses and the notches present in the lap joints.Research limitations/implicationsBecause of the 3D printed polymeric material adopted, the results may be generalized only when the elastic properties of the adherends and of the adhesive are similar, so it is not possible to extend the findings of the work to metallic additive manufactured components.Practical implicationsThe paper shows that the adhesives are feasible way to expand the potentiality of 3 D printed equipment to obtain larger parts with equivalent mechanical properties. The paper also shows that the scarf joint, which fails in the adhesive first, can be used to extract information about the adhesive strength, useful for the designers which have to combine adhesive and additive manufactured polymeric parts.Originality/valueTo the best of the researchers’ knowledge, there are scarce quantitative information in technical literature about the performance of additive manufactured parts in combination with structural adhesives and this work provides an insight on this interesting subject. This manuscript provides a feasible way of using rapid prototyping techniques in combination with adhesive bonding to fully exploit the additive manufacturing capability and to create large and cost-effective 3 D printed parts.

Glacial burst triggered by triangular wedge collapse: a study from Trisul Mountain near Ronti glacier valley

Himalayan mountain ranges separate the Tibetan plateau from the Indian subcontinent, where challenging topography, ongoing orogeny, and weather conditions are significant factors behind mass movements. The detachment of a composite rock-ice mass occurred on 7-Feb-2021 over the north-eastern slope of the Trisul mountain resulting in devastation along the Rishiganga-Dhauliganga valley, Uttarakhand. In this study, an attempt is made to understand the failure mechanism of the overhang wedge, where prolonged glacial mobility is seen as a possible factor behind the formation of such a structure. The temporal movement (2020–2021; annual & seasonal) of metamorphosed ice is assessed using sub-pixel offset tracking of Sentinel-1A-GRD data. Kinematic analysis checks failure susceptibility due to joint sets within the rockmass. Slope stability analysis is performed using probabilistic back analysis for three values of coefficient of variation (CoV), i.e., 10%, 15%, and 20% considering cohesion (c) and angle of internal friction (ϕ) as random variables. The detachment impact is quantified using rockfall simulation and parameters such as maximum bounce height, total kinetic energy, and translational velocity. Finally, probabilistic analysis of parameters is performed that may be useful in developing a mitigation system.

The tabular Strathbogie batholith in central Victoria

The southern boundary of the high level, discordant, Devonian Strathbogie batholith in central Victoria includes two near-linear sections that strike east–west, and one north–south. Field mapping has delineated the 100 km southern boundary with 2200 waypoints taken where granite and hornfels are within 10 m of one another. There is 790 m of topographic relief along the southern boundary and, where the mapping is overlain on contours, there are intervals that reflect a steep-dipping contact and others that reflect near-horizontal contacts. Of the latter, some reflect the granite roof and others the floor. Complementary evidence from mineralogic and textural data indicates a strong correlation between the interpreted roof of the granite and the abundance of tourmaline, aplite and pegmatite. When combined, the roof and floor intervals indicate a batholith thickness up to 350 m; nowhere along the southern boundary can a thickness of 1 km be demonstrated. Along the southern boundary, at least, the batholith shape is a thin, tabular and extensive composite granite sheet analogous to a pizza rather than a pipe. The roof of the granite is nearly horizontal in both east–west and north–south sections, and the plateaux today are close to the batholith roof. On regional and local scales, granite emplacement was determined by pre-existing anisotropies, such as master joint sets, across which the propagation of magma-filled fractures (granite sheets) was arrested. The emplacement records a fine balance between magma pressure, and the interplay of lower confining (overburden) pressures and pre-existing anisotropies that also facilitated roof uplift. The opportunistic magmas used the slightest variations of those parameters. This interpretation of the Strathbogie batholith matches examples in the Himalaya and Chilean Andes but differs markedly from the portrayal of very large batholiths beneath Cu–Au porphyry systems. KEY POINTS The boundary of the Strathbogie batholith can be mapped in moderately outcropping terrain to an accuracy of 10 m or better. Steep intervals of the boundary are interspersed with near-horizontal intervals that delineate the granite floor and roof along the 100 km of the southern boundary. The batholith, at least near its southern boundary, comprises near-horizontal sheets of <500 m aggregate thickness. The boundary determined by geophysics is adequate for regional studies but has been misleading in three-dimensional interpretations.

Gramian‐based vulnerability analysis of dynamic networks

In this paper, the vulnerability of large-dimensional dynamic networks to false data injections is analysed. The malicious data can manipulate input injection at the control nodes and affect the outputs of the network. The objective is to analyse and quantify the potential vulnerability of the dynamics by such adversarial inputs when the opponents try to avoid being detected as much as possible. A joint set of most effective actuation nodes and most vulnerable target nodes are introduced with minimal detectability by the monitoring system. Detection of this joint set of actuation-target nodes is carried out by introducing a Gramian-based measure and reformulating the vulnerability problem as a standard optimisation problem. However, the underlying optimisation problem appears to be a binary program and intractable in large-dimensional systems. Balanced realisation of the system dynamics, combined with a Gauss–Newton approach is employed to provide a two-stage algorithm for the selection of the most effective joint sets. The proposed approach relies on QR decomposition and QR pivoting, does not require iterative computation of Gramian matrices, and scales well with the system dimensions. The proposed approach is evaluated on a set of synthetic and real-life examples including IEEE 118 bus power network.

Multiscale effects caused by the fracturing and fragmentation of rock blocks during rock mass movement: implications for rock avalanche propagation

Abstract. The fracturing and fragmentation of rock blocks are important phenomena that occur ubiquitously during the propagation of rock avalanches. Here, the movement of a rectangular rock block characterized by different joint sets along an upper sloped and lower horizontal plane is simulated using discrete element method (DEM) models. The pattern of the joint set allows the block to break along weak joint planes at the onset of fragmentation. With this design, the fracturing and fragmentation of the sliding rock block and their influences on the conversion and transmission of energy within the system are investigated. The results show that rock fragmentation can significantly alter the horizontal velocities and kinetic energies of fragments in the block system, accelerating the front sub-block while decelerating the rear sub-block. Such energy conversion and transmission between the front and rear sub-blocks are attributed to the accumulation and release of elastic strain energy caused by fragmentation. The energy transfer induced by fragmentation is more efficient than that induced by collision. Furthermore, positive relationships between the kinetic energy increase in the front sub-block induced by joint fracturing and the joint strength can be reliably fitted with linear functions, indicating that a rock mass with a higher joint strength experiences more-energetic fragmentation effects.