Boulder Movement Research Articles

Characterization and implications of a mass movement site in Bennu’s Bralgah Crater

Rubble-pile asteroids such as Bennu and Ryugu have boulder-covered surfaces and latitude-dependent slope distributions, signifying that mass movement of boulders could contribute significantly to the surface evolution of these small bodies. The OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer) mission documented numerous locations on Bennu exhibiting evidence of such mass movements, including one contained within Bralgah Crater. This area was considered (though not used) by the mission as a candidate site for sample collection; thus, high-resolution images collected during reconnaissance of this area enabled us to resolve a smaller minimum boulder size than would be possible elsewhere. Through boulder mapping and topographic analysis, we found evidence of a pileup behind a large central boulder, a flow “wake” downhill with a relative lack of medium-sized boulders, as well as a strong orientational preference of the boulders in this area, with the long axes of the boulders pointing westward of the expected direction of motion. We performed dynamical simulations of seismic shaking using the discrete-element N-body code PKDGRAV to better constrain the conditions that may have formed the landscape. In these simulations, we were able to replicate the pileup of material uphill from the central boulder and the wake downhill from it. Comparisons with previous simulations of seismic shaking–induced mass movements show that material transport is not directly related to the shaking intensity, but instead can be maximized by dominant shaking frequencies. Simulations also showed a preferential orientation emerging, with a strong possibility for preferential orientation parallel to direction of motion. Combined with the orientational preference observed in this and other studies of Bennu's landscape, this indicates that the Coriolis effect could be a major factor in the surface evolution of Bennu and other small bodies. Finally, we estimated the impactor sizes that would instigate our simulated shaking parameters, showing that Bennu could have encountered such impactors within its near-Earth lifetime.

Features of drilling horizontal wells with gas-liquid shock-ejector shells in difficult mining and geological conditions

This article examines the features of drilling horizontal wells with gas-liquid shock-ejector shells in difficult mining and geological conditions, namely in boulder-pebble deposits. The technology of drilling large boulders is considered. In addition, to study the processes of energy transfer and shock pulses from the drilling shell to the bottom of the well during the sinking of boulders, the authors conducted appropriate theoretical studies and provided calculations of the stages of the introduction of the tool into the rock. Based on theoretical studies, drilling analysis, calculations of the dependence of boulder movements, several conclusions were obtained on the technology of drilling wells in boulder-nut deposits.

Деревянные предметы из древнекорякского захоронения в нише на мысе Братьев, обнаруженные С. П. Ефимовым в 1976 году (залив Бабушкина, Северное Приохотье)

The relevance of studying the ancient Koryak culture of the Northern Okhotsk region is noted. A difficult problem is the study of its funeral rituals. One of the most promising sites for studying the ancient Koryak burial complexes is Cape Bratyev and Cape Bukhty Malaya Astronomicheskaya. The article discusses wooden items from the burial in the niche under a stone at Cape Bratyev in the area of Babushkin Bay. The wooden objects are identified as parts of a compound bow. The closest to Cape Bratyev bow fragments are ancient Eskimo bows. Information is provided about wooden finds at ancient Koryak sites. The presented data demonstrate the research potential of the ancient Koryak burial complexes in the Northern Priokhotye. The unsatisfactory condition of some burials, as well as natural destruction of the rock cliff and movement of boulders, among which the burials are located, determine the need for immediate research of these archaeological sites.

Coastal boulder movement on a rocky shoreline in northwest Ireland from repeat UAV surveys using Structure from Motion photogrammetry

The degree of boulder mobility in response to coastal storms likely varies spatially and temporally along rocky shorelines, but this is difficult to evaluate from field monitoring of individual boulders alone. Structure from Motion (SfM) photogrammetry can be used to analyse changes in shoreline geomorphology or boulder distributions over time and space from rocky shorelines. This study employs data from repeated Unpiloted Aerial Vehicle (UAV) surveys in 2017, 2018, 2019 and 2022 along a 1-km stretch of a rocky shoreline in northwest Ireland. SfM techniques were used to generate orthomosaics of the bedrock platform surface from which distributions and transport patterns of boulders were examined. Based on the identification of specific boulders that appear in images from successive time slices, 16–32 % of boulders had remained stationary (had either rotated or flipped on the spot, but experienced no change in boulder position), 18–39 % had moved but less than the calculated Root Mean Square Error (RMSE) value of 23 cm, and 29–66 % of boulders had moved greater than the RMSE value, and <29 m distance in one case. In addition, a significant minority of boulders also appeared or disappeared (3–23 %) between successive time slices, which may reflect their episodic transport to/from the sea or beyond the region of interest. Overall, the results indicate that boulder movement is highly variable over time and space and does not appear to correspond with episodic wave forcing. This is different to previous studies that have described a simple deterministic relationship between boulder movement and singular wave forcing events such as storms. Repeated UAV surveys provide a consistent methodology for understanding rocky shoreline and boulder dynamics, and can offer insight into shoreline sensitivity to regional wave climate operating under more normal or ‘average’ conditions.

Storm or tsunamis: Boulder deposits on the rocky coasts of the Balearic Islands (Spain)

The origin of large imbricate boulders at the edge of coastal cliffs, by storm or tsunamis, is usually controversial. The Balearic Islands are a perfect place to elucidate this origin because the surrounding marine basins have low storm energy compared to oceans, and they are located 250 km N of the main tsunamigenic area of the Western Mediterranean. Thus, there have been recent and historical tsunamis affecting the Balearic Islands, especially in its southern and eastern parts. Tsunami simulations from submarine earthquakes on the North African coast predict the impact of tsunami waves on the Balearic Islands. Large coastal boulders of the Balearic Islands are located in the exact places numerical models predict they will be. Despite the fact that the height and energy of storm waves are much larger from the north and west, these boulders are located in the eastern and southern parts of the islands. Documentary sources confirm a very large tsunami affecting the southeast coast of Majorca in 1756, with a run-in up to 2 km and a run-up up to 45 m. Hydrodynamic equations applied to these boulders results in storm wave height values never recorded in 60 years. In February 2020, the highest storm wave ever recorded (14.33 m) was detected at Minorca buoy, related to storm Gloria. As predicted by hydrodynamic equations, none of the boulders studied moved significantly, and only three new boulders, located at sea level or at the cliff edge, were quarried. According to radiocarbon data and rate of growth of dissolution pans, the year of emplacement of boulders in the studied localities ranges between 1591 CE and 1894 CE. Thus, the distribution of the boulder sites along the islands, the historical record of a large tsunami, the run-up necessary for their placement, and the insignificant boulder movement produced by the highest storm recorded indicates that the cliff-top boulders of the Balearic Islands were quarried by North African tsunami waves.

Monitoring of Coastal Boulder Movements by Storms and Calculating Volumetric Parameters Using the Volume Differential Method Based on Point Cloud Difference

The measurements of boulder volume and axial length play significant roles in exploring the evolution of coastal boulder deposition, which provides a theoretical framework to examine the hydrodynamics of extreme wave events. At present, the application of structure-from-motion (SfM) to unmanned aerial system (UAS) imagery is one of the most used boulder surveying techniques. However, the monitoring of boulder movement and the accurate measurement of boulder morphometrics are rarely investigated in combination. In this study, UAS surveys were used to monitor moving boulders and measure boulder volumes using the volume differential method based on the differences of dense point clouds. This was undertaken at a site on the rocky shoreline of northwest Ireland in three repeated UAS surveys conducted in 2017, 2018, and 2019. The results from UAS monitoring and mapping of the distribution of 832 moving boulders in the study area over the 3-year period showed that boulders located in different zones of the coast vary significantly in their mobility. The main findings reveal that the theoretical error of the volume, obtained using the volume differential method, was estimated as 1–3.9%, which is much smaller than that of the conventional method of estimating volume using a tape measure.

Evaluating Characteristics of an Active Coastal Spreading Area Combining Geophysical Data with Satellite, Aerial, and Unmanned Aerial Vehicles Images

The northern region of the Maltese archipelago is experiencing lateral spreading landslide processes. This region is characterized by cliffs with a hard coralline limestone outcropping layer sitting on a thick layer of clay. Such a geological configuration causes coastal instability that results in lateral spreading which predispose to rockfalls and topplings all over the cliff slopes. The aim of this research was to develop a methodology for evaluating cliff erosion/retreat using the integration of geomatics and geophysical techniques. Starting from a 3D digital model of the Selmun promontory, generated by unmanned aerial vehicle (UAV) photogrammetry, it was possible to map the fractures and conduct geophysical measurements such as electrical resistivity tomography and ground penetrating radar for the identification and mapping of vertical fractures affecting the hard coralline limestone plateau, and to create a 3D geological model of the study area. In addition to this, high-accuracy orthophotos from UAV that were captured between 1957 and 2021 were georeferenced into a GIS and compared to aerial and satellite images. The movement and evolution of boulders and cracks in rocks were then vectorized to highlight, track and quantify the phenomenon through time. The results were used to derive a qualitative assessment of the coastal variations in the geometric properties of the exposed discontinuity surfaces to evaluate the volumes and the stop points of the observed rockfalls. The outcomes of this research were finally imported in a GIS which offers an easy approach for the collection and processing of coastal monitoring data. In principle, such a system could help local authorities to address social, economic and environmental issues of pressing importance as well as facilitate effective planning in view of a risk mitigation strategy.

An overview of the design and development of lunar rover (Chandrayaan-2) for space applications

The paper gives an brief overview of the design and development of lunar rover (Chandrayaan-2) for space applications. The Moon has always been the center of attention for mankind, more than any other heavenly body in More than any other heavenly body in the night sky, the Moon has long been the focus of human interest. The Moon has always presented mankind with a challenge to learn more about it and to marvel at its wonders because it bears the early history of the solar system. We can uncover the early evolution of the solar system and that of planet Earth by having a better understanding of the Moon. With the 2008 launch of the Chandrayaan-1 orbiter mission to the Moon, India's planetary exploration program was launched by the Indian Space Research Organization (ISRO). India launched Chandrayaan-2, its second lunar exploration mission, nearly twelve years after its first lunar exploration mission. Chandrayaan-2, India's most technologically advanced aircraft, is on an unprecedented mission. The South Polar Region of the Moon will be studied by India's second lunar trip, which will draw on nearly ten years of scientific and Engineering advancement. A major accomplishment for both India and humanity, Chandrayaan-2 was the first mission ever to be sent to the southern pole of the moon. Both the high cold and constant darkness in this area make it extremely unsafe and have a bad impact on missions. India faced a tremendously difficult assignment as a result, and the entire world was interested in its outcome. Chandrayaan-1's eleven remote-sensing scientific instruments from ISRO, NASA, and ESA have made important discoveries, such as the identification of a water signature, the discovery of spinel minerals, lunar lava tubes, signs of recent volcanism, impact-triggered boulder movements, and the detection of sputtered atomic oxygen and backscattered helium on the lunar surface. Three components made up Chadrayaan-2: an orbiter, a lander, and a rover. 2019 saw the launch of this mission. During this mission, the Orbiter was successful in reaching the moon's orbit, but communication with the Lander was lost, which caused Lander to perform poorly and crash with the Pragyan rover and other scientific equipment. The work given here is a mini-project that is taken up as a part of the curriculum completed by electronics and communication engineering students in the second year of the electronics &amp; communication engineering department at Dayananda Sagar College of Engineering in Bangalore.

Morphological changes currently occurring in sand-filled gully channels on Mars: Implications for the role of substrates inside channels

Long-term monitoring of dune/non-dune gullies has substantiated extensive and diversified morphological changes whose timing correlates with the time of removal of CO2 frost, thereby implying seasonal control on the active processes. We present evidence for present-day changes in sand-filled gully channels consistent with ripples. These channels are ubiquitous in the mid-latitudes and found in gullies formed over a variety of substrates on crater walls. We investigated 1483 gullied craters having coverage of at least two High Resolution Imaging Science Experiment (HiRISE) images between 30°S and 75°S and identified 98 craters (6.6% of the total) with sand-filled gully channels. Among these 98 craters, sand-filled gully channels in 25 craters (25.5% of the total) exhibit morphological changes indicative of avulsion, narrow channel incision, formation of channels with potential terminal pits, channel widening and extension, downslope flow of mobilized sand inside channels, dark flows and rapid boulder movement inside channels, and local sand rearranging and erasing of channels. Investigation of the sequence of events revealed CO2 frost inside the sand-filled gully channels in the image acquired during winter and prior to the image in which recent changes have been observed. This suggests a connection with the sublimating frost inside the channels and a seasonal control that subsequently produces extensive changes in the sand-filled gully channels during defrosting seasons in approximately a Mars year. Comparison of changes on both sand-filled gully channels and dune gully channels substantiates that the currently active processes have similar effects on the loose, unconsolidated substrate in both the gully types. For example, CO2 frost processes are able to erode both sand-filled gully channels and dune gully channels to form linear channels with terminal pits. In contrast, we have not found similar evidence of linear channels with terminal pits on bedrock and/or LDM substrate on the crater wall suggesting that the bedrock and LDM substrate may not be able to be eroded by CO2 frost processes in a manner similar to the loose, unconsolidated substrate in sand-filled gully channels investigated in this study. Together, the results signify that the sand-filled gully channels represent a significant component of present-day modification of gully channels on Mars.

Using UAV and Structure-From-Motion Photogrammetry for the Detection of Boulder Movement by Storms on a Rocky Shore Platform in Laghdira, Northwest Morocco

The detachment and mobilization of boulders from rocky shore platforms by waves involves complex geomorphic and hydrodynamic processes. Understanding these processes requires precise information on the rates and patterns of movement of these megaclasts scaled against the wave conditions that generate boulder mobility. Repeat photogrammetry and structure-from-motion (SfM) models commonly used in geomorphic analyses are an interesting option for monitoring boulder dynamics. In this study, we used unmanned aerial vehicle (UAV)-based digital photogrammetry and SfM differential models to identify recent boulder movements over a rocky shore platform in Laghdira, Morocco. Combining these results with data on storm occurrence in the study area allowed us to identify storm waves as the unique driver of the dislodged and mobilized boulders. The identified storm event had a significant wave height of 5.2 m. The UAV models were built from imagery captured in September and December 2019 using a DJI MAVIC PRO PLATINUM, and we used QGIS to produce 2D and 3D model outputs. The exploitation of the 2D model differentials allowed us to appreciate the response of the boulders to the storm waves and to determine platform volumetric changes and, therefore, boulder mobility. The 3D models were valuable in determining the mode of transport of the boulders. Mobility patterns included sliding, overturning with no further mobility, and rotation and saltation, as well as boulder breakup. Storm waves did not have a preferential impact on any particular boulder shape, size category, or position at the outer edge of the platform. These results highlight the utility of combining UAV surveys with identified storm events, which are much more frequent than tsunamis, in determining observed boulder initiation and mobility.

Two-step movement of tsunami boulders unveiled by modified viscous remanent magnetization and radiocarbon dating

Massive boulders in landslide and tsunami deposits are prominent geomorphic features in various landscapes. Tracking their movement history is important for reconstructing past geologic dynamics; however, the reworking movements of massive boulders remain unresolved. The boulder field on the Ishigaki Island was formed by repeated tsunamis. Although the individual movement histories of boulders contribute to retrodict the history of different magnitude tsunamis, their radiocarbon ages only correspond to the tsunamis that detached boulders from the reef. Viscous remanent magnetization dating methods have been applied in reworking movements. These methods reveal signals associated with remanent magnetization that gradually grew since the reworking event, which helps to determine the passage of time. The methods were verified by comparison to the radiocarbon ages of un-reworked boulders detached by the recent Meiwa tsunami, while the estimated ages of such two boulders based on the classical relaxation theory contradicted the radiocarbon ages. Here, we show that a method based on the stretched exponential function addressed this contradiction. The reworking movement was estimated using an additional boulder, whose, using our method, radiocarbon age indicated that an older tsunami moved it, whereas the remanent magnetization age unveiled a reworking of the boulder attributed to the Meiwa tsunami.

Boulder transport by ice in the St. Lawrence Estuary (Canada): Influence of shore platform geomorphology and ice-foot development

One hundred mega-boulders were tagged to survey their movements (RFID) for five winters (2012–2017) in Sainte-Luce, St. Lawrence Maritime Estuary, where the foreshore is frozen for two to four months per year. In addition, four boulders were fitted with accelerometers to determine the exact periods of motion. It was found that 81% of the boulders moved during at least one of the winters studied. The maximum transport recorded in one winter was 151.87 m for a 3.1 t boulder, but most boulders moved shorter distances (2012–2017 average transport: 9.74 m, standard deviation 23.71). The relationships between length/direction of boulder movements and fast-ice activity as well as weather and oceanic conditions were analyzed. 61% of mobility events took place at the end of the ice period during ice-foot break-up by storm waves or melting, but 37% took place at the beginning of the fast-ice phase during storms and/or high tide, which was unexpected. The length and direction of transport was found to depend on conditions during ice break-up (wind, waves, currents, ice thickness), which have large interannual variabilities. However, a greater proportion of boulders moved landward between 2012 and 2017. Two transport modes occurred: short pushing by ice floes and ice-rafting over longer distances. The first is much more common (70 to 90%) while the second seems to be more frequent during cold winters, when ice is thicker. Moreover, we demonstrated that the geomorphological setting exerts a strong control on boulder transport distance. The longest movements took place near mean sea level, where the ice foot is thicker and the rock platform smooth while cobble and boulder pavements inhibit movements.

Hydrodynamic Equations for Coastal Boulder Movement: Reflections on a Recent Review

Hydrodynamic Equations for Coastal Boulder Movement: Reflections on a Recent Review

Threshold flow depths to move large boulders by the 2011 Tohoku-oki tsunami

Around the world, numerous coastal boulders with weight of few thousand tons are suspected to have been transported by very large tsunamis, although their origins remain enigmatic. For clarifying origins of these boulders, the relation between the tsunami flow depth and the movement of meter-size boulders should be clarified but there is no proper field dataset. Here we collected first comprehensive dataset of both moved and unmoved boulders as well as the maximum flow depths along the Sanriku coast of Japan, where was affected by the 2011 Tohoku-oki tsunami based on satellite image analyses and field survey. The dataset revealed that up to ca. 1500 tons of boulders and concrete blocks were moved by the 2011 tsunami with approx. 28 m flow depth. We further revealed that most unmoved boulders were not moved because of the local setting rather than their heavy weights. The threshold of moved/unmoved boulders is estimated against the flow depth. The threshold predicted that approx. > 20 m flow depths are required to move approx. > 1000 tons boulders. The results imply that even a few thousand tons of enigmatic boulders in the world could have been moved by these sizes of the tsunami flow depths, although applicability of our results to other examples should be evaluated in the future work. We further tested the validity of an earlier proposed inverse model. Although the model result is consistent with the field observation, assumption of the appropriate parameters is problematic and further improvement of the model is required to estimate hydrodynamic features of the tsunami and to discriminate tsunami boulders from storm ones. Regarding such future work, our dataset is expected to be important for the evaluation of the improved numerical models.

Development of smart boulders to monitor mass movements via the Internet of Things: a pilot study in Nepal

Abstract. Boulder movement can be observed not only in rockfall activity, but also in association with other landslide types such as rockslides, soil slides in colluvium originating from previous rockslides, and debris flows. Large boulders pose a direct threat to life and key infrastructure in terms of amplifying landslide and flood hazards as they move from the slopes to the river network. Despite the hazard they pose, boulders have not been directly targeted as a mean to detect landslide movement or used in dedicated early warning systems. We use an innovative monitoring system to observe boulder movement occurring in different geomorphological settings before reaching the river system. Our study focuses on an area in the upper Bhote Koshi catchment northeast of Kathmandu, where the Araniko highway is subjected to periodic landsliding and floods during the monsoons and was heavily affected by coseismic landslides during the 2015 Gorkha earthquake. In the area, damage by boulders to properties, roads, and other key infrastructure, such as hydropower plants, is observed every year. We embedded trackers in 23 boulders spread between a landslide body and two debris flow channels before the monsoon season of 2019. The trackers, equipped with accelerometers, can detect small angular changes in the orientation of boulders and large forces acting on them. The data can be transmitted in real time via a long-range wide-area network (LoRaWAN®) gateway to a server. Nine of the tagged boulders registered patterns in the accelerometer data compatible with downslope movements. Of these, six lying within the landslide body show small angular changes, indicating a reactivation during the rainfall period and a movement of the landslide mass. Three boulders located in a debris flow channel show sharp changes in orientation, likely corresponding to larger free movements and sudden rotations. This study highlights the fact that this innovative, cost-effective technology can be used to monitor boulders in hazard-prone sites by identifying the onset of potentially hazardous movement in real time and may thus establish the basis for early warning systems, particularly in developing countries where expensive hazard mitigation strategies may be unfeasible.

Evaluating optically stimulated luminescence rock surface exposure dating as a novel approach for reconstructing coastal boulder movement on decadal to centennial timescales

Abstract. Wave-transported boulders represent important records of storm and tsunami impact over geological timescales. Their use for hazard assessment requires chronological information on their displacement that in many cases cannot be achieved by established dating approaches. To fill this gap, this study investigated, for the first time, the potential of optically stimulated luminescence rock surface exposure dating (OSL-RSED) for estimating cliff-detachment ages of wave-transported coastal boulders. The approach was tested on calcarenite clasts at the Rabat coast, Morocco. Calibration of the OSL-RSED model was based on samples with rock surfaces exposed to sunlight for ∼ 2 years, and OSL exposure ages were evaluated against age control deduced from satellite images. Our results show that the dating precision is limited for all targeted boulders due to the local source rock lithology which has low amounts of quartz and feldspar. The dating accuracy may be affected by erosion rates on boulder surfaces of 0.02–0.18 mm yr−1. Nevertheless, we propose a robust relative chronology for boulders that are not affected by significant post-depositional erosion and that share surface angles of inclination with the calibration samples. The relative chronology indicates that (i) most boulders were detached from the cliff by storm waves; (ii) these storms lifted boulders with masses of up to ∼ 24 t; and (iii) the role of storms in the formation of boulder deposits along the Rabat coast is more significant than previously assumed. Although OSL-RSED cannot provide reliable absolute exposure ages for the coastal boulders in this study, the approach has large potential for boulder deposits composed of rocks with larger amounts of quartz or feldspar and less susceptibility to erosion.

Measurement of rock glacier surface change over different timescales using terrestrial laser scanning point clouds

Abstract. Topographic change at a given location usually results from multiple processes operating over different timescales. However, interpretations of surface change are often based upon single values of movement, measured over a specified time period or in a single direction. This work presents a method to help separate surface change types that occur at different timescales related to the deformation of an active rock glacier, drawing on terrestrial lidar monitoring at sub-monthly intervals. To this end, we derive 3D topographic changes across the Äußeres Hochebenkar rock glacier in the Ötztal Alps. These changes are presented as the relative contribution of surface change during a 3-week period (2018) to the annual surface change (2017–2018). They are also separated according to the spatially variable direction perpendicular to the local rock glacier surface (using point cloud distance computation) and a single main direction of rock glacier flow, indicated by movement of individual boulders. In a 1500 m2 sample area in the lower tongue section of the rock glacier, the contribution of the 3-week period to the annual change perpendicular to the surface is 20 %, compared with 6 % in the direction of rock glacier flow. Viewing change in this way, our approach provides estimates of surface change in different directions that are dominant at different times of the year. Our results demonstrate the benefit of more frequent lidar monitoring and, critically, the requirement for novel approaches to quantifying and disaggregating surface change, as a step towards rock glacier observation networks focusing on the analysis of 3D surface change over time.

Дослідження напруженого стану багатоцільового змінного бульдозерно-захватного робочого обладнання

The article is devoted to the development and presentation of the design of changeable, bulldozer-gripping, multi-purpose work equipment for the mobile hinge-united wheeled chassis of high passability, modeling the load on work equipment within the software "SolidWorks" to optimize process or to check geometric and weight parameters in order to justify the material for long-term resistance. The changeable working equipment on the basis of the mobile hinge-united wheeled chassis of high passability, namely the bulldozer dump in combination with the gripping device for performance of a wide range of working operations is presented. Changeable work equipment provides: - development and movement of soils of I-III categories at a distance of up to 100 m, digging up and backfilling of trenches and ditches; - forming of embankments, cutting of terraces, performance of planning, cleaning and preparatory works by the main dump; - capture, fixing and transportation of goods; - loosening of soils of IV-V categories; - uprooting of stumps; - extraction and movement of boulders; - installation and dismantling of vertical elements (racks, pillars), horizontal long elements (curb, paving slabs, pipeline elements,…). Also the study of the stress state of the most responsible elements of the working equipment was carried out in the software environment "SolidWorks" within the existing loads and the accepted material for their manufacture. The number of load cycles before the loss of these elements of long-term resistance beyond the yield strength of the material was determined. The conducted researches allowed to establish: - when modeling the stress state of the element of working equipment (clamping frame) in the environment "SolidWorks" at static load within 710 kN, the clamping frame material and its design withstand working loads according to all criteria of the program "SolidWorks": fatiguing destruction, loss of stability, margin of strength, deformation and displacement that occur under load. The load acting on this element in the process of work was determined using the formed calculation schemes and standard methods; - the design of the clamping frame made of steel 10HSND withstands without signs of destruction of about 1,000,000 load cycles. A further increase in the number of load cycles leads to the destruction of this structural element; - for the manufacture of elements of working equipment, it is advisable to use steel 10HSND. More durable grades of steel are inexpedient from an economic point of view, and steels with a yield strength of less than 390 H/mm2 do not have a sufficient margin of safety.

NUMERICAL STUDY ON MOVEMENT OF TSUNAMI BOULDER AND STORM BOULDER BY SPH METHOD

Smoothed Particle Hydrodynamics (SPH) is known as very useful method for large deformation problems, such as movement of wave absorbing blocks and sliding of caisson breakwater. Also, in the coastal area, boulders launched by tsunami and by high waves with typhoons (named tsunami boulders and storm boulders) are focused on because of risk assessment towards the tsunami or super typhoons. However, the difference of their movement mechanism have been rarely investigated in detail. This study aims to simulate the movement of the tsunami boulders and storm boulders, comparing with the hydraulic experiment, and evaluating the transport characteristics. Wave elevation and boulder displacement were reproduced in the numerical wave flume well compared to physical model. Also, there is difference between solitary and irregular waves when waves act on boulders.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/WOfXbU7m_8E

Multi-directional change detection between point clouds

Point clouds continue to be acquired with greater accuracy and less occlusion over complex scenes, characterised by high roughness and topographic variation in all three dimensions. The most widely adopted approach to change detection, M3C2, measures change along the local surface normal, which varies between points and bypasses the uncertainties involved in mesh or DEM generation. While adaptive, this direction of comparison is nevertheless user-defined and becomes less relevant where the movement direction deviates from the surface normal. Measured change therefore also becomes less meaningful, as it is a projection onto this direction. Sliding of a failing slope, for example, is predominantly surface parallel rather than along the surface normal. We present an approach that derives a dominant movement direction (DMD) at each point based on multi-scale, multi-directional change quantifications. The DMDs differ from the surface normals in three LiDAR-derived test cases; a rockfall, an avalanche, and rock glacier movement, providing more accurate measures of rockfall depth and boulder movement across the rock glacier. When the direction of change detection is orthogonal to local relief (i.e. across the surface), a variable length search cylinder that intersects only a single (corresponding) surface is necessary during change detection. Where movement results in new regions of occlusion in the second point cloud, we show that the proportion of points for which no valid change could be recorded decreases by up to 15% using the DMD rather than the surface normal. We emphasise the importance of examining the direction over which change is measured, and highlight that a comparison direction that adapts to movement rather than to the local surface can provide more relevant and accurate measures of change where the movement is not orthogonal to the surface. Our approach represents a supplementary tool for cloud-to-cloud comparison, where a choice of tool should be made based on the expected DMD deviation from the surface normal.