Creep Movement Research Articles

Quantifying Creep on the Laohushan Fault Using Dense Continuous GNSS

The interseismic behavior of faults (whether they are locked or creeping) and their quantitative kinematic constraints are critical for assessing the seismic hazards of faults and their surrounding areas. Currently, the creep of the eastern segment of the Laohushan Fault in the Haiyuan Fault Zone at the northeastern margin of the Tibetan Plateau, as revealed by InSAR observations, lacks confirmation from other observational methods, particularly high-precision GNSS studies. In this study, we utilized nearly seven years of observation data from a dense GNSS continuous monitoring profile (with a minimum station spacing of 2 km) that crosses the eastern segment of the Laohushan Fault. This dataset was integrated with GNSS data from regional continuous stations, such as those from the Crustal Movement Observation Network of China, and multiple campaign measurements to calculate GNSS baseline change time series across the Laohushan Fault and to obtain a high spatial resolution horizontal crustal velocity field for the region. A comprehensive analysis of this primary dataset indicates that the Laohushan Fault is currently experiencing left-lateral creep, characterized by a partially locked shallow segment and a deeper locked segment. The fault creep is predominantly concentrated in the shallow crustal region, within a depth range of 0–5.7 ± 3.4 km, exhibiting a creep rate of 1.5 ± 0.7 mm/yr. Conversely, at depths of 5.7 ± 3.4 km to 16.8 ± 4.2 km, the fault remains locked, with a loading rate of 3.9 ± 1.1 mm/yr. The shallow creep is primarily confined within 3 km on either side of the fault. Over the nearly seven-year observation period, the creep movement within approximately 5 km of the fault’s near field has shown no significant time-dependent variation, instead demonstrating a steady-state behavior. This steady-state creep appears unaffected by postseismic effects from historical large earthquakes in the adjacent region, although the deeper (far-field) tectonic deformation of the Laohushan Fault may have been influenced by the postseismic effects of the 1920 Haiyuan M8.5 earthquake.

Characterizing an effective magnetic field during asymmetric creep motion of Dzyaloshinskii domain walls

Understanding the role of Landau Lifshitz Gilbert dynamics in describing magnetic domain wall (DW) motion in the creep regime is complicated by the presence of static pinning, but has regained interest due to recently observed directional growth in thin films with significant interfacial Dzyaloshinskii–Moriya interaction. Here, we delve into this directional domain growth behaviour in Pt/Co/Ni-based multi-layers under the influence of combined longitudinal and perpendicular magnetic fields via magneto-optical Kerr effect microscopy. Observations, including the onset field, μ0Honset , where the growth direction reverses by 180 degrees, align with the transient steady-state model predictions. By systematically varying the applied perpendicular magnetic field, we estimate the strength of an effective perpendicular field that acts on the DW during creep movement, which was expectedly found to be much smaller than the applied external field itself. This work further adds to the complexity of asymmetric domain expansion in the creep regime, but also highlights the range of magnetic information that can be extracted from careful analysis of this behavior.

Active Faults, Kinematics, and Seismotectonic Evolution during Tajogaite Eruption 2021 (La Palma, Canary Islands, Spain)

During the 2021 La Palma strombolian and fissure eruption, two faults were identified that controlled the spatial distribution of earthquake hypocenters and effusive eruptive vents. One of these faults has a NW-SE trend (Tazacorte Fault: TZF) and the other one shows an ENE-WSW trend (Mazo Fault: MZF). Previous works on fault structural analysis in La Palma indicated that the eruption zone was compatible with an extensional tectonic strain ellipsoid which activated normal-strike-slip directional faults at the confluence of TZF and MZF. These fractures were activated during the 2021 Tajogaite eruption, determining the NW-SE and WSW-ENE spatial distribution of vents. Both faults were mapped in real time during the volcanic eruption from fieldwork and remote sensing imagery (aerial drone images). We have collected more than 300 fracture data associated with the effusive vents and post-eruption seismic creep. Since the affected area was densely inhabited, most of these fractures affect houses and infrastructures. Some of the houses affected by the TZF were damaged 9 months after the eruption, although they were not damaged during the eruption. Surprisingly, these houses already had repairs made to the same fractures since 1980, giving information of previous fault creep movement. During the 2021 Tajogaite eruption, shallow seismicity was spatially related to both faults, suggesting a seismic behavior instead of the precedent creep movement. However, the lack of seismicity after the eruption indicates that the faults went back to creep aseismic behavior, similarly to 1980. The mapping and monitoring of these faults (TZF and MZF) is relevant bearing in mind that they have been active since 1980 and the post-eruptive phase of the 2021 volcanic eruption, which has to be included in the land use planning in areas affected by the volcanic eruption and creep movement. Furthermore, both faults could act as seismogenic sources triggering volcanic earthquakes with potential high macroseismic intensities and mass movements. The data presented here show the importance of having this type of study before the onset of the eruption, thus allowing a better interpretation of seismic data during volcanic unrest.

Is tree-ring anatomy the key? searching for an optimal dendrogeomorphic approach to distinguish shallow creep and true slide movements

Tree-ring based chronologies of slide movements can serve as an important basis for determining landslide activity, assessing risk and triggers, or potentially predicting future landslide behaviour. Unfortunately, however, the landslide areas studied are often affected by another type of slope movement, namely creep, which can introduce a considerable amount of noise into the resulting chronology. Thus, this study focused on testing different dendrogeomorphic approaches for the extraction of landslide signal from tree-ring series with respect to their ability to filter out the influence of creep movements and slide movements. For this purpose, 45 trees (Fagus sylvatica L. and Acer pseudoplatanus L.) growing on the steep slope of a sub-landslide block whose movement has been monitored for a long time and for which a single landslide event is known (second half of 2010) were sampled.The first tested approach was based on changing tree-ring eccentricity values and has shown its very high sensitivity to all slope movements and is therefore not applicable for creep filtering and slide movements unsuitable on steep slopes. The second approach, using macroscopic identification of the tension tree, proved to be the most suitable, accurately detecting the slide event and successfully filtering out all creep-induced noise. A final approach based on the detection of sudden anatomical changes in tree rings (independent of the presence of tension wood) also captured high amounts of noise and also slide event. Its use would be possible in the case of a suitably set event-response index threshold. The study also includes a discussion of the general effect of creep movements on tree growth, the limitations and advantages of each approach, and recommendations for future research.

Particle flow study on the microscale effects and damage evolution of sandstone creep

The creep damage of hard rock is significantly influenced by its microscopic parameters and pore structure. To explore the correlation between the macroscopic creep characteristics and microscopic properties of sandstone, the construction method of Clumps with random geometry (CRG) that can simulate the creep movement of minerals was proposed. Through seepage corrosion tests and uniaxial creep tests, a rock porous creep model was established, and the CRG model was used to investigate the evolution pattern of rock fracture and the relationship between macro and micro parameters. The results demonstrate that the creep parameters of red sandstone are significantly affected by its microporosity. When particles range from 0.05 to 2 mm, the instantaneous and creep mechanical properties of the CRG model are strongly dependent on contact parameters and porosity, but less sensitive to particles size. The simulation based on CRG is in good agreement with the laboratory tests, with a certain proportional relationship existing between the microscopic contact parameters of the numerical model and the macroscopic creep parameters of the laboratory test.

Specifics of slope movements on slopes with contrasting structural conditions: Evidence from tree-ring records

The geological structure of a slope is one of the key factors that drives the development of landslide types. Various landslide types, although occurring in the same locality, can result in different spatio-temporal dynamics of their movements. Moreover, the presence of shallow creep movements on such slopes can modify the effect of slide movements and possibly cause the false impression of landslide activity. The nonstandard combination of detailed tree-ring-based (dendrogeomorphic) approaches involving the careful assessment of growth disturbance properties (the duration, intensity, mutual ratio of different disturbances), the statistical testing of the spatial pattern of disturbed trees, the analysis of possible extreme precipitation triggers, and geophysical sounding was used in this study in an attempt to distinguish creep and slide movements and assess the general slope movement activity on slopes with contrasting geological structures. Data from 1032 tree-ring series of 516 disturbed individuals of common spruce (Picea abies (L.) Karst.) enabled the reconstruction of 13 slope movements on all three studied sites (3, 7, and 3) for the last approximately 70 years. Although some indices correspond with the general assumption of a specific landslide type to the structure of induced growth disturbances (e.g., an increased ratio of reaction wood on rotational landslides), the advanced dendrogeomorphic approach used suggests that not all dated events are of slide origin and that creep movements significantly modify the effect of original slide movement on tree growth. Some dated events are probably the result of only creep movements themselves. Thus, the present study critically assesses results of the dendrogeomorphic dating of various landslides, presents contrasting behavior of slope movements on slopes with contrasting geological structures, and recommends the use of more advanced tree-ring-based approaches for more effective dendrogeomorphic research of landslides.

Geodetic evidence for aseismic fault movement on the eastern segment of the Gediz Graben system (western Anatolia extensional province, Turkey) and its significance for settlements

Aseismic dip-slip normal fault displacement related to numerous fast-slipping active faults was recently observed in several localities in the western Anatolia extensional province. Still, the characteristics of displacements along with the behavior of individual fault segments are poorly known. Here we analyze an aseismically active normal fault affecting the settlement area of the Sarıgöl district, Turkey, at the surface rupture area of the 1969 magnitude 6.5 Alaşehir earthquake. A precise leveling method was implemented in this area between July 2017 and 2020, to determine the vertical movements of the hanging wall relative to the footwall of the Sarıgöl fault. The yearly vertical movement on the surface along Profile 1 was − 7.0, − 7.3, and − 7.0 cm, respectively, for the three years starting in July 2017, and on Profile 2 it was − 7.7, − 8.7, and − 7.8 cm for the same time period. This persistent deformation, especially in the summer and fall seasons, suggests that may be related to groundwater level changes. Intensive agriculture is conducted in the region and a high level of irrigation activity in the summer period causes a decrease in groundwater levels. In addition, the continued deformation together with intensive precipitation in winter and spring despite high groundwater levels leads to the idea that tectonic creep movement could be a second reason for the deformation in the area. In the current study, the most important result is that the aseismic deformation starting after the 1969 Mw6.5 Alaşehir earthquake still continues rapidly today with a velocity of 70–80 mm/year down-dip. This indicates that the damage zone of the Sarıgöl fault is not appropriate for settlements in the Sarıgöl district due to continuous high amounts of vertical displacement, and that appropriate building policy and awareness campaigns are needed.

The role of creep deformation in pit lake slope stability

Large-scale open-pit mining activities have profound impacts on the surrounding landscape and environment. At the cessation of open-pit mining, the rehabilitation of large void spaces can be achieved by pit-lake filling, where the water body provides a confining pressure on surrounding mine surfaces, reducing both the likelihood of slope failure and the need for ongoing slope maintenance. Although pit-lakes present a range of long-term benefits, the geotechnical performance of mines containing soft soils that are susceptible to creep under increasing loads due to pit-lake filling is seldom considered. From a geotechnical standpoint, creep induced failure is commonly associated with slow, downslope movements, prior to critical slope failure events. In this research, time-dependent slope stability analyses based on creep-sensitive materials are presented for an open-cut mine undergoing pit-lake filling. Numerical simulation provides a mechanism for the assessment of materials exhibiting soft soil creep constitutive behaviour under various loading conditions due to pit-lake filling. The response of mine surfaces is investigated for various filling regimes, highlighting location-dependent deformation rates, pore pressures and slope Factors of Safety for a large Australian open-pit brown coal mine. Results are presented for two separate creep-sensitive materials, identifying the ability to achieve final, stable landforms for a range of long-term pit-lake conditions.Article HighlightsTime-dependent creep deformation behaviour is investigated for a large Victorian open-pit brown coal mine undergoing pit-lake rehabilitation.The soft soil creep model is implemented for a large open-pit rehabilitation model, to assess long-lasting creep movements of a specific mine slope.Mine void filling rates are simulated for a range of rehabilitation scenarios over a 5 to 40 year period, identifying the excess pore water pressure distributions in addition to vertical and horizontal deformations rates.The long-term behaviour of 8 cross-section profiles is presented, identifying the effect of pit-lake filling for silt and clay interseam materials.

Monitoring Slope Creep Motion using Multi Temporal Interferometry Synthetic Aperture Radar in Semarang, Indonesia

Landslide is one type of slope movement, where the slope movement includes creep. Although creep movement does not have an impact on the risk of loss of life, this creep movement takes place constantly and invisible which has an impact on economic losses. In this study, a time-series monitoring was carried out from 2018 to 2020 to see the movement of the slopes in the study area using the Multi-Temporal Interferometry Synthetic Aperture Radar (MTInSAR). A time series method from Sentinel 1A/B data, which includes Trangkil Sejahtera Housing (PTS), Soegijapranata Catholic University (UNIKA), and 17 August 1945 University (UNTAG) in Semarang City, Indonesia. The results of data processing indicate that there are slope movement in the target location, namely Trangkil Sejahtera and Selorejo Housing (southwest of UNIKA). Based on BPBD 2021 data, landslides occurred in the Trangkil Baru Housing Center (to the north of PTS) and the Garang River landslide channel west of Selorejo. This shows that there is a link between crawling in 2018-2020 and landslides in 2021. Although the use of satellite data has some drawbacks, the results can be taken into consideration in building an early warning system and reducing losses due to landslides.

Long-term monitoring of the behavior of a talus-colluvium deposit

This article describes the behavior of a talus-colluvium deposit up to 70-m thick located in the Serra dos Orgaos, Rio de Janeiro/RJ, Brazil. The monitoring dataset of 13 years contributes to a better understanding of the mechanisms of movement associated with talus-colluvium deposits in Southeast Brazil. The study site has had a long history of slow movements, beginning in the 1970s. Field investigations, laboratory tests, monitoring, and theoretical analyses were carried out. In total, 446 groundwater-monitoring campaigns, 120 inclinometer readings, and full-time pluviometric monitoring were completed. Creep movement has been observed with a seasonality that is controlled by variations in the groundwater table (GWT). Due to the large strains, the soil residual shear strength may be mobilized at the failure surface. Analyses indicate that a better slope stability condition may be achieved by reducing the GWT level. The installation of deep horizontal drains (DHDs) led to reductions in the GWT and movement. The displacement rate decreased from 20 mm/month to 2.5 mm/year. Moreover, the monitoring data and analyses evidence the decrease of stability of the talus-colluvium mass with increased GWT and reactivation of movement with blocked drains. Good correlations (r2 up to 0.90) were observed for rainfall, movements, GWT levels, and piezometer readings. Before the installation of the DHDs, there was a direct correlation between displacements and piezometric levels. After that, this correlation was not so evident. The response of the deposit to rainfall is no longer immediate but depends on a significant amount of accumulated rainfall.

Dendrogeomorphic dating vs. low-magnitude landsliding

Landsliding is a major natural hazard; therefore, understanding its activity is an important objective worldwide. For the investigation of the current landslide events, dendrogeomorphic methods are commonly used as they allow quite a precise dating of individual events. Nevertheless, there is still a question of whether dendrogeomorphic methods can successfully work for landslides with low-magnitude movements. To determine their usability and shortcomings, four commonly used dendrogeomorphologic approaches were put to the test: Approach I is based on the detection of abrupt growth suppression; Approach II is focused on the determination of compression wood; and Approaches III and IV that work with eccentric increments. For the detection of landslide events itself, It index thresholds and spatial statistics were used. In total, 329 individuals Picea abies (L.) Karst. Growing on a seemingly dormant landslide in the Outer Western Carpathians were sampled and processed. Overall, obtained landslide chronologies varied considerably although the same trees were used, which allowed pinpointing of the main limitations of each approach. Approach I showed a high sensitivity to water shortages, causing false noise signals. Approach II was not sensitive enough to low-magnitude movements. In contrast, Approaches III and IV recorded many possible landslide events, but most of the events were just noise signals induced by creep movements (and non-geomorphological influences). These conditions made it impossible to filter the real landslide events based on It index thresholds; however, as a substitute, spatial statistics combined with a detailed analysis of real landslide morphology were successfully used. Last but not least, a sensitivity of trees to record possible landslide movements in various stages of their lives was analysed for each approach. Except for Approach IV, all approaches showed high variability in changing sensitivity during a tree's life; thus, during a certain period of the tree's growth, landslide events can hardly be detected. All things considered, findings in our study are crucial for the strategy of the dendrogeomorphic sampling conducted on landslides with low-magnitude movements.

A new tree-ring-based index for the expression of spatial landslide activity and the assessment of landslide hazards

Dendrogeomorphic methods enable a very accurate reconstruction of spatio-temporal landslide behaviour. Unfortunately, existing approaches of spatial reconstruction suffer from many imperfections (e.g. dependence on tree age or impact of forest management). This study developed, presented, and tested a new approach for the spatial reconstruction of landslide movements based on tree-ring data that eliminates the mentioned problems. The new spatial event-response index (SIt ), developed for GIS, follows the logic of the standard event-response index used for the expression of chronological landslide behaviour and considers the uneven spatial pattern of trees. The main advantage of the new approach is in the consideration of the position of disturbed trees but also of undisturbed ones. This principle prevents over-interpretation of results because it can effectively filter the possible effects of soil creep (nonslide) movements. The approach was tested on three landslides of different types using data from 306 tree-ring series. The results suggest good agreement of the new index with the standard chronological event-response index for all landslide types. This index can be used for hazard assessment of large landslide areas and possibly, if research extended to zones outside of the landslide, even for regional landslide hazard assessment.

Creep mathematical model on the example of early age concrete

The objective of the study is development of a creep kernel recording form, which allows obtaining representations for creep curves calculation. Based on the elastic-creeping body theory a possibility of the high-rate creep movement analytical study has been shown. A creep kernel, which contains a formula to describe the aging material properties, has been built. Essential stages of the proposed creep kernel formation have been given. The correspondence of the proposed calculations to real processes has been proved by a comparison with experimental data. In the numerical implementation, decomposition of integration elements into power series has been used. A possibility of calculating functions for a long time interval has been shown. Creep kernel parameters have been determined on the basis of experimental data of early age concrete samples by minimizing the standard deviation of theoretical and empirical values.

Twelve‐Year Dynamics and Rainfall Thresholds for Alternating Creep and Rapid Movement of the Hooskanaden Landslide From Integrating InSAR, Pixel Offset Tracking, and Borehole and Hydrological Measurements

AbstractThe Hooskanaden landslide is a large (~600 m wide × 1,300 m long), deep (~30 – 45 m) slide located in southwestern Oregon. Since 1958, it has had five moderate/major movements that catastrophically damaged the intersecting U.S. Highway 101, along with persistent slow wet‐season movements and a long‐term accelerating trend due to coastal erosion. Multiple remote sensing approaches, borehole measurements, and hydrological observations have been integrated to interpret the motion behaviors of the slide. Pixel offset tracking of both Sentinel‐1 and Sentinel‐2 images was carried out to reconstruct the 3‐D displacement field of the 2019 major event, and the results agree well with field measurements. A 12‐year displacement history of the landslide from 2007 to 2019 has been retrieved by incorporating offsets from Light Detection and Ranging (LiDAR) digital elevation model (DEM) gradients and Interferometric Synthetic Aperture Radar (InSAR) processing of ALOS and Sentinel‐1 images. Comparisons with daily/hourly ground precipitation reveal that the motion dynamics are predominantly controlled by intensity and temporal pattern of rainfall. A new empirical threefold rainfall threshold was therefore proposed to forecast the dates for the moderate/major movements. This threshold relies upon antecedent water‐year and previous 3‐day and daily precipitation and was able to represent observed movement periods well. Adaptation of our threshold methodology could prove useful for other large, deep landslides for which temporal forecasting has long been generally intractable. The averaged characteristic hydraulic conductivity and diffusivity were estimated as 6.6 × 10−6 m/s and 6.6 × 10−4 m2/s, respectively, based on the time lags between rainfall pulses and slide accelerations. Hydrologic modeling using these parameters helps to explain the ability of the new rainfall threshold.

A GNSS-based near real time automatic Earth Crust and Atmosphere Monitoring Service for Turkey

Turkey is located in a highly active earthquake zone. Many geodynamic and seismic activities occur during a day, such as earthquakes, landslides, sinkholes and creep movements. In addition to seismicity, Turkey has unique physical features like being surrounded by seas on three sides, affected by different climate types. It is located on mid latitudes, which makes Turkey very suitable for atmospheric studies. For this reason, Turkey serves as a natural laboratory for geodesy, geophysical and atmospheric scientists. Therefore, Global Navigation Satellite System (GNSS) data are used in many areas. However, not all the scientists can reach or process the data for coordinate-based studies. Within the scope of the study, a GNSS-based Earth Crust and Atmosphere Monitoring Service is established at the Zonguldak Bulent Ecevit University. Using the results of the GNSS processing, time series of GNSS station positions are produced and used to infer strain solutions related to earthquakes. Estimates of the Precipitable Water Vapour (PWV) and the Total Electron Content (TEC) in the ionosphere are made available for tropospheric and ionospheric studies, respectively. Visualisation of the results are intended to be provided to the scientific community. Results show that the root mean square (RMS) differences of the PWV between GNSS and radiosondes are in the range of 1–3 mm. RMS differences of the TEC is in the range of 2–3 TEC units when comparing our GNSS estimates with the Global Ionospheric Maps (GIM) from the International GNSS Service (IGS). One of the main results obtained from the analysis centre is near real-time strain rates and their relations to actual earthquakes. Results show that near real-time strain rates can be assessed as a precursor parameter for earthquakes.

Monitoring Rock Glacier Kinematics with Satellite Synthetic Aperture Radar

Active rock glaciers represent the best visual expression of mountain permafrost that can be mapped and monitored directly using remotely sensed data. Active rock glaciers are bodies that consist of a perennially frozen ice/rock mixture and express a distinct flow-like morphology indicating downslope permafrost creep movement. Annual rates of motion have ranged from a few millimeters to several meters per year, varying within the annual cycle, from year to year, as well as at the decennial time scale. During the last decade, in situ observations in the European Alps have shown that active rock glaciers are responding almost synchronously to inter-annual and decennial changes in ground temperature, suggesting that the relative changes of their kinematics are a general indicator of the evolution of mountain permafrost conditions. Here, we used satellite radar interferometry (InSAR) to monitor the rate of motion of various active rock glaciers in the Swiss Alps, Qeqertarsuaq (Western Greenland), and the semiarid Andes of South America. Velocity time series computed with Sentinel-1 SAR images, regularly acquired since 2014, every six days over Europe and Greenland and every 12 days over the Andes, show annual fluctuations, with higher velocities at the end of the summer. A JERS-1 image pair of 1996 and stacks of very high-resolution SAR images from TerraSAR-X and Cosmo-SkyMed from 2008 to 2017 were analyzed using InSAR and offset tracking over the Western Swiss Alps in order to extend the main observation period of our study. A quantitative assessment of the accuracy of InSAR and offset tracking was performed by comparison with in situ methods. Our results for the three different study regions demonstrate that Sentinel-1 InSAR can complement worldwide in situ measurements of active rock glacier kinematics.

Investigation on hot sizing process based on creep mechanism for laser cladded thin-walled titanium alloy components

Laser cladding is proved to be an effective technique to repair damaged components. However, the generation of thermal stresses due to the heat input and temperature gradient during the laser cladding process is a common issue that leads to a serious distortion in the thin-walled components. It is frustrated to correct distorted titanium alloy components on account of its physical and mechanical properties. In this study, the hot sizing method based on the mechanism of creep aging forming is applied to straighten a laser cladding Ti−6Al−4V thin-walled part. Initially, a local surface damaged part was repaired by laser cladding; accordingly, a bending distortion was induced. Afterward, the hot sizing process (HSP) was used to correct the laser cladding component by first heating the part to 730 °C and then maintaining it for 300 min. With the aid of a three-coordinate measuring instrument, a x-ray stress analyzer, a microhardness tester, and a scanning electron microscope, the parameters such as part distortion, residual stress, microhardness, and microstructure before and after HSP were measured accordingly. It shows that a severe distortion with a maximum deflection of 2.939 mm was observed for the titanium component after the laser cladding process. The distortion is significantly decreased to a value of 0.454 mm after HSP. Microhardness of the cladding layer increased from 503.4HV0.2 to 627.3HV0.2 by 24.6%. The stress generation and evolution mechanism during laser cladding and hot sizing processes were also analyzed. It was found that the HSP influenced the residual stress in the substrate and the laser cladding layer in different ways. Residual stresses in the substrates were decreased to zero, whereas that of the cladding layer keep a large value even if they decreased greatly. By comparing the microstructure of the laser cladding layer before and after HSP, it is found that the creep movement causes the grain refinement. The effectiveness of the hot sizing method in eliminating the distortion of laser repaired thin-walled parts was validated.

Power Law Model to Predict Creep Movement and Creep Failure

AbstractSoils deform as a function of time because of the consolidation and the creep processes. Under undrained conditions, the consolidation process is prevented and the creep deformations are is...

Novel integrated ground anchor technology for the seismic protection of isolated segmented cantilever bridges

An external restraining system which is anchoring the bridge superstructure to the embankment backfill is proposed in this study for the seismic protection of isolated bridges. The restraining system is employed to reduce the seismic demands of the bridge deck by utilising the otherwise inactive ground behind the abutment back-walls. The system can be described as fastening the bridge end-diaphragms to the rocky strata that lie beneath the abutment backfill. The anchoring is achieved through a series of steel strands grouted to the rock to achieve a strong anchoring capacity. Indeed, the proposed anchor is flexible enough to allow the thermal, creep and shrinkage serviceability movements of the deck. A parametric study conducted in this paper shows that the ground anchor external restraining system is truly effective in reducing the seismic demands of the bridge deck.

Mass Wasting in Clastic Rocks (Elmalı Formation Upper Eocene-Lower Miocene; Muğla-SW Turkey)

This study was carried out for determining the type, and factors of mass movements occurred in Upper Eocene-Lower Miocene mudstone and sandstone alternation (with varying ratios) of the Elmali Formation. Those sediments crop out in a vast area in SW Turkey. The main mass movement type is determined as an earthflow understanding of tilting trees, electric pole and bumpy topography. Locally, complex mass wasting including rotational landslide with various sizes, creep, earthflow and translational movement were also determined during the field study. They are threatening people’s life and property. Slope inclination, bed attitudes, joint measurement, hydrogeological observations, in situ strength measurements, geophysical application and rock sampling were performed during the field analysis. In addition, petrographic investigations, XRF and XRD analyses were performed for determining the contents of sample. Basic physico-mechanical properties, including specific gravity, porosity, Atterberg limits of samples were determined in the laboratory. Tectonic history was responsible from sheared, overturned, faulted and fractured lithology. The chaotic mudstone behaves like soil mass on hard-durable sandstone beds. Mid to high inclined slope promote the earthflow. In addition, the surface and ground water increase unstable mass weight and act as a lubricant on durable sandstone, which promote earthflow. The toe of the slope eroded and removed by streams. Thus, the earthflow continues on slope. In addition, local disturbance due to human impact (road cut, settlements, garden opening) caused small-scale but more dangerous complex mass movement.