Unstable Slopes Research Articles

Slope Stability Analysis of Sekayu-Mangun Jaya Road STA 127+350 Reinforced with Retaining Walls

Economic growth that increases the traffic load on national roads requires these roads to have decent, safe and comfortable services. Landslide was occurred on the Sekayu-Mangun Jaya STA 127+350 road section which disrupted traffic activity. This occurrence caused the major road to shift sideways and deteriorate, rendering the route's service capacity insufficient. The road section has been repaired and is planned to use soil retaining wall reinforcement as a countermeasure. This study aims to determine the slope stability of the Sekayu-Mangun Jaya road before and after reinforcement is carried out. Slope stability analysis was performed by empirical methods using infinite slope theory and the finite element method using the Plaxis program. The calculation results show that the safety factor of the slope before the retaining wall is installed at BH-01 is 0.9. This value falls under the category of unstable slope. The safety factor at the BH-02 location was obtained at 1.3 in the moderate stability category. Slope stability after strengthening with the installation of embankments and retaining walls shows an increase in the safety factor at BH-01 to 2.59. After the slope reinforcement was carried out, the slope deformation decreased significantly to 1.5 m. The results implicated that with slope reinforcement, slope stability increases and the possibility of landslides decreases.

An innovative design approach for anchored wire meshes

AbstractAnchored wire meshes are commonly adopted to stabilize potentially unstable soil slopes. This reinforcement technique, employed either as an active or a passive anchoring system, is commonly designed according to ultimate limit state approaches. In this paper, an interaction model, useful for the design of anchored wire meshes, is proposed. The model is based on the results of a series of 3D large displacement finite element numerical analyses, in which the wire mesh mechanical behaviour is modelled as either an elastic or an elastic–plastic membrane. The model is inspired to standard load–displacement curves for shallow foundations, and the wire mesh presence is taken into account by suitably modifying the bearing capacity formula. The proposed model predictions are compared with experimental punching test results. The use of the model, only requiring the definition of geometry and soil–wire mesh mechanical properties, allows the pre-design of the reinforcement system without performing ad hoc finite element numerical analyses.

Landslide susceptibility mapping of Al Taif urban area, Saudi Arabia, using remote sensing data and microtremor measurements: integrated approach

Many people are killed by landslides due to earthquakes or severe rain, and structures and facilities built on or near slopes sustain significant damage. Such landslides on naturally occurring slopes can be large enough to utterly destroy towns or communities. Based on remote sensing and microtremor data, the area around Al Taif has been evaluated for its susceptibility to landslides. Digital elevation model (DEM), slope angle, and slope aspect thematic layers were used to depict remote sensing data. The landslide susceptibility was extracted from remote sensing thematic data. The elevations of the Al Taif area, which range from 832 to 2,594 m amsl, were identified based on the DEM. Al Taif’s slope angles range from 0° to 67.3° degrees. Nearly flat (0° to 4.75°), moderate (4.75° to 11.1°), steep (11.2° to 29.1°), and very steep slope (≤29.1°) are the different classifications for the slope. Additionally, measurements of the microtremor have been taken at 42 locations throughout the region. The horizontal-to-vertical spectral ratio (HVSR) approach was used to process and analyze microtremor data in order to determine the resonance frequency and H/V amplification factor. The findings show that, while the amplification factor varies from 1.17 to 9.28, the dominant frequency values fall between 0.3 and 12.75 Hz. To determine the frequency, amplitude, and azimuthal site response, 11 sites were eventually chosen. Furthermore, the direction of the site response in the sliding areas was parallel to the landslide directional response, indicating that the site response direction tracked the landslide direction. Practical approval of the study’s findings has been given at a number of locations by field measurements at some of the Taif urban area’s most recent landslide occurrence areas. These findings show that the integration between remote sensing and microtremor measurements is a useful tool for pinpointing landslide-prone areas, which helps to lessen the danger to people’s lives and property. This susceptibility zonation applied to the Al Taif area has produced a good match between the distribution of the reported landslides and the zones of high susceptibility. To define the general trend and geographic distribution of potentially unstable slopes and landslide potential zones, this study’s findings must be used as a guide.

Early detection of potential landslides along high‐speed railway lines: A pressing issue

AbstractEarly detection of landslides is important for prevention and mitigation of landslide disasters. Especially, accurately identifying potential landslides along high‐speed railway is becoming a pressing issue for operation safety of high‐speed railway. Here, 161 Sentinel‐1A satellite images from March 2017 to September 2022 were acquired to detect potential landslides along the Lanzhou‐Urumqi high‐speed railway (LUHR) in Qinghai. Results show that rainfall is the main cause for the transition from secondary creep (steady state) to tertiary creep (accelerated) at the Jiujiawan landslide. The hot spot analysis method was used to cluster the average line‐of‐sight deformation velocity along the LUHR, effectively extracting five deformation zones that may pose a threat. Optical satellite image analysis revealed four potential landslides and one unstable slope. Furthermore, the rescaled range analysis documented that the Hurst exponent is greater than 0.8 for all four potential landslide instability points, implying that the identified potential landslide areas are still in motion and may pose a threat to the operation of the LUHR. On this basis, we propose a framework for early identification and monitoring of landslides along the high‐speed railway lines that supports landslide hazard managing with the goal to reduce landslide risk.

Lagoonal Microfacies, Lithostratigraphy, Correlation and Shale Migration of the Basal Middle Eocene Seeb Formation (Rusayl Embayment, Sultanate of Oman)

The study improves the understanding of the basal part of the Eocene Seeb Formation of Oman, informally known as “Unit 1”, in terms of microfacies, lithostratigraphy and shale migration within the context of regional tectonics. We logged four sections bed-by-bed over a distance of 8.3 km, collected samples and analyzed thin-sections as well as XRD samples. For the first time, the microfacies and stratigraphic correlation of the lowermost part of the limestone-dominated Seeb Formation were studied in detail. In the analyzed area, Unit 1 is ~20 to 40 m thick, with the thickness increasing to the SE. In the upper part of Unit 1 is a laterally continuous shale horizon. The limestones of Unit 1 contain mostly packstones and grainstones. The dominant standard microfacies types are SMF 18-FOR and SMF 16. The former is dominated by benthic foraminifera, and the latter by peloids. Both SMFs indicate restricted lagoonal conditions. Foraminifera are common in Unit 1 and indicate a middle Eocene age. Considering the abundance of encountered foraminiferal bioclasts, it appears probable that the lagoon barrier was mainly composed of foraminiferal tests. Gutter casts, slumps and debrites indicate an active, partly unstable syndepositional slope, which was likely initially created by uplift of the Saih Hatat Dome and Jabal Nakhl Subdome. Differential regional uplift due to a more pronounced overall doming in the NW (Jabal Nakhl Subdome) than in the SE (Saih Hatat Dome) explains more accommodation space and greater thickness towards the SE. For the first time, we report visco-plastic shale migration/intrusion within the Seeb Formation, related to a shale horizon of Unit 1. This shale locally migrated as indicated by (1) local thickness variations, (2) detached limestone boulders floating in the shale, (3) limestone beds that have been cut-off by the shale and (4) dragged by the shale (5) an upward shale intrusion/injection which then spread parallelly to bedding similar to a salt tongue and (6) tilting overlying limestones. We suggest that shale migration is related to post-“mid”-Eocene E-W convergence between Arabia and India and to faulting or to the second, late Paleogene/early Neogene, faulting interval of the Frontal Range Fault. The shale horizon in the upper part of Unit 1 is a marker bed, which can be correlated across the study area.

FEM Modelling of Thin Weak Layers in Slope Stability Analysis

Modelling the presence and the effect of a thin weak layer of soil or rock in a slope stability analysis performed through the finite element method (FEM) presents several problems of purely numerical nature. This paper deals with a parametric analysis of three different 2D numerical case studies (both ideal and real) of unstable or potentially unstable slopes containing a thin soft band (or weak layer). The FEM software used is RS2 (Rocscience®). The aim is investigating the influence of some geometrical and numerical characteristics of the soft bands in the stability analyses. The Mohr–Coulomb elastic-perfectly plastic constitutive model for all the involved materials was assumed, and the mechanical parameters were kept constant. Instead, other fundamental parameters of the weak layer, such as the type of mesh elements, the mesh density, and the geometry, in terms of both thickness and outcrop shape, were changed, and results in terms of the critical Strength Reduction Factor (SRF) were compared. The main outcomes of this study represent practical suggestions on some numerical and technical aspects to users of FEM slope stability analyses, in order to obtain a precautionary assessment of slope stability.

Mechanical Properties and Microscopic Study of Steel Slag–Fly Ash-Solidified Loess under Alkaline Conditions

To address the geological hazard posed by unstable loess slopes prone to collapse and landslides, a high-strength geopolymer cementing material was developed utilizing green steel slag–fly ash as its primary constituent and activated through the application of sodium silicate alkalinity. The mechanical properties and microstructure changes of loess under varying dosages of steel slag–fly ash geopolymers and curing age were investigated through a series of tests, including unconfined compressive strength, direct shear, disintegration, electron microscope scanning, and X-ray diffraction. The findings indicate that the incorporation of geopolymers can significantly enhance the internal friction angle, cohesion, and unconfined compressive strength of loess, while mitigating the disintegration quantity and rate of stabilized soil. When 20% geopolymer is mixed into the solidified soil and cured for 28 days, the resulting solidified soil exhibits an internal friction angle of 31.12°, a cohesion of 81.09 kPa, and an unconfined compressive strength of 570.86 kPa. These values are 1.62 times, 1.76 times, and 3.36 times higher than those of loess, respectively. Moreover, the solidified soil shows minimal disintegration within 1800 s, with only 1.97% disintegration. The curing age of solidified soil has a significant impact on its curing effect. Enhancing the curing time can considerably enhance the mechanical properties of solidified soil. When the geopolymer content is 20% and the curing time is extended to 28 days, the internal friction angle, cohesion, and unconfined compressive strength increase by approximately 0.23 times, 0.48 times, and 1.61 times, respectively, compared to a curing time of 7 days. By analyzing SEM and XRD, it was found that the hydration of steel slag–fly ash geopolymer produces C-S-H and C-A-S-H cementing materials, which effectively fill the gaps between soil particles and enhance the mechanical properties of solidified soil. The research findings can serve as a theoretical foundation for the consolidation of loess subgrade utilizing steel slag–fly ash geopolymer.

Stability Analysis of an Unstable Slope in Chongqing Based on Multiple Analysis Methods

The failure of an unstable slope has the characteristics of sudden disaster, rapid sliding speed, and a wide range of influence. This study selected an unstable slope in Chongqing as the evaluation object, divided it into the strong-deformation zone and weak-deformation zone, and analyzed its formation mechanism and deformation failure mode. Macroscopic qualitative analysis was processed by the geological exploration method, the slope stability and the sliding thrust were quantitatively analyzed by the limit equilibrium method, and the sensitivity analysis was calculated and conducted on its shear strength parameters by laboratory tests and a field large shear test. The historical formation process of the slope was deduced, and suggestions for the prevention and control of unstable slopes were proposed. Studies show that the deformation mechanism of an unstable slope is a push type, its deformation is mainly concentrated in the southern area of the rear edge, and the width of the slope ground tensile crack is 1~30 cm, with a visible depth of 3~30 mm and an extension of 3~12 m. The shear strength of potential sliding zone soil in the weak-deformation zone is: cpw = 35.70 kPa, φpw = 14.80°, and in the strong-deformation zone it is: cps = 32.54 kPa, φps = 13.54°. The results show that the formation of a steep cliff by the artificial mining of sandstone is the main cause of slope deformation, the action of groundwater is the main triggering factor for slope deformation, and the inclined rock mass at the front edge is the key block for the deformation. The strong-deformation zone of the slope is in an unstable state under rainstorm, and the weak-deformation zone of the slope is basically-stable under rainstorm. Unstable slopes are prone to slide during a rainstorm period, which threatens the lives and properties of the residents and road traffic safety around the slope. The research results provide an important theoretical basis and data support for the accurate judgment and stability analysis of instability failure modes and for the further effective prevention and control of unstable slopes.

Parametric analysis for the large deformation characteristics of unstable slopes with linearly increasing soil strength by the random material point method

Soils often exhibit spatial variability with nonstationarity, which has not yet been studied in the context of postfailure analysis of slopes. In this study, the random material point method is adopted to investigate the influence of nonstationarity on the large deformation characteristics of a slope with spatially variable undrained shear strength (Su). The nonstationarity has significant influences on the mean and standard deviation of the large deformation characteristics, where ignoring the nonstationarity can lead to higher mean and standard deviation values. In addition, when the nonstationarity is insignificant with a small increase in the rate of the soil strength, the model boundary can significantly affect the standard deviation of influence and run-out distances, but the influence is slight on those of the volume of the sliding mass. In addition, the mean and standard deviation of the large deformation characteristics increase with a higher coefficient of variation of Su. This study reveals that the nonstationarity of soil spatial variability can influence the failure mechanism in the failure initiation stage and thus the volume of the sliding mass, which controls the kinetic energy of the sliding mass in the postfailure stage and affects the influence and run-out distances.

Dune slope, not wind speed, best predicts bare sand in vegetated coastal dunes

Globally vegetation cover on coastal sand dunes has increased since at least the 1950s. With the aim of restoring or increasing biodiversity, land managers in several countries have removed vegetation and/or reprofiled dune slopes to reinvigorate geomorphic activity. However, the longevity of these interventions can be relatively short (on the order of 5 to 10 years), and further active management is required. Hypotheses for controls on geomorphic activity on dunes have frequently suggested that wind speedis the most important controlling factor. Here we show dune slope to be the best predictor of bare sand at four predominantly vegetated coastal sand dunes in England and Wales. We suggest that bare sand on steep dune slopes is maintained by three important factors: (1) Wind erosion, due to topographic acceleration (2) Granular avalanches of unconsolidated sediment and (3) Rotational slumping of unstable slopes. Our results indicate that where land managers wish to ‘rejuvenate’ areas of bare sand, efforts should focus on steep windward dune slopes and reprofiling of the dune slope should mimic the concave profiles of active slope faces on active parabolic dunes with an overall slope angle of between 18° and 23° from the dune toe to the crest.

Influence of Rainfall Pattern on Wetness Index for Infinite Slope Stability Analysis

Landslides are one of the riskiest disasters combining excessive rainfall and unstable slope that a wetness index can quantify. The wetness index generated by water infiltration considering the rainfall pattern such as cumulated rainfall, rainfall duration and rainfall intensity should be estimated for the slope stability analysis. Even though the infiltration capacity of soils has been largely focused to evaluate the slope stability, the temporal patterns of rainfall have commonly been ignored or assumed as a steady state for the prediction of the slope failure in the previous studies. Thus, this study focuses more on evaluating the influence of various rainfall patterns on the slope stability, and compares it with an actual landslide incident that occurred in 2011, in Korea. The factor of safety (FS) considering the time-dependent wetness index variation is used to determine the slope stability. For the various rainfall designs, the uniform rainfall distribution, Yen and Chow, Mononobe, alternating block and second quartile Huff models are adopted. Thereafter, the FS variations from five models are compared with an actual landslide incident in Seoul, Korea. Among the rainfall designs, the models that consider the abrupt rainfall intensity capture the landslide time with an FS < 1. Therefore, the appropriate adoption of a rainfall distribution model should be highlighted for landslide prediction.

Seismic and thermal precursors of crater collapses and overflows at Stromboli volcano

Lava overflows are highly hazardous phenomena that can occur at Stromboli. They can destabilize the crater area and the “Sciara del Fuoco” unstable slope, formed by several sector collapses, which can generate potentially tsunamigenic landslides. In this study, we have identified precursors of the October-November 2022 effusive crisis through seismic and thermal camera measurements. We analyzed the lava overflow on October 9, which was preceded by a crater-rim collapse, and the overflow on November 16. In both cases, seismic precursors anticipating the overflow onset have been observed. The analysis of the seismic and thermal data led to the conclusion that the seismic precursors were caused by an escalating degassing process from the eruptive vent, which climaxed with the overflows. Volcano deformation derived from ground-based InSAR and strainmeter data showed that inflation of the crater area accompanied the escalating degassing process up to the beginning of the lava overflows. The inflation of the crater area was especially evident in the October 9 episode, which also showed a longer seismic precursor compared to the November 16 event (58 and 40 min respectively). These results are important for understanding Stromboli’s eruptive mechanisms and open a perspective for early warning of potentially dangerous phenomena.

InSAR-based method for monitoring the long-time evolutions and spatial-temporal distributions of unstable slopes with the impact of water-level fluctuation: A case study in the Xiluodu reservoir

Slope instability in reservoir areas is one of the greatest concerns for public and governments worldwide. The long-time evolution of the unstable slopes in reservoir areas after the impoundments remain poorly understood. Among the technologies applied to detecting and monitoring unstable slopes, interferometry synthetic aperture radar (InSAR) technology is one of the most effective. However, owing to the slopes in a reservoir suffering from periodic water-level fluctuations, InSAR technology has shortcomings for monitoring unstable slopes with large displacement for a long time. In this study, a post-processing method of InSAR and a practical strategy were proposed to monitor the long-time evolution of the unstable slopes in reservoir areas both spatially and temporally. The strategy can capture the evolution trends of the unstable slopes based on the variations in their deformation areas with reservoir water-level fluctuations for a long time. The case study was carried out in the Xiluodu reservoir area of China. The monitoring data of the unstable slopes before and after reservoir impoundment were extracted from multi-source SAR data, including those from ALOS-1, ENVISAT ASAR, and Sentinel-1. It was found that there were 40 unstable slopes before the reservoir impoundment and 152 unstable slopes after the reservoir impoundment. Of the 152 slopes, 142 slopes (94%) began deforming in the first 3 years after reservoir impoundment, 15 slopes have been experiencing continuous deformation, and 137 slopes underwent intermittent deformation. The areas of 79 slopes (52%) increased during the water-level drawdown periods and decreased during the rising periods. The areas of 22 slopes (14%) demonstrated the opposite trend, and the areas of 51 slopes (34%) increased independently of the water-level fluctuations. In terms of evolution trends in the deformation area, 30% of slopes experienced a decreasing trend, 15% were under a constant deformation trend, and 55% showed an increasing trend. The distribution of the unstable slopes varied from the dam site to the end of the reservoir, and most of them favorited the areas where slope angle and height were 20–35° and 30–300 m, respectively. The soil slopes composed of the previous landslide deposits were prone to deformation, followed by the dip to overdip layered rock slopes.

Hydrologic-geotechnical modelling of shallow landslide and flood hazards caused by heavy rainfall

Landslides and flooding are two of the most common hazards associated with heavy rainfall. Most studies, however, tackle the occurrence of these hazards separately or independently. Therefore, this study introduces a catchment-scale, multihazard approach that unifies the assessment of both phenomena through a combination of hydrological and geotechnical principles. By incorporating surface flow, infiltration, and slope stability analyses, the spatio-temporal response of both landslides and flooding during intense or heavy rainfall is characterized. To improve computational efficiency, a hybrid approach, consisting of the zero- and local-inertia flow models, is introduced to approximate the surface flow. Additionally, rainfall infiltration is estimated using the one-dimensional Green-Ampt model, and the results are incorporated in a deterministic slope stability analysis whose failure mechanism is generated from the forces arising from the effects of surface flow and the downward propagation of water along the assumed failure surface. The model is applied in the catchment of Marumori Town, Japan which suffered numerous landslide and flooding disasters during Typhoon Hagibis in 2019. The results indicate that the proposed model successfully simulates the hydrologic and geotechnical response of the catchment showing the distribution of both unstable slopes and inundated areas indicative of landslide and flooding hazards. The model’s capability to identify the timing and location of potential landslide and flood-prone areas could provide a practical framework for a unified early warning system, enhancing emergency planning and response efforts during heavy rainfall.

Deep learning for the encounter of inorganic nanomaterial for efficient photochemical hydrogen production

A strong photosynthetic multifaceted called photosystem I (PS I) successfully catches photons to produce a charge detached phase through a quantum yield. The low latent reductant that is created is dignified at a redox potential that is conducive to H2 development, and this charge detached phase is constant for around 100 ms. By using dithiol as a molecular wire to link Photo System I to the particles and transport electrons as of the incurable electron transport cofactor of Photo System I, towards the nanoparticle, PS I consumes been covalently connected to the surfaces of like as Pt and also Au nanoparticles. The Photosystem I or molecular wire or nanoparticle bio conjugates are capable of catalysing the reaction 2H+ + 2e H2 when illuminated. H2 development is not slowed down by the transference of electrons from PS I in the direction of the nanoparticle via the molecular wire. The speed of H2 evolution is increased fivefold when the system is supplied by means of more effective donor sideways electron-donating kinds. When evaluating hydrogen production based on predicted energy from the sun with observed values falling on unstable slopes, the root mean square error called as RMSE as well as coefficient of determination called R2 are utilised as performance metrics. The most effective model among those taken into consideration, the Deep Learning model performs well and is quite compatible with the observational data.

Numerical Modelling for effect of rainfall on unsaturated soil slopes

Expansive soils are predominant in many parts of the world. Expansive soil treated as problematic soils, as economic and design a safe slope on expansive soils is major challenge for civil engineers. Expansive soils were compacted under unsaturated condition, in various construction projects. Major failures reported in many countries around the world are due to swell shrinkage characteristics causing unstable slopes. Fills and compacted soils have an inherent suction when they are first compacted. The suction is the most important factor which affects the shear strength of unsaturated soil. variation of suction in unsaturated soil is an important factor considered for solving issues like slope stability and bearing capacity failure in unsaturated soil. Rainwater infiltration are major triggering factor for failureof expansive soil slopes. The strength of unsaturated soil changes with water evaporation and infiltration. Due to infiltration of rainwater into the soil a significant change in the pore water takes place. Hence, this fluctuation in pore water pressure responsible for the distinct mechanical behavior of unsaturated soil under different Geotechnical problems.A numerical modeling was done with Plaxis LE software, considering parameters of unsaturated soil. As the changes in pore-water pressure and moisture content are a function of the flow of moisture through the soil-atmosphere boundary.The effect of soil type, rainfall intensity, location of ground water table, permeability functionsareconsidered to reproduce the soil-atmosphere interaction. Obtain results illustrates the combine effect of suction and increase of saturation due to rainfall on slopes. It was observed that rainfall increase the induced matric suction and increase the positive pore water pressure finally results in slope failures.

Numerical analysis of the impacts of rainfall on permafrost-related slope stability on the Qinghai–Tibet Plateau

Study regionThis study interrogates a landslide in ice-rich permafrost region in the Eastern Qinghai–Tibet Plateau, China. Study focusClimate warming has increased the frequency and intensity of rainfall events, changing hydrothermal processes and the soil mechanical properties, thus affecting slope stability in permafrost region. The purpose of this paper is to elucidate the variations in soil volumetric water content (VWC) which may influence the mechanical properties of unstable slopes in ice-rich permafrost region under different rainfall conditions. New hydrological insights for the regionThis paper integrates the rainfall infiltration boundary conditions and Mohr–Coulomb criterion into a thermo–hydro–mechanical (THM) model and analyzes a landslide case in the permafrost regions. The results show that the THM model can effectively account for the impacts of VWC variation under different rainfall conditions. The influence of rainfall on the VWC diminishes as depth increases, with a more pronounced effect observed at depths less than 1 m. At depths exceeding 1 m, the impact is relatively minor. Under the condition of low-intensity, long-duration rainfall, with accumulated precipitation exceeding 60 mm, the cohesion and internal friction angle decrease to 4.2kPa and 8.1°, respectively, with a deep-layer integral slippage. In contrast, under the condition of high-intensity, short-term rainfall, the accumulated rainfall exceeds 75 mm and the internal friction angle decreases from 39° to 26°, with shallow-layer slippage. The results add on to our understanding engineering problems and periglacial geomorphic processes under the influence of climate warming.

Use of RCC pile, anchor bolt and geogrid for building construction on the unstable slope

Rapid construction of buildings in urban area is creating lack of space available for new construction. This problem enforced to construct building on slope in hilly regions. However, the engineers and designers are concerned with the stability analysis of structures built on soil slopes, as it is difficult to achieve a uniform structural level on mountainous terrain. Also, it cannot be reduced to the same level of structural forms and part of base member may not be bound by an identical horizontal plane. The fundamental stability of the structure built on hill slope depends upon on its slope stability. Slope failure has been identified as one of the frequent devastating natural disasters that have claimed huge loss of property and lives. Therefore, in this research, “Phase 2 (2002)”, a Rocscience Finite Element (FE) program and “Slide”, a Rocscience limit equilibrium program were used to simulate and analyze a complex multi-staged model with RCC pile, Anchor Bolt and Geogrid for the stability analysis of slope. Bishop’s method was used to evaluate and analyze the factor of safety. Analysis of the two section (Section 1-1 and 2-2) of slope was taken into consideration for slope stability analysis. As per the analysis using the limit equilibrium approach, the factor of safety for existing slope at Section 1-1 and Section 1-1 was found to be 0.579 and 0.70 respectively. Moreover, it was found that the factor of safety of slope was increased significantly from 0.579 to 1.593 in Sections 1-1 and 0.70 to 1.319 in Section 2-2. In addition, the factor of safety of slope with strength reduction method is 1.408 and 1.05 for Sections 1 and 2 respectively after slope stabilization work in seismic condition. This shows that, the construction of buildings in slope terrain is possible, but it needs specialized excavation and slope protection work. RCC pile with anchor bolt and geogrid is one of the sustainable solutions for construction of structure in slope area.

Three-dimensional distribution of mass movement signals in disturbed Picea abies (L.) Karst.

Dendrogeomorphologic approaches enable annual absolute dating of various potentially hazardous geomorphic processes. This study tested the dating precision of three commonly used dendrogeomorphic approaches used for the extraction of geomorphic signals from the tree ring series of disturbed trees. The first approach is based on the onset of reaction wood occurrence, and the other two approaches are based on the detection of abrupt changes in tree ring eccentricity. Nine 165 cm long stems of maximally 27 year old Norway spruces (Picea abies (L.) Karst.) growing on unstable slope affected by mass movement events of known age were analysed. Several sampling directions on stems were analysed to reveal the best sampling strategy for each tested approach. The relationships between stem curvature and the dating precision of the approaches were also analysed. The results of dating precision showed crucial differences between the tested approaches. Tree stem curvature did not influence dating precision. Overall, we concluded that the approaches based on eccentric increments are less precise than those based on reaction wood analysis when juvenile P. abies trees that grow on landslide slope are sampled. The importance of this study is in providing new insight into dating precision by analysing the whole tree stems of trees influenced by mass movements. This is unique since the approaches based on eccentricity increments have not been previously tested in such a detail.

Combining InSAR and infrared thermography with numerical simulation to identify the unstable slope of open-pit: Qidashan case study, China

Combining InSAR and infrared thermography with numerical simulation to identify the unstable slope of open-pit: Qidashan case study, China