Modification Of Slope Research Articles

Pre-, Co-, and Post-Failure Deformation Analysis of the Catastrophic Xinjing Open-Pit Coal Mine Landslide, China, from Optical and Radar Remote Sensing Observations

Landslide risks in open-pit mine areas are heightened by artificial slope modifications necessary for mining operations, endangering human life and property. On 22 February 2023, a catastrophic landslide occurred at the Xinjing Open-Pit Coal Mine in Inner Mongolia, China, resulting in 53 fatalities and economic losses totaling 28.7 million USD. Investigating the pre-, co-, and post-failure deformation processes and exploring the potential driving mechanisms are crucial to preventing similar tragedies. In this study, we used multi-source optical and radar images alongside satellite geodetic methods to analyze the event. The results revealed pre-failure acceleration at the slope toe, large-scale southward displacement during collapse, and ongoing deformation across the mine area due to mining operations and waste accumulation. The collapse was primarily triggered by an excessively steep, non-compliant artificial slope design and continuous excavation at the slope’s base. Furthermore, our experiments indicated that the commonly used Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) significantly underestimated landslide deformation due to the maximum detectable deformation gradient (MDDG) limitation. In contrast, the high-spatial-resolution Fucheng-1 provided more accurate monitoring results with a higher MDDG. This underscores the importance of carefully assessing the MDDG when employing InSAR techniques to monitor rapid deformation in mining areas.

Anterior Slope–Modifying Osteotomies Alter the Length Change Behavior of the Superficial Medial Collateral Ligament: A Biomechanical Study

Background: Increased tibial slope has been shown to lead to higher rates of anterior cruciate ligament graft failure. A slope-decreasing osteotomy can reduce in situ anterior cruciate ligament force and may mitigate this risk. However, how this procedure may affect the length change behavior of the medial ligamentous structures is unknown. Purpose/Hypothesis: The purpose of this study was to examine the effect of anterior slope–modifying osteotomies on the medial ligamentous structures. It was hypothesized that (1) decreasing the tibial slope would lead to shortening of the superficial medial collateral ligament (sMCL), (2) while the fibers of the posterior oblique ligament (POL) would be unaffected. Study Design: Descriptive laboratory study. Methods: Eight fresh-frozen cadaveric knee specimens underwent anatomic dissection to precisely identify the medial ligamentous structures. The knees were mounted in a custom-made kinematics rig with the quadriceps muscle and iliotibial tract loaded. An anterior slope–modifying osteotomy was performed and fixed using an external fixator, which allowed modification of the wedge height between −15 and +10 mm in 5-mm increments. Threads were mounted between pins positioned at the anterior, middle, and posterior parts of the tibial and femoral attachments of the sMCL and POL. For different tibial slope modifications, length changes between the tibiofemoral pin combinations were recorded using a rotary encoder as the knee was flexed between 0° and 120°. Results: All sMCL fiber regions shortened with slope reduction (P < .001) and lengthened with slope increase (P < .001), with the anterior sMCL fibers more affected than the posterior sMCL fibers. A 15-mm anterior closing-wedge high tibial osteotomy (ACWHTO) resulted in a 6.9% ± 3.0% decrease in the length of the anterior sMCL fibers compared with a 3.6% ± 2.3% decrease for the posterior sMCL fibers. A 10-mm anterior opening-wedge high tibial osteotomy (AOWHTO) increased anterior sMCL fiber length by 5.9% ± 2.3% and posterior sMCL fiber length by 1.6% ± 1.0%. The POL fibers were not significantly affected by a slope-modifying osteotomy. Conclusion: Tibial slope–modifying osteotomies changed the length change pattern of the sMCL such that an AOWHTO increased whereas an ACWHTO decreased the sMCL strain. This effect was most pronounced for the anterior fibers of the sMCL. The length change pattern of the POL remained unaffected by slope-modifying osteotomy. Clinical Relevance: Surgeons should be aware that anterior tibial slope–modifying osteotomies affect the biomechanics of the sMCL. After an extensive ACWHTO, patients may develop a medial or anteromedial instability, while an AOWHTO may overconstrain the medial compartment.

Analysis of the impact of dam slope modifications on the sensitivity to rapid drawdown, earthquakes, and changes in water level at the Jragung Dam in Semarang Regency

Analysis of the impact of dam slope modifications on the sensitivity to rapid drawdown, earthquakes, and changes in water level at the Jragung Dam in Semarang Regency

Engineering and environmental assessment of soilbag-based slope stabilisation for sustainable landslide mitigation in mountainous area

Changes in land use significantly impact landslide occurrence, particularly in mountainous areas in northern Thailand, where human activities such as urbanization, deforestation, and slope modifications alter natural slope angles, increasing susceptibility to landslides. To address this issue, an appropriate method using soilbags has been widely used for slope stabilisation in northern Thailand, but their effectiveness and sustainability require assessment. This research highlights the need to evaluate the stability of the soilbag-based method. In this study, a case study was conducted in northern Thailand, focusing on an area characterised by high-risk landslide potential. This research focuses on numerical evaluation the slope stability of soilbag-reinforced structures and discusses environmental sustainability. The study includes site investigations using an unmanned aerial photogrammetric survey for slope geometry evaluation and employing the microtremor survey technique for subsurface investigation. Soil and soilbag material parameters are obtained from existing literatures. Modelling incorporates hydrological data, slope geometry, subsurface conditions, and material parameters. Afterwards, the pore-water pressure results and safety factors are analysed. Finally, the sustainability of soilbags is discussed based on the Sustainable Development Goals (SDGs). The results demonstrate that soilbags effectively mitigate pore-water pressures, improve stability, and align with several SDGs objectives. This study enhances understanding of soilbags in slope stabilisation and introduces a sustainable landslide mitigation approach for landslide-prone regions.

National taxation on sugar-sweetened beverages and its association with overweight, obesity, and diabetes

BackgroundConsumption of sugar-sweetened beverages (SSBs) has been linked to several adverse health outcomes, thus many countries introduced taxation to reduce it. ObjectivesTo summarize national SSB taxation laws and to assess their association with obesity, overweight and diabetes. MethodsWe conducted a systematic scoping review up to January 2022 on PubMed, Web of Science, Embase, and Google Search to identify taxes on SSBs. An interrupted time series analysis (ITSA) was conducted on 17 countries with taxation implemented in 2013 or before to evaluate the level and slope modifications in the rate of change of standardized prevalence rates of overweight, obesity, and diabetes. Random-effects meta-regression was used to assess whether year of entry into force of the law, national income, and tax design affected observed results. ResultsWe included 76 tax laws issued between 1940 and 2020 by 43 countries, which were heterogeneous in terms of tax design, amount, and taxed products. Among children and adolescents, ITSA showed level or slope reduction for prevalence of overweight and obesity in 5 (Brazil, Samoa, Palau, Panama, Tonga) and 6 (El Salvador, Uruguay, Nauru, Norway, Palau, Tonga) countries out of 17, respectively. No clear pattern of modification of results according to investigated factors emerged from the meta-regression analysis. ConclusionsTaxation is highly heterogeneous across countries in terms of products and design, which might influence its effectiveness. Our findings provide some evidence regarding a deceleration of the increasing prevalence rates of overweight and obesity among children occurring in some countries following introduction of taxation.PROSPERO registration number: CRD42021233309.

Slope stability assessment in the seismically and landslide-prone road segment of Gerese to Belta, Rift Valley, Ethiopia.

Slope instability on several sections of the Gerese-Belta route in Southern Ethiopia poses a major risk to infrastructure and safety. This research was aimed at evaluating certain areas of the road susceptible to slope instability. Through intensive fieldwork including geological analysis, surveys, and testing, three crucial slope portions were determined. Both limit equilibrium and finite element calculations demonstrated that these sections are problematic under different circumstances. The slope modification analysis shows that the safety factor increases as bench widths and the number of benches increase. In the slope section D1S3, this factor reached 1.222 when two benches measuring 5 meters in width were used on slide 2D. This initially showed an unstable safety factor of 0.26. Three benches of the same width were used under slide 2D. This resulted in a safety factor of 1.219. At the slope section (D1S2), flattening of the slope angle from initial 45⁰ to 35⁰, 28⁰, 25⁰ and 18⁰ increases the factor of safety of the slope from initial 0.284 to 0.77, 0.89, 1.022, and 1.151 respectively under slide 2D analysis. At the slope section (D2S1), flattening the slope angle from initial 46⁰ to 35⁰, 25⁰, 23⁰, and 20⁰ increases the safety factor from initial 0.412 to 0.684, 0.920, 1.02, and 1.315 respectively. Based on the analysis of the study results, it can be concluded that the identified slope sections are susceptible to failure under actual field scenarios, depending on the conditions under which they are predicted to occur. According to this study, the Benching method is an economical method for mitigating soil slopes, as a result of which it was recommended to be used.

Increasing Risk of Silent Disaster in Uttarakhand Himalaya: An Example from Higher Himalaya

Land subsidence is an abrupt and silent disaster worldwide caused by various factors such as tectonics, nature of rocks and climatic variability etc. It is directly triggered by anthropogenic activities. The Uttarakhand Himalayan province in India has witnessed several earthquakes, landslides, avalanches, droughts, and flash floods/floods in the recent past. Among these incidences landslides frequently occurs in the Himalayan region, particularly during the monsoon season. Seismically, this region falls in seismic zones V and IV due to which area witnesses frequent earthquakes. An attempt was made for preparation of an inventory of land subsidence across the state of Uttarakhand to determine the key factors that are responsible for land subsidence. Previous studies and field evidences suggests that land subsidence events mainly occur due to several factors such as carbonate rocks, topography, tectonics, seismicity, climate, flash floods/floods and reservoir drawdown effect in this region. Furthermore, anthropogenic activities such as mining, underground water, unscientifically civil constructions, inadequate drainage, heavy load on ground/slope, and modification of slope for infrastructure developments aggravates the problem. This study also highlights the problem of ongoing chronic land subsidence in Joshimath town which is situated over an old landslide mass as well as its proximity to Vaikrita Thrust.

Unsteady responses and correlation characteristics of propeller blades under turbulence excitation

The turbulence ingestion force acting on the propeller is the primary source of noise and vibration for an underwater vehicle. This paper aims to quantitatively investigate the unsteady responses and blade-to-blade correlation characteristics of the rotating blades, which are two critical factors determining the consequent spectra of broadband unsteady forces. The ingested turbulence and unsteady loading of a 10-blade propeller downstream a turbulence-generating grid are numerically predicted based on Large Eddy Simulation. A theoretical approach of the correlation method is adopted to expound better the physical mechanism for the turbulence ingestion force. Through the partition of blade surface meshes in simulation, the extracted unsteady responses of separate blade strips reveal the broadband loadings varying with radii and blade sections. The distributions of flow field and fluctuating pressure demonstrate the cause of this spanwise discrepancy, as well as the relative contributions of different blade strips to the resultant unsteady loading. The correlation analysis on fluctuating velocity by the rotating sampling of simulated incoming turbulence shows the deviation of ingested flow from homogeneous isotropic turbulence. Additionally, the correlation analysis of unsteady forces distinguishes the sources of different broadband loadings. All of this in turn facilitates the modification of lift-curve slopes of blade strips and stretching factors in turbulence correlation tensors, ultimately improving the prediction accuracy of predominant broadband components by the correlation method. This work provides novel ideas for the mechanism study on turbulence ingestion force and beneficial references to the engineering design of noise-reduced propellers.

Recent geomorphological evolution of channel bar in Magdalena River (Colombia) due to natural and anthropogenic interferences

The growing establishment of port structures in estuarine regions has resulted in alternated sedimentation patterns and new geoforms. The primary purpose of this study is to understand the recent formation and geomorphological evolution of the fluvial bar in the final portion of the Magdalena River. The geomorphological evolution analysis was made possible using Geographic Information Systems tools, satellite images, and bathymetric data. The studied bar formed and stabilized through anthropic and natural factors such as port structures (obstacles to sediment transport), channel morphology, and natural- and anthropic-caused variation to the sediment supply. The lateral bar formation, adjacent to port structures, began in 2017 with surface runoff accumulating and anchored on the riverbank since 2018. At present, the bar covers 45% of the original river width, and an approximate sediment volume worth 4,000,000 m3 has accumulated. Changes in the navigable channel result in slope modification from 2.02° to 5.36°. The construction of port structures, i.e. new pile bridges, changes the natural sediment flow, because they are obstacles, trapping sediments downstream. This period coincides with the end of a weak El Niño cycle, subsequent to a La Nina period also of low intensity, with reduced precipitation rates resulting in a decrease in flow, and therefore contributing to an increase in sedimentation. The observations suggest that it is crucial to understand the channel bars' morphology and origin to avoid possible economic and social impacts due to the disruptions in navigation.

Stroke and cardiovascular disease risk exacerbate brain aging among middle‐age and older Hispanics/Latinos: Preliminary findings from the Study of Latinos‐Investigation of Neurocognitive Aging‐MRI (SOL‐INCA‐MRI)

AbstractBackgroundHispanics/Latinos have high prevalence of cardiovascular disease (CVD) risk factors which increases risk for stroke. However, the downstream impacts of CVD risk and stroke on brain structure in aging Hispanics/Latinos remains largely unknown. We compared Hispanic/Latino brain aging by CVD risk and stroke.MethodHispanics/Latinos (nunweighted=1,156, 50‐85 years) from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) underwent magnetic resonance imaging (MRI) as part of the Study of Latinos ‐ Investigation of Neurocognitive Aging‐MRI (SOL‐INCA‐MRI) ancillary study. Outcomes included global (gray matter, total brain) and regional (lobar cortices, hippocampal) brain, lateral ventricle (log‐transformed), and total white matter hyperintensity (WMH; log‐transformed) volumes residualized for total cranial volume. Ten‐year CVD risk at visit 2 (before MRI) was determined by Framingham Risk Score and recoded into three groups (Low (&lt;10%), Medium (10‐&lt;20%) and High (20+%)). Stroke (yes, no) was based on self‐report of ≥1 strokes or transient ischemic attacks at visit 1 and/or 2. Linear regression models tested 1) whether CVD risk or presence of stroke modified the relationship between age and MRI outcomes, and 2) whether CVD risk or stroke related brain aging differed by sex. All models adjusted for height and Hispanic/Latino background.ResultSample was 64.3± 7.1 years old on average (nunweighted=798 women). High CVD risk was inversely associated with total brain (standardized beta β=–0.26; p&lt;0.001), total gray (β=‐0.23; p=0.006), frontal (β = ‐0.33; p&lt;0.001) and parietal cortical gray (β =‐0.28; p=0.002) matter volumes and positively associated with (log) lateral ventricle (β log=0.23; p=0.006) and (log) WMH (βlog =0.42; p&lt;0.001) volumes. Stroke/TIA (nunweighted=48) showed a similar profile of associations but only the associations with (log) lateral ventricle (βlog=0.27; p=0.049) and (log) WMH (βlog=0.44; p=0.001) reached significance. Accelerated brain aging (age slope modification) through CVD risk and stroke was evident for total brain volume but less so for other MRI outcomes, and equivalently so across sexes.ConclusionAmong Hispanics/Latinos, CVD risk and stroke are associated with poorer brain health across brain MRI indicators. Additionally, CVD risk and stroke may accelerate overall brain aging for both Hispanic/Latino men and women as determined by total brain volumes.

Monitoring the Effects of Slope Hazard Mitigation and Weather on Rockfall along a Colorado Highway Using Terrestrial Laser Scanning

Rockfall is a frequent hazard in mountainous areas, but risks can be mitigated by the construction of protection structures and slope modification. In this study, two rock slopes along a highway in western Colorado were monitored monthly using Terrestrial Laser Scanning (TLS) before, during, and after mitigation activities were performed to observe the influence of construction and weather variables on rockfall activity. Between September 2020 and February 2021, the slopes were mechanically scaled and reinforced using rock bolts, wire mesh, and polyurethane resin injection. We used a state-of-the-art TLS monitoring workflow to process the acquired point clouds, including semi-automated algorithms for alignment, change detection, clustering, and rockfall-volume calculation. Our initial hypotheses were that the slope-construction activities would have an immediate effect on the rockfall rate post-construction and would exhibit a decreased correlation with weather-related triggering factors, such as precipitation and freeze-thaw cycles. However, our observations did not confirm this, and instead an increase in post-construction rockfall was recorded, with strong correlation to weather-related triggering factors. While this does not suggest that the overall mitigation efforts were ineffective in reducing rockfall hazard and risk of large blocks, we did not find evidence that mitigation efforts influenced the rockfall hazard associated with the release of small- to medium-sized blocks (&lt;1 m3). These results can be used to develop improved and tailored mitigation methods for rock slopes in the future.

Modelling multi-hazard threats to cultural heritage sites and environmental sustainability: The present and future scenarios

Cultural heritage sites, particularly those in mountainous regions face serious threats as mountains are hazardous places and many of them are located on shifting tectonic plates and live under the threat of earthquakes and related activities. Alongside, mountains are also exposed to atmospheric interactions and rainfall plays an important role in land movement activities through seepage of rainwater in fragile structures. Moreover, gravity pushing along with land use and climate change induced changing rainfall patterns and modification of slope lead to several hazards in mountainous regions. Environmental degradation in terms of soil erosion, loss of forests, and agricultural products are common phenomena in mountainous regions due to various multi-hazard threats. Therefore, it is necessary to conserve and management of our mountain environments as it is essential to the survival of the global ecosystem. Thus, the current research article focused on multi-hazard susceptibility mapping and evaluation of its risk assessment in some of the famous cultural heritage sites in the eastern Himalayan region of Sikkim state, India. Multi-hazard susceptibility mapping was carried out using boosted regression tree (BRT), Bayesian additive regression tree (BART) and Bayesian generalized linear model (BGLM) considering twenty-two conditioning factors and seismic activity, as this region is highly susceptible to earthquakes. The future climate and land use change were estimated using four representative concentration pathway (RCP) scenarios and Dynamic Conversion of Land-Use and its Effects (Dyna-CLUE) model respectively to identify future multi-hazard susceptibility areas and vulnerable cultural heritage sites. The novelty of this study is to a combination of machine learning, RCPs derived future climate and Dyna-CLUE induced future land use change estimation for multi-hazard modelling and identification of vulnerable cultural heritage sites. The result of this study will help land use planners and archaeologists to adopt proper management strategies for protecting the cultural heritage sites and maintaining environmental sustainability for the proper management of mountain resources.

Tensor spectrum of turbulence-sourced gravitational waves as a constraint on graviton mass

We consider a generic dispersive massive gravity theory and numericallystudy its resulting modified energy and strain spectra of tensor gravitational waves (GWs)sourced by (i) fully developed turbulence during the electroweak phasetransition (EWPT) and (ii) forced hydromagnetic turbulence duringthe QCD phase transition (QCDPT).The GW spectra are then computed in both spatial and temporal Fourier domains.We find, from the spatial spectra, that the slope modifications areweakly dependent on the eddy size at QCDPT, and, from the temporalspectra, that the modifications are pronounced in the 1–10 range — the sensitivity range of the North American Nanohertz Observatoryfor Gravitational Waves (NANOGrav) — for a graviton mass in therange 2×10-23 c27×10-22.

Saraswati River in northern India (Haryana) and its role in populating the Harappan civilization sites—A study based on remote sensing, sedimentology, and strata chronology

AbstractThe Saraswati River used to flow from the glaciated peaks of the Himalaya to the Arabian sea, covering a distance of about 1800 km. It possibly sustained the Harappan civilization in the Indian subcontinent. This river has been studied as a part of the Ghaggar–Satluj–Hakra–Nara channel system in India and Pakistan. This study investigated its independent existence and evolution in the Himalayan foothill terrain and the proximal alluvial plains. Use of satellite imagery, shuttle radar topography mission data, accelerator mass spectrometry14C dating and optically stimulated luminescence chronology is being made to identify the possible palaeo‐path of this ancient river and to characterize the trench sediment log architecture of the Saraswati River palaeochannels in northern India (Haryana). Our investigations reveal that this river formed a dense web of interconnecting channels which are continuously networked for more than 2,984 km in Haryana and their individual floodplain width varies from 1.5 to 13 km. The Harappan settlements in Haryana and Rajasthan nucleated and prospered in the fertile channel bars and interfluves of this river system. Majority of these habitation sites were located within a radius of less than 500 m from these palaeo‐water channel networks. Enormous amount of water was flowing through this channel network until BC 11,147. Sediment characteristics and their chronology reveal that flow of water in the river channel decreased with time as the glacial cover diminished. The varying thickness of clay beds in sediment logs is indicative of the fluctuations in water flow possibly as a consequence of terrain slope modifications and consequent gradual channel avulsion, climate change, and global drought events. The flow of water continued through the Himalayan foothill input channels of the palaeo‐Saraswati River in Haryana until AD 1402.

Corrosion prediction models for steel bars in chloride-contaminated concrete: a review

Concern has been expressed in the recent decades about the corrosion prediction of concrete structures in a chloride environment. This paper summarises the corrosion prediction models developed for chloride-contaminated concrete, including both the empirical and electrochemical corrosion models. The definition methods of the steel de-passivation process for electrochemical models, such as anode–cathode ratio (Aa/Ac), critical chloride concentration (CCl,crit), modification of anodic Tafel slope (βa) or passive film resistance (Rf), are considered essential and discussed in detail. Furthermore, electrochemical parameters regarding the definition and selection in electrochemical models and experimental measurements are discussed. This study confirms that Aa/Acand CCl,crithave been generally used in recent years, and that the modifications of βaand Rfrelated to free chloride concentration are technically feasible. In addition, the discreteness of electrochemical parameters in electrochemical models and experimental measurements are observed, and time-dependent characteristics of electrochemical parameters are scarcely presented in the existing literature.

INTEGRATED MONITORING OF SLOPE PROCESS IN INDIA AND RUSSIA

The common approach to landslide prediction is the integration of the observed landslide displacements, soil properties, and rainfall estimation into predictive models. In general, monitoring the evolution of an unstable slope may provide valuable information to gain a better understanding of the active prediction and early warning processes for potential geodisasters. With this background an initiation has taken between India and Russia to develop cost effective methodology to monitor landslides under the Indo Russian Bilateral Collaborative Projects by DSTRFBR. Based on the hazard assessment The Nilgiris District in Tamil Nadu and Wayanad and Idukki Districts in Kerela area identified for further detailed study on monitoring Vulnerable slopes. On the territory of North Ossetia three sites of different mass volume and differenent activity rates were selected. Landslides that have not moved for years (for example Luarskiy landslide) commonly reactivate if ground water levels change dramatically, particularly when water penetrates old ground cracks, or construction activity creates slope modification that reduces stability.

Assessment of Stormwater Drainage System for Small Urban Watershed: Case of Shambu Town, Oromia Region, Ethiopia

Stormwater runoff in a small urban watershed is one of the major challenging issues facing many countries where financial capacity is very weak to provide sufficient drainage systems. This study aims to assess the stormwater drainage system in the small urban watershed as a case study of Shambu town, Oromia Region, Ethiopia. The main objective of this study was to assess whether this excess stormwater runoff is due to hydrological change or insufficient hydraulic design of the existing drainage system in the town. The existing drainage system in this small urban watershed was analyzed by statistical analysis and the main purpose of this was to know whether the designed drainage systems were sufficient hydraulically. The existing drainage system in this small urban watershed was analyzed by statistical analysis and the main purpose of this was to know whether the designed drainage systems were sufficient hydraulically. The existing design document was taken in this analysis and field analysis also made to check whether the drainage was constructed according to the specification. The area also analyzed hydrologically by delineating the watershed using ArcSWAT and the peak discharge was computed the outlet of the watershed using Rational method. Some data such runoff coefficient and manning’s values were also generated from the watershed based on the reality on the ground. The two results from hydrological and hydraulic models were compared and that of peak discharge obtained from rational method became greater than of the Peak discharge obtained from existing drainage measurement. Therefore, in this study it was concluded that since the watershed is steep in slope, it is contributing additional runoff to this small urban watershed, additional new 50% of the existing drainage system and rehabilitation works should be implemented to modify the draining capacity of the existing scheme. Additionally, managing and improper construction alignment problem in the existing system were identified, so to control this challenge periodic cleaning and modification of slope is recommended. Keywords: Hydraulic Model, Hydrological Model, Runoff, Small Urban Watershed, Stormwater DOI: 10.7176/CER/12-9-01 Publication date: September 30 th 2020

Assessment of Stormwater Drainage System for Small Urban Watershed: A Case of Shambu Town, Oromia Region, Ethiopia

Stormwater runoff in a small urban watershed is one of the major challenging issues facing many countries where financial capacity is very weak to provide sufficient drainage systems. This study aims to assess the stormwater drainage system in the small urban watershed as a case study of Shambu town, Oromia Region, Ethiopia. The main objective of this study was to assess whether this excess stormwater runoff is due to hydrological change or insufficient hydraulic design of the existing drainage system in the town. The existing drainage system in this small urban watershed was analyzed by statistical analysis and the main purpose of this was to know whether the designed drainage systems were sufficient hydraulically. The existing drainage system in this small urban watershed was analyzed by statistical analysis and the main purpose of this was to know whether the designed drainage systems were sufficient hydraulically. The existing design document was taken in this analysis and field analysis also made to check whether the drainage was constructed according to the specification. The area also analyzed hydrologically by delineating the watershed using ArcSWAT and the peak discharge was computed the outlet of the watershed using Rational method. Some data such runoff coefficient and manning’s values were also generated from the watershed based on the reality on the ground. The two results from hydrological and hydraulic models were compared and that of peak discharge obtained from rational method became greater than of the Peak discharge obtained from existing drainage measurement. Therefore, in this study it was concluded that since the watershed is steep in slope, it is contributing additional runoff to this small urban watershed, additional new 50% of the existing drainage system and rehabilitation works should be implemented to modify the draining capacity of the existing scheme. Additionally, managing and improper construction alignment problem in the existing system were identified, so to control this challenge periodic cleaning and modification of slope is recommended.

Application of geographically weighted principal component analysis and fuzzy approach for unsupervised landslide susceptibility mapping on Gish River Basin, India

The reason behind the landslides in Darjeeling Himalaya varies from place to place. Seepage of rainwater through fragile lithological structure initiates shallow landslides, while modification of slope due to unscientific anthropogenic activities led to the occurrence of deep-seated landslides. Besides this, this region does not possess any proper landslide inventory at the micro-scale. All of these together pose a serious challenge to the researchers to develop any landslide susceptibility map for this region. From this end, this study has tried to develop a way of unsupervised landslide susceptibility mapping by applying geographically weighted principal component analysis and fuzzy approach. For this, 12 indicators are selected and categorized into three categories (actuate, lithological and topographic). The final output shows that 23.82 sq. km area lies in the very high landslide susceptible zone. Validation outputs suggest that the proposed methodology with >87% predicted rate is suitable for landslide susceptibility mapping.

Characterization of landslide and its earthwork solutions

A slope has a high tendency to slide due to many factors. In any construction design, two things should be taken into account are stability and settlement. In case of landslide, a slope is not stable which mobilizing stress is higher than allowable stress. In order to reach target slope stability, earthwork solutions can be conducted. This study has the objective to characterize landslide and propose some properly alternative earthwork solutions. In order to realize the objective, field observation, literature review, laboratory test, and landslide modeling are performed. In field observation and literature review, it is obtained the geometry before and after landslide, and surrounding area condition. In this experiment, tested soil is taken from the location of landslide in Jepara, Central Java. The soil test aims to investigate index and engineering properties used as an input. In order to model earthwork in slope and to obtain its safety factor, application program Plaxis is used. From the result of tested material, the soil is dominated by granular soil with the amount of cohesive soil more than 5%. As for mechanical properties of the soil, the friction angle is and the cohesion quite high, classified as Silty Sand (SM). From modeling with Plaxis, the existing slope has safety factor (SF) 0.61 and 1.01 without reinforcement and with reinforced respectively. However with modification of slope into 5 terrace model having slope 1:1 each terrace, the SF increases 1.56.