Sand Excavation Research Articles

The Ecological Changes of Macrozoobenthos to the Sand Excavation Activities in the Southern Continental Shelf of the Korea Strait

The Ecological Changes of Macrozoobenthos to the Sand Excavation Activities in the Southern Continental Shelf of the Korea Strait

Centrifuge modelling of supported excavations using an improved in-flight excavation tool

A modified tool for simulating the entire process of supported excavation in centrifuge modelling was developed based on a Cambridge type of excavating system. Utilising the modified tool, a series of centrifuge tests of braced excavations in sand and clay soils were conducted to investigate the impacts of staged excavation on the characteristics of retaining wall displacement and ground settlement. The experimental results show that before the struts were installed, the movement of the retaining wall follows a cantilever movement pattern, in which the wall rotates about a fixed point near the toe and the maximum wall deflection occurs at the wall crest. For the strut installation process of a multi-strutted excavation, the wall deformation pattern changes to a concave profile. The maximum wall displacement in a multi-strutted excavation in sand is located slightly above the bottom of the excavation; while it is slightly below the bottom of the excavation in clay. The differences between the deformation pattern for multi-strutted excavations in sand and clay are clarified using the profiles of the ground settlement against distance from the wall. The results from this study can provide useful references for predictions of excavation-induced deformations and understanding the associated deformation mechanisms.

Legal Analysis Of Mitigation Of Environmental And Social Impact In Sand Mining Excavation C

Mining sand Excavation C, in particular , has cause degradation environment and impact social , and this just one​ example How operation mining can give benefits and harms public local . Because of this is problem urgent social , we​ must Act fast For finish degradation environment and disasters nature caused by mining​ illegal . Things that become attention main is How problem mitigation impact environmental and social issues in mining sand Excavation C is arranged based on analysis law . With use method study juridical normative , research This aim For analyze aspect law around arrangement mitigation impact environmental and social related mining sand Excavation C. Damage environment that has not resolved , especially in the Cikeruh River , is results direct from research that examines potency consequence law from mining illegal in the District area Majalengka . Opportunity field jobs , opportunities economy , and increasing village treasury , is a number of impact social from mining sand Excavation C. Mining sand Excavation C has impact the environment is a must mitigated Activities performed​ ignore licensing with refer to Constitution Number 3 of 2020 concerning Mineral and Coal Mining and Regency Regional Regulations Majalengka Number 3 of 2004 concerning Mining Business Management . The miners traditional must own Permission Community Mining (IPR).

Optimalisasi Biaya Transportasi Pendistribusian Pasir Menggunakan Model Transportasi Metode Steppingstone (Studi Kasus: Tangkahan Pasir Syawal)

Tangkahan Pasir Syawal is the largest mining or sand excavation business in Gunung Maria Hamlet, Janji Village, West Bilah District, Labuhanbatu Regency. This research aims to determine the optimization of transportation costs in sand distribution. To obtain the objectives of this research, data collection was carried out through direct interviews, while data analysis used the Vogel's Approximation Method (VAM) to determine the initial solution and to determine the optimal solution using the Stepping Stone method. From the research results, an initial solution of Rp. 6.310.000 and the optimal solution is Rp. 6.310.000. Meanwhile, transportation costs from Tangkahan Pasir Syawal before optimization were carried out were Rp. 9.425.000. This shows that Tangkahan Pasir Syawal can optimize transportation costs for sand distribution in November 2023 with cost savings of Rp. 3.115.000 or 4%.

Performance of Pile Group Affected by Adjacent Excavations in Sand below the Water Table

Performance of Pile Group Affected by Adjacent Excavations in Sand below the Water Table

Implementation of Mangrove Forest Rehabilitation in Urumb Village, Semangga District, Merauke Regency

In the Presidential Regulation of the Republic of Indonesia Number 73 of 2012 concerning the National Strategy for Mangrove Ecosystem Management, it is explained that the life support system and natural resources are of very high value, therefore efforts are needed to protect, preserve and use sustainably for the welfare of the community. The purpose of this study is to determine the implementation of the community in mangrove forest rehabilitation in Urumb village, Semangga District, Merauke Regency. The research was conducted from September to November 2022, in Urumb Village. The research method used was qualitative descriptive with Purpusive sampling technique by determining the number of samples using the Slovin formula with a tolerance degree of 10%, so that a sample of 92 respondents from 1020 populations was obtained. The data collected in this study are primary and secondary data. The data analysis used in the study used qualitative data analysis of the Miles and Huberman model. The implementation of mangrove rehabilitation in Urumb Village consists of four activities, namely; Enrichment of biological resources consisting of mangrove planting activities and mangrove habitat improvement. Habitat improvement carried out in Urumb village in habitat improvement activities is a ban on sand excavation. Protection of mangroves so that they grow and develop naturally and are environmentally friendly.
 Keywords: Implementation of Mangrove Rehabilitation; Urumb Village; Merauke

Scheduling and Management of Sand Excavation Quarry

Abstract: With an emphasis on scheduling tactics and operational effectiveness, this study explores the crucial area of sand excavation quarry management. This study provides useful insights for the optimization of sand quarry operations by a thorough investigation of scheduling strategies, resource allocation practices, and management approaches specifically designed for the complex dynamics of quarry excavation

The transformation of river ecosystems caused by mining affects bird breeding in indigenous riparian habitats

Our study considered the excavation of sand and gravel, which modifies the landscapes of riparian ecosystems. It promotes the creation of water bodies with surrounding vegetation, but it also results in the loss of natural habitats.We investigated the species richness, composition, and abundance of aquatic and terrestrial breeding birds and their interaction with three habitat types: managed and abandoned flooded pits, and oxbow lakes. We surveyed 117 sites in medium-sized river valleys in the foreground of the Bohemian Massif (Czech Republic), and in the Carpathian Mountains (Poland, Slovakia) in 2022.Flooded pits were suitable for open-water and colonial birds. Managed flooded pits were also suitable for early successional land birds, but they did not provide habitat for birds that use marshes and wet meadows, or riparian woodlands. The majority of species preferred to breed in oxbow lakes with riparian forests and these areas hosted the highest number of threatened species.We concluded that high levels of disturbance in riparian ecosystems promoted some birds (e.g. colonial or breeding in early-successional habitats), but it negatively affected the overall bird diversity, and it led to a species composition shift with the elimination of taxa associated with indigenous riparian habitats. The importance of flooded pits increases with subsequent plant succession. Our results indicate that gravel or sand mine pits, although beneficial for some taxa, are not substitutes for natural habitats in riparian ecosystems, as they do not support birds breeding in indigenous riparian habitats. Natural oxbow lakes with riparian forests are habitats that need to be preserved to effectively promote local biodiversity.

Shoreline change pattern analysis of Nagapattinam coastal stretch, Tamilnadu, India using digital shoreline analysis system (DSAS)

We analysed Nagapattinam coastal zones of southeast coast of India, using Multitemporal satellite images for five equal interval of time period (i.e. 2000, 2005, 2010, 2015, 2020 and 2021). The EPR and LLR methods enumerate the maximum accretion at rates of 22.35, 17.02 m/year and maximum erosion rates of -22.82, -10.84 m/year at the study area coastal stretch. This modification is due to several disasters (like Tsunami, cyclone) and anthropogenic activities (like construction of harbours, excavation of beach sand, industrialisation of garbage dump, urbanisation and discharge of domestic sewage). The Kalman filter model forecasting the shoreline by using statistical analysis shows 242 and 236 m in 2031 and 2041 accretion and erosion of -239 and -226 m in same period. The accretion was mainly observed in Vedaranyam and Thirupoondi and erosion was observed in Tharangambadi, Nagapattinam Poompuhar, Karaikal and Thirumullaivasal region. The outcome of this research ensures to create awareness to protect our shoreline and manage our coastal zones properly with several remedial measures for the future.

Multispecies fish tracking across newly created shallow and deep habitats in a forward-restored lake

BackgroundFreshwater fish communities typically thrive in heterogenous ecosystems that offer various abiotic conditions. However, human impact increasingly leads to loss of this natural heterogeneity and its associated rich fish communities. To reverse this trend, we need guidelines on how to effectively restore or recreate habitats for multiple fish species. Lake Markermeer in the Netherlands is a human-created 70,000-ha lake with a uniform 4 m-water depth, steep shorelines, high wind-induced turbidity, and a declining fish community. In 2016, a forward-looking restoration project newly created a 1000-ha five-island archipelago in this degrading lake, which offered new sheltered shallow waters and deep sand excavations to the fish community.MethodsIn 2020, we assessed how omnivorous and piscivorous fish species used these new habitats by tracking 78 adult fish of five key species across local and lake-scales. We monitored spring arrival of adult fish and assessed local macro-invertebrate and young-of-the-year fish densities.ResultsAdult omnivorous Cyprinidae and piscivorous Percidae arrived at the archipelago in early spring, corresponding with expected spawning movements. During the productive summer season, 12 species of young-of-the-year fish appeared along the sheltered shorelines, with particularly high densities of common roach (Rutilus rutilus) and European perch (Perca fluviatilis). This suggests the sheltered, shallow, vegetated waters formed new suitable spawning and recruitment habitat for the fish community. Despite highest food densities for adult fish in the shallowest habitats (< 2-m), adult fish preferred minimally 2-m deep water. After spawning most Cyprinidae left the archipelago and moved long distances through the lake system, while most Percidae remained resident. This may be related to (1) high densities of young-of-the-year fish as food for piscivores, (2) medium food densities for omnivores compared to elsewhere in the lake-system, or (3) the attractiveness of 30-m deep sand excavations that were newly created and frequently used by one-third of all tracked fish.ConclusionsNew littoral zones and a deep sand excavation constructed in a uniform shallow lake that lacked these habitat types attracted omnivorous and piscivorous fish species within four years. Both feeding guilds used the littoral zones for reproduction and nursery, and notably piscivorous fish became residents year-round.

Pro-Poor Hydraulic Governmentality: Sustainable Water Management and Local Livelihoods in Mekong Delta.

This article considers and adds empirical nuances to the recent conceptualization of pro-poor water management. Using the concept of pro-poor hydraulic governmentality along the Vietnam-Cambodia border of Thường Phước commune, we argue that water management is linked to local rural livelihoods in a complex and dynamic pro-poor mechanism. While certain policies organize local populations according to cost-effectiveness ignoring local customs, the practicalities of dealing with such constraints are much more ambivalent. This article demonstrates the structural pro-poor complexity among sand excavation, riverbank landslides, water management, local livelihoods, and populace resettlement. The government's resettlement plans and the perceptions of residents of these plans are intertwined with a wider political, economic, social, and cultural significance in the context of strong institutional power in Vietnam. Limitations and future research agenda are also indicated in the discussion and conclusion section.

Characterization of Forest Ecosystems in the Chure (Siwalik Hills) Landscape of Nepal Himalaya and Their Conservation Need

As a basic component of the forest ecosystem, the forest structure refers to the general distribution of plant species of different life forms and sizes. The characterization of forest structure is the key to understanding the vegetation history, present status, and future development trajectory of the forest ecosystems. The Chure region of Nepal covers about 12.78% of the country’s land area and extends east to west along the southern foothills. This biologically rich but geologically fragile region is home to many species and provides many ecosystem services to millions of people. The Chure landscape is severely suffered from anthropogenic disturbances including logging, grazing, fuelwood collection, solid waste disposal, encroachment, forest fire, and excavation of sand, gravel, and boulders. In this study, we aim to characterize the forest ecosystem types outside the protected areas in the Chure region of Nepal and analyze the threat and vulnerability of the landscape from the biodiversity point of view. We sampled 62 sites to study the dominant vegetation type, regeneration status, and major threats to the forest ecosystems. A distribution map of the forest ecosystem types in Chure was prepared. We identified 14 forest ecosystem types in Chure including seven new ones. The newly reported forest ecosystems are Hymenodictyon excelsum Forest, Syzygium cumini Forest, Terminalia anogeissiana Forest, Schima wallichii–Shorea robusta Forest, Pinus roxburghii–Shorea robusta Forest, Pinus roxburghii Forest, and Bamboo thickets. We conclude that intensified human activities including forest encroachment and deforestation are mainly responsible for the ecological imbalance in the Chure region. We emphasize an in-depth analysis of biophysical linkage and immediate conservation efforts for the restoration of the Chure landscape in Nepal.

The Vanishing Island: Socioecological and health challenges of Munroe Thuruth in Kerala, India

Abstract BACKGROUND AND AIMS: Climate change has significantly impacted tropical ecosystems critical for sustaining local economies and community livelihoods. Climate change has also impacted health especially increased prevalence of water borne and vector-borne diseases. Health implications due to climate change are multifarious and often poorly understood. We did a qualitative study in an island in Kerala-Munroe Thirurth which is affected by rising sea levels and large scale inundation and we hoped that this may help in developing a knowledge-base regarding such ecological contexts. The main objectives of the study were to understand how does the distinct ecology affect the health and wellbeing of the inhabitants of the Island especially their habitation and sustenance and also to document the public health challenges including accessibility and availability of health services of the people of the island. MATERIALS AND METHODS: Qualitative design was used given the context and the geographical setting of the island. By adopting a Multi-stage sampling, first, we categorised the island in terms of impact of floods based on the available official information viz. severely affected; moderately affected; mildly affected and; not affected wards of the Munroe Thuruth panchayath. From each of the category, one ward was selected after discussions with the panchayath president and other functionaries and 20 adult members were purposively selected for in-depth interviews. In addition, key informant interviews were also conducted with the panchayath functionaries and health staff. The study was undertaken in three phases covering an exploratory phase, pre-pilot phase and the final data collection phase. RESULTS: The island dwellers know that their land is being reclaimed by water, and that the entire island will be wiped-off the map soon. Even though the island is slowly going under water, many of the island dwellers are optimistic that the scenario may change and the island may return back to its good old days. The reasons for the increased water levels and associated problems in Munroe Thuruth can be attributed to multiple factors , including sand excavation from Ashtamudi Lake and Kallada River, the commissioning of the Kallada Irrigation Project, and the effects of global warming. The observation that pollution is increasing on an exponential rate in Munroe Thuruth, primarily due to the growth of tourism and water logging, raises concerns about the environmental and public health impacts on the island. CONCLUSIONS: It can be concluded the public health challenges are multi-pronged and influenced by the ecology as well as the way of living of the people. The accessibility and availability of healthcare services need to be improved by establishing secondary or tertiary care facilities on the island or improving transportation options for residents to access medical assistance in mainland areas. It is recommended to implement immediate measures to address waterlogging and erosion, including constructing protective infrastructure and improving drainage systems to minimize the impact on houses and living conditions. Also, it is necessary to strengthen environmental conservation efforts by promoting the restoration and protection of mangroves, which play a crucial role in stabilizing the land and mitigating the impact of climate change.

Impacts of reinforced wall on nearby excavation-induced ground and tunnel responses: A centrifugal and numerical study

Reinforced wall is widely adopted to protect existing structures subjected to nearby underground constructions. This study carried out two three-dimensional centrifuge tests (T-W with reinforced wall and T-0 without reinforced wall) and numerical back-analyses to investigate the ground and tunnel responses due to a nearby excavation in dry sand. In terms of the changes of earth pressures on the tunnel, the reinforced wall shows slight impacts at most positions, but areas between right heel and invert, and between left shoulder and crown. Tunnel heaves and longitudinal bending moments in vertical direction are slightly decreased due to the reinforced wall, while horizontal displacements and longitudinal bending moments in horizontal direction are appreciably increased. In terms of the effectiveness of the reinforced wall on mitigating tunnel horizontal displacements, four zones can be divided from shallow to deep: positive, negligible, negative, and negligible. Arching effects induced by the diaphragm wall deformations and continuous reinforced wall displacements are found to be the mechanism behind the reinforced wall-induced increases in tunnel horizontal displacements.

Managed aquifer recharge using a borrow pit in connection with the Mississippi River Valley alluvial aquifer in northeastern Arkansas

The Mississippi River Valley alluvial aquifer (MRVAA) is one of the overexploited aquifers in the United States. Agriculture in Arkansas relies significantly on the MRVAA for irrigation, due to its accessibility and high yield. Increased irrigation demand since the early 1900s with continued expansion and inequitable recharge contributions resulted in groundwater decline. Overdraft of the MRVAA in Arkansas has resulted in the designation of critical groundwater areas. Managed aquifer recharge (MAR) methods intentionally replenish stressed groundwater resources. A MAR case study was conducted to determine whether infiltration basins, as repurposed borrow pits, could be used to enhance groundwater decline in critical groundwater areas of northeast Arkansas. This rehabilitation would be a practical solution to alleviate groundwater decline as well as economically feasible as land would not need to be taken out of production. In 2015, the Arkansas Department of Transportation contracted sand excavation of fallow land owned by a collaborating producer. This borrow pit would serve as a test case to measure infiltration rates into the MRVAA using nearby surface water as the recharge source. Initial soil core analyses revealed soil properties within the confining clay layer of red-brown clay and silty clay soils (0 to 3.7 m deep) with sand below. Excavation completed to a depth of ~6 m exposed the uppermost-unsaturated section of the alluvial aquifer, consisting of well-sorted medium grain size sand. The borrow pit floor was ~27 m above the existing water table, and it was hypothesized that this exposed unsaturated aquifer section would provide a natural filter and an avenue for increased water storage underground. Sediment samples were collected from the pit floor and sidewall pre- and postexperiment to characterize particle size, textural class, and organic matter. Submersible pressure transducers were installed within the pit and in a nearby irrigation well to monitor water level changes. Meteorological data were collected on-site to measure the water budget components of precipitation and evaporation. Water level declines and infiltration were evident throughout the experiment. An initial infiltration rate of 192 mm d⁻¹ was measured in February of 2016 that decreased until March, with steady state rates of 4.43 to 136 mm d⁻¹ that varied until June. An overall integrated infiltration rate of 36.4 mm d⁻¹ was calculated from the water budget. Total subsurface storage increased by 9.3 ML from February to June of 2016, and a two-dimensional simulation predicted a maximum groundwater mounding of 2.6 m during the experiment. Additionally, 14 borrow pits that had not been repurposed were identified in the area using remote sensing. Results of this study demonstrate that a relatively inexpensive MAR strategy could be implemented using former borrow pits repurposed as infiltration basins to alleviate groundwater decline in a critical groundwater area of northeastern Arkansas.

A closed form shape function describing 3D settlement field around a deep excavation in sand

Soil movements produced around deep excavations are one of the main issues to be addressed during design and construction of underground structures in urban environment. Several methods to predict ground movements are currently available. Semi-empirical methods correlate displacements and simple geometrical features of the excavation; these methods predict separately transversal and longitudinal settlement troughs or at least provide a conservative envelope of them and they are mainly based on empirical data of excavations in clay. Numerical methods based on the solutions of FEM or DFM models usually provide prediction of the green field subsidence. In this paper existing 2D semi-empirical methods are first shortly reviewed. Some of these methods are then modified and combined into a new 3D analytical description of the subsidence trough around a deep excavation. The proposed two variable subsidence function depends on several parameters: four independent parameters defining the overall shape and the maximum settlement acting as a scale parameter. Settlement fields reproduced by a 3D FEM nonlinear parametric study of deep excavations inspired by real case studies are thus presented and discussed. The newly proposed 3D analytical description is applied to fit the FEM results and some fundamental relationships among geometrical features of the excavation pit and the 3D shape function parameters are identified. These relationships are validated via the application to three case studies of deep excavations in sand where the subsidence was controlled by the deformation of the retaining structures finding a satisfactory and encouraging agreement.

Centrifugal Test Replicated Numerical Model Updating for 3D Strutted Deep Excavation with the Response-Surface Method

Centrifugal tests provide an efficacious experimental process to predict the behavior of deep excavations, and numerical models are indispensable for demonstrating the test results and analyzing the engineering demand parameters. Uncertainty in material properties can cause simulations to differ from tests; therefore, updating the model becomes inevitable. This study presents a response-surface-based model updating technique for the nonlinear three-dimensional simulation of the centrifugal testing model of strutted deep excavation in sand. An overview of the fundamentals of the response-surface model is provided, including selecting uncertain parameters as input factors, creating a design order for training the model, building a second-order polynomial surface, and updating the input factors through targeted centrifugal results. The bending strains of diaphragm wall panels at multiple points along the depth are used to form the multiobjective function. Response-surface model predictions were well-matched with actual numerical responses, with less than a 0.5% difference. Parametric analyses could be conducted utilizing this updated strutted deep excavation model.

Optimized extreme gradient boosting machine learning for estimating diaphragm wall deflection of 3D deep braced excavation in sand

In a deep braced excavation, wall deflection plays an important role in its safety and also adjacent buildings. However, most of previous studies focused on predicting wall deflection caused by excavations in clay. Therefore, this paper intends to develop a machine learning (ML) method to predict the maximum wall deflections of deep braced excavations in sand, which has not yet received much attention. To this end, an advanced ML model of extreme gradient boosting (XGBoost) is employed. The performance of XGBoost model is optimized by using Bayesian optimization (BO) algorithm and fivefold cross-validation technique. For the development of the ML model, an extensive dataset is generated from large numbers of three-dimensional (3D) numerical simulations. The validation of the numerical model is conducted by using a centrifuge test. The wall deflections predicted by the optimized ML model indicate good agreement with the numerical results. The feature importance and feature interactions of the model are clearly assessed. Parametric study is also implemented to quantitatively investigate the effects of the input parameters on the maximum wall deflection. A web application for predicting the maximum wall deflection induced by excavations in sand is deployed and made available to the public.

Soil disturbance induced by EPB shield tunnelling in multilayered ground with soft sand lying on hard rock: A model test and DEM study

A large scale model test and numerical simulation using three dimensional discrete element method (3D DEM) were carried out in parallel to study the soil disturbance induced by earth pressure balanced (EPB) shield tunnelling in multilayered ground with soft sand lying on hard rock. The model test used a miniature EPB shield machine which could fully reproduce the real tunnel construction of excavation and support. The DEM model simulating the model test was developed to capture the microscopic mechanisms of ground deformation. The surface and subsurface settlement were closely recorded in model test and compared with those of homogeneous ground to clarify the influence of underlying rock on the movement of overlying sand. The volume ratio of rock to sand in excavated muck was closely recorded in DEM simulation to quantitatively analyse the over excavation of soft sand. Results show that both the surface and subsurface settlement trough in multilayered ground are narrower than those in homogeneous ground, while the subsurface settlement in multilayered ground is larger than that in homogeneous ground. The width parameter of settlement trough decreases nonlinearly along the gravitational direction. The over excavation of overlying soft sand is influenced by the ratio of hard rock to tunnel cross section and the rotating speed of shield cutterhead.

Persepsi Masyarakat Dalam Kegiatan Antropogenik Yang Berpengaruh Terhadap Kerentanan Das Hulu Percut

ABSTRACT Anthropogenic danger is a danger that arises as a result of human actions or mistakes. Anthropogenic hazards can affect humans as well as wider ecosystems and various landforms. The influence of human activities on river ecosystems has encouraged the development of the concept of bioindicators to determine the health status of aquatic ecosystems. Percut river water quality is influenced by human activities that utilize the land around the river. The activities carried out by the community are for irrigation sources, pond irrigation, sand excavation and daily needs. Assessment of watershed vulnerability to anthropogenic activities using community perception approach. It is used because people's perceptions can directly build awareness and alertness in the face of danger and vulnerability. This study aims to determine the perception of society in anthropogenic activities in the upstream Percut watershed area and determine the relationship between the perception of the upstream Percut watershed to the behavior of anthropogenic activities that affect the vulnerability of watershed. This study uses survey methods. Data collection was done by: (a) Observation (observation), (b) structured and free interviews (questionnaires), and (c) secondary Data that support the research and the data were analyzed using Spearman rank correlation test. The results showed that the level of public perception in anthropogenic activities that affect the vulnerability of watershed is included in the category of moderate. Upstream communities assume that if the river is damaged, it will cause damage to the downstream, which will then affect the needs of the community directly. The perception and behavior of upstream peoples towards anthropogenic activities falls into the category of moderate. That means that there is no relationship between perception and behavior in the upstream Percut watershed quality. Keywords : Upstream Percut Watershed, Perception, Behavior, Anthropogenic