Rock Piles Research Articles

An Experimental Study on the Socketed Pile in Soft Rock

Pile foundation systems are used in India in many projects such as metro and railways, flyovers, and multi-story buildings. The pile transfers superstructure load to the substructure, i.e. to rock layers by means of skin resistance and end-bearing resistance. In this study, an attempt is made to observe the performance of socketed piles in soft rock. A series of socketed small-scale model pile load laboratory studies have been conducted using the loading frame. Load tests were performed on a model steel pile to calculate its axial load-bearing capability at various socket depths. An unconfined compression test was performed on pseudo-rock variations to find out the properties of the soft rock used. The results showed the ability of the drilled pile to enhance the strength of the pseudo rock. An attempt was also made to calculate the optimum depth for the socketed pile in soft rock.

The Influence of Crest Width and Working States on Wave Transmission of Pile–Rock Breakwaters in the Coastal Mekong Delta

The coastline of the Ca Mau and Kien Giang provinces in the Vietnamese Mekong Delta has been severely eroded in recent decades. Pile–Rock Breakwaters (PRBWs) are among the most widely adopted structures for controlling shoreline erosion in this region. These structures are effective for wave energy dissipation, stimulating sediment accumulation, and facilitating the restoration of mangrove forests. These breakwaters are generally considered to be the best-engineering practice; however, there is currently insufficient scientific evidence with regard to specific structural design aspects. This can lead to PRBW structures being compromised when deployed in the field. This study used a physical model of a PRBW in a laboratory to investigate several design parameters, including crest width and working states (i.e., submerged, transition, and emerged), and investigated their relationship with the wave transmission coefficient, wave reflection coefficient, and wave energy dissipation. To investigate these relationships further, empirical formulas were derived for PRBWs under different sea states and crest widths to aid the design process. The results showed that the PRBW width had a significant influence on the wave energy coefficients. The findings revealed that the crest width of the breakwater was inversely proportional to the wave transmission coefficient (Kt) under the emerged state. The crest width was also proportional to the wave reduction efficiency and wave energy dissipation in both working states (i.e., the submerged and emerged states). The front wave disturbance coefficient (Kf) was found to be proportional to the wave reflection coefficient, and the wave height in front of the structure was found to increase by up to 1.4 times in the emerged state. The wave reflection coefficient requires special consideration to reduce the toe erosion in the structure. Lastly, empirical equations including linear and non-linear formulas were compared with previous studies for different classes of breakwaters. These empirical equations will be useful for understanding the wave transmission efficiency of PRBWs. The findings of this study provide important guidance for PRBW design in the coastal area of the Mekong Delta.

Experimental and Numerical Analysis of Pile–Rock Interaction Characteristics of Steel Pipe Piles Penetrating into Coral Reef Limestone

In order to study the characteristics of pile–rock action of steel pipe driven pile in coral reef limestone stratum, coral reef limestone at the China–Maldives Friendship Bridge site was selected to carry out indoor physical and model tests with red sandstone as the control group. The test outcomes indicate the following: (1) when substantial deformation is permitted, the coral reef limestone has a considerable strength dispersion, a low post-peak stress decrease rate, and a high residual strength, roughly 30% of the peak strength; (2) when the steel pipe pile penetrates the coral reef limestone, the pile top load shows an obvious sawtooth shape, and with the increase in penetration depth, the pile end load of the high-porosity rock sample gradually decreases, and the pile end load of the low-porosity rock sample gradually increases; (3) when the steel pipe pile is penetrated, the strain value of the red sandstone is about twice that of the coral reef limestone at the same position from the steel pipe pile. These findings indicate that the high porosity and heterogeneity cementation characteristics of the coral reef limestone make the extrusion effect during piling significantly less than that of the red sandstone. In addition, the steel pipe pile penetration process is numerically simulated using a four-dimensional discrete spring model method based on the multi-body damage criterion. The numerical simulation results further demonstrate that the pile-side rock fragmentation during steel pipe pile penetration is the primary reason for the lower bearing capacity of steel pipe piles in coral reef limestone stratums. This method provides a novel approach for studying the mechanical properties of reef limestone. The findings can serve as a guide for the design and construction of steel pipe piles in the reef limestone stratum.

Textural and geochemical characteristics of gold-associated scheelites: Implications for the metallogenesis of the Xiaoqinling gold province, north China Craton

Gold deposits in the Xiaoqinling province, southern margin of the North China Craton, are hosted by Neoarchean amphibolite-facies rocks of a metamorphic core complex. Over 630 t of gold resource was concentrated in the narrow-uplifted basement, which was classified into three (northern, middle, and southern) major ore belts. Gold-related scheelite grains from the Qinnan and Qiaoshangzhai (northern belt), Tonggou (middle belt), and Yangzhaiyu (southern belt) deposits were analyzed using a combination of cathodoluminescence (CL) imaging and LA-ICP-MS trace element analysis to decipher their metallogenesis. Our new results indicate that: (1) the Xiaoqinling scheelites are characterized by high Sr content and varying internal texture, replicating fluid-rock reactions. Oscillatory zoning and inhomogeneous trace element compositions suggest a dynamic hydrothermal system with fluctuating chemical properties; (2) the REEs of Xiaoqinling scheelites were mainly controlled by the substitution mechanism 2Ca2+ = REE3+ + Na+. All scheelite grains yielded typical bell-shaped REEN patterns, with negative and positive Eu anomalies occurring in samples from the Qinnan-Qiaoshangzhai and Tonggou-Yangzhaiyu deposits, respectively. Meanwhile, the scheelite Mo concentration in the northern belt (>100 ppm) is much higher than that in the middle and southern belts (<20 ppm), suggestive of significant variations in the oxygen fugacity (fO2). The spatial association of the northern ore belt with the Taiyao detachment fault may imply an increase in the fluid fO2 by percolating meteoric waters; (3) the obtained scheelite 87Sr/86Sr ratios show a broadly increasing trend from north to south (are 0.71480 to 0.71626 for Qinnan, 0.72784 to 0.72920 for Qiaoshangzhai, 0.71864 to 0.76251 for Tonggou, and 0.72760 to 0.74781 for Yangzhaiyu). This trend may depict the ore-fluid flow direction, i.e., the Sr isotopic signature shifted towards a more radiogenic composition with increasing distance from north to south due to fluid reaction with the Taihua Group (amphibolite- to granulite-facies metamorphic rock pile).

EVALUATION OF THE PILE BEARING CAPACITY IN ROCK INTERBEDDED BY COHESION SOILS UNDER VERTICAL LOADING

Introduction . The current regulatory calculation procedure for piles in rocks provides a means to determine the bearing capacity of a pile embedded in a solid rock mass containing no weak interlayers. However, it is not uncommon in actual design practice for rocky soils to be interbedded with softer and less stiff dispersive soils, whose presence affects pile performance. In this case, a summation of estimated resistances along the pile length and at its foot overestimates its estimated bearing capacity, which does not correspond to the actual work due to the different rates of friction force generation in soils of varying formations. Aim . To develop a procedure for determining the bearing capacity of a single bored cast in place pile interacting with rock mass interbedded with cohision soils under vertical indentation loading. Materials and Methods . The procedure for estimating the skin friction resistance of a pile penetrating rocky and dispersive soils is based on the analysis of static pile tests and numerical simulation, taking into account tabulated and analytical solutions given in regulatory literature. Results . A procedure for determining the bearing capacity of a single pile interacting with a rock mass interbedded with cohision soils was developed using tabulated solutions given in regulatory literature, empirical dependencies, and numerical simulation. As a criterion for the ultimate shear resistance of bearing soil, a formula for reference settlement S ref is proposed, which factors in pile dimensions and the characteristics of the pile shaft material. The extent to which the pile bearing capacity is sensitive to the parameters of the model and computational assumptions of numerical modeling is analyzed. The presented examples of determining the design pile bearing capacity via the proposed procedure show results similar to experimental data obtained in the field tests. Conclusions . The presented method allows engineers to factor in the skin friction resistance of cohision soil interbedding in the rock mass to increase its design bearing capacity.

Dynamic Responses of Embedded Rock Pile Groups due to Rock Burst considering Coupled Pile-to-Pile Interaction

Abstract This note presents an analytical solution to investigate the dynamic behavior of pile groups of embedded rock due to rock burst, which takes into account the interaction between piles. The energy generated by the rock burst propagates through the soil in the form of stress waves. It is transmitted to the pile foundation through the interaction between the soil around the pile and the pile. For rock-socketed piles, the condition of pile tip fixing is considered. The horizontal dynamic response calculation model of the pile group is established, and the analytical forms of the pile group stiffness and pile group interaction factor are obtained. In addition, the effect of saturated soil parameters on the dynamic response of pile groups are discussed.

Performance assessment of a rock aggregate heat exchanger exposed to daily temperature variation

Opportunities exist to utilize rock aggregate to condition ventilation air at mine sites in humid continental climates. Vale’s Creighton mine in Canada proved that a natural heat exchanger offered significant energy savings; however, the system was not suitable to establish design guidelines. A novel prototype-scale outdoor 30 m3 rock pile heat exchanger experiment was constructed to characterize the thermal response to measurable aggregate parameters with insight shared regarding their sensitivity. This paper validates an unsteady 3D CFD numerical methodology involving the thermal non-equilibrium porous zone model with lab-scale-derived correlations against weather-influenced temperature data and proposes guidelines for improving performance: Increasing pile flatness was beneficial for damping whereas increasing hemispericality was beneficial for phase shifting. A CFD case study requiring 47 m3/s (100,000 cfm) ventilation flow found that a rock pile constructed using traditional methods could achieve 100% damping with 6,000 m3 of granitic rock aggregate at a pressure penalty of 2,500 Pa.

Field and Economic Studies on Mine Waste: Sustainable Reuse as Aggregates for Low Traffic Pavement Structure

The phosphate extraction and processing has followed a traditional linear consumption model, where wastes are continuously produced and surface land is filled in rock piles. Thus, to promote a circular economy in a mining context, more eco-friendly and sustainable solutions at the regional level are needed. This paper deals with the potential utilization of phosphate screening waste rock 0–100 mm (SWR) as alternative aggregates for pavement applications. Detailed in situ and laboratory tests have been made for SWR characterization, and the practical modalities of implementation have been defined. The findings proved that SWR (10–100 mm) materials can be successfully used without treatment in capping layer construction for low-volume traffic pavement projects. Due to its high apatite content, the remaining fraction (0–10 mm) can be exploited to recover the residual phosphate using the processing method that is currently followed by the mining company. Furthermore, the environmental investigations showed that SWR does not present any potential contamination risk to the surrounding environment. The economic feasibility analysis confirmed the workability of SWR reuse in a radius of 100 km around their dumps due to its lower cost compared to conventional aggregates. This simple amendment may ensure a smooth transition from a current linear extractive approach to a circular economy.

Introduction of advanced water management technologies in the Orenburg mining region

The Orenburg Region is rich in various minerals. Dozens of oil and gas fields are being developed on its platform sediment part, while the mountain-folded areas hold deposits of non-ferrous, ferrous and precious metals, rare and radioactive elements, bituminous coal and lignite, and non-metallic minerals. Huge land areas are disturbed by mining, occupied by stock piles of waste rocks and lowgrade ore, and are polluted with spills of oil and deep brines. The economic development of the region is accompanied with an increase in pollution and depletion of water resources. Wide distribution of alkaline land, saline-alkali soils and granitoids containing radon and toxic products of its decay aggravates the impact on the regional hydrosphere. In this regard, it is necessary to study the complex hydrogeology in the region and to evaluate the water quality. The important problems to be solved include: development of the reservoir appraisal methodology; chemical and bacteriological analysis of water and its sensitivity to secondary salinization processes and relics of the marine salt complex; substantiation of water spreading and contamination prevention technologies. The developed recommendations are meant to reach the objective of introduction of modern water management technologies into production as per the resolution of the Russian Government. The article discusses feasibility of water management technologies as a case-study of the Svetly district of the Eastern Orenburg region and the Orenburg urban agglomeration, and necessitates recommendations for their implementation under diverse conditions within the Orenburg Region. As a result of the methodological approach, calculations and modeling of the situation in the mining areas of the Orenburg Region, the effectiveness of the technology of water spreading by means of accumulation of flood water in the local river is proved. The water spreading approach using the active water intakes and conservation reservoirs can increase the productivity of operating wells by 1.5&ndash;2 times, enable avoiding depletion of the aquifer and allow meeting the needs of the Orenburg Region&rsquo;s population in drinking water.

Improved imaging efficiency of large mine waste rock piles with integrated electrical and electromagnetic geophysical techniques

Acid mine drainage (AMD) can emanate from mine waste rock piles (WRPs) for extended periods, resulting in severe environmental contamination. Since the generation and release of AMD is dependent on the volume and composition of acid-generating waste rock, effective characterization of WRPs is necessary for successful long-term AMD management. Conventional methods such as coring and test pits are invasive and only provide sparsely distributed point information in WRPs which are typically large and highly heterogeneous. Geoelectrical methods such as direct current (DC) resistivity, time-domain induced polarization (TDIP) and electromagnetics (EM) can provide non-invasive and continuous information of WRPs. However, due to the enormous scale of typical WRPs, improved strategies are needed for more efficient imaging. The objective of this study was to demonstrate the improved efficiency of integrated imaging techniques with rapid but low-resolution EM, and laborious but high-resolution DC and TDIP, to characterize the acid-generating regions of a coal mine WRP in Nova Scotia, Canada. EM was first employed to rapidly image the entire pile footprint and locate zones with high conductivity. Focused 3D DC and TDIP surveys were then performed over these zones, which were <10% of entire WRP, to better characterize the associated waste rock composition. DC and TDIP images indicate coincident and continuous areas of low resistivity (<15 Ohm·m) and high chargeability (>15 mV/V), which are indicative of generated AMD (leachate) and stored AMD (sulfides), respectively. This interpretation is validated by corresponding geological and geochemical measurements within the WRP. This study demonstrates the value of integrating complementary electrical and electromagnetic methods for more efficient characterization of large mine WRPs, with EM rapidly locating zones of interest, and simultaneous DC and TDIP imaging then discriminating between areas that generate AMD and areas that are affected by AMD flow paths.

Climate Change and Environmental Influence on Prevalence of Visceral Leishmaniasis in West Pokot County, Kenya.

Kala-azar is a parasitic disease caused by Leishmania species transmitted by sand fly. In Kenya, kala-azar is endemic in thirty subcounties spread over in eleven counties in the arid zones. Climate change-influenced seasonal weather variability and environmental alterations remain important determinants of many vector-borne diseases. The present study focused on climate change and environmental influence on kala-azar in West Pokot. A descriptive cross-sectional and retrospective research design was adapted. Study area was purposively selected. Locations were randomly selected, and households were systematically selected. Three hundred sixty-three household questionnaires, eleven key informant interviews, and five focus group discussions were undertaken. Secondary data were obtained from Kacheliba subcounty hospital records. Statistical Package for the Social Sciences version 24 was used to analyze quantitative data while qualitative data were analyzed to establish connection for interpretation. Kala-azar cases have been on the rise on aggregate and surge towards the end of dry season and just after the rains. Significant environmental factors included the presence of seasonal rain water pathways and rock piles around houses (AOR = 4.7; 95% CI = (2.3-9.6), p < 0.05), presence of acacia trees in and around homesteads (AOR = 8.5; 95% CI = (2.5-28.6), p < 0.05), presence of anthills around the homesteads (AOR = 5.2; 95% CI = (1.2-23.4), p < 0.05), and presence of animal shed within compound (AOR = 2.8; 95% CI = (0.96-8), p < 0.05). Climate change-induced seasonal weather variability, increased temperature and reduced precipitation as well as environmental alterations influence kala-azar occurrence in West Pokot. Community sensitization on disease prevalence, clearing of vector predilection sites, and improving community environmental risk perception are imperative to promote prevention.

DNA barcodes reveal population-dependent cryptic diversity and various cases of sympatry of Korean leptonetid spiders (Araneae: Leptonetidae)

Leptonetidae are tiny, rarely encountered spiders that mainly inhabit moist environments, such as caves, leaf litter, and rock piles. Because they are microhabitat specialists, most leptonetid species have short-range endemism, and rarely occur in sympatry. Their small size, relatively simple habitus features and reproductive organ structure increase the difficulty of identification. The identification of leptonetids and other spiders may also be time-consuming due to their sexual dimorphism, polymorphism, and lack of diagnostic characteristics in juveniles. DNA barcoding has been used as an effective tool for species identification to overcome these obstacles. Herein, we conducted a test of DNA barcoding based on 424 specimens of Korean Leptonetidae representing 76 morphospecies. A threshold of 4.2% based on maximum intraspecific genetic divergence was estimated to efficiently differentiate the morphospecies. The species assignments tested by five species delimitation methods (ABGD, ASAP, GMYC, PTP, and bPTP) were consistent with the morphological identifications for only 47 morphospecies (61.8%), indicating many cases of cryptic diversity among the remaining morphospecies. Furthermore, sympatry in leptonetids, which are known to be rare, was revealed to be common in South Korea, especially in epigean species. Our results showed that sympatries within families, congeners, and intraclades potentially occur throughout the entire region of Korea.

Heavy metal release and acid generation during the oxidation of sulfide waste rock induced by ferric iron

As aby-product of waste rock from sulfide ore, Fe3+ is one of the important factors that promote acid production and heavy metals release from waste rock pile fields. In this paper, the dynamic leaching tests were conducted to investigate the behavior of acid generation and heavy metal release from the sulfide waste rock of Dexing copper mine under different Fe3+ concentrations. The Sulphur content in the waste rock samples was 3.56 % and the net acid production potential (NAPP) reached 47.95 kg·t−1 H2SO4. Under the oxidation of 600 mg·L-1 Fe3+, the pH value of the leaching system decreased to 5.53, which is 1.85 units lower than that of the control check group (CK). However, the quantity of SO42- in the leachate was reduced by 41.81 % compared to the CK group, as the jarosite precipitation was more likely to form under high Fe3+ conditions. The oxidation of Fe3+ effectively accelerated the release of heavy metals from the waste rock. In addition, the heavy metals release quantity gradually increased with the increase of the Fe3+ concentration, with the maximum release quantities of Cu, Pb, Zn, and As of 569.69, 333.75, 222.69, and 31.11 μg·kg−1, respectively, which increased by 27.66 %-129.60 % compared to the CK group. The release of SO42-, Cu, Pb, and Zn was controlled by the combined internal diffusion and the chemical reaction, while the release of As was best fitted to the interfacial chemical reaction-controlled model. The SEM analysis showed that the waste rock near the top of the column was strongly corroded, resulting in the increase of the specific surface area of the waste stone by 24.48 %. The re-precipitation reaction of heavy metals mainly occurred near the bottom of the leaching column. Leaching under Fe3+ oxidation caused a decrease in the proportion of residual heavy metals in the waste rock, which will lead to the easier release of heavy metals.

Influence of scour on the vertical response of rock‐socketed piles in layered saturated rock–soil mass

AbstractThe influence of scour on the vertical response of rock‐socketed piles in a layered saturated rock–soil mass is studied through the finite element‐boundary element coupling method. By utilizing the theoretical solution of layered saturated media as the kernel function, the boundary element method (BEM) is used to deduce the boundary integral equations of rock–soil mass. Meanwhile, the pile is modelled with the three‐node bar element and the global stiffness matrix of the pile is assembled by the finite element method (FEM). Then according to the scour type, the flexibility matrix of the foundation is recombined and extended, which is consistent with the stiffness matrix dimension of the pile. In consideration of the force balance and continuity conditions at the pile‐soil‐rock interface, the FEM–BEM coupling equation is established to solve the interaction between layered rock–soil mass and rock‐socketed pile that considers different scour types. A corresponding MATLAB program is compiled to verify the correctness of the present theory by comparisons with the existing literature solutions, field tests and the finite element solutions. The influences of the scour type, scour depth, socketed length as well as pile‐rock mass modulus ratio and rock mass stratification on the vertical response of a rock‐socketed single pile are further discussed through several numerical examples.

Ice-locked huts, snow-buried cairns, and sunken ships: the prevailing discourse on heritage in antarctica

ABSTRACT Cultural heritage in Antarctica simultaneously represents vulnerable historic remains and powerful political resources curated by nation states, for nation states. Political actors transform dilapidated huts, piles of rocks, and submerged ships into opportunities for strategic gain within the practice of Antarctic affairs – but what is the nature of this political discourse? This paper proposes the existence of a prevailing discourse on cultural heritage found in Antarctica comparable to that of Smith’s Authorised Heritage Discourse (the AHD). This discourse embodies how nation states active in the region – the Antarctic Treaty Consultative Parties – think and talk about heritage in Antarctica, and subsequently determines how this heritage is managed in practice. The first two sections investigate how discourse on Antarctic cultural heritage is situated, and how it has been realised. The third and final section scrutinises the characteristics of the Antarctic discourse in relation to the AHD. Consideration of the situation, realisation, and characterisation of a discourse on Antarctic cultural heritage, produces an in-depth account of the discourse overall. Key findings reveal that this discourse behaves very similarly to pre-existing models for global heritage.

Territorializing polar heritage: cultural heritage as a means to exercise symbolic sovereignty in Antarctica

ABSTRACT Cultural heritage in Antarctica is deployed by states for means other than conservation and preservation. Historic remains in this part of the world have come to represent powerful political resources, as well as vulnerable cultural assets. One of the primary geopolitical applications by states is the exercise of symbolic or de facto sovereignty in which states use heritage as a method to demonstrate their durable occupation of territory on and around the continent, and to affect decision-making processes within Antarctic affairs. Ultimately, dilapidated huts and piles of rocks provide states with tangible evidence to assert their past, present and intended future presence in the polar region. This paper investigates the notion of sovereignty within the Antarctic context, before selecting a case example to perform a geopolitical reading of one historic site. It reveals that just as the practice of international relations is often considered a zero-sum game, so can the governance of Antarctic cultural heritage.

Gamma-ray spectrometry applied in the identification of potential acid mine drainage generation zones in waste rock pile with uranium ore and associated sulfides (caldas, Brazil)

Metal mining deeply modifies local environmental dynamics and produces large volumes of waste rock and residues, which is expected to be carefully disposed in order to prevent soil, water, and environment degradation. The Osamu Utsumi mine was a pioneer uranium ore exploitation site in Brazil, located in the State of Minas Gerais. The open pit and the high concentration of sulfide in waste rock piles are nowadays a dispendious concern to the Nuclear Industries of Brazil (INB, in Portuguese), due to sulfide oxidation and the resultant acid mine drainage (AMD). The objective of this research is to analyze the correlation between gamma-ray spectrometry data and the genera- tion of AMD in a waste rock pile, locally known as BF-04. Potassium concentrations can be used to distinguish zones of rock depletion, lowest concentrations, and radioelement sedimentation. The radiometric data acquisition combined with previous studies indicates that high uranium and tho- rium concentrations are associated with high sulfide zones. The mineralized uranium ore includes sulfides that are rapidly destroyed by surface hydration conditions, responsible for generating acid mine drainage. In this sense, superficial zones in the waste rock pile with high levels of eU and eTh are areas exposed to oxidation and hydration of sulfides, and, therefore, their recognition and neutralization can contribute to decrease AMD generation in the study site and areas with similar characteristics. The gamma-ray spectrometry results can subsidize more effective and low-cost reme- diation techniques.

Experimental and Numerical Investigation of the Load-Bearing Mechanisms of Piles Socketed in Soft Rocks

Rock-socket pile design predominantly depends on the shaft resistance to support the load at the serviceability state. However, due to limited understanding of the pile–rock interactions, the pile capacity is normally calculated using empirical correlations. In this study, the load-bearing mechanisms of rock-socketed piles were investigated through a miniaturised pile–load test setup in a soft synthetic rock. X-ray CT imaging and numerical discrete element modelling were used to investigate the micro-mechanics influencing the load-bearing mechanisms at the pile–rock interface. The numerical pile model was established based on suitable constitutive models capable of simulating the soft rock behaviour. The analysis of X-ray CT images at various displacements revealed three different interface mechanisms, namely sliding, local shearing and progressive shearing. The numerical model validated this observed micro-mechanics in the rock asperities through the evolution of damage and micro-cracks. Insights from the experimental and numerical results indicated that the height of the rock asperities significantly dictates the failure mode. Results also illustrated that the shaft load–displacement response primarily depends on the forces acting on the leading edges of the pile asperity. In particular, it was observed that the bottom leading edge carried a predominant portion of the shaft loads due to its connectivity with the rock at the base of the pile. Though negligible, the forces on the trailing edges provided valuable information on the contribution of residual shaft resistance by the debris at the interface. Moreover, the numerical studies revealed the different failure modes at the pile–rock interface. The discussions presented in this study provide novel insights into the load-bearing mechanisms of piles socketed in soft rocks, which will help to improve design guidelines in the future.

Geophysical Diagnosis of Diversion Channel Infiltration in a Uranium Waste Rock Pile

Geophysical Diagnosis of Diversion Channel Infiltration in a Uranium Waste Rock Pile

A method of blasted rock image segmentation based on improved watershed algorithm

It is of great theoretical significance and practical value to establish a fast and accurate detection method for particle size of rock fragmentation. This study introduces the Phansalkar binarization method, proposes the watershed seed point marking method based on the solidity of rock block contour, and forms an adaptive watershed segmentation algorithm for blasted rock piles images based on rock block shape, which is to better solve the problem of incorrect segmentation caused by adhesion, stacking and blurred edges in blasted rock images. The algorithm first obtains the binary image after image pre-processing and performs distance transformation; then by selecting the appropriate gray threshold, the adherent part of the distance transformation image, i.e., the adherent rock blocks in the blasted rock image, is segmented and the seed points are marked based on the solidity of the contour calculated by contour detection; finally, the watershed algorithm is used to segment. The area cumulative distribution curve of the segmentation result is highly consistent with the manual segmentation, and the segmentation accuracy was above 95.65% for both limestone and granite for rock blocks with area over 100 cm2, indicating that the algorithm can accurately perform seed point marking and watershed segmentation for blasted rock image, and effectively reduce the possibility of incorrect segmentation. The method provides a new idea for particle segmentation in other fields, which has good application and promotion value.