Subjects -> MINES AND MINING INDUSTRY (Total: 81 journals)
Showing 1 - 42 of 42 Journals sorted alphabetically
American Mineralogist     Hybrid Journal   (Followers: 16)
Applied Earth Science : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 4)
Archives of Mining Sciences     Open Access   (Followers: 3)
AusiMM Bulletin     Full-text available via subscription   (Followers: 1)
BHM Berg- und Hüttenmännische Monatshefte     Hybrid Journal   (Followers: 2)
Canadian Mineralogist     Full-text available via subscription   (Followers: 7)
Clay Minerals     Hybrid Journal   (Followers: 9)
Clays and Clay Minerals     Hybrid Journal   (Followers: 5)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Contributions to Mineralogy and Petrology     Hybrid Journal   (Followers: 14)
Environmental Geochemistry and Health     Hybrid Journal   (Followers: 2)
European Journal of Mineralogy     Hybrid Journal   (Followers: 14)
Exploration and Mining Geology     Full-text available via subscription   (Followers: 3)
Extractive Industries and Society     Hybrid Journal   (Followers: 2)
Gems & Gemology     Full-text available via subscription   (Followers: 2)
Geology of Ore Deposits     Hybrid Journal   (Followers: 5)
Geomaterials     Open Access   (Followers: 3)
Geotechnical and Geological Engineering     Hybrid Journal   (Followers: 9)
Ghana Mining Journal     Full-text available via subscription   (Followers: 3)
Gold Bulletin     Hybrid Journal   (Followers: 2)
Inside Mining     Full-text available via subscription  
International Journal of Coal Geology     Hybrid Journal   (Followers: 4)
International Journal of Coal Preparation and Utilization     Hybrid Journal   (Followers: 2)
International Journal of Coal Science & Technology     Open Access   (Followers: 1)
International Journal of Hospitality & Tourism Administration     Hybrid Journal   (Followers: 15)
International Journal of Mineral Processing     Hybrid Journal   (Followers: 8)
International Journal of Minerals, Metallurgy, and Materials     Hybrid Journal   (Followers: 11)
International Journal of Mining and Geo-Engineering     Open Access   (Followers: 4)
International Journal of Mining and Mineral Engineering     Hybrid Journal   (Followers: 8)
International Journal of Mining Engineering and Mineral Processing     Open Access   (Followers: 6)
International Journal of Mining Science and Technology     Open Access   (Followers: 4)
International Journal of Mining, Reclamation and Environment     Hybrid Journal   (Followers: 6)
International Journal of Rock Mechanics and Mining Sciences     Hybrid Journal   (Followers: 9)
Journal of Analytical and Numerical Methods in Mining Engineering     Open Access  
Journal of Applied Geophysics     Hybrid Journal   (Followers: 17)
Journal of Central South University     Hybrid Journal   (Followers: 1)
Journal of China Coal Society     Open Access  
Journal of China University of Mining and Technology     Full-text available via subscription   (Followers: 1)
Journal of Convention & Event Tourism     Hybrid Journal   (Followers: 6)
Journal of Geology and Mining Research     Open Access   (Followers: 10)
Journal of Human Resources in Hospitality & Tourism     Hybrid Journal   (Followers: 9)
Journal of Materials Research and Technology     Open Access   (Followers: 2)
Journal of Metamorphic Geology     Hybrid Journal   (Followers: 17)
Journal of Mining Institute     Open Access  
Journal of Mining Science     Hybrid Journal   (Followers: 5)
Journal of Quality Assurance in Hospitality & Tourism     Hybrid Journal   (Followers: 6)
Journal of Sustainable Mining     Open Access   (Followers: 3)
Journal of the Southern African Institute of Mining and Metallurgy     Open Access   (Followers: 6)
Lithology and Mineral Resources     Hybrid Journal   (Followers: 4)
Lithos     Hybrid Journal   (Followers: 12)
Mine Water and the Environment     Hybrid Journal   (Followers: 5)
Mineral Economics     Hybrid Journal   (Followers: 2)
Mineral Processing and Extractive Metallurgy : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 14)
Mineral Processing and Extractive Metallurgy Review     Hybrid Journal   (Followers: 5)
Mineralium Deposita     Hybrid Journal   (Followers: 5)
Mineralogia     Open Access   (Followers: 2)
Mineralogical Magazine     Hybrid Journal   (Followers: 1)
Mineralogy and Petrology     Hybrid Journal   (Followers: 5)
Minerals     Open Access   (Followers: 2)
Minerals & Energy - Raw Materials Report     Hybrid Journal   (Followers: 1)
Minerals Engineering     Hybrid Journal   (Followers: 14)
Mining Engineering     Full-text available via subscription   (Followers: 7)
Mining Journal     Full-text available via subscription   (Followers: 4)
Mining Report     Hybrid Journal   (Followers: 3)
Mining Technology : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 4)
Mining, Metallurgy & Exploration     Hybrid Journal  
Natural Resources & Engineering     Hybrid Journal  
Natural Resources Research     Hybrid Journal   (Followers: 4)
Neues Jahrbuch für Mineralogie - Abhandlungen     Full-text available via subscription   (Followers: 1)
Physics and Chemistry of Minerals     Hybrid Journal   (Followers: 4)
Podzemni Radovi     Open Access  
Rangeland Journal     Hybrid Journal   (Followers: 4)
Réalités industrielles     Full-text available via subscription  
Rem : Revista Escola de Minas     Open Access  
Resources Policy     Hybrid Journal   (Followers: 4)
Reviews in Mineralogy and Geochemistry     Hybrid Journal   (Followers: 5)
Revista del Instituto de Investigación de la Facultad de Ingeniería Geológica, Minera, Metalurgica y Geográfica     Open Access  
Rock Mechanics and Rock Engineering     Hybrid Journal   (Followers: 9)
Rocks & Minerals     Hybrid Journal   (Followers: 5)
Rudarsko-geološko-naftni Zbornik     Open Access  
Transactions of Nonferrous Metals Society of China     Hybrid Journal   (Followers: 9)
Similar Journals
Journal Cover
Geotechnical and Geological Engineering
Journal Prestige (SJR): 0.611
Citation Impact (citeScore): 1
Number of Followers: 9  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0960-3182 - ISSN (Online) 1573-1529
Published by Springer-Verlag Homepage  [2626 journals]
  • Amelioration of Soil Expansion Using Calcined Ornamental Stones Hazardous
           Carbonate Wastes
    • Abstract: Abstract Serious environmental hazards can be created due to the accumulation of the ornamental stone carbonate wastes in the Shak Al-Thoaban industrial area, Cairo, Egypt. The present study investigates the use of this waste, after calcination, as a soil stabilizing agent. The effect of the calcined carbonate waste (CCW) on the soil swelling, plasticity, and microstructural and mineralogical compositions has been studied. The stabilization was performed using different CCW doses (1.25–12.5%) and various water amounts (20%, 50%, and 80% by the liquid limit of the natural soil). The stabilized samples were cured for different periods (1 h–90 days). The pH, electrical conductivity (EC), and the mineralogical and microstructural characteristics of the stabilized samples were studied with the proceeding of curing time. The Addition of a small amount of the CCW induced significant improvement in the soil swelling and plasticity in the short term. Significant microstructural and mineralogical modifications were achieved after stabilization. A densely packed cement block-like microstructure developed after two weeks of curing. The XRD results indicated the modification of Na-montmorillonite of the natural soil to Ca-montmorillonite in the stabilized one. Formation of hydrocalumite pozzolanic phase was detected starting from the first day of curing up to 90 days. The results of the thermal gravimetric analysis confirmed the development of the Ca hydrate phase in the stabilized soil sample.
      PubDate: 2021-01-20
       
  • Effect of Drain Pipes on Uplift Force and Exit Hydraulic Gradient and the
           Design of Gravity Dams Using the Finite Element Method
    • Abstract: Abstract The effects of diameter and location of drain pipes on the uplift force and exit hydraulic gradient for a gravity dam are investigated. A numerical model of a gravity dam is simulated using the finite element method. The results indicate that drain pipes under a gravity dam reduce the uplift force and exit hydraulic gradient. The optimal location of the drain pipe with respect to reducing uplift force is 0.25 L (where L is the dam width) from the dam heel, and is 0.75 L with respect to the exit hydraulic gradient. In addition, with increasing drain depth, the uplift force first decreases and then increases. The drain pipe diameter has little effect on uplift force and exit hydraulic gradient and thus its selection should depend on other considerations. When the drain pipe is located at its optimum location with respect to minimizing the uplift force, the volume of dam materials is reduced ~ 30–50%.
      PubDate: 2021-01-20
       
  • Physical Model Testing and Analysis of Hard Rock Tailings Consolidation
           Considering the Effect of a Drainage Inclusion
    • Abstract: Abstract The use of waste rock inclusions (WRI) in tailings impoundments is a novel technique offering various advantages. It is however relatively new and not yet commonly used, so a few key technical issues must still be addressed to optimize the design of WRI. This paper presents an experimental investigation, conducted as a part of a major research program, aimed at assessing the consolidation behavior of tailings during and shortly after hydraulic deposition and the effects of placing a waste rock inclusion in contact with the tailings. The results of a first series of physical model tests performed in an instrumented column with hard rock tailings deposited in successive layers are presented and analyzed to investigate the evolution of pore water pressures, strains and related consolidation parameters at each stage of filling. The results of a second series of experimental tests on tailings with a cylindrical WRI placed at the center of the physical model are then presented and analysed to evaluate how the inclusion influences drainage and pore water pressure at different locations in the tailings. Numerical simulations are also conducted to further assess the consolidation behavior of tailings during sequential deposition and the influence of the WRI. Additional analyses and discussion of the results are also presented to address complementary aspects.
      PubDate: 2021-01-10
       
  • Corrected Rock Fracture Parameters and Other Empirical Considerations for
           the Rock Mechanics of Rock Masses of Doha, Qatar
    • Abstract: Abstract The objective of this paper is to provide insights into the intact rock and rock mass properties of the rock formations under the city of Doha, State of Qatar. We also intend to scientifically clarify these properties by presenting and statistically characterizing the ranges of the parameters, and by discussing the correlations between the parameters with respect to their usage and research potential. The rock quality designation corrected (RQDC) parameter is validated and a new parameter, the fracture index corrected (FIC), is proposed. The significantly improved correlation between RQDC and FIC is demonstrated and their derivation is explained. The paper demonstrates the correlation between the rock mass estimation parameters obtained through rock face mapping and discusses the applicability of the Hoek–Brown criterion to the studied rock masses, which is found to be relevant. A discussion about how properly performed triaxial tests can directly provide the rock constant mi values for all geological members is presented. Other estimation approaches for mi are also validated and compared with the existing knowledge base. Data for laboratory and field intact rock and rock mass parameters are combined using equations from various authors to obtain narrow ranges for rock mass strength and rock mass elasticity modulus values. Finally, within the framework of previous studies by other authors on the low-end transition range of rocks toward soils, it is shown that only the Rus formation member is sufficiently soft and can be included in the range.
      PubDate: 2021-01-05
       
  • The Utilisation of Colloidal Silica Grout in Soil Stabilisation and
           Liquefaction Mitigation: A State of the Art Review
    • Abstract: Abstract Liquefaction mitigation in already existing sites has become a cause of concern for geotechnical engineers across the world. One of the possible solutions for such sites is the recently developed technique called colloidal silica grouting. The technique utilises the slow injection of colloidal silica grout at the edge of the location through injection wells and delivers it to the required location through natural groundwater flow. Later, silica particles gel and bind the soil particle together by changing the pH that, in turn, increases the strength and rigidity of loose soil. The test results obtained from the laboratory and field studies are promising and feasible to recommend colloidal silica as a potential grout material for various soil engineering applications. The present review explains the use of colloidal silica stabilisation for ground enhancement and discusses the treatment method, together with the gelation and significant factors affecting the gel formation. The current paper reviews the tests performed in colloidal silica treated soil to determine the mechanical properties, hydraulic conductivity, and evaluation of liquefaction potential. Scanning electron microscopy analysis of colloidal silica treated soil was also included to explore the microstructural bonding of soil grouted with colloidal silica. Also, the advantages and challenges of colloidal silica grouting techniques in ground improvement are included in the study. Furthermore, future research scope of colloidal silica treated soil in unexplored areas is also mentioned based on the current literature review.
      PubDate: 2021-01-03
       
  • Numerical Analysis of Shallow Tunnels Under Static Loading: A Finite
           Element Approach
    • Abstract: Abstract In the present world, the need for underground structures has grown many folds due to the increasing population, the advancement of public infrastructure, and the scarcity of land. Underground structures also provide attractive alternatives for storage of explosives and other military hardware. Being at shallow depth, their potential impact on the environment and surrounding structures can be significant. Therefore, it is crucial to understand the surrounding material behaviour for the safe and economical design of underground facilities. In the present work, an attempt is made to simulate the in situ condition using finite element, which has been validated by experimental results, to understand the tunnel deformation behaviour under static loading condition in soft rocks. 3D non-linear finite element analysis has been carried out by using Abaqus. Rockmass-tunnel model considered in this study has dimensions of 30 cm × 30 cm and 35 cm. The diameter of the tunnel has been varied from 2.5 cm, 3.5 cm to 5.0 cm. Similarly, the overburden depth is taken as 2.5 cm, 3.5 cm and 5.0 cm. Both the lined and unlined cases of the tunnel have been considered. Geo-material has been prepared in the laboratory having four different compositions of POP, sand, clay and mica. The weathering effect of the rockmass is also considered in the study. Fresh, slightly weathered, medium weathered, and highly weathered are the four different weathering stages of basalt rock taken into consideration. The elasto-plastic behaviour is considered for the natural and synthetic rock, and a Mohr–Coulomb constitutive model is incorporated. Stress and deformation behaviour is monitored for different rocks and geo-materials. Longitudinal and transverse profiles of the tunnel have been plotted to understand the response of tunnel lining and the surrounding rockmass, along and across the point of loading. The paper concludes that the diameter of the tunnel, overburden depth of the tunnel, and weathering of rock has a significant effect on the stability of tunnels under severe loading conditions.
      PubDate: 2021-01-03
       
  • Investigation of the Height of Fractured Water-Conducting Zone: A Case
           Study
    • Abstract: Abstract At present, the prediction of the height of fractured water-conducting zone has become increasingly important for the safety of underground mining, since the mining depth increase continuously. According to mining conditions and petrophysical parameters of overburden strata, a suitable numerical model is established by FLAC3D to carry out numerical analysis on the failure of the plastic zone, the stress distribution and the vertical displacement in the overburden strata with the advancement of 1311 working face. Combining the stress characteristics of the typical “three-zones” theoretical, numerical resolutions of the height of fractured water-conducting zone is obtained by comprehensively analyzing simulation results. Synthesize the numerical solutions and the in situ investigation results, the height of caved zone and fractured water-conducting zone are determined as 53 m and 125 m, respectively. It is pointed out that numerical simulation has the advantages of easy implementation and good accuracy, and can be combined with other methods to accurately predict the fractured water-conducting zone height. The outcome of this work has vital guiding significance for the prevention of roof water disasters and ensuring mine safety in 1311 working face mining.
      PubDate: 2021-01-03
       
  • Anisotropic Behavior of Cohesive Soils by Considering Effect of Gradation
           and Plasticity Characteristics
    • Abstract: Abstract In practice, strength of soils commonly is measured isotropically, while for accurate design of structure foundations and earth structures, it is essential to consider the effect of anisotropy phenomenon on the mechanical behavior of the soils. In previous research, the effect of anisotropy on shear strength of sandy soils has been known and there is some limited work on cohesive soil. Moreover, anisotropy impact is not known on shear-induced pore water pressure. In this research, a series of triaxial tests were carried out on the undisturbed samples of different fine-grained soils, taken at different directions in the sites. The samples were consolidated under effective isotropic stresses of 200, 300, 500 and 700 kPa, and loaded in undrained condition. The results revealed that the behavior of all soils significantly depends on the sample orientation in the field. As the direction of samples changed from “perpendicular to bedding orientation” to “parallel to bedding orientation”, the shear strength decreased gradually and it has the minimum value at anisotropy angle of 72°, 59° and 90° for red clay, yellow marl and olive marl, respectively. The reduction rate completely depends on the soil plasticity and level of confining pressure.
      PubDate: 2021-01-03
       
  • Prediction of Homogeneous Earthen Slope Safety Factors Using the Forest
           and Tree Based Modelling
    • Abstract: Abstract This study assesses the potential of soft-computing based models i.e. Random Forest (RF), Random Tree (RT), M5P, Bagging M5P and Stochastic M5P for predicting safety factors (FS) of homogenous earthen slopes. For this purpose, a homogenous earthen slope was simulated with Slope/W software that uses the limit equilibrium method (LEM). Validation of the method was performed by comparing the calculations with accepted graphical results. For the model performance evaluation, five different statistical parameters including the coefficient of correlation (CC), root mean square error (RMSE), mean absolute error (MAE), scattering index (SI) and Nash–Sutcliffe model efficiency coefficient (NS) were used. Results showed the stochastic M5P based model performing better than other models with CC = 0.9950, RMSE = 0.0716, MAE = 0.0522, SI = 0.0405 and NS = s 0.9894 for the testing stages. The accuracy of the best performing model was confirmed by comparison with reported real FS and common methods. Another important conclusion was that Hybrid M5P-based models work better than traditional M5P-based models for predicting FS of soil slope. Results of a sensitivity analysis suggest that stability number (m) is the most influencing parameter for predicting the FS.
      PubDate: 2021-01-03
       
  • Experimental Investigation on the Influence of Water Content on Mechanical
           Properties and Failure Characteristics of Tuff
    • Abstract: Abstract In order to explore the influence of water content on the mechanical properties and failure characteristics of tuff, uniaxial compression experiments are conducted for tuff with different drying times. The tuff samples are divided into three groups by different drying time named group #, group H and group G, with the drying time increasing in turn. The change rate of water content (WCR) in group H increases linearly with drying time, while that in group G increases steeply first and then slowly, and finally tends to be stable with the mean of WCR at 2.58%. The WCR of tuff is negatively correlated with the mechanical parameters such as the uniaxial compressive strength, and is directly proportional to the coefficient CV of the discreteness in mechanical parameters for each group samples, which means that the lower the WCR, the higher the tuff strength, and the smaller the discreteness in mechanical parameters of same group rock samples. The coincident degree of the stress–strain curves of rock samples in group # and group H is high at the fracture compaction stage, while the difference is obvious in the curves of tuff sample for group G. The rock samples of group # are affected by the pore water pressure, and the microscopic tensile failure characteristics are significant. The specimens of group # show a “shear-tension” mixed failure, and the samples in group H and group G are affected by the localized defects to appear shear failure.
      PubDate: 2021-01-03
       
  • Ground Support Design of Underground Openings in Seismically Active Mine:
           A Case Study from a Lead and Zinc Underground Mine
    • Abstract: Abstract Ground control is multi-tasking and continuous process for the stability of underground openings. Balya underground lead and zinc mine is an important case study area due to its deepest working condition and the highest production amount among Turkish underground metalliferous mines. Mining-induced seismicity needs to be investigated especially for deep as well as tectonically active mine sites. Increasing depth will increase the stress around an underground opening that is a key factor of rock-burst hazard. Rock burst potential can be estimated from analytical approaches based on the relation between rock mass strength and stress around openings; however, one of the best way is to monitor the mining-induced seismicity. The support system is designed based on the actual geotechnical conditions determined from the excavated working face prior to support applications in the mine. Empirical methods are then used to make a decision about the support system. If the location is designated as a seismically active region based on micro-seismic event results, support components are selected as a dynamic support system that must absorb the energy released from the surrounding rock masses. The purpose of this study is to investigate seismically active locations according to mining-induced seismicity and the support system design principles for that locations to protect the openings against seismic loads.
      PubDate: 2021-01-03
       
  • Instability Modes and Stability Analysis of Perilous Rock Groups with
           Control Fissures Under the Conditions of Excavation and Rainfall
    • Abstract: Abstract Influenced by external factors, perilous rock is prone to evolve into geo-hazard. Prevention and control design of geo-hazard is closely related to the correct quantitative analysis of the stability as well as in-depth study of the instability mode. As the main rock, limestone is widely exposed in the study area, which has resulted in perilous rock groups with control fissures at trailing edges. Monitoring data and investigation reveal that rainfall and roadway excavation are the main external inducing factors of perilous rock groups. Representative geo-mechanical models of the perilous rock groups were constructed based on the engineering geological investigation. Their mechanical behaviour affected by different inducing factors was analyzed, and the instability mode under the most dangerous condition was examined by the numerical simulation based on the discrete element theory. It is found that influenced by rainstorm and excavation, the overall instability mode of perilous rocks with specific geological structure can be divided into sliding and toppling tensile-shear failure. Furthermore, the overall stability of perilous rocks corresponding to these two modes was quantitatively analyzed using the limit equilibrium and fracture mechanics theories. The calculation results are considered to be reasonable and reliable due to the good agreement of the calculation theories with the failure mechanism of perilous rocks.
      PubDate: 2021-01-03
       
  • Study on Surrounding Rock Movement of Fully Mechanized Top-Coal Caving
           with Strong Impact Under Thick-Hard Strata
    • Abstract: Abstract In view of the serious damage of roadway and the severe roof weighting of the 3302 working face, microseismic monitoring and surrounding rock displacement monitoring system were used to conduct on-line in-situ monitoring. In this paper, the energy distribution and microseismic event distribution of stope in the primary impact stage and the “square” stage (The working face is pushed to the stage where the strike length of the mined-out area is equal to the dip length, i.e., the stage of “square” of the working face.) are studied. On this basis, the deformation and failure law of the roadways is analyzed. Furthermore, the breaking regularity of multiple thick and hard strata with fully mechanized top-coal caving is obtained. Due to the high span of the fully mechanized caving face, the failure region of the overlying strata expands. As the fracture of the 3rd hard layer, the rotation and deformation of the upper rocks expand. With the periodic fracture of the 3rd hard layer, the hanging area of the 6th hard rock layer increases, which finally leads to its fracture. The weighting of stope is severe during the “square” stage, which is recorded through field monitoring. Through the preliminary analysis, it is concluded that the fracture of the 3rd and the 6th hard stratum contribute to the severe weighting during the “squire” stage, which is easy to induce rock burst. Over the primary impact period, the occurrence of seismic events is frequent and the ground pressure is strong. The maximum approach between two sides of roadway is about 750 mm, and that between the top and bottom is 1300 mm. The periodic weighting of three different “source points” is analyzed by numerical simulation. It is found that the peak value of leading abutment pressure in “square” stage is 82.09 MPa. Finally, the high risk zone of rock burst is obtained, and the predictable “pressure relief zone” is determined, which provides an important reference value for the prevention of rock burst in multi-layer thick and hard rock strata in a super kilometer deep well.
      PubDate: 2021-01-03
       
  • Exploring the Applicability of Low-Cost Capacitive and Resistive Water
           Content Sensors on Compacted Soils
    • Abstract: Abstract Soil water content measurement is crucial during compaction control of embankments. The current techniques used to measure the soil water content in the field are outlined, and their advantages and limitations are indicated. Most techniques require destructive sampling and yields late results, or involve expensive equipment and are hard to set up. Low-cost capacitive and resistive moisture sensors entered successfully in last decades in agronomy applications to automatize crops irrigation. The purpose of this study is to identify whether these sensors are reliable to be used in geotechnical engineering and, in particular, to what extent can they aid compaction control of embankments. Three resistive sensors and two capacitive sensors are tested on five types of soils prepared with a wide range of water contents. The experimental procedures are described, and the sensors output data are compared with water contents obtained from the oven-drying technique. A new device that allows calibration of the sensors on compacted soils is developed. Soils characteristics that can influence moisture measurement using capacitive and resistive sensors are also explored. Test results suggest that some of the sensors can estimate the soil water content on compacted fine grained soils, when proper calibration procedure is successfully achieved. Sensors accuracy tend to increase as the soil void ratio decreases. Such sensors may be useful for expedite measurements, especially, when later counter-prof is available, or when a wide interval for the water content is acceptable.
      PubDate: 2021-01-03
       
  • Dynamic Responses of Reinforced Soil Model Wall on Soft Clay Foundation
    • Abstract: Abstract This paper investigated the relative seismic response of reinforced soil retaining wall overlying a soft clayey soil layer—applicable to road or railway embankment. A series of 1D shaking table tests, 0.1 to 0.5 g, were conducted on the 1 m high physical model. The scaled physical model was subjected to harmonic sinusoidal input motions at frequencies of 1 Hz, 3 Hz, 5 Hz, 10 Hz, 12 Hz, and 15 Hz. A laminar box was used to enclose the soil during the experiment. The variation of parameters such as base motion excitations; frequencies; and surcharge pressures were studied. The results of this study revealed that these parameters have a significant influence on the model wall and vary along the elevation; impacting pore water pressure as well. It also had an impact on the variation along the depth of the clayey soil layer. Maximum face deformation was observed at the top layer of the wall.
      PubDate: 2021-01-03
       
  • Research on Roof Cutting and Pressure Releasing Technology of Cumulative
           Blasting in Deep and High Stress Roadway
    • Abstract: Abstract Affected by high in-situ stress and mining activities, In the original support scheme, entry of guotun coal mine is seriously deformed. The side of the head entry bulges out seriously and the roof sinks seriously. In order to solve the problem of large deformation of roadway, guotun coal mine adopts the technology of a nonpillar mining method with entry automatically retained in 4306 mining face. First, taking method of theoretical analysis, the stress model of blasthole under the deep condition is established, the mechanical conditions of crack propagation under the action of directional detonation wave and high surrounding rock binding force are obtained theoretically. Next, the mechanical model of roof cutting and pressure relief is established. Afterwards, The mechanical model of directional blasting under the condition of stress constraint is established by using LS-DYNA numerical calculation software, the evolution characteristics of effective stress and the law of crack growth are analyzed. In the end, the field test was carried out in 4306 mining face, and the blasting effect was observed by drilling peep, and the deformation of the head entry before and after pressure relief was monitored and analyzed. The results show that directional fracture blasting can produce a continuous crack, and the effect of pressure relief is remarkable, effectively controlling the deformation of surrounding rock under high in-situ stress.
      PubDate: 2021-01-03
       
  • A Quick Approach for Estimating Load Transfer of Conventional and Helical
           Piles in Ice-Rich Frozen Soils
    • Abstract: Abstract This paper introduces a new approach for predicting load carrying capacity of circular section piles and helical piles in frozen ice-rich soils based on ground's freezing temperature and the temperature-dependent cohesion. Results obtained using this approach were validated against a field measured load carrying capacity for model single-helix helical piles, steel open-ended pipe piles, and cylindrical concrete piles in unfrozen and frozen Leda clay. The piles were first tested before wintertime while the ground was in unfrozen condition. The measured load carrying capacity in the unfrozen condition agreed well with the predicted capacity obtained from a modified previous design model for helical piles and the alpha method for the circular section piles. Modified formulae from these models were developed and used for predicting the load carrying capacity of the test piles in the ground after freezing. The predicted pile capacities agreed well with the measured load carrying capacities in the frozen ground. The introduced design approach was beneficial in providing accurate predictions for different pile types, under different loading conditions, and using readily obtained input parameters (i.e., ground temperature and the temperature-dependent cohesion strength). The presence of a snow layer on the ground surface reduced the frost depth penetration and led to a significant reduction of the load carrying capacity of the test piles particularly the helical piles.
      PubDate: 2021-01-03
       
  • Laboratory Investigation of Pullout Behavior of Open-Ended Pipe Helical
           Soil Nail in Frictional Soil
    • Abstract: Abstract In the present work, an experimental study has been conducted to investigate the pullout behavior of helical soil nails fabricated using a hollow pipe with an open end. The main objective of the study is to evaluate the contribution of soil plugging during torque installation and progressive pullout of open-ended helical soil nail (OPHN). The OPHN is installed in a model tank filled with cohesionless soil and subjected to pullout testing. Five different combinations of OPHN varying in shaft diameter (d), helix diameter (Dh), and the number of helices have been used. The test results show that with an increase in Dh/d ratio and surcharge pressure, both installation torque and peak pullout capacity increases. For OPHN, pullout capacity is related to installation torque by a torque coefficient (Kt) varying from 28.12 to 53.3 m−1. The effect of soil plugging is examined in terms of plug length ratio depicting values from 0.19 to 0.28 and constituting 12% of total mobilized shaft friction. The results also depict that installation torque and pullout increase with increasing plug length which depends on ‘d’ and is independent of the number of helices. Smaller soil plug length corresponds to higher axial strains during the pullout of OPHN.
      PubDate: 2021-01-02
       
  • Experimental Study on the Mechanical Behavior of Cemented Soil Reinforced
           with Straw Fiber
    • Abstract: Abstract An experimental program was conducted to evaluate the effect of straw fibers and cement percents on the mechanical properties of low plasticity clay soil. This research work aimed to assess if the straw fibers addition can enhance the strength properties of untreated and cement treated soil. Further, a few numbers of researches have been done on using straw fibers in reinforcing clay soils. In the present study, four percent; based on the dry weight of soil; of straw fibers (0.25, 0.5, 1.0 and 1.5%) and three percent of cement (2, 4 and 6%) were used. All soil samples (untreated and cement treated samples) were prepared at optimum moisture content (OMC) and maximum dry unit weight (γdmax) of natural soil. The cemented un-reinforced and fiber-reinforced samples were cured for different curing periods (varied between 3 to 90 days) at 20 °C. Different tests including unconfined compression, P-wave velocity, water absorption capacity (WAC) of straw fiber, electrical conductivity, pH and scanning electron microscopy tests were investigated. The test results show that the strength behavior of soil samples depends considerably on the percents of both straw fibers and cement. The increase in the unconfined compressive strength (UCS) is most apparent in the un-cemented and cemented soil samples having 0.5% straw fibers percent. While this increase in the UCS is linear with increasing cement percent (i.e. as cement percent increase the UCS increased). Further, the contribution of both straw fibers and cement percents in the increasing the UCS is much more than the increase caused by them individually. The stress–strain behavior of soil samples changes from brittle behavior to ductile one with straw fiber addition.
      PubDate: 2021-01-02
       
  • Centrifuge Modeling of Soft Soil Reinforced with Granular Columns
    • Abstract: Abstract This paper presents a geotechnical centrifuge model of an embankment built in stages, over a 6.0 m layer of soft soil reinforced with nine floating granular columns arranged in a 3 × 3 square grid. The container was divided in two compartments where reinforced and unreinforced soil were tested simultaneously for comparison purposes. The load was applied by means of a 4 m high sand embankment (prototype dimensions) built in three steps. For each step, the centrifuge was stopped to allow the placement of the embankment layer and then re-accelerated up to 26 g and the excess of pore pressure was allowed to dissipate after each step. The instrumentation, comprised of total stress cells, pore pressure transducers and displacement transducers, was configured to collect information about the load transfer mechanism between the soil and the instrumented central column for each loading step during pore pressure dissipation. Results showed that despite representing only 30% of the total load, the first step provoked almost 70% of total vertical displacement. Finally, the columns were exhumed for a detailed and comprehensive visual analysis aiming to support and explain the results obtained.
      PubDate: 2021-01-02
       
 
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