Engineering Properties Of Rocks Research Articles

Study of Mineralogy and Engineering Properties of Volcanic Rock at the Base of the Pamukkulu DAM Foundation, South Sulawesi, Indonesia

At the location of the Pamukkulu dam, it has engineering geological characteristics that are less supportive of the construction above it, especially for the foundation of the dam. By taking data directly in the field and by laboratory testing, information is needed regarding the characterization of mineralogy and the engineering properties of rocks. Mineralogical analysis was performed with petrography and X-Ray Diffraction (XRD) while the engineering properties of the rock were performed with Plate Bearing Tests (PBT), Standard Penetration Tests (SPT), and Rock Mass Rating (RMR). Based on mineralogical data, rocks have undergone weathering and converted the chemical-physical properties of minerals into porous, fine-grained minerals, forming mineral oxides as well as clay minerals. The carrying capacity of surface soils in the dam area based on the plate bearing test is relatively poor. As for subsurface rocks, the weight of the rock mass rating belongs to the class (II) Good to (III) Medium. Meanwhile, from the density value of hard soils, there are different depths from a depth of 1 meter to 6 meters. Weathering conditions of rocks affect the engineering value of soils and rocks where due to weathering minerals formed in the form of porous clay minerals, they are not well consolidated.

Predicting the Engineering Properties of Rocks from Textural Characteristics Using Some Soft Computing Approaches.

Rock is used as a foundation and building material in many engineering projects and it is important to determine/predict its engineering properties before project construction. Petrographic and textural characteristics are useful parameters for predicting engineering properties of rocks in such applications. In this research, fifteen rock samples were taken and their engineering characteristics, namely dry and saturated unit weights, porosity, water absorption, slake durability index (SDI), Schmidt rebound hardness (SRH), ultrasonic P-wave velocity (UPV), and uniaxial compressive strength (UCS), were measured in the laboratory. Petrographic and textural characteristics of the rocks, determined from thin section and X-ray diffraction investigations, led to the evaluation of the texture coefficient (TC). Based on simple regression analysis (SRA), the TC values have direct relationships with density, SDI, SRH, UPV, and UCS, and inverse relationships with porosity and water absorption. Experimental models were developed using multiple regression analysis (MRA) and artificial neural network (ANN) to predict Id2, SRH, UPV, and UCS of the tested rocks from the values of TC. Some statistical parameters including Pearson regression coefficient (R), coefficient values account for (VAF), root mean square error (RMSE), mean absolute percentage error (MAPE), and performance index (PI) were calculated to assess the performances of the MRA and ANN models. The correlations between experimental and calculated values of Id2, SRH, UPV, and UCS indicated that predicted values of the ANN models are more valid than the MRA. Additionally, the residual error of the ANN models varies less than the MRA. Finally, it has been concluded that the SRA, MRA, and ANN methods can successfully predict the rock engineering properties from the TC.

Experimental study on the effect of thermal treatment on the mechanical properties of clay-rich rocks (mudstone)

Temperature is one of the most important environmental factors that affect rock engineering properties. The clay-rich rocks such as mudstone are abundant in the earth's crust and have a high affinity to water. So the behavior of these rocks differs from others after thermal treatment, which might force the water out of the clay. Therefore, we investigated the effect of thermal treatment on the mechanical properties of clay-rich rock, mudstone, under three temperatures; ambient temperature, 250, and 500 °C. Our results showed that thermal cracks begin to appear in the mudstone at a temperature between 500 and 600 °C. Several mechanical properties were measured in the lab; uniaxial compressive strength (UCS), elastic modulus (E), Poisson's ratio (ν), Brazilian tensile strength (BTS), fracture toughness of tensile (KIC), and shear (KIIC) cracks. Due to the drying of clay minerals through the dehydration and dihydroxylation processes, the following mechanical properties of mudstone significantly increased after treating the rock with a temperature of 500 °C; UCS, E, BTS, KIC, and KIIC have improved by 91%, 39%, 16%, 41%, and 94%, respectively, while ν decreased by 80%. This reduction of ν, due to increasing the thermal treatment temperature, caused the behavior of mudstone to transform gradually from ductile to brittle material which means that the failure of such rocks, at this temperature, might be a sudden one. This research presents new insights into the effect of temperatures below 500 °C on clay-rich rocks for use in different engineering fields.

Influence of Petrogenesis on the Engineering Properties of Ultramafic Aggregates and on Their Suitability in Concrete

This study focuses on the use of petrology as a useful tool in construction applications (i.e., concrete). More specifically, this study investigates how the petrogenetic characteristics of ultramafic rocks derived from ophiolite complexes (Veria–Naousa, Gerania) can act as a key tool for the prediction of the final behaviour of ultramafic aggregates as concrete aggregates. For this reason, their petrographic, chemical and mineralogical characteristics were examined and correlated with their engineering properties for evaluating their suitability as concrete aggregates. This study had come up, for the first time, that the genesis environment of the ultramafic rocks is the determinant factor for their physico-mechanical characteristics. Their suitability is relevant to the impact of their mineralogical and structural characteristics both from the two different ophiolite complexes (Veria–Naousa and Gerania). Except serpentinization, the basic alteration process-index of ultramafic rocks, there are also other chemical indices which can be used for ultramafic rocks that may determine their properties. In this context the term ‘fertility rate’ (FR) was introduced which may characterize ultramafic rocks as fertile or not. Furthermore, the Ultramafic Rock Health Index (U.R.H.I.) as well as the Normalized U.R.H.I. (U.R.H.I.N) was also introduced and correlated with the engineering properties of the investigated aggregate rocks. The last index aims to assess and quantify the overall health conditions, encompassing the two major modifying factors that include removal of primary mineral phases, as well as the extent of serpentinization. The main conclusion of this paper is that the genesis environment of the ultramafic rocks is the critical factor that determines their mineralogical, petrographic and chemical characteristics which consequently determines the basic engineering properties of rocks that determine their suitability or not as concrete aggregates.

THE INFLUENCE OF PHYSICAL PROPERTIES ON THE COMPRESSIVE STRENGTH OF THE ROCK IN THE SAMIGALUH AREA, KULON PROGO, INDONESIA

The Samigaluh area, Kulon Progo, Indonesia, is composed of rocks from the Old Andesite and Jonggrangan Formations, with very different physical properties. The difference in physical properties indeed results in the engineering properties of rocks, for example, in terms of compressive strength. Studying the relationship between physical properties and rock compressive strength in these two different formations is exciting to find out the extent of the relationship between physical properties and rock engineering. A geological engineering survey was carried out simultaneously with the collection of six rock samples representing intrusive andesite, andesite (breccia and lava fragments), and tuff of the Old Andesite Formation (OAF), limestone (reef/calcarenite) Jonggrangan Formation. Furthermore, rock samples were analyzed physically (petrographically) and mechanically (compressive strength) in the laboratory. The results of field surveys and analysis of laboratory data yield knowledge about the relationship between the physical properties of rocks and their compressive strength. The intrusion andesites and OAF andesites generally have a porphyroaphanitic texture, anhedral - subhedral, hypocrystalline, inequigranular crystal form, with a massive structure, and the composition of plagioclase, quartz, and accessory minerals (hornblende). Fine-textured tuff, hypocrystalline, in the form of glass and crystal tuffs. The Jonggrangan limestones are fine to medium textured, well-sorted, grain supported, with variations of wackestone – packstone. The compressive strength of andesite is 39.98 – 49.36 MPa, calcarenite is 43.32 MPa, reef limestone is 20.44 MPa, and tuff is 11.15 MPa. The compressive strength of rock is influenced by texture (grain size/crystal) with a correlation coefficient of 68% (strong correlation). In comparison, rock composition (percentage of quartz) has a very weak correlation (correlation coefficient of 18%).

Tunnel stability in fault zone base on 3D numerical simulation

Tunnel construction in complex geological environments such as fault zones and discontinuities are some problems in tunnel stability. This research focused on rock mass characterization and 3D numerical modelling of the finite element method to evaluate the diversion tunnel stability at the Bener Dam in Purworejo Regency. Rock deformation and stress distribution around the tunnel was the main discussions in this study to comprehend the design of a support system that could overcome these geological conditions. The diversion tunnel was located on the right side of the dam, where the fault was found and extended in the area around the intake, passing through the tunnel path. Geological surveys, point load tests, and rock engineering properties tests were then carried out, showing the rock in the location was dominated by andesite breccias with GSI values 30-68 and moderate to high weathering levels. The fault plane obtained in the study area had an N305°E/87° orientation. The simulation result showed a redistribution of displacement within the fault zone. Displacement and maximum stress occurred in the tunnel that intersected the fault zone, resulting in a decrease in the stability of rock around the fault. Therefore, an adjustment of the support system is required.

Korelasi Point Load Index dan Uniaxial Compressive Strength pada Satuan Batupasir dan Batulempung Formasi Latih untuk Penentuan Koefisien Kekuatan Batuan di Pit X Tambang Batubara PT Berau Coal, Kalimantan Timur

Physical and mechanical properties of rock for engineering purposes are indispensable for any civil/construction, mining and other engineering requirment. The results of the uniaxial compressive strength (UCS) test are very much needed in various geotechnical analyzes or engineering, in particular in the mining industry in relation to the calculation of the pit slope design and other mining infrastructure. Rock samples used in this study were obtained from the results of geotechnical drilling (full core drilling). The rock engineering properties test to obtain UCS and PLI values was carried out in the laboratory. Testing the rock hardness index using the point load index (PLI) can be done more quickly, cheaply, practically and can use rock samples with a variety of sample shapes. The focus and object of the research are mudstone and sandstone units as part of the Lati Formation. These two types of layers are the most dominant rock types as a constituent of the pit slopes in the research area. To ensure that the correlation results are in accordance with the rules of scientific research, the distribution of UCS and PLI data from laboratory test results is verified using a statistical approach / testing. Correlation and analysis between the two rock engineering properties test results are very useful for geotechnical analysis data input. The coefficient or constant values obtained can be used to determine the rock strength values used in various geotechnical analyzes so that the analysis can be carried out more efficiently, effectively and quickly and can support geotechnical engineering work.

Research on Red-Bed Soft Rock Engineering Properties and Foundation Appraisement of Construction Engineering in Guangzhou

Based on the methods of geological drilling, literature research, induction and statistics, the site investigation of an old industrial park reconstruction project in Haizhu District of Guangzhou city was completed. The landform, formation lithology, structure and hydrogeological characteristics were systematically identified. Combined with indoor test and in-situ test, the variation rules of physical and mechanical parameters of argillaceous siltstone with different weathering degrees in the site were analyzed, and the evaluation results were given. The engineering suitability and the foundation stability are evaluated. The results showed that the weathering of soft rock makes the statistical standard values of compression coefficient, compression modulus, direct fast shear cohesion and internal friction angle of rock and soil decrease. Under the saturated state, the average value of strongly weathered argillaceous siltstone is 1.51 MPa, and that of moderately weathered argillaceous siltstone is 6.2 MPa. The strength of soft rock is low after softening with water, and the differential weathering of rock mass is strong. There are great differences in rock strength, local differences between fully and strongly weathered rock surfaces, and great changes in thickness. The weathering is extremely heterogeneous, in which the influence of structure, lithology, fissures and groundwater played a key role. The foundation is generally in a stable state, and the site is suitable for the construction of the project. The research results can provide reference for similar geotechnical engineering investigation and design.

Assessment of Geo-Mechanical Characteristics of Carbonate Rocks Using Non-destructive Pulse Velocity Measurements

Determining the geomechanical characteristics of the rock formations is critical to the design and analysis of various underground geotechnical structures. This research applied an experimental approach to determining the properties of rock cores based on ultrasonic wave velocities. Three types of carbonate rocks sampled from three different regions were thus experimentally tested and evaluated, with the regions from which the rock samples were collected being located in south-eastern, south-western, and north-eastern areas of Iraq. The geomechanical characteristics of the carbonate rocks were compiled based on ultrasonic pulse velocity tests and uniaxial compressive strength tests implemented under two sets of laboratory testing conditions: dry and saturated. The data are thus reported and discussed for both dry and saturated rock specimens. In general, the results showed a reduction in rock engineering properties with increasing moisture content. The measurements of compressional and shear wave velocities were analysed and correlated with various mechanical properties including: strength, elastic moduli, bulk density, Poisson’s ratio and Lame’s constant; the results of this process revealed that there is a strong correlation between velocity measurements and rock engineering properties. Several statistical relationships with high degrees of regression coefficient are thus proposed to efficiently the evaluate geomechanical properties of carbonate rocks based on compressional and shear wave measurements.

Engineering characterisation of weathered rock at Sri Jaya, Pahang, Malaysia

Erosion and weathering are major processes that may reduce the strength of rock slope material or may cause significant change in the physical state of the slope. These can lead to landslide or slope failure, bringing significant risk in terms of properties damage and/or human safety. In Sri Jaya, Pahang, a large body of granite is exposed as cut rock slope, which shows different zones of weathering grade. Field and laboratory tests were carried out to determine the mechanical properties and the physical properties of weathered rocks of the slope, which involved a number of testing for the Schmidt rebound hammer test, point load test, moisture content, water absorption and specific gravity. From the tests, the study has determined the engineering properties of weathered rock of the slope where weathering grade and engineering properties of rock were correlated. A strong correlation was found between the weathering grade and engineering properties where they showed significant correlations for this site. It is proven that the engineering properties could be used as reliable parameters in determining the weathering grade of material in the field.

Engineering properties of four different rocks after heat treatment

The effect of high temperature on engineering properties of rocks has recently become an important topic for geotechnical engineering applications due to the development in geothermal energy extraction, underground coal gasification, disposal of nuclear waste and deep mining applications. This study aims to investigate the engineering properties of four rocks heated at high temperatures and to identify the corresponding mineralogical changes. Two types of sandstone (Beaudesert sandstone and Jimboomba sandstone), basalt and argillite were subjected to a range of temperatures from 25 to 800 °C and their properties such as porosity and point load index were studied through a series of laboratory experiments. The physical and mineralogical alteration of the heated rock specimens were also investigated to better understand the thermally induced processes that occurred in each rock type using the X-Ray Diffraction, Thermogravimetry (TG), Differential Scanning Calorimetry (DSC) and Derivative Thermogravimetry (DTG) techniques. The obtained data indicated the important role of mineral composition in the thermal behaviour of the studied rocks. Noticeable changes in the mineral compositions at the threshold temperature were observed for each rock type. This behaviour was confirmed with TG/DSC/DTG analysis. This temperature-related process resulted in the formation of cracks, an increase in porosity and a decrease in strength. However, the effects of high temperatures on engineering properties were found to be different in the two sandstone types. While Beaudesert sandstone underwent significant weakening at high temperatures, only a slight change in the strength of Jimboomba sandstone was recorded. The threshold temperatures were identified as 400 °C, 400 °C, 500 °C and 300 °C, for the tested Beaudesert sandstone, Jimboomba sandstone, basalt and argillite samples, respectively. The critical temperatures (obtained using a damage coefficient) were found as 570 °C for both Beaudesert sandstone and basalt, and 440 °C for argillite. Analysis of the laboratory data revealed the difference between the threshold temperatures and the critical temperatures. It is recommended to use both threshold temperature and critical temperature parameters to provide more accurate estimations of the temperature range at which rock undergoes significant changes.

A novel systematic and evolved approach based on XGBoost-firefly algorithm to predict Young’s modulus and unconfined compressive strength of rock

To design the tunnel excavations, the most important parameters are the engineering properties of rock, e.g., Young’s modulus (E) and unconfined compressive strength (UCS). Numerous researchers have attempted to propose methods to estimate E and UCS indirectly. This task is complex due to the difficulty of preparing and carrying out such experiments in a laboratory. The main aim of the present study is to propose a new and efficient machine learning model to predict E and UCS. The proposed model combines the extreme gradient boosting machine (XGBoost) with the firefly algorithm (FA), called the XGBoost-FA model. To verify the feasibility of the XGBoost-FA model, a support vector machine (SVM), classical XGBoost, and radial basis function neural network (RBFN) were also employed. Forty-five granite sample sets, collected from the Pahang-Selangor tunnel, Malaysia, were used in the modeling. Several statistical functions, such as coefficient of determination (R2), mean absolute percentage error (MAPE) and root mean square error (RMSE) were calculated to check the acceptability of the methods mentioned above. A review of the results of the proposed models revealed that the XGBoost-FA was more feasible than the others in predicting both E and UCS and could generalize.

EFFECTS OF CONTROLLABLE AND UNCONTROLLABLE PARAMETERS ON DIAMOND WIRE CUTTING PERFORMANCE USING STATISTICAL ANALYSIS: A CASE STUDY

Nowadays, most mining and quarrying industries utilize a diamond wire saw machine for bench cutting operations. This method uses a metal wire or cable assembled by diamond beads to cut the hard stone into large blocks. Many parameters classified into controllable and uncontrollable parameters affect the performance of the diamond wire saw cutting method. The uncontrollable parameters are related to rock engineering properties, and controllable parameters are related to operational aspects and machine performance. The diamond wire sawing process’s production rate is one of the most critical parameters influencing the design optimization and quarrying cost estimation. The cutting rate and wear rate of diamond beads are the most important factors to evaluate quarries’ production performance. This study aims to determine the effects of different controllable and uncontrollable parameters on different quarries’ production rates. Rock engineering properties like strength, hardness, and abrasivity, and operational aspects, such as cutting angle and drive wheel diameters, are considered as the main factors affecting the production performance of the diamond wire saw method. To discover the influence of these parameters, a detailed investigation in ten quarry operations was carried out. The relation between cutting rate and diamond bead wear with different parameters is estimated. It was observed that different controllable and uncontrollable parameters could increase or decrease the cutting rate and diamond bead wearing. Furthermore, using simple and multiple regression analysis, performance prediction of the cutting rate and wearing of diamond beads was developed, and the best equations were proposed.

Study on Influence of Joint Orientation on Rock Engineering Properties for Mining and Infrastructure Design

Rock strength is the most important parameter for mining and infrastructure design. Accurate determination of rock strength is needed as a basis for implementing safe and economical rock engineering projects such as tunnels, open pit mines, and slope cutting for roadways. Rock is heterogeneous, anisotropic, and discontinuous materials. The discontinuities can be found as joints, faults, fissures, bedding, etc. In rock mechanics, the term of joint is generally used to represent all types of discontinuities. Joints are the planes of weakness in rock masses and can be found in various geometrical shapes, depending on past geological processes. This research briefly focuses to study the influence of joint orientation on rock strength based on UCS test. Application of this research could be recommend applying for mining and infrastructure design.

Granite Exploration by using Electrical Resistivity Imaging (ERI): A Case Study in Johor

Electrical Resistivity Imaging (ERI) is a tool used in near surface geophysical surveys by flowing an electric current through electrodes that were injected into the ground. The usage of electrical resistivity imaging (ERI) method dominated by geophysicist has increased tremendously in geotechnical engineering application owing to the efficiency and effectiveness of the method in term of time, cost and also data coverage. The survey performed with respect to the particular reference to ERI in determining the granite rock underneath the ground. There were seven (7) lines of ERI performed at the study area by using ABEM Terrameter LS 2 set of equipment based on Schlumberger protocol. Six (6) boreholes were also drilled to obtain engineering properties of rock at the study area. In order to develop the relationship between resistivity and engineering properties, a comparison between borehole field test result and the resistivity value were made. Results from the ERI indicated the presence of zones with high resistivity values identified as overburden soil, fractured granite and solid granite. The findings of this study also showed that the electrical resistivity imaging coupled with borehole drillings were applicable tools for the determination of the granite rock underneath the ground via subsurface profiles and such as depth of overburden soil and engineering properties of soil. In conclusion, ERI is a method that does not disturb the structure or the function of the soil which successfully became the best method in exploring the granite rock.

Evaluation of P and S Wave Velocities and Their Return Energy of Rock Specimen at Various Lateral and Axial Stresses

Determining the engineering characteristics of rocks is one of the most important challenges in designing construction projects. The triaxial rock testing is one of the most common tests to determine rock engineering properties. In this paper, dynamic properties of a pyroclastic rock specimen have been investigated using multiple ultrasonic tests during rock loading in the servo-controlled triaxial machine. In order to determine these properties, the velocity of P and S waves and the return energy of these waves at different axial and lateral stresses on a rock specimen were evaluated. The results show that the increase of the axial stress to the rock specimen increases the velocity of these waves and their return energy. However, the effect of increasing lateral stress can only be clearly seen in the return energy of the wave. In addition, the ratio of P to S wave velocities (VP/VS) at different axial and lateral stresses ranges from 1.25 to 1.40 and the ratio of the return energies of these waves is approximately between 1.5 and 2.5.

Evaluation of Engineering Properties of Rocks from Selected Location from Sikanian Region-Kirkuk / NE Iraq

The research included the study of some Geotechnical properties of selected Locations from the Sikanian region, which is Miocene – Pliocene and quaternary deposits. The study area located in the northeastern part of kirkuk governorate. The samples were collected from four sites. Moisture content, dry density, porosity, sciemic wave velocity, and uniaxial compressive strength tests were conducted of the rock samples in the laboratory. The results of petrophysical tests showed that the Dry Density ranged between (1.38-2.58) gm.cm-3 and Porosity between (13.22- 24.5)%. The uniaxail compresive strength results ranged between (6.71-52.45) Mpa The seismic velocity of the sandstone was higher than the seismic velocity of the claystone and showed a good positive correlation between Dynamic and Mechanic properties, This relation can be used to find and extract Uniaxial compressive strength values for sandstone and claystone of Sikanian region in the case of absence of standard sample. .

Rock Mass Characterization for Assessment of Safe Cut Slope and Rock Bearing Capacity at Gondang Dam Site, Karanganyar, Indonesia

This paper presents results of surface rock mass characterization for assessment of safe cut slopes and allowable bearing capacity of foundation rocks at the construction area of Gondang Dam. The rock mass characterization involved determination of intact rock engineering properties and rock mass quality based on the Geological Strength Index. The rock mass characterization results showed that the research area consisted of moderately to highly weathered and very weak to weak andesite breccia and andesite tuff breccia. The andesite breccia had very poor to fair rock mass quality, while the andesite tuff breccia had poor to fair rock mass quality. The research area was divided into three zones of safe cut slope and allowable bearing capacity. Landslides occurred at natural slopes having poor to very poor rock mass quality and inclinations greater than the determined safe cut slopes.The foundation rock of the embankment dam had fair rock massquality and 135–280 T/m2 allowable bearing capacity

Mineralogical Characteristics of Hydrothermally-altered Andesite in Kalirejo Village and The Surrounding Areas, Indonesia

Type and intensity of hydrothermal alterations affect rock engineering properties and slope stability. Identification of mineralogical characteristics of rocks is essential in determination of rock slope failure mechanism in a hydrothermal alteration zone.This research was conducted to identify mineralogical characteristics of hydrothermallyaltered andesite in Kalirejo Village and surrounding areas, Indonesia. The research was conducted by field observation and laboratory analyses involving petrographic and X-ray Powder Diffraction (XRD) analyses. The results showed that the research area was dominated by argillic alteration type and high alteration intensity implying high susceptibility to slope failures

Experimental Study of the Mechanism of Acid Rain-Gabbro Interaction

As a common natural disaster, acid rain could not only cause serious environmental pollution, but also endanger the engineering properties of rock due to water-rock interactions. The failure of slopes of mafic igneous or ultramafic igneous rock is not unusual in areas affected by acid rain, but the specific mechanism of instability remains to be studied. In this study, fresh gabbro samples were processed, and a simulated acid rain treatment of pH 3.0 in the laboratory was carried out. Then the shear strength parameters were evaluated on samples before and after the acid rain test. Finally, the samples were analyzed by X-ray Diffraction (XRD), Polarizing Microscope and Scanning Electron Microscope (SEM) to analyze the mechanism of acid rain-gabbro interaction. Overall, this study provided useful insights toward the evaluation of engineering properties of mafic igneous and ultramafic igneous rocks in acid rain area.