Effects of quarry blasting towards the residential area at Kangkar Pulai, Johor, Malaysia

The drill and blast technique have been widely used recently due to demand for natural building materials like rock aggregates. However, the intensity of blasting effects has been questioned on its validity towards the nearby residential areas. In this study, the blasting effects from Quarry A and B has been assessed based on constant location of the residential areas (Taman Pulai Hijauan and Taman Bandar Baru Kangkar Pulai, respectively) using the empirical formulations only. The blasting effects are highly dependent on the maximum instantaneous charge in blast holes (Q) which are dependent on parameters like number of blast holes, charge per column, Powder Factor and number of blast per delay. This study was able to show that with an increase of the independent variables, the Q value rises significantly. The average Q value from Quarry A (181.07 kg) was slightly higher than Quarry B (180.22 kg). The correlations made for each quarry showed that Quarry A had a better regression line with lower standard error due to the high number of blast data obtained during the monitoring period of about 1 year and 8 months. Meanwhile, the impact assessments showed higher PPV (Peak Particle Velocity) value at higher Q holding blast holes in Quarry A compared to Quarry B and decreases with increasing distance. The similar relationship was observed for the air blast assessments. Yet, all of the blasts produced are relatively within safe limits which are less than 5 mm/s Mineral & Geosciences Department (JMG) and less than 125 dBL United States Bureau of Mining (USBM). Thus, extra precaution can be taken by estimating the suitable Q value such as A (97.66 kg) and B (271.68 to 495.01 kg) to maintain safe blasting operations and prevent damages to the nearby residential areas

Evaluation of tensile strength of Brazilian test under solid and ring disks using finite element analysis

The tensile strength of intact rock materials has been determined by indirect method more frequent than the direct method. The most commonly used indirect method is Brazilian test. Stress and deformability undergo during the test reflected by geometry shape of the samples with respect to the different diameter ratio. This study focuses on influence of geometry shape in solid and ring disk with different diameter ratio on the stress distribution and deformations within sandstone subjected to indirect tensile loading by Brazilian test. Then, the finite element method in RS2 software was utilised to simulate and gain in depth understanding the behaviour of Brazilian test. The analysis shown that the maximum tensile strength in a ring disk with diameter ratio of 0.1 is three times higher than in solid disk. Meanwhile, as the diameter ratio of ring disk increases, it produces lower tensile strength. The numerical simulation also has successfully illustrated the shear failure which observed near the loading platen of solid disk during Brazilian test. The finite element analysis utilised in this research has successfully enables the stress distribution and deformation behaviour of the rock under tension to be studied closely

Effects of quarry blasting towards the residential area at Kangkar Pulai, Johor, Malaysia

The drill and blast technique have been widely used recently due to demand for natural building materials like rock aggregates. However, the intensity of blasting effects has been questioned on its validity towards the nearby residential areas. In this study, the blasting effects from Quarry A and B has been assessed based on constant location of the residential areas (Taman Pulai Hijauan and Taman Bandar Baru Kangkar Pulai, respectively) using the empirical formulations only. The blasting effects are highly dependent on the maximum instantaneous charge in blast holes (Q) which are dependent on parameters like number of blast holes, charge per column, Powder Factor and number of blast per delay. This study was able to show that with an increase of the independent variables, the Q value rises significantly. The average Q value from Quarry A (181.07 kg) was slightly higher than Quarry B (180.22 kg). The correlations made for each quarry showed that Quarry A had a better regression line with lower standard error due to the high number of blast data obtained during the monitoring period of about 1 year and 8 months. Meanwhile, the impact assessments showed higher PPV (Peak Particle Velocity) value at higher Q holding blast holes in Quarry A compared to Quarry B and decreases with increasing distance. The similar relationship was observed for the air blast assessments. Yet, all of the blasts produced are relatively within safe limits which are less than 5 mm/s Mineral & Geosciences Department (JMG) and less than 125 dBL United States Bureau of Mining (USBM). Thus, extra precaution can be taken by estimating the suitable Q value such as A (97.66 kg) and B (271.68 to 495.01 kg) to maintain safe blasting operations and prevent damages to the nearby residential areas

Empirical strength envelope for shale

Effectively, strength envelope describes behavior of rock when subjected to common stresses in construction, i.e. compressive, triaxial and tensile stresses. This study is aimed at investigating the strength envelope for shale, a sedimentary rock obtained from dam project site in Baram, Sarawak. Series of triaxial compression tests were carried out to obtain the strength envelope for the rock samples. For verification of failure criterion, uniaxial compression and Brazilian tests were also conducted on the rock samples. Results from the relevant tests were analysed using RocData software to obtain the strength envelope. Subsequently, Mohr-Coulomb and Hoek-Brown failure criterion are used to determine failure envelop for the rock samples. Based on the failure envelopes and the related strengths (i.e. compressive and tensile strength), suitability of both approach, in defining strength envelope for shale, is verified. The study shows that for highly laminated sedimentary rock like shale, Hoek-Brown criterion gave a more representative failure behaviour. The failure envelope clearly shown all the strength limits when the rock is subjected to triaxial, uniaxial and tensile stress, which is not clearly shown in the Mohr-Coulomb criterion. Therefore, Hoek-Brown criterion is a more appropriate method for describing strength envelope, as it able to show the limiting stresses when rock samples are subjected to common stresses in construction

Tunnel and Microtunnel For Future Smart and Sustainable Infrastructure Solution

Underground facilities and tunnels is not a rare discussion anymore. More and more underground explorations were carried out as to fulfil the need of mankind. In this paper, discussion on how to utilise tunnel and underground space knowledge in order to sustain green development thus to provide smart solution for infrastructure facilities (electrical cable, manhole etc) is discussed. Types of tunnel and its excavation methods especially the recent micro-tunnelling method also presented. Affect to the green and sustainable development and case study are also presented

Distribution of maximum principal stress under distributed load from loading plate in specimen for Brazilian test

In this study, the distribution of the maximum principal stress in the specimen is shown under Brazilian test. Generally, Brazilian test is dealt under a pair of concentrated force to obtain the tensile strength. However, it is assumed that the contact area induces between specimen and loading plate. Therefore, the cosine curve is adopted as the distribution of load applied on the loading plates in a theoretical model for Brazilian test. The results from this study are shown in the graphical representation and compared with those under the uniform loading

Performance of vapour pressure models in the computation of vapour pressure and evapotranspiration in ABHA, ASIR region, Saudi Arabia

The FAO-56 Penman-Monteith model is recognized as the standard method for estimating reference evapotranspiration (ETo) which requires daily meteorological data as inputs. Among all input data, vapour pressure deficit (VPD) is one of the critical parameter that drives evapotranspiration (ETo), and is of fundamental importance in crop models. In this study effort has been made to compare six vapour pressure models during four seasons. Three vapour pressure models (Models 1–3) selected as mentioned in Irrigation and Drainage Paper-56 of the Food and Agriculture Organization (FAO-56) and Models 4-6 has been selected from literature survey. Model 1, which uses daily maximum and minimum temperature, relative humidity (RH), is the preferred method to estimate actual air pressure (AE) hence it is used as standard for comparing other models. The effectiveness of vapour pressure models were measured by statistical tools and ranked according to Global Performance Indicator (GPI) where higher value of GPI represent best model. The ranking order using GPI shows that Model 5 resulted in best estimation capability with a GPI of 2.77. Moreover, the effect of variation in wind speed on the performance of the vapour pressure models in ETo estimation is also assessed

Effect of rainfall on traffic flow characteristics during night time

Understanding traffic behavior for obtaining a smooth, safe and economical traffic operation requires a thorough knowledge of traffic flow parameters and their mutual relationships.Eventhough adverse weather can reduce traffic efficiencies, there are still questions to answer regarding the relationship between weather conditions and traffic flow at night. This paper presents an investigation of the rainfall effects to the traffic flow characteristics on atwo-lane rural highway during night time. The traffic data and corresponding rainfall data for uninterrupted road segment of Federal route 3 at Dungun, Terengganu were collected under road lighting condition during the north-east monsoon season. The effect of good weather condition, light rain, moderate rain and heavy rain conditions on speed, flow and density were quantified and compared. Results from the analysis indicate that mean speed, mean flow and mean density are reduced under various rainfall conditions. In general, the impact of good weather and various rainfall conditions on Greenshield’s fundamental traffic flow relationship have weak correlations except for the relationship between flow and density. The important points in the fundamental diagram derived from flow-density relationships indicated that critical density, maximum flow, critical speed, jam density and free flow speed of roadway all decrease as rainfall intensity increases. It can be concluded that traffic flow characteristics of two-lane rural highway in Terengganu are affected by rainfall conditions

Geotechnical aspects of tunnel lining with segmental joint parameters to improve soil surface settlement prediction

Conventional lining design usually considers tunnel lining as a uniform rigid ring model by implying high partial safety factor on the bending moment which is overestimated, due to inaccurate assumptions. To overcome this problem, investigation on the influence of joints on the behaviour of the global lining is significantly important especially when the interaction between segments is included. This paper presents investigation in tunnel segment joint influence on global tunnel lining behaviour especially when the interaction between segments becomes nonlinear, in different type of soil, so that more realistic soil-tunnel lining response can be obtained. The effect of segment joint parameters (linear or nonlinear) and soil parameters was investigated via numerical modelling. The predicted stress and displacement results from the numerical model were verified with the result obtained from field data collection. FEM model of original soil and settlement monitoring data depicted similar pattern of settlement but the FEM model did not captured the sudden settlement at the distance of 40 m from starting point. This was due to the simplification of FEM model and assumption of greenfield. The sand model gave similar result pattern like original case study soil behaviour. Clay model, in opposite, showed heaving at the beginning of construction that caused by the pressure induced by the weight of concrete and moving the water pressure toward the ground. One could conclude that, the elastic settlement profile occurred due to selected parameters of soil and Mohr Coulomb model

Convergence Study for Rock Unconfined Compression Test Using Discrete Element Method

Mesh convergence is a vital issue that needs to be addressed in a numerical model. This study investigated the effects of mesh element number on the Discrete Element Method (DEM) to granite rock response under compression loading. This study used the 3D finite-element code LS-DYNA to model the Unconfined Compression Test (UCT) numerical simulation. Models with five different mesh types were conducted for convergence mesh, namely normal mesh, fine mesh, super fine mesh, coarse mesh, and super coarse mesh. The mesh convergence of rock media has been conducted using DEM and steel plates simulated using the Finite Element Method (FEM). The DEM-FEM numerical analysis is compared with the results obtained from the experimental test. The best mesh was obtained as the simulation could reproduce the stress-strain curve trends, the failure behaviour and compression strength observed in the experimental test. The normal mesh was selected as the best mesh type in this study based on the comparisons that have been made. This study shows that the DEM-FEM numerical simulation can represent granite rock and can be used for further study based on mesh convergence