ENGINEERING GEOLOGY
Year:2022 | Volume:15 | Issue:1|Papers Count:8

Prediction of maximum safe charge per delay (Q , kg) by Distance (D) from blasting point and adaptive Peak Particle Velocity (PPV) is a critical key for successful blasting. Safe charge per delay is calculated by using PPV estimators indirectly or Q estimator directly. This paper presents the results of ground vibration measurement induced by bench blasting in Sungun copper mine. The scope of this study is to evaluate the capability of different methods in order to predict maximum safe charge per delay. Conventional empirical models and two type of new non-linear dirict estimator models are prsented. An application of Imperialist Competitive Algorithm (ICA) has used to determine the Q estimator coefficients in Sungun bench blasting. A comparison between two ways of investigations including conventional empirical equations and ICA are done. It has been shown that the applicability of ICA-based equations is more promising than any selected traditional empirical equations.

In urban areas, based on the space constraints, one of the most important issues in the stabilization of slopes is to choose a suitable method for the design of the slope by considering technical and executive problems. Despite the proper design and execution of slopes, a variety of the natural and the artificial factors in a particular period of time may greatly affect their stability. In this study, the investigate the effect of microclimates on the stability of gables under the effect of steady state seepage, seepage analysis was performed using Seep / W software and finite element method, assuming unsaturated saturation flow and in steady state flow. Also, using Slope / W software, slope stability in different conditions including distance, diameter and angle of micropile has been investigated and the sensitivity of the results for permeability and soil resistance parameter has been investigated. The innovation of the present study is using the special parts which eliminates the common assumptions of the limit equilibrium method. Therefore, it is expected that this method will has less error in determining the reliability coefficient. According to the results, it was observed that seepage in the slope, diameter and distances of small piles have a great effect on the stability of the slope, which can be varied according to different conditions. As the distance between the micropiles increases, the slope reliability coefficient with different micropiles diameters becomes closer to the slope reliability coefficient without micropiles and somehow converges to this reliability coefficient.

The operation parameters of EPB-TBM have always been significant factors in tunnel constructions. So it is crucial to estimate the cutterhead torque and thrust force of the machine. In this study, by employing the multilayer perceptron artificial neural network (ANN-MLP) and multivariate regression (MVR) methods, the empirical models were developed to estimate the EPB operating parameters, including cutterhead torque and thrust force, in the rock section of the Tehran metro line 6, South extension (TML6-SE) project. In this section, the excavation was performed in a strong, blocky to massive rock. The machine was equipped with the disc cutters on the cutterhead as a cutting tool instead of rippers and drag bits. The mechanized excavation in this situation is unusual with using the EPB machines. The input data included the performance parameters such as penetration rate, earth pressure, cutterhead rotation speed, and cutter load. The statistical indices were used to verify the developed models. The results confirmed the accuracy of the models. The MAE loss function determined for torque in both training and testing stages predicted by the ANN was 0.0001 and 0.005, respectively. The MAE loss function determined for thrust force in both training and testing stages predicted by the ANN was 0.00016 and 0.010, respectively. The relationships between parameters in the dataset were investigated to obtain and offer new equations using the multivariable regression statistical method (MVR). The MAE loss function determined for cutterhead torque and thrust force was 0.0018 and 0.0010, respectively.

Reinforcement of soil with polymer waste materials is one of the new and practical methods for improvement and stabilization of soil. The purpose of soil reinforcement is to improve shear strength, increase ductility, increase stability, increase bearing capacity, increase the slope stability, safety factor and reduce the settlement. One of the common types of polymer waste used in soil reinforcement is waste from textile and carpet production factories. In this paper, the effect of reinforcing the soil with carpet waste by randomized distribution, has been studied. Laboratory study program includes the effect of parameters such as weight percentage (0.5, 1, 1.5 and 2% of soil dry weight) and the ratio of sides (1, 2 and 5) of carpet waste under overheads of 100, 200, and 400 kPa in dense conditions and the moisture obtained from a proctor standard compaction test is on the shear strength of the samples. The results of direct shear and standard compaction tests, reveal that the addition of carpet waste to sandy soil improves the shear strength parameters, reduces the maximum dry unit weight and increases the optimum moisture content. Thus, due to the recyclability of this type of material, their use in civil engineering and geotechnical projects is both economically viable and reduces the environmental problems caused by the accumulation of these wastes in nature.

Esfidan village is one of the historical and tourist areas in 45 km southeast of Bojnourd in North Khorasan, which is located in a mountainous area. The rock falls in this area can lead to the closure of the village communication road and also damage to part of the village houses. In this paper, the possible occurrence of rock fall is analyzed by software and also the risk of rock fall in it is evaluated. Field investigations have shown that rock falls in this area are mostly due to the tectonics of rock units, the presence of discontinuities, seasonal precipitation or a combination of these factors. Jointing studies have shown that the main discontinuities in the rock slope consist of three sets of joints with two major layers. Also, sampling of rock layers and performing various physico-mechanical tests indicated that the rock layers are mainly made of high-strength limestone. Software analysis of rock fall in this slope was performed on two selected sections by Rock fall software. Then, by combining the data obtained from the software analysis of rock fall and also the field data collected from the status of the slope activity, using evolutionary method, the potential of rock fall in two selected sections was evaluated. The results showed that the slope is in the middle to high risk category in terms of the risk of rock fall and needs to implement protective measures to prevent damage to roads and residential houses.

In recent decades, the importance of the geological features of the site on the severity and extent of damages has become apparent in many seismic events. How these properties relate to the amplitude and the frequency content of the movements is studied as the title of site seismic response. In the present study, the seismic response of a two-dimensional section of sediments located in the eastern part of the sedimentary basin Qom city has been investigated. For this purpose, numerical modeling has been performed using Spectral Element Method in time domain and the results also studied and presented in frequency domain by applying Fourier transform. The results in the time domain show that the largest amplitudes of movements can be observed in the southeastern parts of the urban area. These findings are in agreement with previous studies. Also, it is revealed that the main reason for increase of the duration of the movements in the basin is the surface waves originating from the edges of the basin. The results in the frequency domain indicate that the most important amplifications in the basin can be seen from about 0.8 Hz for the southern parts of the profile to about 2 Hz for the northern parts. This amplification range also agrees with previous observations.

Probabilistic slope stability analysis provides a tool for considering uncertainty of the soil parameters in design. In this paper, using Slide software, the Monte Carlo simulation is used as an analytical method to develop probabilistic models of slope stability based on equilibrium methods. The limit equilibrium methods are the most popular approaches in slope stability analysis. These methods are well known to be a statically indeterminate problem, and assumptions on the inter-slice shear forces are required to render the problem statically determinate. In modeling using this methodology, the selected stochastic parameters are internal friction angle, cohesion and unit weight of soil, which are modeled using a truncated normal probability density function (pdf). In this research, the abilities offered using models were presented by using field data obtained from Cannon dam in Iran. The results obtained show that the hybrid Monte Carlo simulation and equilibrium methods can be used successfully for slopes stability assessment.

Strength measurement of rock requires testing that must be carried out on test specimens with particular sizes in order to fulfill testing standards or suggested methods. Often, the coring process breaks up the weaker core pieces, and they are too small to be used in either index tests or conventional strength tests such as point load index (Is) and Brazilian tensile strength (BTS). One of the index tests to indirectly determine the rock strength is the block punch index (BPI) test, which requires flat disc specimens without special treatment. This study aimed to evaluate the applicability of the BPI test for predicting the uniaxial compressive strength (UCS), BTS and IS of the sandstones by empirical equations. Also, we have compared the performance of the BPI and IS for predicting the UCS and BTS. It was experimentally shown that BPI is a reliable method for predicting the UCS, BTS and Is of the sandstones under study. Moreover, the results indicate that BPI could be utilized with same importance as Is for predicting the UCS, while predicting the BTS by Is appears to be more reliable than BPI.