Journal of Engineering Geology

Landslide hazard zonation along Tuskestan road using analytical hierarchy process (AHP) method in GIS environment

Aliakbar Momeni

The purpose of this study is to create a map of landslide hazard potential along the Tuskestan road using Analytical Hierarchy Process (AHP) model. The effective parameters on landslides that were used in this study are lithology, slope, slope aspect, vegetation, distance from the road, distance from the stream, and distance from the fault. At the first, a map of each of these parameters is prepared and divided into three or four subgroups based on their changes. Then, using hierarchical analysis, for each of these subgroups based on the degree of superiority , a weight was assigned to compare them together, so that qualitative maps are converted into quantitative maps. The result of this weighting showed that lithology and slope had the greatest effect, while the distance from the fault had the least effect in landslide hazard zoning. The final weight of each layer was obtained by multiplying the weight of each parameter by the weight of its sub-group. Finally, these quantitative maps were integrated into the Geographic Information System (GIS) environment to obtain the final landslide hazard zonation map. Assessment of the location of the previous landslides showed that among the 7 old landslides, 6 landslides were in the range of high hazard potential and 1 landslide was in the relatively high hazard category, which indicates the accuracy of the landslide hazard map. The obtained hazard zoning map showed that 9.3% of this area with an area of 355 hectares is located in the category of high hazard potential of landslides.

Comparison of Mechanized Tunneling Costs in Iran with Other Countries

Masoud Esmaeilzadeh

Estimating tunnel construction costs is one of the critical steps in project management. Several factors influence the total cost of a tunnel project, and the complexity and uncertainty in identifying these factors often lead to inaccurate cost estimates. Various analytical methods have been developed to estimate tunnel construction costs, but all have drawbacks. Utilizing real data from other projects can mitigate these shortcomings. In this research, we first discuss the growth of the tunneling industry and its impact on the development of economic infrastructure. We then review the historical research on tunnel cost estimation and the methodologies that have been developed in this area. The lack of a pricing schedule for tunnel construction in Iran, unlike in developed countries, results in inaccurate cost estimates for tunnel projects. This study examines both definite and probabilistic methods for estimating the cost of mechanized tunneling, based on the price schedule of "Dam Field 1403." We compare the cost of tunneling in Iran with other countries. The results indicate a 30% difference in the ratio of labor costs to the total project cost and a 92% difference in the cost per meter for mechanized tunnels in Iran compared to other countries. This discrepancy discourages private contractors from engaging in tunnel projects in Iran. Therefore, we propose the development of a comprehensive pricing schedule for tunneling to enhance the accuracy of cost estimation for tunnel projects in Iran.

Examining the impact of Flat-Joint and Linear Parallel Bond behavioral models on Aghajari sandstone failure mechanism in PFC2D simulations

Ebrahim Rahimi

Numerical modeling is an essential tool in engineering analysis, particularly within the fields of geoscience and geotechnics. The PFC2D software stands out in this field, using the Distinct Element Method (DEM) to simulate processes related to engineering geology and geotechnical assessment. This study focuses on the analysis and comparison of two common contact models: the Flat Joint Model (FJM) and the Linear Parallel Bond Model (LPBM). The Unconfined Compressive Strength (UCS) test is chosen as a the benchmark for calibrating and validating the PFC models. Sandstone samples for this study are taken from the Aghajari Formation located on the southern limb of the Madar Anticline. The results show that both contact models have a high ability to simulate the UCS in the calibration process. As this test is primarily used to calibrate the failure point (σ_c) and Young's modulus, the output values for both models are almost identical. However, the post-failure behavior in the stress-strain curves differs between the models, with the FJM demonstrating a more brittle response compared to the LPBM. The ability of the FJM model to simulate rough surfaces and material discontinuities allows for the representation of tensile cracking.

Investigating the role of physical and strength characteristics on the durability of building stones subjected to deterioration processes

Amin Jamshidi

The durability of a building stone is its resistance to deterioration processes under the climatic conditions of a given geographical area. This parameter plays an important role in the selection of a suitable building stone, as ignoring it can lead to premature deterioration of the stone during the life of a building. Therefore, before selecting a building stone, it is necessary to pay special attention to its durability and to select a stone that has a suitable resistance to environmental degradation processes. The physical and strength characteristics are among the factors that influence the durability of a building stone. The evaluation of these characteristics can provide valuable information about the durability of stone subjected to deterioration processes. In this work, the effects of physical and strength characteristics on the durability of building stones were investigated. The results indicate that porosity, water content, degree of saturation and pore size distribution are the most important physical characteristics determining the durability of a building stone. In addition, strength properties, including uniaxial compressive strength, tensile strength, flexural strength and abrasion resistance, also play an important role in the durability of a building stone. The results of the present study can be used as a simple, quick, inexpensive and practical tool to indirectly evaluate the durability of building stone against environmental degradation processes.

Numerical study on the effect of topography on seismic response of building adjacent to slope

Ali Ghanbari

Examining the seismic response of the ground surface and its impact on structures due to topographic effects and soil-structure interaction (TSSI) is highly significant. If the site has sloping topography, the importance of this study is further amplified, and the slope effect on soil-structure interaction must be considered. This research uses Loma Prieta (1989) earthquake records to analyze the seismic response of a 5-story concrete building located 5 meters from the crest of the slope for four angles: 15, 30, 45, and zero degrees (SSI), using 3D numerical analysis. Modeling was conducted with MIDAS GTS NX software for both TSSI and SSI systems. An elastic model and an HSS model were used for the building and soil, respectively. The seismic response of the building was evaluated by comparing maximum lateral displacements, base shear forces, inter-story drifts, and horizontal accelerations in TSSI and SSI analyses. As the slope angle increased from zero degrees (SSI) to 15, 30, and 45 degrees (TSSI), the average lateral displacement of the floors increased by 44%, and the average maximum horizontal acceleration increased by 21%. Additionally, with the slope angle increasing from zero degrees (SSI) to 15, 30, and 45 degrees (TSSI), the average ratios of inter-story drift and maximum base shear force increased by 14% and 21%, respectively.

The effect of soil internal friction angle on Gougerd landslide stability with a key analysis of the results obtained from various methods

Hassan Moomivand

In this study, the stability of the Gougerd landslide of Khoy was investigated with respect to changes in the soil internal friction angle. Statistical analysis of the results of changes in the FS of different methods in analyzing the stability of the Gougerd landslide in 282 analyses showed that: 1) In static conditions, under the influence of groundwater conditions, the results of the stability analysis of various methods showed up to 35.2% changes in the FS, and the largest differences in the FS values were obtained in the conventional Fellenius, Spencer, and Morgenstern-Price methods. 2) In static conditions, the FS of various methods showed changes of up to 35% with respect to the effect of the internal friction angle, and the largest difference in the FS values compared to other methods was obtained in the conventional Fellenius method and the Spencer method. 3) In pseudo-static conditions and in the dry state, up to 5% changes in the FS were obtained in different analysis methods, and under the influence of groundwater conditions, the changes in the FS were up to 39.9%. The largest changes in the FS of the dry state were obtained in the simplified Janbu method, Spencer and Morgenstern-Price methods, and under the influence of groundwater, the largest changes in the FS were obtained in the conventional Fellenius method and Spencer method. In examining the results of this research, the effect of different conditions of groundwater level, soil internal friction angle, and earthquake force on the analytical mechanism of the relationships existing in various methods is recognized as the main cause of the difference in the results of different stability analysis methods.

Investigation of Carbonate Aggregates and the Use of Petrography in Predicting Alkali-Aggregate Reaction (AAR)

Mohammad Fathollahy

In order to produce strong and durable concrete, it is essential to accurately assess the alkali reactivity potential of aggregates. Alkali reactions occur gradually over time and are therefore often overlooked in the early stages of a project.. This research investigates the alkali-aggregate reaction (AAR) potential of concrete aggregates. Petrographic analysis of aggregates, based on ASTM C295, is a simple and rapid method for identifyingminerals that may react with the alkalis in cement. In this study, susceptible aggregates were identified through petrography, and then the accuracy of the results and the importance of petrographic analysis were verified using laboratory methods (ASTM C586 and ASTM C1260) to select suitable materials with minimal cost and time before designing the concrete mix. The results indicate that carbonate aggregates may contain silica and have alkali reactivity potential, necessitating the use of ASR testing methods as well. In addition, the results demonstrate that petrographic analysis is an effective and valuable method for identifying minerals with alkali reactivity potential.