• Geomechanics and Engineering
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• 제13권4호
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• pp.571-584
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• 2017

Slope mass rating (SMR) is commonly used for the geomechanical classification of rock masses in an attempt to evaluate the stability of slopes. SMR is calculated from the $RMR_{89-basic}$ (basic rock mass rating) and from the characteristic features of discontinuities, and may be applied to slope stability analysis as well as to slope support recommendations. This study attempts to utilize the SMR classification system for slope stability analysis and to investigate the engineering geological conditions of the slopes and the slope stability analysis of the Gas Flare site in phases 6, 7 and 8 of the South Pars Gas Complex in Assalouyeh, south of Iran. After studying a total of twelve slopes, the results of the SMR classification system indicated that three slope failure modes, namely, wedge, plane and mass failure were possible along the slopes. In addition, the stability analyses conducted by a number of computer programs indicated that three of the slopes were stable, three of the slopes were unstable and the remaining six slopes were categorized as 'needs attention'classes.

• Geomechanics and Engineering
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• 제19권5호
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• pp.393-405
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• 2019

This paper evaluates the geotechnical and geo-engineering properties of the South Pars Zone (SPZ) marls in Assalouyeh, Iran. These marly beds mostly belong to the Aghajari and Mishan formations which entail the gray, cream, black, green, dark red and pink types. Marls can be observed as rock (soft rock) or soil. Marlstone outcrops show a relatively rapid change to soils in the presence of weathering. To geotechnically characterise the marls, field and laboratory experiments such as particle-size distribution, hydrometer, Atterberg limits, uniaxial compression, laboratory direct-shear, durability and carbonate content tests have been performed on soil and rock samples to investigate the physico-mechanical properties and behaviour of the SPZ marls in order to establish empirical relations between the geo-engineering features of the marls. Based on the experiments conducted on marly soils, the USCS classes of the marls is CL to CH which has a LL ranging from 32 to 57% and PL ranging from 18 to 27%. Mineralogical analyses of the samples revealed that the major clay minerals of the marls belong to the smectite or illite groups with low to moderate swelling activities. The geomechanical investigations revealed that the SPZ marls are classified as argillaceous lime, calcareous marl and marlstone (based on the carbonate content) which show variations in the geomechanical properties (i.e., with a cohesion ranging from 97 to 320 kPa and a friction angle ranging from 16 to 35 degrees). The results of the durability tests revealed that the degradation potential showed a wide variation from none to fully disintegrated. According to the results of the experiments, the studied marls have been classified as calcareous marl, marlstone and argillaceous lime due to the variations in the carbonate and clay contents. The results have shown that an increase in the carbonate content leads to a decrease in the degradation potential and an increase in the density and strength parameters such as durability and compressive strength. A comparison of the empirical relationships obtained from the regression analyses with similar studies revealed that the results obtained herein are reasonably reliable.

• Geomechanics and Engineering
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• 제6권5호
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• pp.487-502
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• 2014

A three dimensional finite element model was used to simulate rapid impact compaction (RIC) in loose granular soils using ABAQUS software for one impact point. The behavior of soil under impact loading was expressed using a cap-plasticity model. Numerical modeling was done for a site in Assalouyeh petrochemical complex in southern Iran to verify the results. In-situ settlements per blow were compared to those in the numerical model. Measurements of improvement by depth were obtained from the in-situ standard penetration, plate loading, and large density tests and were compared with the numerical model results. Contours of the equal relative density clearly showed the efficiency of RIC laterally and at depth. Plastic volumetric strains below the anvil and the effect of RIC set indicated that a set of 10 mm can be considered to be a threshold value for soil improvement using this method. The results showed that RIC strongly improved the soil up to 2 m in depth and commonly influenced the soil up to depths of 4 m.

• Computers and Concrete
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• 제19권5호
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• pp.509-514
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• 2017

Concrete retaining walls are the most common types of geotechnical structures for controlling instable slopes resulting from lateral pressure. In analytical stability, calculation of the concrete retaining walls is regarded as a rigid mass when its safety is required. When cracks in these structures are created, the stability may be enforced and causes to defeat. Therefore, identification, creation and propagation of cracks are among the important steps in control of lacks and stabilization. Using the numerical methods for simulation of crack propagation in concrete retaining walls bodies are among the new aspects of geotechnical analysis. Among the considered analytical methods in geotechnical appraisal, the boundary element method (BEM) for simulation of crack propagation in concrete retaining walls is very convenient. Considered concrete retaining wall of this paper is Pars Power Plant structured in south side in Assalouyeh, SW of Iran. This wall's type is RW6 with 11 m height and 440 m length and endurance of refinery construction lateral forces. To evaluate displacement and stress distributions (${\sigma}_{1,max}/{\sigma}_{3,min}$), the surrounding, especially in tip and its opening crack BEM, is considered an appropriate method. By considering the result of this study, with accurate simulation of crack propagation, it is possible to determine the final status of progressive failure in concrete retaining walls and anticipate the suitable stabilization method.

• Geomechanics and Engineering
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• 제35권5호
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• pp.539-554
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• 2023

This article is dedicated to the pursuit of establishing a robust empirical relationship that allows for the estimation of in-situ modulus of deformations (E_m and G_m) within sedimentary rock slope masses through the utilization of Q_slope values. To achieve this significant objective, an expansive and thorough methodology is employed, encompassing a comprehensive field survey, meticulous sample collection, and rigorous laboratory testing. The study sources a total of 26 specimens from five distinct locations within the South Pars (known as Assalouyeh) region, ensuring a representative dataset for robust correlations. The results of this extensive analysis reveal compelling empirical connections between E_m, geomechanical characteristics of the rock mass, and the calculated Q_slope values. Specifically, these relationships are expressed as follows: E_m = 2.859 Q_slope + 4.628 (R² = 0.554), and G_m = 1.856 Q_slope + 3.008 (R² = 0.524). Moreover, the study unravels intriguing insights into the interplay between in-situ deformation moduli and the widely utilized Rock Mass Rating (RMR) computations, leading to the formulation of equations that facilitate predictions: RMR = 18.12 E_m0.460 (R² = 0.798) and RMR = 22.09 G_m0.460 (R² = 0.766). Beyond these correlations, the study delves into the intricate relationship between RMR and Rock Quality Designation (RQD) with Qslope values. The findings elucidate the following relationships: RMR = 34.05e^0.33Qslope (R² = 0.712) and RQD = 31.42e^0.549Qslope (R² = 0.902). Furthermore, leveraging the insights garnered from this comprehensive analysis, the study offers an empirically derived support system tailored to the distinct characteristics of discontinuous rock slopes, grounded firmly within the framework of the Q_slope methodology. This holistic approach contributes significantly to advancing the understanding of sedimentary rock slope stability and provides valuable tools for informed engineering decisions.