Journal of Geotechnical Geology
Volume:17 Issue: 2, Summer and Autumn 2021

Slope stability of rock structures considered as the most important field in rock mechanics. Stability analysis of the jointed rock slopes are evolved during many years. The different methods are developed to understand and analysis various rock failures and describe sliding mechanism. The rock engineering experts in this field have provided significant achievements in terms of stability analysis and monitoring in jointed rock slopes and introduced extensive stability analysis and stabilization methods. The presented study is tried to prepare a review study on several works conducted on rock slope stability and stabilizations. In this regard, while examining the structured analysis of the stability of rocky slopes, some of the most important achievements in this field have been considered.

Landslides are one of the most important natural hazards that occur widely in the dam’s sites as well as dam’s reservoirs. In this regard, the landslides susceptibility assessments for dam’s reservoirs can be utilized to estimate the floods risks, dam failures due to slope instabilities in reservoir. Additionally, obtain the hazard risk potential in dam’s reservoir capable to investigate the risk-able zones and categorized prone areas to land-sliding. For this purpose, the present study has tried to use a combined computational model based on fuzzy-hierarchical approach (FAHP) and geographic information system (GIS) to assessment of landslides susceptibility and hazard zonation in Shirin-darreh Dam’s Reservoir (North Khorasan) to provide the hazard risk potential maps. Methodologically, after identifying the effective factors in landslides’ occurrence (including 6 main factors as morphological, geological, climatic, seismic, in-field and susceptible and human parameters), these factors are weighted by FAHP model and layered Information has entered GIS, which has led to estimates of areas with high to low landslide risk sensitivity. Based on the results of the evaluation, it has been determined that in the peripheral margin of the southern and upstream part of Shirin-darreh dam, it has a high slip sensitivity, which can be considered as a dangerous point for dam destruction and flooding downstream of the dam.

In the present study, the performance of micro-piles for the improvement of loose sandy soils under dynamic loading on strip foundations was investigated. For this purpose, finite element numerical method (FEM) by Plaxis3D software has been used to implement loading conditions and evaluate deformations in loose sandy soils below the strip. The modeling process includes geometrical, behavioral models, boundary condition, material properties and dynamic modeling which that implemented on both unreinforced and reinforced strip foundation by micro-pile. Based on the results of the study, it can be well stated that the implementation of micro-piles has been able to improve loose sandy soils in strip foundations under dynamic loading conditions. So, the use of micro-communities in improving soil conditions against similar soils can be suggested.

The geotechnical and civil projects are very special tasks for different range of workers which is provided wide stress levels in persons. In the meantime, the construction tasks have faced with hard working and accidents during job. The presented study attempted to investigate the empirical relationship related job stress and workers’ accident during the constrictions. In this regards, 50 individuals with a history of occupational accidents and 120 without accidents experiences on construction are considered in Zanjan. The experiment was conducted based on Belkic occupational stress index (BOSI) and general health (GHQ28) questionnaires and during the study, the types of job stressors were identified and the odds ratio of occupational accidents in the study population in relation to job stress was determined. According to the results, the most important job stressors in construction projects are time pressure, working with machines, interacting with colleagues, and environmental pressure.

Based on the increasing the usage of the resources and population growth, the soil with suitable properties for civil engineering project such as pavement construction is not available. Therefore, it is obligatory that the enhancement of local soils properties should be appropriately deliberated. If for some reason it is not possible to relocate the project and replace the soil, or if the cost of soil replacement is not cost-effective, the soil remediation method should be considered so that if this method is economically and technically justifiable, it should be done. From this perspective, the effects of Nano-silica on soil compressive strength are important and necessary. In this study, a specific and different number of samples are prepared for comparison. The purpose of this study is to measure the uniaxial compressive strength of granular soils. It was concluded that Nano-silica filled pore space between Sand particles and a dense matrix were formed. This textural event caused an improvement in compressive strength of stabilized soils In this regard, the use of Nano-silica as a suitable and efficient additive in the thickening processes is recommended.

In the design and operation of earthen dams, leakage control and permeability of the bed can be considered as one of the most important geotechnical and hydraulic issues of the dam. Studies have shown that the optimal implementation and functional control of the sealing curtain significantly plays a significant role in reducing leakage flow and also the stability of the dam. In this regard, in the present study, an attempt has been made to pay attention to this issue and to evaluate the leakage and permeability conditions to evaluate the performance of the sealing curtain for Abbasabad earthen dams based on layered bed sediments. To take. For this purpose, the finite element numerical approach and Plaxis software have been used. Methodologically, two modeling groups were implemented for the dam state without sealing the curtain and with the sealing curtain, and then the dam was dewatered and the hydraulic behavior was measured. The results of the simulation show that when the sealing curtain was not implemented, these elements had limited changes in the range of the dam core, which has become more widespread with the implementation of the sealing curtain. This issue indicates the movement and effect of the current resulting from the implementation of the sealing curtain in the area of the dam core. However, the stress drop in the dam area indicates the activity of the drains in order to relieve the pore water pressure. On the other hand, the strain expansion in the core range reflects the phenomenon of fine-grained plastic behavior resulting from in-situ stress and pore-water pressure.