The investigation of Cut-and-cover, top-down construction method for a metro underground station; case study: 'Naghsh-e-Jahan Metro Station, Esfahan, Iran'

Naghsh-e-Jahan subway station is located in Esfahan historical context with 186 meters' distance to the Sheikh Fazlolah mosque – one of the historical cosmopolitan attractions. The subway station is in a shallow depth, soft surrounding soils and with wide span and in a downtown location, have made the situation so critical that precise assessments, not only for the station support but also for compensating the ground settlement, are needed. One of the prerequisite procedures for large underground structures, the cut-and-cover approach, is constructed top-down using the Diaphragm Wall system. This method can be functional in conditions where minimum vertical displacements are essential since roof covering and improvement can be performed even when the excavation operation is not terminated. The embankment process can be done just right after the roof slab is complete and reaches reliable strength. This study uses the Finite Element method to simulate all the construction stages and analyze the ground behavior. It has been observed that the width and the length of diaphragm walls and middle barrettes on the ground settlements. Ground settlement for various stages of excavation at the cross-section and longitudinal section of the station is shown that settlements are spandrel and maximum settlements occur close to the diaphragm walls. As excavation continues, ground surface settlements become concave, and the maximum surface settlements occur at a bit of distance from the diaphragm walls for about 17mm. Furthermore, the diaphragm wall's thickness of 100 cm of diaphragm wall is recommended for optimum values

The investigation of Cut-and-cover, top-down construction method for a metro underground station; case study: 'Naghsh-e-Jahan Metro Station, Esfahan, Iran'

Naghsh-e-Jahan subway station is located in Esfahan historical context with 186 meters' distance to the Sheikh Fazlolah mosque – one of the historical cosmopolitan attractions. The subway station is in a shallow depth, soft surrounding soils and with wide span and in a downtown location, have made the situation so critical that precise assessments, not only for the station support but also for compensating the ground settlement, are needed. One of the prerequisite procedures for large underground structures, the cut-and-cover approach, is constructed top-down using the Diaphragm Wall system. This method can be functional in conditions where minimum vertical displacements are essential since roof covering and improvement can be performed even when the excavation operation is not terminated. The embankment process can be done just right after the roof slab is complete and reaches reliable strength. This study uses the Finite Element method to simulate all the construction stages and analyze the ground behavior. It has been observed that the width and the length of diaphragm walls and middle barrettes on the ground settlements. Ground settlement for various stages of excavation at the cross-section and longitudinal section of the station is shown that settlements are spandrel and maximum settlements occur close to the diaphragm walls. As excavation continues, ground surface settlements become concave, and the maximum surface settlements occur at a bit of distance from the diaphragm walls for about 17mm. Furthermore, the diaphragm wall's thickness of 100 cm of diaphragm wall is recommended for optimum values

A numerical model for caprock analysis for subsurface gas storage applications

In considering a site for gas storage, it will be important to evaluate the effects of gas storage on the formation, so as to minimize the risk of a breach occurring in the system. Gas injection will result in an increase in formation fluid pressure, especially around the injection source, which in turn results in redistribution of the stress field. The induced deformations within the reservoir can potentially result in a damage zone within the caprock formation. This mechanical failure may involve shear along many of the existing fractures or creation of new fractures that reduce the sealing properties of the caprock system. The main objective of this paper is to develop a model to estimate the growth and extension of cracks in the caprock. In order to achieve this, the smeared crack approach is used to model the process of cracking in the caprock. Smeared cracking is a continuum approach for damage mechanics which is based on the idea that a crack is modeled by modifying the strength and stiffness of the material. The main model presented in this paper has three sub-models, which are the reservoir model, the caprock model and the smeared crack model. The reservoir model is a simplified coupled hydro-mechanical model that numerically simulates the radial fluid flow and analytically estimates the associated stress and strain within the reservoir. The results of the reservoir model are used as boundary conditions for the caprock model that estimates the stress and strain within the sealing caprock due to the deformation of the reservoir. Using the calculated stress and strain, the smeared crack model predicts the growth and extension of cracks within the caprock. The caprock is assumed to be initially crack free and impermeable. The developed model is then used to study the Yort-e-shah aquifer caprock in Iran to predict the growth and extension of cracks

The global burden of cancer attributable to risk factors, 2010-19 : a systematic analysis for the Global Burden of Disease Study 2019

Background Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. Methods The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk-outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. Findings Globally, in 2019, the risk factors included in this analysis accounted for 4.45 million (95% uncertainty interval 4.01-4.94) deaths and 105 million (95.0-116) DALYs for both sexes combined, representing 44.4% (41.3-48.4) of all cancer deaths and 42.0% (39.1-45.6) of all DALYs. There were 2.88 million (2.60-3.18) risk-attributable cancer deaths in males (50.6% [47.8-54.1] of all male cancer deaths) and 1.58 million (1.36-1.84) risk-attributable cancer deaths in females (36.3% [32.5-41.3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20.4% (12.6-28.4) and DALYs by 16.8% (8.8-25.0), with the greatest percentage increase in metabolic risks (34.7% [27.9-42.8] and 33.3% [25.8-42.0]). Interpretation The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.Peer reviewe

Numerical Analysis of the Segmental Supporting System Under Earthquake Loading

Today, precast concrete lining (segmental) are used as system maintenance in the majority of tunnels excavated by TBM. On the other hand, the mechanism of the joint between two segments is not known under seismic loads. In this paper a numerical study about the effect of the earthquake on the segmental supporting system and the resultant vertical and shear forces on the contact surface between two segments is investigated. The Tehran -Karaj water conveyance tunnel (Amirkabir) was used as a case study. In this study, the UDEC software was used. At the first step, the segmental lining were simulated under no slip and full slip conditions and the normal and shear forces were studied. Finally, the effect of joint stiffness between two segments were investigated. Results showed that with increasing the interface properties, the normal and shear forces in the segmental joints increased. Also with increasing the joints stiffness, the normal and shear forces on the joints increased and the normal and shear displacement decreased. In other words, the rigidity increament of supporting system is associated with flexibility decrement of lining with respect to rock medium. So, the stresses increased and displacement decreased

The global burden of cancer attributable to risk factors, 2010-19: a systematic analysis for the Global Burden of Disease Study 2019

Background Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. Methods The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk-outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. Findings Globally, in 2019, the risk factors included in this analysis accounted for 4.45 million (95% uncertainty interval 4.01-4.94) deaths and 105 million (95.0-116) DALYs for both sexes combined, representing 44.4% (41.3-48.4) of all cancer deaths and 42.0% (39.1-45.6) of all DALYs. There were 2.88 million (2.60-3.18) risk-attributable cancer deaths in males (50.6% 47.8-54.1] of all male cancer deaths) and 1.58 million (1.36-1.84) risk-attributable cancer deaths in females (36.3% 32.5-41.3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20.4% (12.6-28.4) and DALYs by 16.8% (8.8-25.0), with the greatest percentage increase in metabolic risks (34.7% 27.9-42.8] and 33.3% 25.8-42.0]). Interpretation The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license