massoud bayati - Academia.edu (original) (raw)

Papers by massoud bayati

Research paper thumbnail of A Numerical Approach to Simulate Stresses Around Tunnels in Swelling Rocks

The stresses generated from rock expansion in a confined underground environment will exert addit... more The stresses generated from rock expansion in a confined underground environment will exert additional loads to the existing support system resulting in severe damage during tunnel construction. In this study numerical investigations were carried out for Zagros tunnel in Iran, where swelling has been reported to be an inherent formation property. The presence of expandable clay was investigated using X-ray diffraction mineralogical analyses. The swelling volume strain was used to estimate the amount of stress increased due to swelling. The stress path method is used to obtain the location of swelling stresses. The stress relief zone (SRZ) was considered as the criterion to define the area around the tunnel where swelling stresses exist. In doing so, in the areas where the first stress invariant after excavation becomes lesser than its corresponding value before excavation, the swelling pressure can be built up. Then tunnel stability was investigated by numerical simulations using FL...

Research paper thumbnail of Wellbore Stability Analysis Due to Turbulent Flow in Coiled Tubing Drilling

Research paper thumbnail of A case study on TBM tunnelling in fault zones and lessons learned from ground improvement

Tunnelling and Underground Space Technology, 2017

Research paper thumbnail of Prediction of TBM penetration rate using intact and mass rock properties (case study: Zagros long tunnel, Iran)

Arabian Journal of Geosciences

In this paper, the correlations between the different measurements of rock brittleness (i.e., B 1... more In this paper, the correlations between the different measurements of rock brittleness (i.e., B 1, B 2, B 3, and BI) and the penetration rate (PR) of tunnel boring machine (TBM) through Zagros long tunnel were evaluated. According to the results of simple regression analyses, there was no correlation between the penetration rate of TBM and the brittleness of B 1, but stronger log-linear correlations have been observed between the penetration rate of TBM and the B 2, B 3, and BI brittleness indices. As part of the present study, correlations between some of rock mass classification systems (RQD, RMR, GSI, Q, and Q TBM) and penetration rate of TBM have been investigated. The results of simple regression analyses showed that the first four rock mass classification systems did not exhibit a good correlation with the TBM penetration rate, but the Q TBM had strong correlation with that. Multiple linear regression (MLR) analyses were applied for estimating the TBM penetration rate based on...

Research paper thumbnail of Analytical investigation of well/perforation scale effect on sand production of weakly consolidated sandstones

The APPEA Journal

Investigating the risk of sand production is a common practice for developing unconsolidated and ... more Investigating the risk of sand production is a common practice for developing unconsolidated and weakly consolidated reservoirs, particularly with designing the completion system of development wells. The risk of sanding may be different for open hole and cased and perforated completion systems. Part of this difference is a result of the different size of the boreholes—that is, open hole versus perforation tunnels— which is known as borehole scale effect. The amount of research dedicated to investigate the borehole scale effect on sand production is very limited. Research has been carried out by conducting thick-walled cylinder (TWC) tests on samples with different inner to outer diameter ratios. The impacts of sample size and boundaries on the induced stresses around the borehole and failure were, however, not differentiated from the borehole scale effect. In this paper, a comprehensive analytical approach is performed to investigate the effect of the size of the sample and boundar...

Research paper thumbnail of A Numerical Approach to Simulate Stresses Around Tunnels in Swelling Rocks

The stresses generated from rock expansion in a confined underground environment will exert addit... more The stresses generated from rock expansion in a confined underground environment will exert additional loads to the existing support system resulting in severe damage during tunnel construction. In this study numerical investigations were carried out for Zagros tunnel in Iran, where swelling has been reported to be an inherent formation property. The presence of expandable clay was investigated using X-ray diffraction mineralogical analyses. The swelling volume strain was used to estimate the amount of stress increased due to swelling. The stress path method is used to obtain the location of swelling stresses. The stress relief zone (SRZ) was considered as the criterion to define the area around the tunnel where swelling stresses exist. In doing so, in the areas where the first stress invariant after excavation becomes lesser than its corresponding value before excavation, the swelling pressure can be built up. Then tunnel stability was investigated by numerical simulations using FL...

Research paper thumbnail of Wellbore Stability Analysis Due to Turbulent Flow in Coiled Tubing Drilling

Research paper thumbnail of A case study on TBM tunnelling in fault zones and lessons learned from ground improvement

Tunnelling and Underground Space Technology, 2017

Research paper thumbnail of Prediction of TBM penetration rate using intact and mass rock properties (case study: Zagros long tunnel, Iran)

Arabian Journal of Geosciences

In this paper, the correlations between the different measurements of rock brittleness (i.e., B 1... more In this paper, the correlations between the different measurements of rock brittleness (i.e., B 1, B 2, B 3, and BI) and the penetration rate (PR) of tunnel boring machine (TBM) through Zagros long tunnel were evaluated. According to the results of simple regression analyses, there was no correlation between the penetration rate of TBM and the brittleness of B 1, but stronger log-linear correlations have been observed between the penetration rate of TBM and the B 2, B 3, and BI brittleness indices. As part of the present study, correlations between some of rock mass classification systems (RQD, RMR, GSI, Q, and Q TBM) and penetration rate of TBM have been investigated. The results of simple regression analyses showed that the first four rock mass classification systems did not exhibit a good correlation with the TBM penetration rate, but the Q TBM had strong correlation with that. Multiple linear regression (MLR) analyses were applied for estimating the TBM penetration rate based on...

Research paper thumbnail of Analytical investigation of well/perforation scale effect on sand production of weakly consolidated sandstones

The APPEA Journal

Investigating the risk of sand production is a common practice for developing unconsolidated and ... more Investigating the risk of sand production is a common practice for developing unconsolidated and weakly consolidated reservoirs, particularly with designing the completion system of development wells. The risk of sanding may be different for open hole and cased and perforated completion systems. Part of this difference is a result of the different size of the boreholes—that is, open hole versus perforation tunnels— which is known as borehole scale effect. The amount of research dedicated to investigate the borehole scale effect on sand production is very limited. Research has been carried out by conducting thick-walled cylinder (TWC) tests on samples with different inner to outer diameter ratios. The impacts of sample size and boundaries on the induced stresses around the borehole and failure were, however, not differentiated from the borehole scale effect. In this paper, a comprehensive analytical approach is performed to investigate the effect of the size of the sample and boundar...