شبیه سازی عددی

One of the main challenges of tunnel excavation in urban areas is subsidence control, which can affect surface and underground structures. Nowadays, the performance of the umbrella arch system is accepted as an effective solution for controlling subsidence and tunnel excavation in conditions where face of tunnel is unstable. In this research, using the Birgel tunnel instrumentation data and its construction method, the numerical model has been calibrated and the three scenarios of cantilever beam, critical strain and reinforced zone have been investigated applying numerical simulation. The first scenario showed that if the internal forces of the pile element are examined, the stability factor 1 should be used as the design criterion. In the second scenario, using the level there of Sakurai warning is proposed as a design criterion. In the third scenario, relationships are developed to calculate the geometry and geomechanical parameters of the reinforced zone considering the second scenario. Based on the analysis results, the internal friction angle in the reinforced zone could be kept unchanged and just the modulus of deformation and cohesion in the reinforced zone are raised up according to the proposed relationships.

In this paper developed a model by COMSOL software that able to predict operational parameters effect on the components and heating value of produced gas during underground coal gasification. In this model for shown the effects of Operational Parameters on UCG process a Case Study has been developed. The results show that this model able to predict the effects of operational parameters on the components and heating value of produced gas in UCG process.

Underground Coal Gasification (UCG) process have a good adaptation with environment, in this process at the first insitu-coal seam converted to syngas and then would be explorated. The main purpose in UCG process is producing syngas with a heating value or producing each gases that producing in UCG process (for example Hydrogen production). Before implement of UCG process, predict of the components and heating value of syngas is necessary to economic analysis. In this paper presented a new model to gasify all coal in each stope, however; the produced gas have a high heating value.

According to this model, moreover to gasify all of coal in each stope, the extent of heating value of produced gas is the same requested amount. Presented model in this research have been introduced with a Case Study for K10 coal seam of Takht region. Finally Operational Parameters to produce syngas with appropriate components and heating value for gasify K10 coal seam is calculated (it should be noted that this design shows only one possible scenarios).

The results for this case study shown that in a period of 11 months, 9 stopes must be active simultaneously and Operational Parameters in each stope including temperature, cavity pressure, oxygen injection rate, steam injection rate and operation time should be consider 1273K, 1MPa, 10 mol/s, 20 mol/s and 11 months respectively. In this case, K10 coal seam can support feed of 27 MW IGCC-based power plant for 22 years.