In the present study,a comparison between the new shallow tunneling method(STM)and the traditional pile and rib method(PRM)was conducted to excavate and construct subway stations in the geological conditions of Tehran...In the present study,a comparison between the new shallow tunneling method(STM)and the traditional pile and rib method(PRM)was conducted to excavate and construct subway stations in the geological conditions of Tehran.First,by selecting Station Z6 located in the Tehran Subway Line 6 as a case study,the construction process was analyzed by PRM.The maximum ground settlement of 29.84 mm obtained from this method was related to the station axis,and it was within the allowable settlement limit of 30 mm.The acceptable agreement between the results of numerical modeling and instrumentation data indicated the confirmation and accuracy of the excavation and construction process of Station Z6 by PRM.In the next stage,based on the numerical model validated by instrumentation data,the value of the ground surface settlement was investigated during the station excavation and construction by STM.The results obtained from STM showed a significant reduction in the ground surface settlement compared to PRM.The maximum settlement obtained from STM was 6.09 mm as related to the front of the excavation face.Also,the sensitivity analysis results denoted that in addition to controlling the surface settlement by STM,it is possible to optimize some critical geometric parameters of the support system during the station excavation and construction.展开更多
Sand production is considered as one of the significant production issues that significantly reduce wellbore productivity.The process of sand or solids production in production operations is one of the crucial operati...Sand production is considered as one of the significant production issues that significantly reduce wellbore productivity.The process of sand or solids production in production operations is one of the crucial operational inefficiencies that can lead to wells collapsing.Besides,the drilling mud might erupt through the formation.Therefore,it is essential to properly determine what types of solids or sand are produced to correctly predict efficient sand control mechanisms.This paper aimed to compare different sand production control mechanisms and how to control or minimize sand production.Moreover,we consider injection pressure and sand moisture on the sand production rate.According to this study’s findings,pressure injection and moisture increase had caused sand production increase,which should be considered in operational performances.Furthermore,chemical injection such as resin and hydrogel injection usually has efficient sand production control methods.An expandable sand screen is an expandable three-layer component that is driven into the well and expanded.展开更多
文摘In the present study,a comparison between the new shallow tunneling method(STM)and the traditional pile and rib method(PRM)was conducted to excavate and construct subway stations in the geological conditions of Tehran.First,by selecting Station Z6 located in the Tehran Subway Line 6 as a case study,the construction process was analyzed by PRM.The maximum ground settlement of 29.84 mm obtained from this method was related to the station axis,and it was within the allowable settlement limit of 30 mm.The acceptable agreement between the results of numerical modeling and instrumentation data indicated the confirmation and accuracy of the excavation and construction process of Station Z6 by PRM.In the next stage,based on the numerical model validated by instrumentation data,the value of the ground surface settlement was investigated during the station excavation and construction by STM.The results obtained from STM showed a significant reduction in the ground surface settlement compared to PRM.The maximum settlement obtained from STM was 6.09 mm as related to the front of the excavation face.Also,the sensitivity analysis results denoted that in addition to controlling the surface settlement by STM,it is possible to optimize some critical geometric parameters of the support system during the station excavation and construction.
文摘Sand production is considered as one of the significant production issues that significantly reduce wellbore productivity.The process of sand or solids production in production operations is one of the crucial operational inefficiencies that can lead to wells collapsing.Besides,the drilling mud might erupt through the formation.Therefore,it is essential to properly determine what types of solids or sand are produced to correctly predict efficient sand control mechanisms.This paper aimed to compare different sand production control mechanisms and how to control or minimize sand production.Moreover,we consider injection pressure and sand moisture on the sand production rate.According to this study’s findings,pressure injection and moisture increase had caused sand production increase,which should be considered in operational performances.Furthermore,chemical injection such as resin and hydrogel injection usually has efficient sand production control methods.An expandable sand screen is an expandable three-layer component that is driven into the well and expanded.
