The tunnel industry has considered that tunnels,especially tunnels in rock,are naturally resistant to earthquake action,including faulting,shaking,deflection and ground failure.As the number of case histories of tunne...The tunnel industry has considered that tunnels,especially tunnels in rock,are naturally resistant to earthquake action,including faulting,shaking,deflection and ground failure.As the number of case histories of tunnels subject to earthquake action has increased,the industry has started to recognize that,although tunnels in rock have good resistance against earthquakes generating peak ground accelerations(PGA)lower than 0.5 g,it is important to include the dynamic forces and displacements generated by seismic ground motions in the design process to obtain a more reliable design.These additional earthquake forces impact the final design,potentially requiring changes to the ground support and additional reinforcement of the concrete lining,as illustrated by case histories presented in this paper.展开更多
Basic concepts of seismic zonation in Russia are the degree of intensity and soil categories that correspond to discrete structure in the ratio “seismic impact-ground reaction”. Meanwhile, the parameters of seismic ...Basic concepts of seismic zonation in Russia are the degree of intensity and soil categories that correspond to discrete structure in the ratio “seismic impact-ground reaction”. Meanwhile, the parameters of seismic effects, and the parameters of soil properties are continuous in the space. The report expounds the basic theory, adequately representing the above mentioned continuality. Thus, many the concepts of seismic zonation, used now, become either more correct, or unnecessary.展开更多
Introduction With rapid development and advancement of economy and society, lots of city groups or city belts with ex-tra-large cities as their centers have been formed in China. The regions these city groups lie i...Introduction With rapid development and advancement of economy and society, lots of city groups or city belts with ex-tra-large cities as their centers have been formed in China. The regions these city groups lie in usually havewell-developed economy, dense population, and are regional politics and culture centers. Some groups lie in theregions with high level of earthquake activity, such as the Surrounding Capital City Group with the centers of Bei-jing and Tianjin. Once a large earthquake occurs, its influence will spread to very extensive region and its disasterwill be tremendous too. So earthquake resistance and disaster mitigation of city group will be very significant issue.The cities in a group have close distance with each other; they can carry out unified preparation for disaster as onewhole and reduce the heavy load of single city before an earthquake, and have an advantage of prompt mutual-aidafter an earthquake because of close distance. It is especially significant to mitigate the lose of lives. One importantprecondition is that all the cities in one group cannot be exposed to the same level of destroy during one earth-quake. So the division of city group in the region with dense cities distribution shall be very significant to theemergent mutual-aid in early time after a large earthquake. For this goal, the characteristics and correlativity ofearthquake′s impact on cities in one group need to clearly be considered. The cities with similar features and strongcorrelativity of historical earthquake influence have large chance to suffer same level destroy during the futurestrong earthquake and are disadvantage to provide mutual-aid and shall not be divided into one group. ……展开更多
文摘The tunnel industry has considered that tunnels,especially tunnels in rock,are naturally resistant to earthquake action,including faulting,shaking,deflection and ground failure.As the number of case histories of tunnels subject to earthquake action has increased,the industry has started to recognize that,although tunnels in rock have good resistance against earthquakes generating peak ground accelerations(PGA)lower than 0.5 g,it is important to include the dynamic forces and displacements generated by seismic ground motions in the design process to obtain a more reliable design.These additional earthquake forces impact the final design,potentially requiring changes to the ground support and additional reinforcement of the concrete lining,as illustrated by case histories presented in this paper.
文摘Basic concepts of seismic zonation in Russia are the degree of intensity and soil categories that correspond to discrete structure in the ratio “seismic impact-ground reaction”. Meanwhile, the parameters of seismic effects, and the parameters of soil properties are continuous in the space. The report expounds the basic theory, adequately representing the above mentioned continuality. Thus, many the concepts of seismic zonation, used now, become either more correct, or unnecessary.
文摘Introduction With rapid development and advancement of economy and society, lots of city groups or city belts with ex-tra-large cities as their centers have been formed in China. The regions these city groups lie in usually havewell-developed economy, dense population, and are regional politics and culture centers. Some groups lie in theregions with high level of earthquake activity, such as the Surrounding Capital City Group with the centers of Bei-jing and Tianjin. Once a large earthquake occurs, its influence will spread to very extensive region and its disasterwill be tremendous too. So earthquake resistance and disaster mitigation of city group will be very significant issue.The cities in a group have close distance with each other; they can carry out unified preparation for disaster as onewhole and reduce the heavy load of single city before an earthquake, and have an advantage of prompt mutual-aidafter an earthquake because of close distance. It is especially significant to mitigate the lose of lives. One importantprecondition is that all the cities in one group cannot be exposed to the same level of destroy during one earth-quake. So the division of city group in the region with dense cities distribution shall be very significant to theemergent mutual-aid in early time after a large earthquake. For this goal, the characteristics and correlativity ofearthquake′s impact on cities in one group need to clearly be considered. The cities with similar features and strongcorrelativity of historical earthquake influence have large chance to suffer same level destroy during the futurestrong earthquake and are disadvantage to provide mutual-aid and shall not be divided into one group. ……
