Full utilization of underground space and buildings could have positive economic and social effects. However, the microclimate and air quality must be well controlled so that they are not harmful to human health. This...Full utilization of underground space and buildings could have positive economic and social effects. However, the microclimate and air quality must be well controlled so that they are not harmful to human health. This survey indicated that relative humidity is a common hygienic problem in underground space and buildings. Attention should be paid to humidity control and to the strengthening of routine ventilation at the construction stage. Carbon dioxide can be used as a hygiene index of air pollution; the sanitary standard for it in the air of underground buildings is 10%. The hygienic survey shows that the concentration of carbon dioxide is usually below this standard in the environments of underground space and buildings. (c)1989 Academic Press,Inc.展开更多
The drill and blast(D&B)method is widely used to excavate underground spaces,but explosions generally cause damage to the rock.Still,no blast simulation method can provide computational accuracy and efficiency.In ...The drill and blast(D&B)method is widely used to excavate underground spaces,but explosions generally cause damage to the rock.Still,no blast simulation method can provide computational accuracy and efficiency.In this paper,a blast equivalent simulation method called the blast damage zone strength reduction(BDZSR)method is proposed.This method first calculates the range of the blast-induced damage zone(BDZ)by formulae,then reduces the strength and deformation parameters of the rock within the BDZ ahead of excavation,and finally calculates the excavation damage zone(EDZ)for the D&B method by numerical simulation.This method combines stress wave attenuation,rock damage criteria and stress path variation to derive the BDZ depth calculation formulae.The formulae consider the initial geo-stress,and the reliability is verified by numerical simulations.The calculation of BDZ depth with these formulae allows the corresponding numerical simulation to avoid the time-consuming dynamic calculation process,thus greatly enhancing the calculation efficiency.The method was applied to the excavation in Jinping Class II hydropower station to verify its feasibility.The results show that the BDZSR method can be applied to blast simulation of underground caverns and provide a new way to study blast-induced damage.展开更多
文摘Full utilization of underground space and buildings could have positive economic and social effects. However, the microclimate and air quality must be well controlled so that they are not harmful to human health. This survey indicated that relative humidity is a common hygienic problem in underground space and buildings. Attention should be paid to humidity control and to the strengthening of routine ventilation at the construction stage. Carbon dioxide can be used as a hygiene index of air pollution; the sanitary standard for it in the air of underground buildings is 10%. The hygienic survey shows that the concentration of carbon dioxide is usually below this standard in the environments of underground space and buildings. (c)1989 Academic Press,Inc.
基金the financial support from the National Natural Science Foundation of China(Grant No.U1965203).
文摘The drill and blast(D&B)method is widely used to excavate underground spaces,but explosions generally cause damage to the rock.Still,no blast simulation method can provide computational accuracy and efficiency.In this paper,a blast equivalent simulation method called the blast damage zone strength reduction(BDZSR)method is proposed.This method first calculates the range of the blast-induced damage zone(BDZ)by formulae,then reduces the strength and deformation parameters of the rock within the BDZ ahead of excavation,and finally calculates the excavation damage zone(EDZ)for the D&B method by numerical simulation.This method combines stress wave attenuation,rock damage criteria and stress path variation to derive the BDZ depth calculation formulae.The formulae consider the initial geo-stress,and the reliability is verified by numerical simulations.The calculation of BDZ depth with these formulae allows the corresponding numerical simulation to avoid the time-consuming dynamic calculation process,thus greatly enhancing the calculation efficiency.The method was applied to the excavation in Jinping Class II hydropower station to verify its feasibility.The results show that the BDZSR method can be applied to blast simulation of underground caverns and provide a new way to study blast-induced damage.
