Longitudinal seismic performance is a critical aspect to be considered during the tunnel design process,in addition to cross-sectional considerations.The present study proposed using a laminated shear energy dissipati...Longitudinal seismic performance is a critical aspect to be considered during the tunnel design process,in addition to cross-sectional considerations.The present study proposed using a laminated shear energy dissipation(LSED)structure to achieve effective longitudinal seismic design.The proposed structure consists of thin steel plates and alternately bonded layers of rubber,which can be installed around the periphery of the secondary lining.This configuration guarantees that the tunnels will exhibit optimal axial deformation capacity and robust rigid resistance to circumferential compression from the surrounding rock.To evaluate the impact of the LSED structure on the longitudinal seismic performance of the tunnel,a fine numerical model of the LSED structureetunnel liningesurrounding rock system was developed using finite element simulation.The evaluation criteria include maximum principal stress and strain energy.The seismic response of the tunnel with the LSED structure exhibited a notable reduction of over 40%in terms of seismic attenuation rate when subjected to the Trinidad seismic wave compared to the tunnel without the LSED structure.Furthermore,the aseismic mechanism of the proposed LSED structure is discussed,considering both internal factors such as the rubber shear modulus,steel plate dimensions,and number and location of structures,and external influencing factors such as seismic wave parameters and surrounding rock quality.Meanwhile,the effectiveness of the tunnel with the LSED structure has been quantitatively demonstrated in terms of seismic fragility curves.展开更多
目的总结腹腔镜脾切断流术(laparoscopic splenectomy and esophagogastric devascularization,LSED)治疗门静脉高压消化道出血的诊治经验及手术入路。方法选取2018年1月至2020年4月首都医科大学附属北京佑安医院收治的因门静脉高压导...目的总结腹腔镜脾切断流术(laparoscopic splenectomy and esophagogastric devascularization,LSED)治疗门静脉高压消化道出血的诊治经验及手术入路。方法选取2018年1月至2020年4月首都医科大学附属北京佑安医院收治的因门静脉高压导致顽固性消化道出血接受LSED治疗的24例患者,分析其临床疗效及手术入路。结果24例患者中有22例(91.7%)应用腹膜后优先解剖入路,术中平均出血量为402.1 ml,术后复查WBC和PLT较术前显著回升(P<0.05),最常见的并发症为腹水(8/24,33.3%)和一过性胰漏(5/24,20.8%),均对症处理痊愈,无二次手术及死亡病例。术后早期、3个月及1年的门静脉血栓形成率分别为4.2%、41.7%和33.3%,术后1年内消化道出血复发率为4.2%。结论LSED治疗门静脉高压消化道出血安全有效,腹膜后优先解剖手术入路可以提供清晰的安全边界,有助于LSED的成功实施。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52109132)the Shandong Provincial Natural Science Foundation(Grant No.ZR2020QE270).
文摘Longitudinal seismic performance is a critical aspect to be considered during the tunnel design process,in addition to cross-sectional considerations.The present study proposed using a laminated shear energy dissipation(LSED)structure to achieve effective longitudinal seismic design.The proposed structure consists of thin steel plates and alternately bonded layers of rubber,which can be installed around the periphery of the secondary lining.This configuration guarantees that the tunnels will exhibit optimal axial deformation capacity and robust rigid resistance to circumferential compression from the surrounding rock.To evaluate the impact of the LSED structure on the longitudinal seismic performance of the tunnel,a fine numerical model of the LSED structureetunnel liningesurrounding rock system was developed using finite element simulation.The evaluation criteria include maximum principal stress and strain energy.The seismic response of the tunnel with the LSED structure exhibited a notable reduction of over 40%in terms of seismic attenuation rate when subjected to the Trinidad seismic wave compared to the tunnel without the LSED structure.Furthermore,the aseismic mechanism of the proposed LSED structure is discussed,considering both internal factors such as the rubber shear modulus,steel plate dimensions,and number and location of structures,and external influencing factors such as seismic wave parameters and surrounding rock quality.Meanwhile,the effectiveness of the tunnel with the LSED structure has been quantitatively demonstrated in terms of seismic fragility curves.
