Segmental tunnel lining strengthened with steel plates is widely used worldwide to provide a permanent strengthening method.Most existing studies assume an ideal steel-concrete interface,ignoring discontinuous deforma...Segmental tunnel lining strengthened with steel plates is widely used worldwide to provide a permanent strengthening method.Most existing studies assume an ideal steel-concrete interface,ignoring discontinuous deformation characteristics,making it difficult to accurately analyze the strengthened structure’s failure mechanism.In this study,interfacial fracture mechanics of composite material was applied to the segmental tunnel lining strengthened with steel plates,and a numerical three-dimensional solid nonlinear model of the lining structure was established,combining the extended finite element method with a cohesive-zone model to account for the discontinuous deformation characteristics of the interface.The results accurately describe the crack propagation process,and are verified by full-scale testing.Next,dynamic simulations based on the calibrated model were conducted to analyze the sliding failure and cracking of the steel-concrete interface.Lastly,detailed location of the interface bonding failure are further verified by model test.The results show that,the cracking failure and bond failure of the interface are the decisive factors determining the instability and failure of the strengthened structure.The proposed numerical analysis is a major step forward in revealing the interface failure mechanism of strengthened composite material structures.展开更多
BACKGROUND Shoulder injuries caused by trauma are common,including clavicle fractures.Even so,bipolar segmental fracture of the clavicle is extremely rare and seldom reported.Therefore,there is still a controversial i...BACKGROUND Shoulder injuries caused by trauma are common,including clavicle fractures.Even so,bipolar segmental fracture of the clavicle is extremely rare and seldom reported.Therefore,there is still a controversial issue about how to treat these bipolar segmental clavicle fractures.CASE SUMMARY A 56-year-old security guard arrived at our emergency room after falling on his electric bicycle.There was no loss of consciousness or other pain.He had no numbness in his fingers.X-rays and 3D computed tomography revealed that the patient’s right shoulder had a bipolar segmental clavicle fracture.The surgical procedure included both open reduction and internal fixation.At the 1-year follow-up,he had a full range of motion and minimal discomfort in the injured shoulder.CONCLUSION We provide a rare case of bipolar clavicle facture in the right clavicle.We hold the opinion that such patients would get better clinical and radiological outcomes by early and correct operation.展开更多
基金the financial support provided by the National Key Basic Research Program of China(No.2015CB057801)the Projects of the Construction Department of Zhejiang Province(Nos.2022K073 and 2022K169).
文摘Segmental tunnel lining strengthened with steel plates is widely used worldwide to provide a permanent strengthening method.Most existing studies assume an ideal steel-concrete interface,ignoring discontinuous deformation characteristics,making it difficult to accurately analyze the strengthened structure’s failure mechanism.In this study,interfacial fracture mechanics of composite material was applied to the segmental tunnel lining strengthened with steel plates,and a numerical three-dimensional solid nonlinear model of the lining structure was established,combining the extended finite element method with a cohesive-zone model to account for the discontinuous deformation characteristics of the interface.The results accurately describe the crack propagation process,and are verified by full-scale testing.Next,dynamic simulations based on the calibrated model were conducted to analyze the sliding failure and cracking of the steel-concrete interface.Lastly,detailed location of the interface bonding failure are further verified by model test.The results show that,the cracking failure and bond failure of the interface are the decisive factors determining the instability and failure of the strengthened structure.The proposed numerical analysis is a major step forward in revealing the interface failure mechanism of strengthened composite material structures.
文摘BACKGROUND Shoulder injuries caused by trauma are common,including clavicle fractures.Even so,bipolar segmental fracture of the clavicle is extremely rare and seldom reported.Therefore,there is still a controversial issue about how to treat these bipolar segmental clavicle fractures.CASE SUMMARY A 56-year-old security guard arrived at our emergency room after falling on his electric bicycle.There was no loss of consciousness or other pain.He had no numbness in his fingers.X-rays and 3D computed tomography revealed that the patient’s right shoulder had a bipolar segmental clavicle fracture.The surgical procedure included both open reduction and internal fixation.At the 1-year follow-up,he had a full range of motion and minimal discomfort in the injured shoulder.CONCLUSION We provide a rare case of bipolar clavicle facture in the right clavicle.We hold the opinion that such patients would get better clinical and radiological outcomes by early and correct operation.
