The tunnel subjected to strike-slip fault dislocation exhibits severe and catastrophic damage.The existing analysis models frequently assume uniform fault displacement and fixed fault plane position.In contrast,post-e...The tunnel subjected to strike-slip fault dislocation exhibits severe and catastrophic damage.The existing analysis models frequently assume uniform fault displacement and fixed fault plane position.In contrast,post-earthquake observations indicate that the displacement near the fault zone is typically nonuniform,and the fault plane position is uncertain.In this study,we first established a series of improved governing equations to analyze the mechanical response of tunnels under strike-slip fault dislocation.The proposed methodology incorporated key factors such as nonuniform fault displacement and uncertain fault plane position into the governing equations,thereby significantly enhancing the applicability range and accuracy of the model.In contrast to previous analytical models,the maximum computational error has decreased from 57.1%to 1.1%.Subsequently,we conducted a rigorous validation of the proposed methodology by undertaking a comparative analysis with a 3D finite element numerical model,and the results from both approaches exhibited a high degree of qualitative and quantitative agreement with a maximum error of 9.9%.Finally,the proposed methodology was utilized to perform a parametric analysis to explore the effects of various parameters,such as fault displacement,fault zone width,fault zone strength,the ratio of maximum fault displacement of the hanging wall to the footwall,and fault plane position,on the response of tunnels subjected to strike-slip fault dislocation.The findings indicate a progressive increase in the peak internal forces of the tunnel with the rise in fault displacement and fault zone strength.Conversely,an augmentation in fault zone width is found to contribute to a decrease in the peak internal forces.For example,for a fault zone width of 10 m,the peak values of bending moment,shear force,and axial force are approximately 46.9%,102.4%,and 28.7% higher,respectively,compared to those observed for a fault zone width of 50 m.Furthermore,the position of the peak internal forces is influenced by variations in the ratio of maximum fault displacement of the hanging wall to footwall and the fault plane location,while the peak values of shear force and axial force always align with the fault plane.The maximum peak internal forces are observed when the footwall exclusively bears the entirety of the fault displacement,corresponding to a ratio of 0:1.The peak values of bending moment,shear force,and axial force for the ratio of 0:1 amount to approximately 123.8%,148.6%,and 111.1% of those for the ratio of 0.5:0.5,respectively.展开更多
Biliary cysts(BC) are rare dilatations of different parts of a biliary tract.They account for approximately 1% of all benign biliary diseases.BC occur the most frequently in Asian and female populations.They are an im...Biliary cysts(BC) are rare dilatations of different parts of a biliary tract.They account for approximately 1% of all benign biliary diseases.BC occur the most frequently in Asian and female populations.They are an important problem for pediatricians,gastroenterologists,radiologists and surgeons.Clinical presentation and management depend on the BC type.Cholangiocarcinoma is the most serious and dangerous BC complication.The other complications associated with BC involve cholelithiasis and hepatolithiasis,cholangitis,acute and chronic pancreatitis,portal hypertension,liver fibrosis and secondary liver cirrhosis and spontaneous cyst perforation.Different BC classifications have been described in the literature.Todani classification dividing BC into five types is the most useful in clinical practice.The early diagnosis and proper treatment are very important,because BC are associated with a risk of carcinogenesis.A malignancy risk increases with the age.Radiological investigations(ultrasonography,computed tomography,endoscopic retrograde cholangiopancreatography and magnetic resonance cholangiopancreatography) play an important role in BC diagnostics.Currently,prenatal diagnosis using ultrasonography is possible.It allows to differentiate biliary disorders in fetals and to perform the early surgical treatment that improves results.In most patients,total cyst excision with Roux-Y hepaticojejunostomy is the treatment of choice.Surgical treat-ment of BC is associated with high success rate and low morbidity and mortality.The early treatment is associated with a lower number of complications.Patients following BC surgery require permanent and careful postoperative observation using laboratory and imaging investigations because of possibility of biliary anastomosis stricture and biliary cancer in tissue remnant.展开更多
Functional gastrointestinal disorders （FGIDs） represent a common and important class of disorders within gastroenterology. Rome Ⅰ, the first edition was published in 1994, with symptom-based diagnostic criteria for...Functional gastrointestinal disorders （FGIDs） represent a common and important class of disorders within gastroenterology. Rome Ⅰ, the first edition was published in 1994, with symptom-based diagnostic criteria for FGIDs. These criteria began to change the diagnostic approach to F-GIDs, and no longer considered ＂diagnoses of exclusion＂ but rather ＂diagnoses of inclusion＂. Rome Ⅱ, the second edition published in 2000, resulted from the continual process of analyzing new scientific and clinical evidence in the study of F-GIDs. Rome Ⅱ, diagnostic criteria for irritable bowel syndrome （IBS）, was extended with a focus on the frequency of symptoms occurring twelve weeks （not necessarily consecutive weeks） within twelve months. ROlE Ⅲ, the third edition, conservative one, was published in September 2006, with changes made only where there is good evidence to do so. Some of the differences between Rome Ⅱ and Rome Ⅲ criteria are highlighted in this issue.展开更多
With the increasing traffic demand, the closely built three or more tunnels with large section play a significant role in the tunnel construction. However, the interaction among tunnels has important influences on the...With the increasing traffic demand, the closely built three or more tunnels with large section play a significant role in the tunnel construction. However, the interaction among tunnels has important influences on the security and economy of tunnel engineering, and the calculation of pressure from the surrounding rock during the excavation is one of the problems that need to be solved urgently. Based on the practical engineering of three tunnels, the load model of three tunnels was proposed in consideration of the interaction and excavation sequence between tunnels. In comparison with the load model of single tunnel, the construction mechanical characteristics of the three tunnels were analyzed. The results show that the rock pressure of three tunnels calculated by the current tunnel design code is not reliable, and the interaction force increases with the spacing between tunnels.展开更多
基金Projects(52378411,52208404)supported by the National Natural Science Foundation of China。
文摘The tunnel subjected to strike-slip fault dislocation exhibits severe and catastrophic damage.The existing analysis models frequently assume uniform fault displacement and fixed fault plane position.In contrast,post-earthquake observations indicate that the displacement near the fault zone is typically nonuniform,and the fault plane position is uncertain.In this study,we first established a series of improved governing equations to analyze the mechanical response of tunnels under strike-slip fault dislocation.The proposed methodology incorporated key factors such as nonuniform fault displacement and uncertain fault plane position into the governing equations,thereby significantly enhancing the applicability range and accuracy of the model.In contrast to previous analytical models,the maximum computational error has decreased from 57.1%to 1.1%.Subsequently,we conducted a rigorous validation of the proposed methodology by undertaking a comparative analysis with a 3D finite element numerical model,and the results from both approaches exhibited a high degree of qualitative and quantitative agreement with a maximum error of 9.9%.Finally,the proposed methodology was utilized to perform a parametric analysis to explore the effects of various parameters,such as fault displacement,fault zone width,fault zone strength,the ratio of maximum fault displacement of the hanging wall to the footwall,and fault plane position,on the response of tunnels subjected to strike-slip fault dislocation.The findings indicate a progressive increase in the peak internal forces of the tunnel with the rise in fault displacement and fault zone strength.Conversely,an augmentation in fault zone width is found to contribute to a decrease in the peak internal forces.For example,for a fault zone width of 10 m,the peak values of bending moment,shear force,and axial force are approximately 46.9%,102.4%,and 28.7% higher,respectively,compared to those observed for a fault zone width of 50 m.Furthermore,the position of the peak internal forces is influenced by variations in the ratio of maximum fault displacement of the hanging wall to footwall and the fault plane location,while the peak values of shear force and axial force always align with the fault plane.The maximum peak internal forces are observed when the footwall exclusively bears the entirety of the fault displacement,corresponding to a ratio of 0:1.The peak values of bending moment,shear force,and axial force for the ratio of 0:1 amount to approximately 123.8%,148.6%,and 111.1% of those for the ratio of 0.5:0.5,respectively.
文摘Biliary cysts(BC) are rare dilatations of different parts of a biliary tract.They account for approximately 1% of all benign biliary diseases.BC occur the most frequently in Asian and female populations.They are an important problem for pediatricians,gastroenterologists,radiologists and surgeons.Clinical presentation and management depend on the BC type.Cholangiocarcinoma is the most serious and dangerous BC complication.The other complications associated with BC involve cholelithiasis and hepatolithiasis,cholangitis,acute and chronic pancreatitis,portal hypertension,liver fibrosis and secondary liver cirrhosis and spontaneous cyst perforation.Different BC classifications have been described in the literature.Todani classification dividing BC into five types is the most useful in clinical practice.The early diagnosis and proper treatment are very important,because BC are associated with a risk of carcinogenesis.A malignancy risk increases with the age.Radiological investigations(ultrasonography,computed tomography,endoscopic retrograde cholangiopancreatography and magnetic resonance cholangiopancreatography) play an important role in BC diagnostics.Currently,prenatal diagnosis using ultrasonography is possible.It allows to differentiate biliary disorders in fetals and to perform the early surgical treatment that improves results.In most patients,total cyst excision with Roux-Y hepaticojejunostomy is the treatment of choice.Surgical treat-ment of BC is associated with high success rate and low morbidity and mortality.The early treatment is associated with a lower number of complications.Patients following BC surgery require permanent and careful postoperative observation using laboratory and imaging investigations because of possibility of biliary anastomosis stricture and biliary cancer in tissue remnant.
文摘Functional gastrointestinal disorders （FGIDs） represent a common and important class of disorders within gastroenterology. Rome Ⅰ, the first edition was published in 1994, with symptom-based diagnostic criteria for FGIDs. These criteria began to change the diagnostic approach to F-GIDs, and no longer considered ＂diagnoses of exclusion＂ but rather ＂diagnoses of inclusion＂. Rome Ⅱ, the second edition published in 2000, resulted from the continual process of analyzing new scientific and clinical evidence in the study of F-GIDs. Rome Ⅱ, diagnostic criteria for irritable bowel syndrome （IBS）, was extended with a focus on the frequency of symptoms occurring twelve weeks （not necessarily consecutive weeks） within twelve months. ROlE Ⅲ, the third edition, conservative one, was published in September 2006, with changes made only where there is good evidence to do so. Some of the differences between Rome Ⅱ and Rome Ⅲ criteria are highlighted in this issue.
基金Project(2011CB01380) supported by the National Basic Research Program of ChinaProject(51178468) supported by the National Natural Science Foundation of ChinaProject(2011G013-B) supported by Science and Technology Development of Railways Department in China
文摘With the increasing traffic demand, the closely built three or more tunnels with large section play a significant role in the tunnel construction. However, the interaction among tunnels has important influences on the security and economy of tunnel engineering, and the calculation of pressure from the surrounding rock during the excavation is one of the problems that need to be solved urgently. Based on the practical engineering of three tunnels, the load model of three tunnels was proposed in consideration of the interaction and excavation sequence between tunnels. In comparison with the load model of single tunnel, the construction mechanical characteristics of the three tunnels were analyzed. The results show that the rock pressure of three tunnels calculated by the current tunnel design code is not reliable, and the interaction force increases with the spacing between tunnels.
