The strength of structural loess consists of the shear strength and tensile strength. In this study, the stress path, the failure envelope of principal stress （ Kf line）, and the strength failure envelope of structu...The strength of structural loess consists of the shear strength and tensile strength. In this study, the stress path, the failure envelope of principal stress （ Kf line）, and the strength failure envelope of structurally intact loess and remolded loess were analyzed through three kinds of tests： the tensile strength test, the uniaxial compressive strength test, and the conventional triaxial shear strength test. Then, in order to describe the tensile strength and shear strength of structural loess comprehensively and reasonably, a joint strength formula for structural loess was established. This formula comprehensively considers tensile and shear properties. Studies have shown that the tensile strength exhibits a decreasing trend with increasing water content. When the water content is constant, the tensile strength of the structurally intact soil is greater than that ofremolded soil. In the studies, no loss of the originally cured cohesion in the structurally intact soil samples was observed, given that the soil samples did not experience loading disturbance during the uniaxial compressive strength test, meaning there is a high initial structural strength. The results of the conventional triaxial shear strength test show that the water content is correlated with the strength of the structural loess. When the water content is low, the structural properties are strong, and when the water content is high, the structural properties are weak, which means that the water content and the ambient pressure have significant effects on the stress-strain relationship of structural loess. The established joint strength formula of structural loess effectively avoids overestimating the role of soil tensile strength in the traditional theory of Mohr-Coulomb strength.展开更多
Extensive data of undrained shear strength for various remolded soils are compiled to normalize the remolded undrained strength. Remolded soils have a wide spectrum of liquid limits ranging from 25% to 412%. It is fou...Extensive data of undrained shear strength for various remolded soils are compiled to normalize the remolded undrained strength. Remolded soils have a wide spectrum of liquid limits ranging from 25% to 412%. It is found that the remolded undrained strength is a function of water content and liquid limit. Furthermore, a simple index designated as normalized water content w * is introduced for normalizing remolded undrained strength for various soils. The normalized water content w * is the ratio of water content to liquid limit. The relationship between the remolded undrained strength and the normalized water content can be expressed by a simple equation. The new simple equation is not only valuable theoretically for helping in assessing the in situ mechanical behavior, but also useful to ocean engineering practice.展开更多
Chandler proposed the intrinsic strength line to correlate the undrained shear strength of samples one-dimensionally consolidated from slurry with the void index proposed by Burland. The undrained shear strength on th...Chandler proposed the intrinsic strength line to correlate the undrained shear strength of samples one-dimensionally consolidated from slurry with the void index proposed by Burland. The undrained shear strength on the intrinsic strength line is different from the remolded undrained shear strength that is an important parameter for design and construction of land reclamation. The void index is used in this study for normalizing the remolded strength behavior of dredged deposits. A quantitative relationship between remolded undrained shear strength and void index is established based on extensive data of dredged deposits available from sources of literature. Furthermore, the normalized remolded undrained shear strength is compared with intrinsic strength line. The comparison result indicates that the ratio of undrained shear strength on the intrinsic strength line over remolded undrained shear strength increases with an increase in applied consolidated stress.展开更多
Regulatory science for medical devices aims to develop new tools,standards and approaches to assess the safety,effectiveness,quality and performance of medical devices.In the field of biomaterials,hernia mesh is a cla...Regulatory science for medical devices aims to develop new tools,standards and approaches to assess the safety,effectiveness,quality and performance of medical devices.In the field of biomaterials,hernia mesh is a class of implants that have been successfully translated to clinical applications.With a focus on hernia mesh and its regulatory science system,this paper collected and reviewed information on hernia mesh products and biomaterials in both Chinese and American markets.The current development of regulatory science for hernia mesh,including its regulations,standards,guidance documents and classification,and the scientific evaluation of its safety and effectiveness was first reported.Then the research prospect of regulatory science for hernia mesh was discussed.New methods for the preclinical animal study and new tools for the evaluation of the safety and effectiveness of hernia mesh,such as computational modeling,big data platform and evidence-based research,were assessed.By taking the regulatory science of hernia mesh as a case study,this review provided a research basis for developing a regulatory science system of implantable medical devices,furthering the systematic evaluation of the safety and effectiveness of medical devices for better regulatory decision-making.This was the first article reviewing the regulatory science of hernia mesh and biomaterial-based implants.It also proposed and explained the concepts of evidence-based regulatory science and technical review for the first time.展开更多
The protective remolding and reusing of industrial historic buildings and sites is regarded as a great scientific matter in today's urban development. Based on discussing its significance and value,this paper,taki...The protective remolding and reusing of industrial historic buildings and sites is regarded as a great scientific matter in today's urban development. Based on discussing its significance and value,this paper,taking a specific example,makes a systematic discussion on the design strategy and method from the aspects of overall planning,remolding the old buildings,designing the new buildings,etc.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11072193)the Fundamental Research Funds for the Central Universities(Grant No.2013G1502009)the China Postdoctoral Science Foundation(Grant No.20100481354)
文摘The strength of structural loess consists of the shear strength and tensile strength. In this study, the stress path, the failure envelope of principal stress （ Kf line）, and the strength failure envelope of structurally intact loess and remolded loess were analyzed through three kinds of tests： the tensile strength test, the uniaxial compressive strength test, and the conventional triaxial shear strength test. Then, in order to describe the tensile strength and shear strength of structural loess comprehensively and reasonably, a joint strength formula for structural loess was established. This formula comprehensively considers tensile and shear properties. Studies have shown that the tensile strength exhibits a decreasing trend with increasing water content. When the water content is constant, the tensile strength of the structurally intact soil is greater than that ofremolded soil. In the studies, no loss of the originally cured cohesion in the structurally intact soil samples was observed, given that the soil samples did not experience loading disturbance during the uniaxial compressive strength test, meaning there is a high initial structural strength. The results of the conventional triaxial shear strength test show that the water content is correlated with the strength of the structural loess. When the water content is low, the structural properties are strong, and when the water content is high, the structural properties are weak, which means that the water content and the ambient pressure have significant effects on the stress-strain relationship of structural loess. The established joint strength formula of structural loess effectively avoids overestimating the role of soil tensile strength in the traditional theory of Mohr-Coulomb strength.
基金ThisresearchprojectwasfinanciallysupportedbytheMinistryofScienceandTechnology Japan (DomesticResearchFellowship 1999 2 0 0 1) .
文摘Extensive data of undrained shear strength for various remolded soils are compiled to normalize the remolded undrained strength. Remolded soils have a wide spectrum of liquid limits ranging from 25% to 412%. It is found that the remolded undrained strength is a function of water content and liquid limit. Furthermore, a simple index designated as normalized water content w * is introduced for normalizing remolded undrained strength for various soils. The normalized water content w * is the ratio of water content to liquid limit. The relationship between the remolded undrained strength and the normalized water content can be expressed by a simple equation. The new simple equation is not only valuable theoretically for helping in assessing the in situ mechanical behavior, but also useful to ocean engineering practice.
文摘Chandler proposed the intrinsic strength line to correlate the undrained shear strength of samples one-dimensionally consolidated from slurry with the void index proposed by Burland. The undrained shear strength on the intrinsic strength line is different from the remolded undrained shear strength that is an important parameter for design and construction of land reclamation. The void index is used in this study for normalizing the remolded strength behavior of dredged deposits. A quantitative relationship between remolded undrained shear strength and void index is established based on extensive data of dredged deposits available from sources of literature. Furthermore, the normalized remolded undrained shear strength is compared with intrinsic strength line. The comparison result indicates that the ratio of undrained shear strength on the intrinsic strength line over remolded undrained shear strength increases with an increase in applied consolidated stress.
基金The authors thank the financial support from National Natural Science Foundation of China(51973018)National Natural Science Foundation of China(51773018)Beijing Municipal Science and Technology Commission Projects(No.Z191100002019017).
文摘Regulatory science for medical devices aims to develop new tools,standards and approaches to assess the safety,effectiveness,quality and performance of medical devices.In the field of biomaterials,hernia mesh is a class of implants that have been successfully translated to clinical applications.With a focus on hernia mesh and its regulatory science system,this paper collected and reviewed information on hernia mesh products and biomaterials in both Chinese and American markets.The current development of regulatory science for hernia mesh,including its regulations,standards,guidance documents and classification,and the scientific evaluation of its safety and effectiveness was first reported.Then the research prospect of regulatory science for hernia mesh was discussed.New methods for the preclinical animal study and new tools for the evaluation of the safety and effectiveness of hernia mesh,such as computational modeling,big data platform and evidence-based research,were assessed.By taking the regulatory science of hernia mesh as a case study,this review provided a research basis for developing a regulatory science system of implantable medical devices,furthering the systematic evaluation of the safety and effectiveness of medical devices for better regulatory decision-making.This was the first article reviewing the regulatory science of hernia mesh and biomaterial-based implants.It also proposed and explained the concepts of evidence-based regulatory science and technical review for the first time.
基金Supported by the Key Program of the National Natural Science Foundation of China (Grant No. 50878042)
文摘The protective remolding and reusing of industrial historic buildings and sites is regarded as a great scientific matter in today's urban development. Based on discussing its significance and value,this paper,taking a specific example,makes a systematic discussion on the design strategy and method from the aspects of overall planning,remolding the old buildings,designing the new buildings,etc.
