In the finite element method,the numerical simulation of three-dimensional crack propagation is relatively rare,and it is often realized by commercial programs.In addition to the geometric complexity,the determination...In the finite element method,the numerical simulation of three-dimensional crack propagation is relatively rare,and it is often realized by commercial programs.In addition to the geometric complexity,the determination of the cracking direction constitutes a great challenge.In most cases,the local stress state provides the fundamental criterion to judge the presence of cracks and the direction of crack propagation.However,in the case of three-dimensional analysis,the coordination relationship between grid elements due to occurrence of cracks becomes a difficult problem for this method.In this paper,based on the extended finite element method,the stress-related function field is introduced into the calculation domain,and then the boundary value problem of the function is solved.Subsequently,the envelope surface of all propagation directions can be obtained at one time.At last,the possible surface can be selected as the direction of crack development.Based on the aforementioned procedure,such method greatly reduces the programming complexity of tracking the crack propagation.As a suitable method for simulating tension-induced failure,it can simulate multiple cracks simultaneously.展开更多
The complex tunnelling constructive environment in urban area in similar green field situations is faced through analytical evaluations in order to control the design calculation process and subsequently manage the in...The complex tunnelling constructive environment in urban area in similar green field situations is faced through analytical evaluations in order to control the design calculation process and subsequently manage the interventions techniques with the aim of totally reducing the typical settlements trough above the tunnel either during the construction stage or during the serviceability stage. Recently, the author has proposed an operative and mathematical method by an opportune choice of tensioned anchors to control the tunnel lining settlements. In order to completely eliminate the remainder typical soft soil trough which is normal to the line of the tunnel, it is here proposed to use and properly calculate the interventions of stone columns by the SAVE （silent, advanced, vibration-erasing） Compozer method, in combination with the anchorages.展开更多
基金Project(2017YFC0404802)supported by the National Key R&D Program of ChinaProjects(U1965206,51979143)supported by the National Natural Science Foundation of China。
文摘In the finite element method,the numerical simulation of three-dimensional crack propagation is relatively rare,and it is often realized by commercial programs.In addition to the geometric complexity,the determination of the cracking direction constitutes a great challenge.In most cases,the local stress state provides the fundamental criterion to judge the presence of cracks and the direction of crack propagation.However,in the case of three-dimensional analysis,the coordination relationship between grid elements due to occurrence of cracks becomes a difficult problem for this method.In this paper,based on the extended finite element method,the stress-related function field is introduced into the calculation domain,and then the boundary value problem of the function is solved.Subsequently,the envelope surface of all propagation directions can be obtained at one time.At last,the possible surface can be selected as the direction of crack development.Based on the aforementioned procedure,such method greatly reduces the programming complexity of tracking the crack propagation.As a suitable method for simulating tension-induced failure,it can simulate multiple cracks simultaneously.
文摘The complex tunnelling constructive environment in urban area in similar green field situations is faced through analytical evaluations in order to control the design calculation process and subsequently manage the interventions techniques with the aim of totally reducing the typical settlements trough above the tunnel either during the construction stage or during the serviceability stage. Recently, the author has proposed an operative and mathematical method by an opportune choice of tensioned anchors to control the tunnel lining settlements. In order to completely eliminate the remainder typical soft soil trough which is normal to the line of the tunnel, it is here proposed to use and properly calculate the interventions of stone columns by the SAVE （silent, advanced, vibration-erasing） Compozer method, in combination with the anchorages.
