Tunnels in an urban area, in many cases, are constructed in soft ground which contains underground water, near existing facilities and structures. Structural stability for the tunnel and also the nearby structures and...Tunnels in an urban area, in many cases, are constructed in soft ground which contains underground water, near existing facilities and structures. Structural stability for the tunnel and also the nearby structures and facilities is vital in this kind of work. Slurry pipe jacking was firmly established as a special method for the non-disruptive construction of underground pipelines of sewage systems. This method utilizes mud slurry that is formed around the pipes in order to stabilize the surrounding soil. In the pipe roof method the tubing elements that are constructed by slurry pipe jacking are near each other longitudinally, and create a rigid and stable lining before the excavation of the main tunnel. This paper discusses ＇the application of a slurry pipe jacking system on ＇the pipe roof method by means of numerical analysis. Because of the rigid behavior of the lining, the results show little subsidence, making this method a reliable method of constructing large tunnels with small cover in an urban area.展开更多
The behavior of viscous fluid damper applied in coupling structures subjected to near-fault earthquake was studied.The structural nonlinearity was characterized by Bouc-Wen model and several near-fault ground motions ...The behavior of viscous fluid damper applied in coupling structures subjected to near-fault earthquake was studied.The structural nonlinearity was characterized by Bouc-Wen model and several near-fault ground motions were simulated by the combination of a recorded earthquake(background ground motion) with equivalent velocity pulses that possess near-fault features.Extensive parametric studies were carried out to find the appropriate damping coefficient.Performances of viscous fluid dampers were demonstrated by the relationship between the force and displacement,the maximal damper force and stroke.The control performances were demonstrated in terms of the response reductions of adjacent structures.The results show that the dynamic responses of adjacent structures are mitigated greatly.Proper damping coefficients of connecting fluid dampers have a small difference,while adjacent structures under different near-fault ground motions with the same peak acceleration.The maximum force of damper is about 0.8 MN,and the maximum damper stroke is about ±550 mm.Satisfied viscous fluid dampers can be produced according to the current manufacturing skills.展开更多
A generalized multi-layered granulation structure used by neighborhood systems is proposed. With granulated views, the concepts of approximations under incomplete information systems are studied, which are represented...A generalized multi-layered granulation structure used by neighborhood systems is proposed. With granulated views, the concepts of approximations under incomplete information systems are studied, which are represented by covering of the universe. With respect to different levels of granulations, a pair of lower and upper approximations is defined and an approximation structure is investigated, which lead to a more general approximation structure. The generalized multi-layered granulation structure provides a basis of the proposed framework of granular computing. Using this framework, the interesting and useful results about information granulation and approximation reasoning can be obtained. This paper presents some useful explorations about the incomplete information systems from information views.展开更多
In this study, the flows in an enclosed annular rotor-stator system with the Reynolds number ranging from 0.75×105 to 3.75×105 and an aspect ratio of 36.5 are investigated using the LES method. Few studies h...In this study, the flows in an enclosed annular rotor-stator system with the Reynolds number ranging from 0.75×105 to 3.75×105 and an aspect ratio of 36.5 are investigated using the LES method. Few studies have explored such a rotor-stator system with this aspect ratio and the flow structure on the rotor side. The mean flow structure varies from a torsional Couette type to a Batchelor type as the Reynolds number increases. The onset of the instability in the B?dewadt layer adjacent to the stator is delayed,whereas it is promoted in the Ekman layer adjacent to the rotor. Both the layers demonstrate rich spiral structures. Turbulent spirals are observed to occur at the rotor disk side that also generates TS-wave-like(Tollmien-Schlichting) structures between adjacent spiral arms. Further, the turbulence at the stator is complex and interesting. Statistically, the turbulence is highly anisotropic near both the rotating and nonrotating disks, which is depicted by the Reynolds stresses.展开更多
The salt beds of the Middle-Lower Cambrian are widespread in the middle-west parts of the Central Uplift and adjacent areas, the Tarim Basin. This paper presents the results of seismic interpretation and drilling data...The salt beds of the Middle-Lower Cambrian are widespread in the middle-west parts of the Central Uplift and adjacent areas, the Tarim Basin. This paper presents the results of seismic interpretation and drilling data analysis, which discovered that the salt beds were formed in an old geologic age, deeply buried, with relatively small scaled flowing and gathering and uneven distribution. As the regional detachment layers, the salt sequences considerably control the structural deformation of the up-salt Paleozoic, forming a series of hydrocarbon traps. In due course, the salt beds of the Middle-Lower Cambrian provide excellent cap rocks and trap conditions; thus the value of exploring hydrocabon reservoir in the target strata of the sub-salt Sinian- Cambrian is greatly increased. Research has shown that the salt-related structures of the Middle-Lower Cambrian in the area mainly exist in the form of salt pillow, salt roller, up-salt anticline, salt diapir, assemblage of the salt arch and up-salt fault-block, assemblage of basement fault and salt anticline, assemblage of the basement fault-block and salt dome, assemblage of salt detachment and fault-related fold, and assemblage of basement fault-block, salt arch and up-salt imbricated thrusts. The evolution and deformation mechanisms of the salt-related structures are controlled largely by basement faulting, compressional shortening, plastic flowing and gathering, superstratum gravitation, and up-salt faulting and detaching. They are distributed in rows or belts along basement faults or fault block belts.展开更多
文摘Tunnels in an urban area, in many cases, are constructed in soft ground which contains underground water, near existing facilities and structures. Structural stability for the tunnel and also the nearby structures and facilities is vital in this kind of work. Slurry pipe jacking was firmly established as a special method for the non-disruptive construction of underground pipelines of sewage systems. This method utilizes mud slurry that is formed around the pipes in order to stabilize the surrounding soil. In the pipe roof method the tubing elements that are constructed by slurry pipe jacking are near each other longitudinally, and create a rigid and stable lining before the excavation of the main tunnel. This paper discusses ＇the application of a slurry pipe jacking system on ＇the pipe roof method by means of numerical analysis. Because of the rigid behavior of the lining, the results show little subsidence, making this method a reliable method of constructing large tunnels with small cover in an urban area.
基金Project(50778077) supported by the National Natural Science Foundation of ChinaProject(50925828) supported by the National Science Foundation for Distinguished Young Scholars of China
文摘The behavior of viscous fluid damper applied in coupling structures subjected to near-fault earthquake was studied.The structural nonlinearity was characterized by Bouc-Wen model and several near-fault ground motions were simulated by the combination of a recorded earthquake(background ground motion) with equivalent velocity pulses that possess near-fault features.Extensive parametric studies were carried out to find the appropriate damping coefficient.Performances of viscous fluid dampers were demonstrated by the relationship between the force and displacement,the maximal damper force and stroke.The control performances were demonstrated in terms of the response reductions of adjacent structures.The results show that the dynamic responses of adjacent structures are mitigated greatly.Proper damping coefficients of connecting fluid dampers have a small difference,while adjacent structures under different near-fault ground motions with the same peak acceleration.The maximum force of damper is about 0.8 MN,and the maximum damper stroke is about ±550 mm.Satisfied viscous fluid dampers can be produced according to the current manufacturing skills.
文摘A generalized multi-layered granulation structure used by neighborhood systems is proposed. With granulated views, the concepts of approximations under incomplete information systems are studied, which are represented by covering of the universe. With respect to different levels of granulations, a pair of lower and upper approximations is defined and an approximation structure is investigated, which lead to a more general approximation structure. The generalized multi-layered granulation structure provides a basis of the proposed framework of granular computing. Using this framework, the interesting and useful results about information granulation and approximation reasoning can be obtained. This paper presents some useful explorations about the incomplete information systems from information views.
基金supported by the National Natural Science Foundation of China(Grant Nos.11272183,and 11572176)the National Key Basic Research Programme of China(Grant No.2014CB744801)supported by IHI Corporation
文摘In this study, the flows in an enclosed annular rotor-stator system with the Reynolds number ranging from 0.75×105 to 3.75×105 and an aspect ratio of 36.5 are investigated using the LES method. Few studies have explored such a rotor-stator system with this aspect ratio and the flow structure on the rotor side. The mean flow structure varies from a torsional Couette type to a Batchelor type as the Reynolds number increases. The onset of the instability in the B?dewadt layer adjacent to the stator is delayed,whereas it is promoted in the Ekman layer adjacent to the rotor. Both the layers demonstrate rich spiral structures. Turbulent spirals are observed to occur at the rotor disk side that also generates TS-wave-like(Tollmien-Schlichting) structures between adjacent spiral arms. Further, the turbulence at the stator is complex and interesting. Statistically, the turbulence is highly anisotropic near both the rotating and nonrotating disks, which is depicted by the Reynolds stresses.
基金supported by National Natural Science Foundation of China (Grant Nos. 41172125, 40972090, 40802030, 40672143 and 40472107)National Basic Research Program of China (Grant Nos. 2012CB214804,2005CB422107 and G1999043305)+3 种基金Investigation and Evaluation on Strategic Region of National Oil and Gas Resource (Grant No. 2009GYXQ0205)Doctoral Fund of Ministry of Education of China (Grant No.200804250001)National Key Scientific Project (Grant No.2011ZX05002-003-001HZ)Northwest Oilfield Company of SINOPEC has given full support with fundamental geologic data
文摘The salt beds of the Middle-Lower Cambrian are widespread in the middle-west parts of the Central Uplift and adjacent areas, the Tarim Basin. This paper presents the results of seismic interpretation and drilling data analysis, which discovered that the salt beds were formed in an old geologic age, deeply buried, with relatively small scaled flowing and gathering and uneven distribution. As the regional detachment layers, the salt sequences considerably control the structural deformation of the up-salt Paleozoic, forming a series of hydrocarbon traps. In due course, the salt beds of the Middle-Lower Cambrian provide excellent cap rocks and trap conditions; thus the value of exploring hydrocabon reservoir in the target strata of the sub-salt Sinian- Cambrian is greatly increased. Research has shown that the salt-related structures of the Middle-Lower Cambrian in the area mainly exist in the form of salt pillow, salt roller, up-salt anticline, salt diapir, assemblage of the salt arch and up-salt fault-block, assemblage of basement fault and salt anticline, assemblage of the basement fault-block and salt dome, assemblage of salt detachment and fault-related fold, and assemblage of basement fault-block, salt arch and up-salt imbricated thrusts. The evolution and deformation mechanisms of the salt-related structures are controlled largely by basement faulting, compressional shortening, plastic flowing and gathering, superstratum gravitation, and up-salt faulting and detaching. They are distributed in rows or belts along basement faults or fault block belts.
