In the paper, a solution of one dimensional fore region pressure build up is put forward. The performance of spring supported thrust bearing is carried out with 3 dimensional thermo elasto hydrodynamic (TEHD) lub...In the paper, a solution of one dimensional fore region pressure build up is put forward. The performance of spring supported thrust bearing is carried out with 3 dimensional thermo elasto hydrodynamic (TEHD) lubrication theory inclusive of inlet pressure build up, thermal elastic distortion of pad and thermal effect. The effects of fore region pressure build up and the variation of some operating conditions on the performance of the pad are studied.展开更多
According to the convergence confinement theory,it is an effective measure to control the large deformation of high ground stress in fractured soft rock tunnels by using yielding support.The yielding support can be cl...According to the convergence confinement theory,it is an effective measure to control the large deformation of high ground stress in fractured soft rock tunnels by using yielding support.The yielding support can be classified as either radial or circumferential yielding support.Circumferential yielding support is achieved by transforming radial displacement into circumferential tangential closure without compromising the support capacity of the primary lining support structure.Based on this,and inspired by the design principle of dampers,a yielding support structure system with spring damping elements as its core was developed,based on the connection characteristics of steel arches in highway tunnel,which can provide increasing support resistance in the yielding deformation section.Then the mechanical properties of spring damping elements were obtained through indoor axial pressure and flexural tests.In addition,according to these results with numerical calculations,the yielding support structure system with embedded spring damping elements can reduce the internal force of the support structure by approximately 10%and increase the area of the plastic zone of the surrounding rock by 11.23%,which can fully utilize the self-bearing capacity of surrounding rock and verify the effectiveness of circumferential yielding support.Finally,the spring damping support structure system was designed with reference to the construction process of the tunnel excavated by drilling and blasting method,and the transformation of the spring damping element to spring damping support structure was achieved.Based on field test results,surrounding ground pressure for the yielding support optimization scheme was reduced by 40%and more evenly distributed,resulting in the successful application and a reduction in the construction cost of large deformation tunnels in soft rock.展开更多
WHEN Chen Lijuan, a girl from a poor mountainous area in Zanhuang County, Hebei Province, lost both her father and mother at the age of three, she went to live with her elderly grandmother. Her straitened circumstance...WHEN Chen Lijuan, a girl from a poor mountainous area in Zanhuang County, Hebei Province, lost both her father and mother at the age of three, she went to live with her elderly grandmother. Her straitened circumstances made her strong. Even at the tender age of five, the little girl knew to be a good helper to her grandma.展开更多
文摘In the paper, a solution of one dimensional fore region pressure build up is put forward. The performance of spring supported thrust bearing is carried out with 3 dimensional thermo elasto hydrodynamic (TEHD) lubrication theory inclusive of inlet pressure build up, thermal elastic distortion of pad and thermal effect. The effects of fore region pressure build up and the variation of some operating conditions on the performance of the pad are studied.
基金supported by the National Nature Science Funds of China(Grant Nos.52038008,and 42207176)the Science and Technology Project of the Department of Transport of Yunnan Province China(Yunnan Transportation Science and Education[2021]No.7)Ningbo Natural Science Funds(Grant No.2022J116).The authors gratefully acknowledge their financial support.
文摘According to the convergence confinement theory,it is an effective measure to control the large deformation of high ground stress in fractured soft rock tunnels by using yielding support.The yielding support can be classified as either radial or circumferential yielding support.Circumferential yielding support is achieved by transforming radial displacement into circumferential tangential closure without compromising the support capacity of the primary lining support structure.Based on this,and inspired by the design principle of dampers,a yielding support structure system with spring damping elements as its core was developed,based on the connection characteristics of steel arches in highway tunnel,which can provide increasing support resistance in the yielding deformation section.Then the mechanical properties of spring damping elements were obtained through indoor axial pressure and flexural tests.In addition,according to these results with numerical calculations,the yielding support structure system with embedded spring damping elements can reduce the internal force of the support structure by approximately 10%and increase the area of the plastic zone of the surrounding rock by 11.23%,which can fully utilize the self-bearing capacity of surrounding rock and verify the effectiveness of circumferential yielding support.Finally,the spring damping support structure system was designed with reference to the construction process of the tunnel excavated by drilling and blasting method,and the transformation of the spring damping element to spring damping support structure was achieved.Based on field test results,surrounding ground pressure for the yielding support optimization scheme was reduced by 40%and more evenly distributed,resulting in the successful application and a reduction in the construction cost of large deformation tunnels in soft rock.
文摘WHEN Chen Lijuan, a girl from a poor mountainous area in Zanhuang County, Hebei Province, lost both her father and mother at the age of three, she went to live with her elderly grandmother. Her straitened circumstances made her strong. Even at the tender age of five, the little girl knew to be a good helper to her grandma.
