This paper aims to reveal the depth distribution law of non-limit passive soil pressure on rigid retaining wall that rotates about the top of the wall(rotation around the top(RT) model). Based on Coulomb theory, the d...This paper aims to reveal the depth distribution law of non-limit passive soil pressure on rigid retaining wall that rotates about the top of the wall(rotation around the top(RT) model). Based on Coulomb theory, the disturbance degree theory, as well as the spring-element model, by setting the rotation angle of the wall as the disturbance parameter, we establish both a depth distribution function for sand and a nonlinear depth distribution calculation method for the non-limit passive soil pressure on a rigid retaining wall under the RT model, which is then compared with experiment. The results suggest that under the RT model: the non-limit soil pressure has a nonlinear distribution; the backfill disturbance degree and the lateral soil pressure increase with an increase in the wall rotation angle; and, the points where the resultant lateral soil pressure acts on the retaining wall are less than 2/3 of the height of the wall. The soil pressure predicted by the theoretical calculation put forward in this paper are quite similar to those obtained by the model experiment, which verifies the theoretical value, and the engineering guidance provided by the calculations are of significance.展开更多
This paper presents a method to create concept models for the tapered thin-walled tubes using beam elements and spring elements.Developed concept tapered beam models with different taper angles and cross sections are ...This paper presents a method to create concept models for the tapered thin-walled tubes using beam elements and spring elements.Developed concept tapered beam models with different taper angles and cross sections are compared with those detailed models through impact analyses.Important crash results are recorded and compared,and the relatively good agreement is achieved between these analyses.Concept modeling steps are illustrated in detail,and a general concept modeling method for such thin-walled tubes is summarized and presented.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
Considering the CRTS-II track slab,which is commonly used in the Chinese high-speed railway system,a vehicle-track-bridge dynamic analysis method is proposed in which the vehicle subsystem equations are established by...Considering the CRTS-II track slab,which is commonly used in the Chinese high-speed railway system,a vehicle-track-bridge dynamic analysis method is proposed in which the vehicle subsystem equations are established by the rigid body dynamics method,the track subsystem and the bridge subsystem equations are established by the FEM,the wheel-rail contact relation is defined by the corresponding assumption in vertical direction and the Kalker linear creep theory in lateral direction.The in-span spring element is derived to model the track-bridge interaction;the equal-band-width storage is adopted to fit the track structure with multilayer uniform section beam;and the dynamic equilibrium equations are solved by the inter-history iteration method.As a case study,the response of a CRH2 high-speed train transverses a simply-supported bridge with successive 31.5m double bound pre-stress beams is simulated.The result shows that using the vehicle-track-bridge interaction model instead of the vehicle-bridge interaction model helps predict the rotation angle at beam ends and choose an economic beam vertical stiffness.展开更多
The loading capacity in the axial direction of a bolted thin steel plate was investigated.A refined numerical model of bolt was first constructed and then validated using existing experiment results.Parametrical analy...The loading capacity in the axial direction of a bolted thin steel plate was investigated.A refined numerical model of bolt was first constructed and then validated using existing experiment results.Parametrical analysis was performed to reveal the influences of geometric parameters,including the effective depth of the cap nut,the yield strength of the steel plate,the preload of the bolt,and shear force,on the ultimate loading capacity.Then,an analytical method was proposed to predict the ultimate load of the bolted thin steel plate.Results derived using the numerical and analytical methods were compared and the results indicated that the analytical method can accurately predict the pull-through capacity of bolted thin steel plates.The work reported in this paper can provide a simplified calculation method for the loading capacity in the axial direction of a bolt.展开更多
基金financially supported by the National Natural Science Foundation of China (No.51274192)Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Engineering Open Foundation of China (No.JSKL2014K12)Jiangsu Ordinary University Graduate Students Research and Innovation Project of China (No.KYLX-1392)
文摘This paper aims to reveal the depth distribution law of non-limit passive soil pressure on rigid retaining wall that rotates about the top of the wall(rotation around the top(RT) model). Based on Coulomb theory, the disturbance degree theory, as well as the spring-element model, by setting the rotation angle of the wall as the disturbance parameter, we establish both a depth distribution function for sand and a nonlinear depth distribution calculation method for the non-limit passive soil pressure on a rigid retaining wall under the RT model, which is then compared with experiment. The results suggest that under the RT model: the non-limit soil pressure has a nonlinear distribution; the backfill disturbance degree and the lateral soil pressure increase with an increase in the wall rotation angle; and, the points where the resultant lateral soil pressure acts on the retaining wall are less than 2/3 of the height of the wall. The soil pressure predicted by the theoretical calculation put forward in this paper are quite similar to those obtained by the model experiment, which verifies the theoretical value, and the engineering guidance provided by the calculations are of significance.
文摘This paper presents a method to create concept models for the tapered thin-walled tubes using beam elements and spring elements.Developed concept tapered beam models with different taper angles and cross sections are compared with those detailed models through impact analyses.Important crash results are recorded and compared,and the relatively good agreement is achieved between these analyses.Concept modeling steps are illustrated in detail,and a general concept modeling method for such thin-walled tubes is summarized and presented.
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.
基金supported by the National Basic Research Program of China("973"Project)(Grant No.2013CB036203)the National Natural Science Foundation of China(Grant No.U1134206)+1 种基金the 111 project(Grant No.B13002)the Doctoral Fund of Ministry of Education of China(Grant No.20130009110036)
文摘Considering the CRTS-II track slab,which is commonly used in the Chinese high-speed railway system,a vehicle-track-bridge dynamic analysis method is proposed in which the vehicle subsystem equations are established by the rigid body dynamics method,the track subsystem and the bridge subsystem equations are established by the FEM,the wheel-rail contact relation is defined by the corresponding assumption in vertical direction and the Kalker linear creep theory in lateral direction.The in-span spring element is derived to model the track-bridge interaction;the equal-band-width storage is adopted to fit the track structure with multilayer uniform section beam;and the dynamic equilibrium equations are solved by the inter-history iteration method.As a case study,the response of a CRH2 high-speed train transverses a simply-supported bridge with successive 31.5m double bound pre-stress beams is simulated.The result shows that using the vehicle-track-bridge interaction model instead of the vehicle-bridge interaction model helps predict the rotation angle at beam ends and choose an economic beam vertical stiffness.
基金The work described in this paper was financially supported by the Project funded by China Postdoctoral Science Foundation(No.2017M621156)the State Key Research Development Program of China(Nos.2016YFC0801404 and 2016YFC0600704).
文摘The loading capacity in the axial direction of a bolted thin steel plate was investigated.A refined numerical model of bolt was first constructed and then validated using existing experiment results.Parametrical analysis was performed to reveal the influences of geometric parameters,including the effective depth of the cap nut,the yield strength of the steel plate,the preload of the bolt,and shear force,on the ultimate loading capacity.Then,an analytical method was proposed to predict the ultimate load of the bolted thin steel plate.Results derived using the numerical and analytical methods were compared and the results indicated that the analytical method can accurately predict the pull-through capacity of bolted thin steel plates.The work reported in this paper can provide a simplified calculation method for the loading capacity in the axial direction of a bolt.
