The residual stress generated in the laser cladding could lead to undesirable distortions or even crack formation. In order to better understand the evolution/yielding process of stress field,a 3 D finite-element ther...The residual stress generated in the laser cladding could lead to undesirable distortions or even crack formation. In order to better understand the evolution/yielding process of stress field,a 3 D finite-element thermo-mechanical model was established for the laser cladding formation of thin wall with the 17-4 PH powder on the FV520( B) steel. The temperature field was firstly analyzed,based on which the stress field and strain field of the laser cladding forming process were analyzed.In order to validate the prediction,the final residual stress field in the obtained thin wall was tested by X-ray diffraction in comparison with the predicted results.展开更多
Model tests and numerical analyses of stepped reinforced retaining wall were performed to investigate the effects of rheology of backfill and creep of geogrids on the long-term performance of the structure.The geogrid...Model tests and numerical analyses of stepped reinforced retaining wall were performed to investigate the effects of rheology of backfill and creep of geogrids on the long-term performance of the structure.The geogrid tensions,soil pressures,wall deformations and foundation pressure were measured during model construction and loading.A visco-elasto-plastic model and an empirical nonlinear visco-elastic model were utilized to simulate the stresses and deformations of geogrid-reinforced earth-retaining wall under long-term loads.By comparing test data with numerical results,it is shown that the foundation pressure distribution is nonlinear,and the lateral constraint of geogrids for backfill can cause a redistribution of foundation pressure.The curve of soil pressure is outside convex at each step initially,and it is close to the distribution for the case of vertical wall subsequently.The variation trend of geogrid tensions at different heights is obtained.Moreover,the failure mechanism and development mode of potential slip surface in retaining wall are proposed.展开更多
The application of a double-face reinforced retaining wall during road construction can reduce engineering costs, speed road paving and have a good influence on environment. An ABAQUS numerical model of a double-face ...The application of a double-face reinforced retaining wall during road construction can reduce engineering costs, speed road paving and have a good influence on environment. An ABAQUS numerical model of a double-face reinforced retaining wall was built. The influence of surface subsidence induced by mining was considered. A physical model test was also performed in the laboratory on a reinforced retaining wall. The influence of subsidence induced by mining was observed. The numerical results match measurements in the laboratory very well. The vertical pressure on the base of the retaining wall, the horizontal displacement of the wall and the horizontal soil pressure acting on the wall were analyzed. The differential settlement of the reinforced belt and axial forces in the wall were also studied.展开更多
Short-leg shear wall structures are a new form of building structure that combine the merits of both frame and shear wall structures. Its architectural features, structure bearing and engineering cost are reasonable. ...Short-leg shear wall structures are a new form of building structure that combine the merits of both frame and shear wall structures. Its architectural features, structure bearing and engineering cost are reasonable. To analyze the elastic-plastic response of a short-leg shear wall structure during an earthquake, this study modified the multiple-vertical-rod element model of the shear wall, considered the shear lag effect and proposed a multiple-vertical-rod element coupling beam model with a new local stiffness domain. Based on the principle of minimum potential energy and the variational principle, the stiffness matrixes of a short-leg shear wall and a coupling beam are derived in this study. Furthermore, the bending shear correlation for the analysis of different parameters to describe the structure, such as the beam height to span ratio, short-leg shear wall height to thickness ratio, and steel ratio are introduced. The results show that the height to span ratio directly affects the structural integrity; and the short-leg shear wall height to thickness ratio should be limited to a range of approximately 6.0 to 7.0. The design of short-leg shear walls should be in accordance with the "strong wall and weak beam" principle.展开更多
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
基金supported by a great from the Major State Basic Research Development Program of China(No.2011CB013403)the Scientific Research Foundation for Talent,Guizhou University(No.201665)
文摘The residual stress generated in the laser cladding could lead to undesirable distortions or even crack formation. In order to better understand the evolution/yielding process of stress field,a 3 D finite-element thermo-mechanical model was established for the laser cladding formation of thin wall with the 17-4 PH powder on the FV520( B) steel. The temperature field was firstly analyzed,based on which the stress field and strain field of the laser cladding forming process were analyzed.In order to validate the prediction,the final residual stress field in the obtained thin wall was tested by X-ray diffraction in comparison with the predicted results.
基金Supported by National Natural Science Foundation of China (No. 50678032 and No. 90715042)Key Project of Ministry of Education of China (No. 210176)
文摘Model tests and numerical analyses of stepped reinforced retaining wall were performed to investigate the effects of rheology of backfill and creep of geogrids on the long-term performance of the structure.The geogrid tensions,soil pressures,wall deformations and foundation pressure were measured during model construction and loading.A visco-elasto-plastic model and an empirical nonlinear visco-elastic model were utilized to simulate the stresses and deformations of geogrid-reinforced earth-retaining wall under long-term loads.By comparing test data with numerical results,it is shown that the foundation pressure distribution is nonlinear,and the lateral constraint of geogrids for backfill can cause a redistribution of foundation pressure.The curve of soil pressure is outside convex at each step initially,and it is close to the distribution for the case of vertical wall subsequently.The variation trend of geogrid tensions at different heights is obtained.Moreover,the failure mechanism and development mode of potential slip surface in retaining wall are proposed.
基金Projects 50874105 supported by the National Natural Science Foundation of China20070290532 by the Specialized Research Fund for Doctoral Program of Higher Education
文摘The application of a double-face reinforced retaining wall during road construction can reduce engineering costs, speed road paving and have a good influence on environment. An ABAQUS numerical model of a double-face reinforced retaining wall was built. The influence of surface subsidence induced by mining was considered. A physical model test was also performed in the laboratory on a reinforced retaining wall. The influence of subsidence induced by mining was observed. The numerical results match measurements in the laboratory very well. The vertical pressure on the base of the retaining wall, the horizontal displacement of the wall and the horizontal soil pressure acting on the wall were analyzed. The differential settlement of the reinforced belt and axial forces in the wall were also studied.
文摘Short-leg shear wall structures are a new form of building structure that combine the merits of both frame and shear wall structures. Its architectural features, structure bearing and engineering cost are reasonable. To analyze the elastic-plastic response of a short-leg shear wall structure during an earthquake, this study modified the multiple-vertical-rod element model of the shear wall, considered the shear lag effect and proposed a multiple-vertical-rod element coupling beam model with a new local stiffness domain. Based on the principle of minimum potential energy and the variational principle, the stiffness matrixes of a short-leg shear wall and a coupling beam are derived in this study. Furthermore, the bending shear correlation for the analysis of different parameters to describe the structure, such as the beam height to span ratio, short-leg shear wall height to thickness ratio, and steel ratio are introduced. The results show that the height to span ratio directly affects the structural integrity; and the short-leg shear wall height to thickness ratio should be limited to a range of approximately 6.0 to 7.0. The design of short-leg shear walls should be in accordance with the "strong wall and weak beam" principle.
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.