Based on the idea of optimization design of pile type, the two kinds of the typical pile type are selected, which containing flexibility pile (e.g. rammed cement-soil pile is for short RCSP), and rigid pile (e.g. ceme...Based on the idea of optimization design of pile type, the two kinds of the typical pile type are selected, which containing flexibility pile (e.g. rammed cement-soil pile is for short RCSP), and rigid pile (e.g. cement-flyash-gravel pile is for short CFGP). The three kinds of the composite foundation are designed, which are CFGP, CFG long pile and CFG short pile (for short CFGLP-CFGSP), CFG long-short pile and rammed cement-soil short pile (for short CFGLP-RCSSP). Natural earthquake is simulated by using the engineering blasting;the dynamic characteristics and dynamic response of the composite foundation are studied through field test. CFGLP-RCSSP is closed to linear relation. The bearing capacity of the four composite foundation of the CFGP, CFGLP-CFGSP, and CFGLP-RCSSP in the site are 225 kPa, 179 kPa, and 197 kPa, separately increases 150%, 98.8% and 119% compared to the natural foundation. The vibration main frequency is mainly depended on properties of foundation soil and piles between vibration source and measuring point, pilling load value. Horizontal vibration main frequency greater than the vertical vibration main frequency and the vertical vibration main frequency close to the first-order natural frequency of composite foundation. With the pilling load increasing, the CFGLP-RCSSP pile composite foundation combined frequency decreased. Under the same blast energy, the acceleration peak on the CFG pile composite foundation is less than CFGLP-CFGSP the corresponding values, as the load increases, the peak acceleration gently. CFG pile composite foundation is favorable on seismic. The distribution of peak acceleration is consistent within 4 m from pile top in the CFGLP_RCSSP composite foundation. The maximum of the horizontal acceleration peak along the pile body occurs at a distance of pile top 4 m or the pile top, and that of vertical acceleration peak occurred at a pile top.展开更多
Based on the idea of optimization design of pile type, the composite foundations, which include cememt-flyash-gaavel (for short CFG) long piles and cement-soil (for short CS) short piles, and CS piles with CFG core as...Based on the idea of optimization design of pile type, the composite foundations, which include cememt-flyash-gaavel (for short CFG) long piles and cement-soil (for short CS) short piles, and CS piles with CFG core as well, are formed. The method of the site dynamic characteristic tests of the composite foundations is discussed. The test results show that fireworks bomb may replace demolitions as the vibration resource. Vibration time is about 0.1 sec. Horizontal vibration major frequency is at 22.476 - 56.436 Hz, and vertical vibration major frequency is at 15.538 - 55.884 Hz. The pile arrangements of the composite foundation in the same site have more effect on the acceleration peak value. From the point of vibration, the anti-seismic effect of the CS piles with CFG core is better than others.展开更多
Detection navigation baseline is primary for the automation of maize weeder in seedling.In the navigation technology based on machine vision,maize seeding or weed near the camera is photographed as a discrete area,whi...Detection navigation baseline is primary for the automation of maize weeder in seedling.In the navigation technology based on machine vision,maize seeding or weed near the camera is photographed as a discrete area,while a plant far away from the camera is photographed as a strip area along with other plants in the same row.The two problems cannot be solved by one method.However,in this paper,an algorithm of detection navigation baseline in the row-following operation of maize weeder based on axis extraction was proposed to solve the both problems.Firstly,plants are distinguished from the background based on color feature,and the binary image is acquired.Secondly,plants are described as a set of connected components with numbers after connected components labeling and noise clearing.Thirdly,the axes of all connected components are extracted according to the calculation method of rotary inertia in physics.Next,the abnormal connected components with axes are deleted because the angles between the axes and X-axis are above angle threshold.Then,the judgment model is built based on angle tolerance and distance tolerance,the connected components in a same row based on this model through two-step traversal are merged,and a new axis is re-extracted as the axis of the plant row.Finally,the navigation baselines are detected based on the axes of the plant row.The experimental results show that the accuracy of this algorithm is more than 93%,and the computing time is less than 1.6 s,which can meet the accuracy and real-time performance requirements of maize weeder.展开更多
文摘Based on the idea of optimization design of pile type, the two kinds of the typical pile type are selected, which containing flexibility pile (e.g. rammed cement-soil pile is for short RCSP), and rigid pile (e.g. cement-flyash-gravel pile is for short CFGP). The three kinds of the composite foundation are designed, which are CFGP, CFG long pile and CFG short pile (for short CFGLP-CFGSP), CFG long-short pile and rammed cement-soil short pile (for short CFGLP-RCSSP). Natural earthquake is simulated by using the engineering blasting;the dynamic characteristics and dynamic response of the composite foundation are studied through field test. CFGLP-RCSSP is closed to linear relation. The bearing capacity of the four composite foundation of the CFGP, CFGLP-CFGSP, and CFGLP-RCSSP in the site are 225 kPa, 179 kPa, and 197 kPa, separately increases 150%, 98.8% and 119% compared to the natural foundation. The vibration main frequency is mainly depended on properties of foundation soil and piles between vibration source and measuring point, pilling load value. Horizontal vibration main frequency greater than the vertical vibration main frequency and the vertical vibration main frequency close to the first-order natural frequency of composite foundation. With the pilling load increasing, the CFGLP-RCSSP pile composite foundation combined frequency decreased. Under the same blast energy, the acceleration peak on the CFG pile composite foundation is less than CFGLP-CFGSP the corresponding values, as the load increases, the peak acceleration gently. CFG pile composite foundation is favorable on seismic. The distribution of peak acceleration is consistent within 4 m from pile top in the CFGLP_RCSSP composite foundation. The maximum of the horizontal acceleration peak along the pile body occurs at a distance of pile top 4 m or the pile top, and that of vertical acceleration peak occurred at a pile top.
文摘Based on the idea of optimization design of pile type, the composite foundations, which include cememt-flyash-gaavel (for short CFG) long piles and cement-soil (for short CS) short piles, and CS piles with CFG core as well, are formed. The method of the site dynamic characteristic tests of the composite foundations is discussed. The test results show that fireworks bomb may replace demolitions as the vibration resource. Vibration time is about 0.1 sec. Horizontal vibration major frequency is at 22.476 - 56.436 Hz, and vertical vibration major frequency is at 15.538 - 55.884 Hz. The pile arrangements of the composite foundation in the same site have more effect on the acceleration peak value. From the point of vibration, the anti-seismic effect of the CS piles with CFG core is better than others.
基金This work was supported by National Key Research and Development Program of China(2017YED0701500)Shanxi Provincial Program for Youth Science and Technology(201801D221289)Shanxi Agriculture University Youth Science and Technology Innovation Project(J141802199).
文摘Detection navigation baseline is primary for the automation of maize weeder in seedling.In the navigation technology based on machine vision,maize seeding or weed near the camera is photographed as a discrete area,while a plant far away from the camera is photographed as a strip area along with other plants in the same row.The two problems cannot be solved by one method.However,in this paper,an algorithm of detection navigation baseline in the row-following operation of maize weeder based on axis extraction was proposed to solve the both problems.Firstly,plants are distinguished from the background based on color feature,and the binary image is acquired.Secondly,plants are described as a set of connected components with numbers after connected components labeling and noise clearing.Thirdly,the axes of all connected components are extracted according to the calculation method of rotary inertia in physics.Next,the abnormal connected components with axes are deleted because the angles between the axes and X-axis are above angle threshold.Then,the judgment model is built based on angle tolerance and distance tolerance,the connected components in a same row based on this model through two-step traversal are merged,and a new axis is re-extracted as the axis of the plant row.Finally,the navigation baselines are detected based on the axes of the plant row.The experimental results show that the accuracy of this algorithm is more than 93%,and the computing time is less than 1.6 s,which can meet the accuracy and real-time performance requirements of maize weeder.
