To obtain a complete picture of the epoxy asphalt pavement condition on the Second Nanjing Yangtze River Bridge, an on-site survey is conducted to collect information regarding traffic composition and extents of pavem...To obtain a complete picture of the epoxy asphalt pavement condition on the Second Nanjing Yangtze River Bridge, an on-site survey is conducted to collect information regarding traffic composition and extents of pavement distresses. The survey shows that 30 m2 out of the entire 3.8 × 104 m2 pavement exhibits potholes and alligator cracks. Other surface cracks are also found, including regular longitudinal cracks, short hairline cracks, bubble cracks, and ring cracks. Rutting and shoving are not observed on the pavement. The causes of pavement distresses are discussed by analyzing the pavement mechanical response with actual traffic composition. Research results indicate that the regular longitudinal cracks occurring at ribs near wheelpaths are due to fatigue damage. Short hair cracking and bubble cracking are mainly related to construction defects. Alligator cracks are the results of the development of regular, short hair and bubble cracks lacking effective maintenance. Potholes are induced by the cracking and moisture ingression.展开更多
Seismic AVAZ inversion method based on an orthorhombic model can be used to invert anisotropy parameters of the Longmaxi shale gas reservoir in the Sichuan Basin..As traditional seismic inversion workfl ow does not su...Seismic AVAZ inversion method based on an orthorhombic model can be used to invert anisotropy parameters of the Longmaxi shale gas reservoir in the Sichuan Basin..As traditional seismic inversion workfl ow does not suffi ciently consider the infl uence of fracture orientation,we predict fracture orientation using the method based on the Fourier series to correct pre-stacked azimuth gathers to guarantee the accuracy of input data,and then conduct seismic AVAZ inversion based on the VTI constraints and Bayesian framework to predict anisotropy parameters of the shale gas reservoir in the study area.We further analyze the rock physical relation between anisotropy parameters and fracture compliance and mineral content for quantitative interpretation of seismic inversion results.Research results reveal that the inverted anisotropy parameters are related to P-and S-wave respectively,and thus can be used to distinguish the effect of fracture and fl uids by the joint interpretation.Meanwhile high values of anisotropy parameters correspond to high values of fracture compliance,so the anisotropy parameters can refl ect the development of fractures in reservoir.There is two sets of data from different sources,including the content of brittle mineral quartz obtained from well data and the anisotropy parameters inverted from seismic data,also show the positive correlation.This further indicates high content of brittle mineral makes fractures developing in shale reservoir and enhances seismic anisotropy of the shale reservoir.The inversion results demonstrate the characterization of fractures and brittleness for the Longmaxi shale gas reservoir in the Sichuan Basin.展开更多
The plane crack problem of an orthotropic functionally graded strip under concentrated loads is studied. The edge crack is perpendicular to the boundary and the elastic property of the material is assumed to vary depe...The plane crack problem of an orthotropic functionally graded strip under concentrated loads is studied. The edge crack is perpendicular to the boundary and the elastic property of the material is assumed to vary depending on thickness. By using an integral transform method, the present problem can be reduced to a single integral equation which is solved numerically. The influences of parameters such as the nonhomogeneity constant and the geometry parameters on the stress intensity factors (SIFs) are studied. It is found that the nonhomogeneity constant has important influences on the SIFs.展开更多
基金The National Key Technology R&D Program during the 11th Five-Year Plan Period(No.2009BAG15B03)
文摘To obtain a complete picture of the epoxy asphalt pavement condition on the Second Nanjing Yangtze River Bridge, an on-site survey is conducted to collect information regarding traffic composition and extents of pavement distresses. The survey shows that 30 m2 out of the entire 3.8 × 104 m2 pavement exhibits potholes and alligator cracks. Other surface cracks are also found, including regular longitudinal cracks, short hairline cracks, bubble cracks, and ring cracks. Rutting and shoving are not observed on the pavement. The causes of pavement distresses are discussed by analyzing the pavement mechanical response with actual traffic composition. Research results indicate that the regular longitudinal cracks occurring at ribs near wheelpaths are due to fatigue damage. Short hair cracking and bubble cracking are mainly related to construction defects. Alligator cracks are the results of the development of regular, short hair and bubble cracks lacking effective maintenance. Potholes are induced by the cracking and moisture ingression.
基金supported by the National Key S&T Special Project of China(No.2017ZX05049-002)the NSFC and Sino PEC Joint Key Project(No.U1663207)the National Natural Science Foundation of China(No.41430322)
文摘Seismic AVAZ inversion method based on an orthorhombic model can be used to invert anisotropy parameters of the Longmaxi shale gas reservoir in the Sichuan Basin..As traditional seismic inversion workfl ow does not suffi ciently consider the infl uence of fracture orientation,we predict fracture orientation using the method based on the Fourier series to correct pre-stacked azimuth gathers to guarantee the accuracy of input data,and then conduct seismic AVAZ inversion based on the VTI constraints and Bayesian framework to predict anisotropy parameters of the shale gas reservoir in the study area.We further analyze the rock physical relation between anisotropy parameters and fracture compliance and mineral content for quantitative interpretation of seismic inversion results.Research results reveal that the inverted anisotropy parameters are related to P-and S-wave respectively,and thus can be used to distinguish the effect of fracture and fl uids by the joint interpretation.Meanwhile high values of anisotropy parameters correspond to high values of fracture compliance,so the anisotropy parameters can refl ect the development of fractures in reservoir.There is two sets of data from different sources,including the content of brittle mineral quartz obtained from well data and the anisotropy parameters inverted from seismic data,also show the positive correlation.This further indicates high content of brittle mineral makes fractures developing in shale reservoir and enhances seismic anisotropy of the shale reservoir.The inversion results demonstrate the characterization of fractures and brittleness for the Longmaxi shale gas reservoir in the Sichuan Basin.
文摘The plane crack problem of an orthotropic functionally graded strip under concentrated loads is studied. The edge crack is perpendicular to the boundary and the elastic property of the material is assumed to vary depending on thickness. By using an integral transform method, the present problem can be reduced to a single integral equation which is solved numerically. The influences of parameters such as the nonhomogeneity constant and the geometry parameters on the stress intensity factors (SIFs) are studied. It is found that the nonhomogeneity constant has important influences on the SIFs.
