According to the daily precipitation data in artificial precipitation season during May to September from 1961 to 2008 in Liaoning Province,the maximum consecutive precipitation in the artificial precipitation test ar...According to the daily precipitation data in artificial precipitation season during May to September from 1961 to 2008 in Liaoning Province,the maximum consecutive precipitation in the artificial precipitation test area is studied based on the maximum consecutive precipitation from May to September in 48 years.The results shows that the period of maximum consecutive precipitation in each month is different,and the variance trends of maximum consecutive precipitation in May,July,August and September are decreasing,while the variance trend of maximum consecutive precipitation in June is increasing.展开更多
The size and shape of the effective test area are crucial to consider when short-crested waves are created by segmented wavemakers. The range of the effective test area of short-crested waves simulated by two-sided se...The size and shape of the effective test area are crucial to consider when short-crested waves are created by segmented wavemakers. The range of the effective test area of short-crested waves simulated by two-sided segmented wavemakers is analyzed in this paper. The experimental investigation on the wave field distribution of short-crested waves generated by two-sided segmented wavemakers is conducted by using an array of wave gauges. Wave spectra and directional spreading function are analyzed and the results show that when the main direction is at a certain angle with the normal line of wave generators, the wave field of 3D short-crested waves generated by two-sided segmented wavemakers has good spatial uniformity within the model test area. The effective test area can provide good wave environments for seakeeping model tests of various ocean engineering structures in the deep ocean engineering basin.展开更多
Selecting Chaoying small watershed with representative karst rocky desertification in the Bijie test area of Guizhou Province as an example, according to karst rocky desertiflcation degree and the existing eco-environ...Selecting Chaoying small watershed with representative karst rocky desertification in the Bijie test area of Guizhou Province as an example, according to karst rocky desertiflcation degree and the existing eco-environmental problems in the small watershed, we study developmental model and technique support system for integrated rehabilitation of rocky desertification in the small watershed, and bring forward the development model and technique integration for integrated rehabilitation of rocky desertification, which adapt to the karst areas of Bijie test area, Guizhou Province and even South China.展开更多
The distribution of sedimentary microfacies in the eighth member of the Shihezi formation（the H8 member） in the Sul4 3D seismic test area was investigated.A Support Vector Machine（SVM） model was introduced for the...The distribution of sedimentary microfacies in the eighth member of the Shihezi formation（the H8 member） in the Sul4 3D seismic test area was investigated.A Support Vector Machine（SVM） model was introduced for the first time as a way of predicting sandstone thickness in the study area.The model was constructed by analysis and optimization of measured seismic attributes.The distribution of the sedimentary microfacies in the study area was determined from predicted sandstone thickness and an analysis of sedimentary characteristics of the area.The results indicate that sandstone thickness predictions in the study area using an SVM method are good.The distribution of the sedimentary microfacies in the study area has been depicted at a fine scale.展开更多
The test panels have been set for one year in the waters of Daguanban reclamation area of Luoyuan Bay to investigate the ecology of fouling community. 39 species of animals and 8 species of algae have been recorded du...The test panels have been set for one year in the waters of Daguanban reclamation area of Luoyuan Bay to investigate the ecology of fouling community. 39 species of animals and 8 species of algae have been recorded during the investigation. The main period of settlement extends from May to October. The peak periods of biomass and covered area rate of the panels have been observed from Juneto September Balanus reticulatus, Bugula neritina, Molgula manhattensis, Tubularia mesembryanthemun and Enteromopha interstinalis are the dominant species in the fouling community. Species diversity index, species richness, species evenness and environmental factors are determined, the results of which indicate that water flow speed is the most important factor influencing the species and quantity composition of the fouling community.As to the mariculture production in the reclamation area, the main harmful period ranges from June to September.展开更多
The ecological greening technology of the bare rock area of the arbor governance be-longs to the field of ecological environment restoration, selection of suitable arbors for vegetation restoration in bare rock area, ...The ecological greening technology of the bare rock area of the arbor governance be-longs to the field of ecological environment restoration, selection of suitable arbors for vegetation restoration in bare rock area, vegetation recovery is the primary approach to governance the ecological environment of bare rock area. The reconstruction of bare rock area arbor-shrub-grass ecosystems is a global environmental science problem. Paying attention to Geological conditions with rich rock fissures and abundant groundwater in these fissures, following the idea to reconstruct ecosystem from arbor to shrub and grass and the principle one tree in a baseplate, authors develop a baseplate technique for tree planting in bare rock area. The baseplate includes the parent body, the root, and the cover to prevent evaporation. Especially, there are filled in nutritional soil for the parent body and the root, and the composition of nutritional soil are selected by test in laboratory, while optimal mix ratio of the composition is obtained. Then, application method in field is put forward. The technique can guarantee survival at early stage and growth in the later for tree planting in the baseplate. In particular, the root provides a good channel to guide tree roots into fissure rock and absorb groundwater in rock. Test in field shows that the baseplate technique has strong practicality in vegetation recovery of bare rock area. Test in field shows that the baseplate technique has strong practicality in vegetation recovery of bare rock area in the world.展开更多
The undrained shear strength of shallow strata is a critical parameter for safety design in deep-water operations.In situ piezocone penetration tests(CPTU) and laboratory experiments are performed at Site W18-19 in th...The undrained shear strength of shallow strata is a critical parameter for safety design in deep-water operations.In situ piezocone penetration tests(CPTU) and laboratory experiments are performed at Site W18-19 in the Shenhu area, northern South China Sea, where China's first marine hydrate exploitation operation is due to be located. The validation of the undrained shear strength prediction model based on CPTU parameters. Different laboratory tests, including pocket penetrometer, torvane, miniature vane and unconsolidated undrained triaxial tests, are employed to solve empirical cone coefficients by statistical and mathematical methods. Finally, an optimized model is proposed to describe the longitudinal distribution of undrained shear strength in calcareous clay strata in the Shenhu area. Research results reveal that average empirical cone coefficients based on total cone resistance, effective resistance, and excess-pore pressure are 13.8, 4.2 and 14.4, respectively. The undrained shear strength prediction model shows a good fit with the laboratory results only within specific intervals based on their compaction degree and gas-bearing conditions. The optimized prediction model in piecewise function format can be used to describe the longitudinal distribution of the undrained shear strength for calcareous clay within all depth intervals from the mud-line to the upper boundary of hydrate-bearing sediments(HBS). The optimized prediction result indicates that the effective cone resistance model is suitable for very soft to firm calcareous clays,the excess-pore pressure model can depict the undrained shear strength for firm to very stiff but gas-free clays,while the total cone resistance model is advantageous for evaluating the undrained shear strength for very stiff and gassy clays. The optimized model in piecewise function format can considerably improve the adaptability of empirical models for calcareous clay in the Shenhu area. These results are significant for safety evaluations of proposed hydrate exploitation projects.展开更多
Regarding the freezing damage of high-grade highway subgrade in seasonally frozen area,the thesis explores the effect on the dynamic behavior of subgrade soil under freeze–thaw cycles and draws the change law of para...Regarding the freezing damage of high-grade highway subgrade in seasonally frozen area,the thesis explores the effect on the dynamic behavior of subgrade soil under freeze–thaw cycles and draws the change law of parameters(including dynamic strength,dynamic cohesion,and internal friction angle;and dynamic elastic modulus)of high-grade highway-subgrade soil with the number of freeze–thaw cycles.It aims to provide the reference for operation and maintenance of a high-grade highway.Conclusions:(1)Dynamic strength tends to decline evidently after freeze–thaw cycles,with 60%~70%decline after three cycles,and remains stable after five to seven cycles.(2)With the number of freeze–thaw cycles increasing,the internal friction angle fluctuates within a certain range without an obvious change law,only presenting the tendency of dropping off.The dynamic cohesion declines obviously,about 20%~40%after seven freeze–thaw cycles,and then tends to be stable.(3)With the number of freeze-thaw cycles increasing,the dynamic elastic modulus and maximum dynamic elastic modulus are inclined to decrease distinctly.After five freeze–thaw cycles,the former declines 30%~40%and then remains stable.Meanwhile,the latter falls 20%~40%.展开更多
The spatial and temporal variation characteristics of temperature were analyzed by using climate tendency coefficient, climatic inclination rate and Mann-Kendall catastrophe test,based on the annual and seasonal avera...The spatial and temporal variation characteristics of temperature were analyzed by using climate tendency coefficient, climatic inclination rate and Mann-Kendall catastrophe test,based on the annual and seasonal average temperatures of 28 meteorological stations in Guangxi from 1971 to 2013. Under the global warming,the annual and seasonal average temperatures in typical karst area of Guangxi had an increasing trend. The cli- mate inclination rate of annual average temperature reached a significant level, which was about 0.17 ℃/10 a, and the year of abrupt changes ap- peared in 1996. About seasonal temperature＇s trend, average temperatures of all the four seasons had an increase trend in the past 43 years, and the significant increase was happened in autumn with the temperature increase rate of 0.28 ℃/10 a, followed by increase rate of average tempera- ture in winter with 0.25 ℃/10 a. A long-term warming tendency was observed by seasonal average temperature from 1971 to 2013, especially dur- ing 2002 - 2013.展开更多
文摘According to the daily precipitation data in artificial precipitation season during May to September from 1961 to 2008 in Liaoning Province,the maximum consecutive precipitation in the artificial precipitation test area is studied based on the maximum consecutive precipitation from May to September in 48 years.The results shows that the period of maximum consecutive precipitation in each month is different,and the variance trends of maximum consecutive precipitation in May,July,August and September are decreasing,while the variance trend of maximum consecutive precipitation in June is increasing.
基金financially supported by the National Natural Science Foundation of China(Grant No.51239007)
文摘The size and shape of the effective test area are crucial to consider when short-crested waves are created by segmented wavemakers. The range of the effective test area of short-crested waves simulated by two-sided segmented wavemakers is analyzed in this paper. The experimental investigation on the wave field distribution of short-crested waves generated by two-sided segmented wavemakers is conducted by using an array of wave gauges. Wave spectra and directional spreading function are analyzed and the results show that when the main direction is at a certain angle with the normal line of wave generators, the wave field of 3D short-crested waves generated by two-sided segmented wavemakers has good spatial uniformity within the model test area. The effective test area can provide good wave environments for seakeeping model tests of various ocean engineering structures in the deep ocean engineering basin.
基金Supported by Major Issue of National "12~(th) Five-year Plan"Science and Technology Support Plan,China(2011BAC09B01)
文摘Selecting Chaoying small watershed with representative karst rocky desertification in the Bijie test area of Guizhou Province as an example, according to karst rocky desertiflcation degree and the existing eco-environmental problems in the small watershed, we study developmental model and technique support system for integrated rehabilitation of rocky desertification in the small watershed, and bring forward the development model and technique integration for integrated rehabilitation of rocky desertification, which adapt to the karst areas of Bijie test area, Guizhou Province and even South China.
基金Financial support for this work,provided by the Major National Science and Technology Special Projects(No.2008ZX05008)
文摘The distribution of sedimentary microfacies in the eighth member of the Shihezi formation（the H8 member） in the Sul4 3D seismic test area was investigated.A Support Vector Machine（SVM） model was introduced for the first time as a way of predicting sandstone thickness in the study area.The model was constructed by analysis and optimization of measured seismic attributes.The distribution of the sedimentary microfacies in the study area was determined from predicted sandstone thickness and an analysis of sedimentary characteristics of the area.The results indicate that sandstone thickness predictions in the study area using an SVM method are good.The distribution of the sedimentary microfacies in the study area has been depicted at a fine scale.
文摘The test panels have been set for one year in the waters of Daguanban reclamation area of Luoyuan Bay to investigate the ecology of fouling community. 39 species of animals and 8 species of algae have been recorded during the investigation. The main period of settlement extends from May to October. The peak periods of biomass and covered area rate of the panels have been observed from Juneto September Balanus reticulatus, Bugula neritina, Molgula manhattensis, Tubularia mesembryanthemun and Enteromopha interstinalis are the dominant species in the fouling community. Species diversity index, species richness, species evenness and environmental factors are determined, the results of which indicate that water flow speed is the most important factor influencing the species and quantity composition of the fouling community.As to the mariculture production in the reclamation area, the main harmful period ranges from June to September.
文摘The ecological greening technology of the bare rock area of the arbor governance be-longs to the field of ecological environment restoration, selection of suitable arbors for vegetation restoration in bare rock area, vegetation recovery is the primary approach to governance the ecological environment of bare rock area. The reconstruction of bare rock area arbor-shrub-grass ecosystems is a global environmental science problem. Paying attention to Geological conditions with rich rock fissures and abundant groundwater in these fissures, following the idea to reconstruct ecosystem from arbor to shrub and grass and the principle one tree in a baseplate, authors develop a baseplate technique for tree planting in bare rock area. The baseplate includes the parent body, the root, and the cover to prevent evaporation. Especially, there are filled in nutritional soil for the parent body and the root, and the composition of nutritional soil are selected by test in laboratory, while optimal mix ratio of the composition is obtained. Then, application method in field is put forward. The technique can guarantee survival at early stage and growth in the later for tree planting in the baseplate. In particular, the root provides a good channel to guide tree roots into fissure rock and absorb groundwater in rock. Test in field shows that the baseplate technique has strong practicality in vegetation recovery of bare rock area. Test in field shows that the baseplate technique has strong practicality in vegetation recovery of bare rock area in the world.
基金The National Natural Science Foundation of China under contract No.41606078the Taishan Scholar Special Experts Project under contract No.ts201712079+1 种基金the National Key Research and Development Plan under contract No.2017YFC0307600the Open Fund of Qingdao National Laboratory for Marine Science and Technology of China under contract Nos QNLM2016ORP0203 and QNLM2016ORP0207
文摘The undrained shear strength of shallow strata is a critical parameter for safety design in deep-water operations.In situ piezocone penetration tests(CPTU) and laboratory experiments are performed at Site W18-19 in the Shenhu area, northern South China Sea, where China's first marine hydrate exploitation operation is due to be located. The validation of the undrained shear strength prediction model based on CPTU parameters. Different laboratory tests, including pocket penetrometer, torvane, miniature vane and unconsolidated undrained triaxial tests, are employed to solve empirical cone coefficients by statistical and mathematical methods. Finally, an optimized model is proposed to describe the longitudinal distribution of undrained shear strength in calcareous clay strata in the Shenhu area. Research results reveal that average empirical cone coefficients based on total cone resistance, effective resistance, and excess-pore pressure are 13.8, 4.2 and 14.4, respectively. The undrained shear strength prediction model shows a good fit with the laboratory results only within specific intervals based on their compaction degree and gas-bearing conditions. The optimized prediction model in piecewise function format can be used to describe the longitudinal distribution of the undrained shear strength for calcareous clay within all depth intervals from the mud-line to the upper boundary of hydrate-bearing sediments(HBS). The optimized prediction result indicates that the effective cone resistance model is suitable for very soft to firm calcareous clays,the excess-pore pressure model can depict the undrained shear strength for firm to very stiff but gas-free clays,while the total cone resistance model is advantageous for evaluating the undrained shear strength for very stiff and gassy clays. The optimized model in piecewise function format can considerably improve the adaptability of empirical models for calcareous clay in the Shenhu area. These results are significant for safety evaluations of proposed hydrate exploitation projects.
基金funded by the National Natural Science Foundation of China (No. 51378057)
文摘Regarding the freezing damage of high-grade highway subgrade in seasonally frozen area,the thesis explores the effect on the dynamic behavior of subgrade soil under freeze–thaw cycles and draws the change law of parameters(including dynamic strength,dynamic cohesion,and internal friction angle;and dynamic elastic modulus)of high-grade highway-subgrade soil with the number of freeze–thaw cycles.It aims to provide the reference for operation and maintenance of a high-grade highway.Conclusions:(1)Dynamic strength tends to decline evidently after freeze–thaw cycles,with 60%~70%decline after three cycles,and remains stable after five to seven cycles.(2)With the number of freeze–thaw cycles increasing,the internal friction angle fluctuates within a certain range without an obvious change law,only presenting the tendency of dropping off.The dynamic cohesion declines obviously,about 20%~40%after seven freeze–thaw cycles,and then tends to be stable.(3)With the number of freeze-thaw cycles increasing,the dynamic elastic modulus and maximum dynamic elastic modulus are inclined to decrease distinctly.After five freeze–thaw cycles,the former declines 30%~40%and then remains stable.Meanwhile,the latter falls 20%~40%.
基金Supported by Guangxi Natural Science Foundation ProjectChina(2013GXNSFAA019283)
文摘The spatial and temporal variation characteristics of temperature were analyzed by using climate tendency coefficient, climatic inclination rate and Mann-Kendall catastrophe test,based on the annual and seasonal average temperatures of 28 meteorological stations in Guangxi from 1971 to 2013. Under the global warming,the annual and seasonal average temperatures in typical karst area of Guangxi had an increasing trend. The cli- mate inclination rate of annual average temperature reached a significant level, which was about 0.17 ℃/10 a, and the year of abrupt changes ap- peared in 1996. About seasonal temperature＇s trend, average temperatures of all the four seasons had an increase trend in the past 43 years, and the significant increase was happened in autumn with the temperature increase rate of 0.28 ℃/10 a, followed by increase rate of average tempera- ture in winter with 0.25 ℃/10 a. A long-term warming tendency was observed by seasonal average temperature from 1971 to 2013, especially dur- ing 2002 - 2013.
