Mixed Reality(MR)Head Mounted Displays(HMDs)offer a hitherto underutilized set of advantages compared to conventional 3D scanners.These benefits,inherent to MR-HMDs albeit not originally intended for such appli-cation...Mixed Reality(MR)Head Mounted Displays(HMDs)offer a hitherto underutilized set of advantages compared to conventional 3D scanners.These benefits,inherent to MR-HMDs albeit not originally intended for such appli-cations,encompass the freedom of hand movement,hand tracking capabilities,and real-time mesh visualization.This study leverages these attributes to enhance indoor scanning process.The primary innovation lies in the con-ceptualization of manual-positioned MR virtual seeds for the purpose of indoor point cloud segmentation via a region-growing approach.The proposed methodology is effectively implemented using the HoloLens 2 platform.An application is designed to enable the remote placement of virtual tags based on the user’s visual focus on the MR-HMD display.This non-intrusive interface is further enriched with expedited tag saving and deletion functionalities,as well as augmented tag visualization through overlaying them on real-world objects.To assess the practicality of the proposed method,a comprehensive real-world case study spanning an area of 330 s^(2) is conducted.Remarkably,the survey demonstrates remarkable efficiency,with 20 virtual tags swiftly deployed,each requiring a mere 2 s for precise positioning.Subsequently,these virtual tags are employed as seeds in a region-growing algorithm for point cloud segmentation.The accuracy of virtual tag positioning is found to be exceptional,with an average error of 2.4±1.8 cm.Importantly,the user experience is significantly enhanced,leading to improved seed positioning and,consequently,more accurate final segmentation results.展开更多
The degradation strength of soils under cyclic loading is studied and a method for determining the cyclic degradation strength with cyclic triaxial tests is given in the paper. Furthermore, a dum my static method for ...The degradation strength of soils under cyclic loading is studied and a method for determining the cyclic degradation strength with cyclic triaxial tests is given in the paper. Furthermore, a dum my static method for estimating the undrained bearing capacity for offshore soft foundation under wave loads is developed. It can consider the effect of the difference of cyclic stress for different parts of the foundation on both the degradation strength of the foundation soil and the bearing capacity so that the estimated result can better reflect the real condition of foundation under cyclic loading. The method can be applied to plane and space problem.展开更多
Effective stress analysis is performed to evaluate the residual displacement of a caisson quaywall during 1994 Hokkaido- Toho- Oki Earthquake and 1993 Kushiro- Oki Earthquake. The constitutive model used in this study...Effective stress analysis is performed to evaluate the residual displacement of a caisson quaywall during 1994 Hokkaido- Toho- Oki Earthquake and 1993 Kushiro- Oki Earthquake. The constitutive model used in this study is a multiple shear mechanism type defined in strain space and can take into account the effect of rotation of principal stress axis. The earthquake accelerations recorded at the outcropping rock during the earthquake are used as input bedrock motion. The results of finite element analysis are in good agreement with the observed behaviour of the quaywall. The analysis also indicates that liquefaction and high excess porewater pressure have a significant effect on the deformation of the caisson. Soil improvement is speculated as the most reliable measures against liquefaction. The influence of soil improvement and the reasonable improved area are discussed in the paper.展开更多
According to the Mohr-Coulomb yield criterion, the stress field of the infinite slope is derived under a vertical uniform load q on the top of the slope. It is indicated that elastic and elasto-plastic states would oc...According to the Mohr-Coulomb yield criterion, the stress field of the infinite slope is derived under a vertical uniform load q on the top of the slope. It is indicated that elastic and elasto-plastic states would occur in the slope. When q is smaller than the critical load, q(p), the slope is in the elastic state. If q equals q(p), the slope is in the critical state, and the plastic deformation would occur along the critical angle. With the increase of q, the plastic zone would extend, and the slope is in the elasto-plastic State. If q equals limit load, the slope is in the limit equilibrium state. The slope may be divided into three zones. Some charts of the critical angle, the critical and limit load coefficients are presented in this paper.展开更多
Based on comprehensive analyses of occurrence,petrological observation,pore structure and geochemistry,the different reservoir characteristics and reservoir evolutionary pathways between different oolitic shoal reserv...Based on comprehensive analyses of occurrence,petrological observation,pore structure and geochemistry,the different reservoir characteristics and reservoir evolutionary pathways between different oolitic shoal reservoir types of the Feixianguan Formation on the west side of the Kaijiang-Liangping Trough have been studied.There exist three stages of high-energy slope break belts in the Feixianguan period,the corresponding three stages of oolitic shoals gradually migrating in the direction of the trough.Three types of oolitic shoal reservoirs,namely,residual-oolitic dolomite,mold-oolitic dolomite and sparry oolitic limestone,were formed during sedimentary-diagenetic evolution,the pore types being intergranular dissolved pore,mold pore(or intragranular dissolved pore)and residual intergranular pore,respectively.The petrology,physical properties and pore structure of the different types of oolitic shoal reservoirs are quite different.Residual-oolitic dolomite reservoirs have the best quality,while sparry oolitic limestone reservoirs have the poorest.Combined with analyses of trace elements,rare earth elements and carbon-oxygen isotopes,it is suggested that the formation of residual-oolitic dolomite reservoirs is jointly controlled by penesaline seawater seepage-reflux dolomitization and hydrothermal dolomitization.Mold-pore oolitic dolomite reservoirs are controlled by penesaline seawater seepage-reflux dolomitization and meteoric water solution.The burial dissolution of organic acid not only further improves the reservoir qualities of previously formed oolitic dolomite reservoirs,but also preserves residual intergranular pores in the sparry oolitic limestone reservoirs.展开更多
The accumulation and productivity of shale gas are mainly controlled by the characteristics of shale reservoirs;study of these characteristics forms the basis for the shale gas exploitation of the Lower Cambrian Niuti...The accumulation and productivity of shale gas are mainly controlled by the characteristics of shale reservoirs;study of these characteristics forms the basis for the shale gas exploitation of the Lower Cambrian Niutitang Formation(Fm),Southern China.In this study,core observation and lithology study were conducted along with X-ray diffraction(XRD)and electronic scanning microscopy(SEM)examinations and liquid nitrogen(N2)adsorption/desorption and CH4 isothermal adsorption experiments for several exploration wells in northwestern Hunan Province,China.The results show that one or two intervals with high-quality source rocks(TOC>2 wt%)were deposited in the deep-shelf facies.The source rocks,which were mainly composed of carbonaceous shales and siliceous shales,had high quartz contents(>40 wt%)and low clay mineral(<30 wt%,mainly illites)and carbonate mineral(<20 wt%)contents.The SEM observations and liquid nitrogen(N2)adsorption/desorption experiments showed that the shale is tight,and nanoscale pores and microscale fractures are well developed.BJH volume(VBJH)of shale ranged from 2.144×10^-3 to 20.07×10^-3 cm^3/g,with an average of 11.752×10^-3 cm3/g.Pores mainly consisted of opened and interconnected mesopores(2–50 nm in diameter)or macropores(>50 nm in diameter).The shale reservoir has strong adsorption capacity for CH4.The Langmuir volume(VL)varied from 1.63 to 7.39 cm^3/g,with an average of 3.95 cm^3/g.The characteristics of shale reservoir are controlled by several factors:(1)A deep muddy continental shelf is the most favorable environment for the development of shale reservoirs,which is controlled by the development of basic materials.(2)The storage capacity of the shale reservoir is positively related to the TOC contents and plastic minerals and negatively related to cement minerals.(3)High maturity or overmaturity leads to the growth of organic pores and microfractures,thereby improving the reservoir storage capacity.It can be deduced that the high percentage of residual gas in Niutitang Fm results from the strong reservoir storage capacity of adsorbed gas.Two layers of sweet spots with strong storage capacity of free gas,and they are characterized by the relatively high TOC contents ranging from 4 wt%to 8 wt%.展开更多
Nigeria lies very close to the equator(hot country) at the west coast of Africa between latitude 4°-14°N and longitude 2°-15°E.The country is located at the northern end of eastern branch of west c...Nigeria lies very close to the equator(hot country) at the west coast of Africa between latitude 4°-14°N and longitude 2°-15°E.The country is located at the northern end of eastern branch of west coast of Africa rift system.Nigeria geological setting comprises broadly sedimentary formation and crystalline basement complex,which occur more or less in equal proportion all over the country.The sediment展开更多
The zones of thawed ground in the permafrost area are most dangerous from engineer-geologist effect point of view. Detection of such zones, as making forecast of their movement is the main task of engineer-geologist s...The zones of thawed ground in the permafrost area are most dangerous from engineer-geologist effect point of view. Detection of such zones, as making forecast of their movement is the main task of engineer-geologist survey been held in railway industry. This paper presents general issues concerning railway construction and operation in permafrost areas. Comprehensive geophysical methods to monitor the development of thawed soils axe considered in detail. The main physical parameters which help define permafrost and thawed soil patches are described. Author of current paper pointed out main factors, allowing predicting potential areas of development of thawed grounds. They offered set non-destructive methods： GPR investigations, seismic survey and elec- tric exploration. Whole sets of geophysical data： electric resistivity, velocity of S-wave and P-wave （and their correlation）, allow us with high confidence specify characteristics and state of soil either under the line of road, or near it. At the same time the meth- od allows to predict direction of further development of thawed ground area.展开更多
In this paper the theoretical background was analyzed for vibration diagnostics method and experience in its application for weak base embankments. General schemes of survey and recommendations on hardware systems and...In this paper the theoretical background was analyzed for vibration diagnostics method and experience in its application for weak base embankments. General schemes of survey and recommendations on hardware systems and further prospective development are outlined.展开更多
In this paper, a general solution for three-dimensional staticpiezothermoleastic prob- lems of crystal class 6mm solids ispresented. The general solution involves four piezoelastic potentialfunctions and a piezothermo...In this paper, a general solution for three-dimensional staticpiezothermoleastic prob- lems of crystal class 6mm solids ispresented. The general solution involves four piezoelastic potentialfunctions and a piezothermoelastic potential function, of which fourpiezoelastic potential functions are governed by weighted harmonicdifferential equations. Compared with the general solution given byAshida et al., in which seven potential functions are introduced, thegeneral solution proposed in the Present paper is more rigorouslyderived.展开更多
A non-local continuum model for strain-softening simply takingplastic strain or damage vari- able as a non-local variable isderived by using the additive decomposition principle of finitedeformation gra- dient. At the...A non-local continuum model for strain-softening simply takingplastic strain or damage vari- able as a non-local variable isderived by using the additive decomposition principle of finitedeformation gra- dient. At the same time, variational equations,their finite element formulations and numerical convolutedintegration algorithm of the model in current configuration usuallycalled co-moving coordinate system are given. stability andconvergence of the model are proven by means of the weak convergencetheorem of gen- eral function and the convoluted integration theory.展开更多
During the last decade, large rockfalls occurred on the steep limestone slopes along the Adriatic Coast of Croatia, causing injury to people and serious damage to buildings and traffic facilities. The rockfalls along ...During the last decade, large rockfalls occurred on the steep limestone slopes along the Adriatic Coast of Croatia, causing injury to people and serious damage to buildings and traffic facilities. The rockfalls along the limestone slopes were caused by unfavorable characteristics of the rock mass, weathering in combination with heavy rainfall and artificial influences during highway construction. Rockfall protection projects were conducted to protect human lives and facilities from future rockfalls. The rockfall protection program started with rockfall hazard analyses to identify the potential of rockfalls to occur and the potential consequences. At the locations of hazards where related risks were determined, detailed field investigations were conducted. Based on the indentified characteristics of potentially unstable rock masses, analyses of movement and resulting pathways were conducted. The trajectories, impact energy and the height of bouncing are dependent on slope geometry, slope surface roughness and rockfall block characteristics. Two protection measure approaches were adopted： prevention of rockfalls by removing potentially unstable rock mass or installation of rock mass support systems and suspending running rockfall masses with rockfall protection barriers. In this paper, rockfall hazard determination, rockfall analyses and rockfall protection designs for rockfall protection systems at selected locations on the limestone slopes along the Adriatic coast of Croatia are presented.展开更多
The red clay in Chenzhou, Hunan province is mostly in unsaturated state. Simply applying the mechanical properties that derived from classic saturated soil mechanics often leads to slope failures in this region. In or...The red clay in Chenzhou, Hunan province is mostly in unsaturated state. Simply applying the mechanical properties that derived from classic saturated soil mechanics often leads to slope failures in this region. In order to study the shear strength characteristic of unsaturated red clay in Chenzhou and to explore a shear strength equation that can be easily applied in engineering practice, a series of triaxial tests of saturated and unsaturated red clay samples were performed using the regular triaxial testing apparatus. The testing results show that the peak strength of red clay drops slightly before the moisture content of 30% but decreases sharply after that. The friction angle of red clay under unsaturated state is basically equal to the effective friction angle under saturated state, while the cohesion of unsaturated red clay is far much bigger than that of saturated one, which indicates that the matric suction makes a great contribution to the cohesion. By fitting the testing results with appropriate curves, the relationships between total strength parameters and with moisture content were obtained. The total increases logarithmically before the moisture content of 35% then decreases linearly, while decreases cubically with increasing moisture content.展开更多
Based on the three dimensional elastic theory, the state equationfo the axisymmetric free vibration of transversely isotropic circularplates is established. Taking the advantage of finite Hankeltransform, tow exact so...Based on the three dimensional elastic theory, the state equationfo the axisymmetric free vibration of transversely isotropic circularplates is established. Taking the advantage of finite Hankeltransform, tow exact solutions are derived for two boundaryconditions, i.e. the rigid-slipping boundary and elastic simplysupported boundary. Finally, numerical results are presented and com-pared with those of FEM.展开更多
基金partially supported by RYC2022-038100-I and RYC2020-029193-I funded by MCIN/AEI/10.13039/501100011033 and FSE‘El FSE invierte en tu futuro’a result of the project PID2021-123475OA-I00,funded by MCIN/AEI/10.13039/501100011033/FEDER,UE."+1 种基金the framework of the SUM4Re project(Creating materials banks from digital urban mining),which has received funding from the Horizon Europe research and innovation program under grant agreement no.101129961Funded by the European Union.
文摘Mixed Reality(MR)Head Mounted Displays(HMDs)offer a hitherto underutilized set of advantages compared to conventional 3D scanners.These benefits,inherent to MR-HMDs albeit not originally intended for such appli-cations,encompass the freedom of hand movement,hand tracking capabilities,and real-time mesh visualization.This study leverages these attributes to enhance indoor scanning process.The primary innovation lies in the con-ceptualization of manual-positioned MR virtual seeds for the purpose of indoor point cloud segmentation via a region-growing approach.The proposed methodology is effectively implemented using the HoloLens 2 platform.An application is designed to enable the remote placement of virtual tags based on the user’s visual focus on the MR-HMD display.This non-intrusive interface is further enriched with expedited tag saving and deletion functionalities,as well as augmented tag visualization through overlaying them on real-world objects.To assess the practicality of the proposed method,a comprehensive real-world case study spanning an area of 330 s^(2) is conducted.Remarkably,the survey demonstrates remarkable efficiency,with 20 virtual tags swiftly deployed,each requiring a mere 2 s for precise positioning.Subsequently,these virtual tags are employed as seeds in a region-growing algorithm for point cloud segmentation.The accuracy of virtual tag positioning is found to be exceptional,with an average error of 2.4±1.8 cm.Importantly,the user experience is significantly enhanced,leading to improved seed positioning and,consequently,more accurate final segmentation results.
基金This project was financially supported by the National Natural Science Foundation of China(No.59679018)
文摘The degradation strength of soils under cyclic loading is studied and a method for determining the cyclic degradation strength with cyclic triaxial tests is given in the paper. Furthermore, a dum my static method for estimating the undrained bearing capacity for offshore soft foundation under wave loads is developed. It can consider the effect of the difference of cyclic stress for different parts of the foundation on both the degradation strength of the foundation soil and the bearing capacity so that the estimated result can better reflect the real condition of foundation under cyclic loading. The method can be applied to plane and space problem.
文摘Effective stress analysis is performed to evaluate the residual displacement of a caisson quaywall during 1994 Hokkaido- Toho- Oki Earthquake and 1993 Kushiro- Oki Earthquake. The constitutive model used in this study is a multiple shear mechanism type defined in strain space and can take into account the effect of rotation of principal stress axis. The earthquake accelerations recorded at the outcropping rock during the earthquake are used as input bedrock motion. The results of finite element analysis are in good agreement with the observed behaviour of the quaywall. The analysis also indicates that liquefaction and high excess porewater pressure have a significant effect on the deformation of the caisson. Soil improvement is speculated as the most reliable measures against liquefaction. The influence of soil improvement and the reasonable improved area are discussed in the paper.
文摘According to the Mohr-Coulomb yield criterion, the stress field of the infinite slope is derived under a vertical uniform load q on the top of the slope. It is indicated that elastic and elasto-plastic states would occur in the slope. When q is smaller than the critical load, q(p), the slope is in the elastic state. If q equals q(p), the slope is in the critical state, and the plastic deformation would occur along the critical angle. With the increase of q, the plastic zone would extend, and the slope is in the elasto-plastic State. If q equals limit load, the slope is in the limit equilibrium state. The slope may be divided into three zones. Some charts of the critical angle, the critical and limit load coefficients are presented in this paper.
基金This research was supported jointly by the National Natural Science Foundation of China(Grant No.41972165)National Science and Technology Major Project(Grant No.2017ZX05008-004-008)National Science and Technology Major Project(Grant No.2016E-0607).
文摘Based on comprehensive analyses of occurrence,petrological observation,pore structure and geochemistry,the different reservoir characteristics and reservoir evolutionary pathways between different oolitic shoal reservoir types of the Feixianguan Formation on the west side of the Kaijiang-Liangping Trough have been studied.There exist three stages of high-energy slope break belts in the Feixianguan period,the corresponding three stages of oolitic shoals gradually migrating in the direction of the trough.Three types of oolitic shoal reservoirs,namely,residual-oolitic dolomite,mold-oolitic dolomite and sparry oolitic limestone,were formed during sedimentary-diagenetic evolution,the pore types being intergranular dissolved pore,mold pore(or intragranular dissolved pore)and residual intergranular pore,respectively.The petrology,physical properties and pore structure of the different types of oolitic shoal reservoirs are quite different.Residual-oolitic dolomite reservoirs have the best quality,while sparry oolitic limestone reservoirs have the poorest.Combined with analyses of trace elements,rare earth elements and carbon-oxygen isotopes,it is suggested that the formation of residual-oolitic dolomite reservoirs is jointly controlled by penesaline seawater seepage-reflux dolomitization and hydrothermal dolomitization.Mold-pore oolitic dolomite reservoirs are controlled by penesaline seawater seepage-reflux dolomitization and meteoric water solution.The burial dissolution of organic acid not only further improves the reservoir qualities of previously formed oolitic dolomite reservoirs,but also preserves residual intergranular pores in the sparry oolitic limestone reservoirs.
基金granted by the National Natural Science Foundation of China (41603046)the Natural Science Foundation of Hunan Province (2017JJ1034)
文摘The accumulation and productivity of shale gas are mainly controlled by the characteristics of shale reservoirs;study of these characteristics forms the basis for the shale gas exploitation of the Lower Cambrian Niutitang Formation(Fm),Southern China.In this study,core observation and lithology study were conducted along with X-ray diffraction(XRD)and electronic scanning microscopy(SEM)examinations and liquid nitrogen(N2)adsorption/desorption and CH4 isothermal adsorption experiments for several exploration wells in northwestern Hunan Province,China.The results show that one or two intervals with high-quality source rocks(TOC>2 wt%)were deposited in the deep-shelf facies.The source rocks,which were mainly composed of carbonaceous shales and siliceous shales,had high quartz contents(>40 wt%)and low clay mineral(<30 wt%,mainly illites)and carbonate mineral(<20 wt%)contents.The SEM observations and liquid nitrogen(N2)adsorption/desorption experiments showed that the shale is tight,and nanoscale pores and microscale fractures are well developed.BJH volume(VBJH)of shale ranged from 2.144×10^-3 to 20.07×10^-3 cm^3/g,with an average of 11.752×10^-3 cm3/g.Pores mainly consisted of opened and interconnected mesopores(2–50 nm in diameter)or macropores(>50 nm in diameter).The shale reservoir has strong adsorption capacity for CH4.The Langmuir volume(VL)varied from 1.63 to 7.39 cm^3/g,with an average of 3.95 cm^3/g.The characteristics of shale reservoir are controlled by several factors:(1)A deep muddy continental shelf is the most favorable environment for the development of shale reservoirs,which is controlled by the development of basic materials.(2)The storage capacity of the shale reservoir is positively related to the TOC contents and plastic minerals and negatively related to cement minerals.(3)High maturity or overmaturity leads to the growth of organic pores and microfractures,thereby improving the reservoir storage capacity.It can be deduced that the high percentage of residual gas in Niutitang Fm results from the strong reservoir storage capacity of adsorbed gas.Two layers of sweet spots with strong storage capacity of free gas,and they are characterized by the relatively high TOC contents ranging from 4 wt%to 8 wt%.
文摘Nigeria lies very close to the equator(hot country) at the west coast of Africa between latitude 4°-14°N and longitude 2°-15°E.The country is located at the northern end of eastern branch of west coast of Africa rift system.Nigeria geological setting comprises broadly sedimentary formation and crystalline basement complex,which occur more or less in equal proportion all over the country.The sediment
基金Russian Railways,and Nauka-MSURT for financial support
文摘The zones of thawed ground in the permafrost area are most dangerous from engineer-geologist effect point of view. Detection of such zones, as making forecast of their movement is the main task of engineer-geologist survey been held in railway industry. This paper presents general issues concerning railway construction and operation in permafrost areas. Comprehensive geophysical methods to monitor the development of thawed soils axe considered in detail. The main physical parameters which help define permafrost and thawed soil patches are described. Author of current paper pointed out main factors, allowing predicting potential areas of development of thawed grounds. They offered set non-destructive methods： GPR investigations, seismic survey and elec- tric exploration. Whole sets of geophysical data： electric resistivity, velocity of S-wave and P-wave （and their correlation）, allow us with high confidence specify characteristics and state of soil either under the line of road, or near it. At the same time the meth- od allows to predict direction of further development of thawed ground area.
文摘In this paper the theoretical background was analyzed for vibration diagnostics method and experience in its application for weak base embankments. General schemes of survey and recommendations on hardware systems and further prospective development are outlined.
基金the National Natural Science Foundation of China(19872060)
文摘In this paper, a general solution for three-dimensional staticpiezothermoleastic prob- lems of crystal class 6mm solids ispresented. The general solution involves four piezoelastic potentialfunctions and a piezothermoelastic potential function, of which fourpiezoelastic potential functions are governed by weighted harmonicdifferential equations. Compared with the general solution given byAshida et al., in which seven potential functions are introduced, thegeneral solution proposed in the Present paper is more rigorouslyderived.
基金the National Natural Science Foundation of China(No.19632030)
文摘A non-local continuum model for strain-softening simply takingplastic strain or damage vari- able as a non-local variable isderived by using the additive decomposition principle of finitedeformation gra- dient. At the same time, variational equations,their finite element formulations and numerical convolutedintegration algorithm of the model in current configuration usuallycalled co-moving coordinate system are given. stability andconvergence of the model are proven by means of the weak convergencetheorem of gen- eral function and the convoluted integration theory.
文摘During the last decade, large rockfalls occurred on the steep limestone slopes along the Adriatic Coast of Croatia, causing injury to people and serious damage to buildings and traffic facilities. The rockfalls along the limestone slopes were caused by unfavorable characteristics of the rock mass, weathering in combination with heavy rainfall and artificial influences during highway construction. Rockfall protection projects were conducted to protect human lives and facilities from future rockfalls. The rockfall protection program started with rockfall hazard analyses to identify the potential of rockfalls to occur and the potential consequences. At the locations of hazards where related risks were determined, detailed field investigations were conducted. Based on the indentified characteristics of potentially unstable rock masses, analyses of movement and resulting pathways were conducted. The trajectories, impact energy and the height of bouncing are dependent on slope geometry, slope surface roughness and rockfall block characteristics. Two protection measure approaches were adopted： prevention of rockfalls by removing potentially unstable rock mass or installation of rock mass support systems and suspending running rockfall masses with rockfall protection barriers. In this paper, rockfall hazard determination, rockfall analyses and rockfall protection designs for rockfall protection systems at selected locations on the limestone slopes along the Adriatic coast of Croatia are presented.
文摘The red clay in Chenzhou, Hunan province is mostly in unsaturated state. Simply applying the mechanical properties that derived from classic saturated soil mechanics often leads to slope failures in this region. In order to study the shear strength characteristic of unsaturated red clay in Chenzhou and to explore a shear strength equation that can be easily applied in engineering practice, a series of triaxial tests of saturated and unsaturated red clay samples were performed using the regular triaxial testing apparatus. The testing results show that the peak strength of red clay drops slightly before the moisture content of 30% but decreases sharply after that. The friction angle of red clay under unsaturated state is basically equal to the effective friction angle under saturated state, while the cohesion of unsaturated red clay is far much bigger than that of saturated one, which indicates that the matric suction makes a great contribution to the cohesion. By fitting the testing results with appropriate curves, the relationships between total strength parameters and with moisture content were obtained. The total increases logarithmically before the moisture content of 35% then decreases linearly, while decreases cubically with increasing moisture content.
基金the National Natural Science Foundation of Chinathe Zhejiang Provincial Natural Science Foundation
文摘Based on the three dimensional elastic theory, the state equationfo the axisymmetric free vibration of transversely isotropic circularplates is established. Taking the advantage of finite Hankeltransform, tow exact solutions are derived for two boundaryconditions, i.e. the rigid-slipping boundary and elastic simplysupported boundary. Finally, numerical results are presented and com-pared with those of FEM.
