The settling of sediments is an accelerative process in which the concentration of the main sediments zone will heavily influence settling velocity,but the explicit relationship between the concentration and settling ...The settling of sediments is an accelerative process in which the concentration of the main sediments zone will heavily influence settling velocity,but the explicit relationship between the concentration and settling velocity has not been reported in literature. Here a theoretical function was built for the time dependent concentration and time dependent settling velocity of sediments;then the entire settling process reflecting concentration was shown on the basis of sediments instant\|settlement theory and mathematical method. Agreement of computed results and experimental data was found. Several governing parameters,including particle size,particle density,initial suspended sediments concentration and suspension height,were discussed with a series of calculated velocity curves. The research indicated that ⑴ the presented concentration\|velocity time relationship is rational,⑵ settling process of the sediments group with variation of concentration consists of acceleration stage,uniform motion stage and deceleration stage,and ⑶ particle size,particle density and initial suspended sediments concentration have more influence on the settling velocity than the suspension height and water temperature.展开更多
A new approach is proposed to analyze the settlement behavior for single pile embedded in layered soils. Firstly, soil layers surrounding pile shaft are simulated by using distributed Voigt model, and finite soil laye...A new approach is proposed to analyze the settlement behavior for single pile embedded in layered soils. Firstly, soil layers surrounding pile shaft are simulated by using distributed Voigt model, and finite soil layers under the pile end are assumed to be virtual soil-pile whose cross-section area is the same as that of the pile shaft. Then, by means of Laplace transform and impedance function transfer method to solve the static equilibrium equation of pile, the analytical solution of the displacement impedance fimction at the pile head is derived. Furthermore, the analytical solution of the settlement at the head of single pile is theoretically derived by virtue of convolution theorem. Based on these solutions, the influences of parameters of soil-pile system on the settlement behavior for single pile are analyzed. Also, comparison of the load-settlement response for two well-instrumented field tests in multilayered soils is given to demonstrate the effectiveness and accuracy of the proposed approach. It can be noted that the presented solution can be used to calculate the settlement of single pile for the preliminary design of pile foundation.展开更多
The place change of the key inserts,different kinds of magnets for instance,in an accelerator caused by the uneven earth subside will affect the accelerator commission.All accelerator laboratories,at home and abroad h...The place change of the key inserts,different kinds of magnets for instance,in an accelerator caused by the uneven earth subside will affect the accelerator commission.All accelerator laboratories,at home and abroad have taken the influences more and more seriously.The Shanghai Synchrotron Radiation Facility(SSRF)under construction is located at Pudong,Shanhai,where geological condition is complicated.It is necessary to establish a monitoring system to monitor the uneven subside of foundation and key parts of the accelerator.The Hydrostatic Leveling System (HLS)is used to real time monitor the vertical displacement of the foundation and the supports of the key inserts in accelerator.This paper discusses the HLS's design plan,the principal parameters and the theoretical calculation.By discussion we can comprehend the importance and necessity to establish HLS in an accelerator in an all-round way.展开更多
文摘The settling of sediments is an accelerative process in which the concentration of the main sediments zone will heavily influence settling velocity,but the explicit relationship between the concentration and settling velocity has not been reported in literature. Here a theoretical function was built for the time dependent concentration and time dependent settling velocity of sediments;then the entire settling process reflecting concentration was shown on the basis of sediments instant\|settlement theory and mathematical method. Agreement of computed results and experimental data was found. Several governing parameters,including particle size,particle density,initial suspended sediments concentration and suspension height,were discussed with a series of calculated velocity curves. The research indicated that ⑴ the presented concentration\|velocity time relationship is rational,⑵ settling process of the sediments group with variation of concentration consists of acceleration stage,uniform motion stage and deceleration stage,and ⑶ particle size,particle density and initial suspended sediments concentration have more influence on the settling velocity than the suspension height and water temperature.
基金Project(50879077) supported by the National Natural Science Foundation of China
文摘A new approach is proposed to analyze the settlement behavior for single pile embedded in layered soils. Firstly, soil layers surrounding pile shaft are simulated by using distributed Voigt model, and finite soil layers under the pile end are assumed to be virtual soil-pile whose cross-section area is the same as that of the pile shaft. Then, by means of Laplace transform and impedance function transfer method to solve the static equilibrium equation of pile, the analytical solution of the displacement impedance fimction at the pile head is derived. Furthermore, the analytical solution of the settlement at the head of single pile is theoretically derived by virtue of convolution theorem. Based on these solutions, the influences of parameters of soil-pile system on the settlement behavior for single pile are analyzed. Also, comparison of the load-settlement response for two well-instrumented field tests in multilayered soils is given to demonstrate the effectiveness and accuracy of the proposed approach. It can be noted that the presented solution can be used to calculate the settlement of single pile for the preliminary design of pile foundation.
文摘The place change of the key inserts,different kinds of magnets for instance,in an accelerator caused by the uneven earth subside will affect the accelerator commission.All accelerator laboratories,at home and abroad have taken the influences more and more seriously.The Shanghai Synchrotron Radiation Facility(SSRF)under construction is located at Pudong,Shanhai,where geological condition is complicated.It is necessary to establish a monitoring system to monitor the uneven subside of foundation and key parts of the accelerator.The Hydrostatic Leveling System (HLS)is used to real time monitor the vertical displacement of the foundation and the supports of the key inserts in accelerator.This paper discusses the HLS's design plan,the principal parameters and the theoretical calculation.By discussion we can comprehend the importance and necessity to establish HLS in an accelerator in an all-round way.
