Quasi-rectangular shield tunneling is a cutting-edge trenchless method for constructing metro tunnels with double tubes,owing to its advantages in saving underground space and reducing ground disturbance.However,the c...Quasi-rectangular shield tunneling is a cutting-edge trenchless method for constructing metro tunnels with double tubes,owing to its advantages in saving underground space and reducing ground disturbance.However,the conventional quasi-rectangular shield tunneling method is not applicable when constructing a tunnel without a center pillar,such as a scissor crossover section of a metro line.Therefore,the O-0 tunneling method,which combines the quasirectangular shield and pipe jacking methods,was investigated in this study to solve the aforementioned construction challenges.This study presents a case study of the Sijiqing Station of the Hangzhou Metro Line 9 in China,in which the O-0 method was first proposed and applied.Key techniques such as switching between two types of tunneling modes and the tunneling process control in complex construction environments were investigated.The results demonstrated that the O-0 method can address the technical challenges presented by the post-transition line with a high curvature and a scissors crossover line.In addition,the adoption of the 0-0 method ensured that the transformation between shield tunneling and pipe jacking was safe and efficient.The ground settlement monitoring results demonstrated that the disturbance to the surrounding environment can be limited to a safe level.This case study contributes to the construction technology for a metro tunnel containing both post-transition lines with a small turning radius and a scissors crossover line.A practical construction experience and theoretical guidance were provided in this study,which are of significance for both the industry and academia.展开更多
To achieve high parallel efficiency for the global MASNUM surface wave model, the algorithm of an irregular quasirectangular domain decomposition and related serializing of calculating points and data exchanging schem...To achieve high parallel efficiency for the global MASNUM surface wave model, the algorithm of an irregular quasirectangular domain decomposition and related serializing of calculating points and data exchanging schemes are developed and conducted, based on the environment of Message Passing Interface(MPI). The new parallel version of the surface wave model is tested for parallel computing on the platform of the Sunway BlueLight supercomputer in the National Supercomputing Center in Jinan. The testing involves four horizontal resolutions, which are 1°×1°,(1/2)°×(1/2)°,(1/4)°×(1/4)°, and(1/8)°×(1/8)°. These tests are performed without data Input/Output(IO) and the maximum amount of processors used in these tests reaches to 131072. The testing results show that the computing speeds of the model with different resolutions are all increased with the increasing of numbers of processors. When the number of processors is four times that of the base processor number, the parallel efficiencies of all resolutions are greater than 80%. When the number of processors is eight times that of the base processor number, the parallel efficiency of tests with resolutions of 1°×1°,(1/2)°×(1/2)° and(1/4)°×(1/4)° is greater than 80%, and it is 62% for the test with a resolution of(1/8)°×(1/8)° using 131072 processors, which is the nearly all processors of Sunway BlueLight. When the processor's number is 24 times that of the base processor number, the parallel efficiencies for tests with resolutions of 1°×1°,(1/2)°×(1/2)°, and(1/4)°×(1/4)° are 72%, 62%, and 38%, respectively. The speedup and parallel efficiency indicate that the irregular quasi-rectangular domain decomposition and serialization schemes lead to high parallel efficiency and good scalability for a global numerical wave model.展开更多
A quasi-rectangular mesh (denoted by △QR) is basically a rectangular mesh (△R) that allows local modifications, including T-mesh (△T) and L-mesh (△L). In this paper, the dimensions of the bivariate spline spaces S...A quasi-rectangular mesh (denoted by △QR) is basically a rectangular mesh (△R) that allows local modifications, including T-mesh (△T) and L-mesh (△L). In this paper, the dimensions of the bivariate spline spaces Skμ(△QR) are discussed by using the Smoothing Cofactor-Conformality method. The dimension formulae are obtained with some constraints depending on the order of the smoothness, the degree of the spline functions and the structure of the mesh as well.展开更多
Considering that the particular geometric shape of a quasi-rectangular shield,the grout flowing law and its motion process are more complicated than those of a conventional circular shield.To interpret the grouting me...Considering that the particular geometric shape of a quasi-rectangular shield,the grout flowing law and its motion process are more complicated than those of a conventional circular shield.To interpret the grouting mechanical ehaviour in the special-shape shield tail void,the filling and diffusion mechanism of synchronous grouting was analysed.The grout flowing is separated into two independent motion processes,which contains a circumferential filling and a longitudinal diffusion.The theoretical model of the grout pressure spatial distribution was derived based on the principle of fluid mechanics.Then,the pressure distributions in the two directions were obtained using a case study and compared with the field measured data to verify the validation of the model.Although the overall spatial pattern of grout pressure distribution on the tunnel profile show a change trend dominated by the self-weight effect mostly,its local fluctuation characteristics is very abnormal relative to that of a circular shield tunnel.Moreover,the important factors in the model were analysed,including the grout material parameters,the grouting construction parameters,and some geometry parameters.The results show that the pressure loss along this way is positively correlated with the grout flow velocity and is sensitive to the shear yield stress of the grout.The pressure loss along the circumferential direction is the most sensitive to the thickness of the ring cake,and the value range suitable for the model should be 0.02-0.03 m.The pressure loss along the longitudinal diffusion direction is the most sensitive to the size of the tail void.The research results can provide a theoretical basis for the control of special-shape shield construction.展开更多
基金theSSocial Development Project of Science and Technology Commission of Shanghai Municipality(No.21DZ1201105)the Fundamental Research Funds for the Central Universities(No.21D111320)the National Natural Science Foundation of China(Grant No.42201489).
文摘Quasi-rectangular shield tunneling is a cutting-edge trenchless method for constructing metro tunnels with double tubes,owing to its advantages in saving underground space and reducing ground disturbance.However,the conventional quasi-rectangular shield tunneling method is not applicable when constructing a tunnel without a center pillar,such as a scissor crossover section of a metro line.Therefore,the O-0 tunneling method,which combines the quasirectangular shield and pipe jacking methods,was investigated in this study to solve the aforementioned construction challenges.This study presents a case study of the Sijiqing Station of the Hangzhou Metro Line 9 in China,in which the O-0 method was first proposed and applied.Key techniques such as switching between two types of tunneling modes and the tunneling process control in complex construction environments were investigated.The results demonstrated that the O-0 method can address the technical challenges presented by the post-transition line with a high curvature and a scissors crossover line.In addition,the adoption of the 0-0 method ensured that the transformation between shield tunneling and pipe jacking was safe and efficient.The ground settlement monitoring results demonstrated that the disturbance to the surrounding environment can be limited to a safe level.This case study contributes to the construction technology for a metro tunnel containing both post-transition lines with a small turning radius and a scissors crossover line.A practical construction experience and theoretical guidance were provided in this study,which are of significance for both the industry and academia.
基金supported by National Basic Research Program of China (Grant Nos. 2010CB950300, 2010CB950500)Public Science and Technology Research Funds Projects of Ocean (Grant No. 201105019)+1 种基金Key Supercomputing Science-Technology Project of Shandong Province of China (Grant No. 2011YD01107)Scientific Research Foundation of the First Institute of Oceanography, State Oceanic Administration (Grant No. GY02-2010G22)
文摘To achieve high parallel efficiency for the global MASNUM surface wave model, the algorithm of an irregular quasirectangular domain decomposition and related serializing of calculating points and data exchanging schemes are developed and conducted, based on the environment of Message Passing Interface(MPI). The new parallel version of the surface wave model is tested for parallel computing on the platform of the Sunway BlueLight supercomputer in the National Supercomputing Center in Jinan. The testing involves four horizontal resolutions, which are 1°×1°,(1/2)°×(1/2)°,(1/4)°×(1/4)°, and(1/8)°×(1/8)°. These tests are performed without data Input/Output(IO) and the maximum amount of processors used in these tests reaches to 131072. The testing results show that the computing speeds of the model with different resolutions are all increased with the increasing of numbers of processors. When the number of processors is four times that of the base processor number, the parallel efficiencies of all resolutions are greater than 80%. When the number of processors is eight times that of the base processor number, the parallel efficiency of tests with resolutions of 1°×1°,(1/2)°×(1/2)° and(1/4)°×(1/4)° is greater than 80%, and it is 62% for the test with a resolution of(1/8)°×(1/8)° using 131072 processors, which is the nearly all processors of Sunway BlueLight. When the processor's number is 24 times that of the base processor number, the parallel efficiencies for tests with resolutions of 1°×1°,(1/2)°×(1/2)°, and(1/4)°×(1/4)° are 72%, 62%, and 38%, respectively. The speedup and parallel efficiency indicate that the irregular quasi-rectangular domain decomposition and serialization schemes lead to high parallel efficiency and good scalability for a global numerical wave model.
基金the National Natural Science Foundation of China (Nos.60533060 10726067)+1 种基金the Natural Science Foundation for Doctoral Career of Liaoning Province (No.20061060)the Science Foundation of Dalian University of Technology (No.SFDUT07001)
文摘A quasi-rectangular mesh (denoted by △QR) is basically a rectangular mesh (△R) that allows local modifications, including T-mesh (△T) and L-mesh (△L). In this paper, the dimensions of the bivariate spline spaces Skμ(△QR) are discussed by using the Smoothing Cofactor-Conformality method. The dimension formulae are obtained with some constraints depending on the order of the smoothness, the degree of the spline functions and the structure of the mesh as well.
基金sponsored by the Shanghai Rising-Star Program of China(Grant No.18QB1403800)supported by the Fundamental Research Funds for the Central Universities(Grant No.21D111320).
文摘Considering that the particular geometric shape of a quasi-rectangular shield,the grout flowing law and its motion process are more complicated than those of a conventional circular shield.To interpret the grouting mechanical ehaviour in the special-shape shield tail void,the filling and diffusion mechanism of synchronous grouting was analysed.The grout flowing is separated into two independent motion processes,which contains a circumferential filling and a longitudinal diffusion.The theoretical model of the grout pressure spatial distribution was derived based on the principle of fluid mechanics.Then,the pressure distributions in the two directions were obtained using a case study and compared with the field measured data to verify the validation of the model.Although the overall spatial pattern of grout pressure distribution on the tunnel profile show a change trend dominated by the self-weight effect mostly,its local fluctuation characteristics is very abnormal relative to that of a circular shield tunnel.Moreover,the important factors in the model were analysed,including the grout material parameters,the grouting construction parameters,and some geometry parameters.The results show that the pressure loss along this way is positively correlated with the grout flow velocity and is sensitive to the shear yield stress of the grout.The pressure loss along the circumferential direction is the most sensitive to the thickness of the ring cake,and the value range suitable for the model should be 0.02-0.03 m.The pressure loss along the longitudinal diffusion direction is the most sensitive to the size of the tail void.The research results can provide a theoretical basis for the control of special-shape shield construction.
