With the rapid development of modern society and the public's demand for travel efficiency, cities around the country with the ability and conditions are building subways, but most of the subway lines in the city ...With the rapid development of modern society and the public's demand for travel efficiency, cities around the country with the ability and conditions are building subways, but most of the subway lines in the city underground, so the construction environment is easy to be affected by geological conditions and other factors, leading to frequent safety accidents. This paper enumerates the relevant accident cases for discussion, analyzes and studies the risk sources of subway shield construction by combining the background, and puts forward relevant control measures for typical risk points, so as to provide reference for the same type of subway shield construction and promote the development of the industry.展开更多
In order to study the shield construction under an existing highway,the initial displacement and the excess pore water pressure solution from Biot consolidation equation were used to derive the analytical solutions of...In order to study the shield construction under an existing highway,the initial displacement and the excess pore water pressure solution from Biot consolidation equation were used to derive the analytical solutions of the vertical deformation and pore water pressure of saturated soil caused by the frontal friction and side friction of the cutterhead.In addition,by introducing the layered method and combining it with other theoretical analytical equations,the expressions of total vertical deformation and total pore water pressure caused by tunnel excavation with different overlying materials were obtained.The simulation results on an engineering project showed that the angleαbetween the direction of the road and the propulsion axis of the shield had a significant influence on the surface settlement of the road.When the angleαwas increased,the settlement curve had higher variation;but the variation would not exceed the maximum settlement value above the shield axis.When the road was perpendicular to the shield axis,a critical point of the road bulging and settlement was formed above the incision.Due to the grinding resistance of the cutterhead,the pore water pressure under the roadbed was distributed asymmetrically on both sides of the shield axis.展开更多
This study delves into the effects of shield tunneling in complex coastal strata, focusing on how this constructionmethod impacts surface settlement, the mechanical properties of adjacent rock, and the deformation of ...This study delves into the effects of shield tunneling in complex coastal strata, focusing on how this constructionmethod impacts surface settlement, the mechanical properties of adjacent rock, and the deformation of tunnelsegments. It investigates the impact of shield construction on surface settlement, mechanical characteristics ofnearby rock, and segment deformation in complex coastal strata susceptible to construction disturbances. Utilizingthe Fuzhou Binhai express line as a case study, we developed a comprehensive numerical model using theABAQUS finite element software. The model incorporates factors such as face force, grouting pressure, jack force,and cutterhead torque. Its accuracy is validated against field monitoring data from engineering projects. Simulationswere conducted to analyze ground settlement and mechanical changes in adjacent rock and segments acrossfive soil layers. The results indicate that disturbances are most significant near the excavation zone of the shieldmachine, with a prominent settlement trough forming and stabilizing around 2.0–3.0 D from the excavation. Theexcavation face compresses the soil, inducing lateral expansion. As grouting pressure decreases, the segmentexperiences upward buoyancy. In mixed strata, softer layers witness increased cutting, intensifying disturbancesbut reducing segment floatation. These findings offer valuable insights for predicting settlements, ensuring segmentand rock safety, and optimizing tunneling parameters.展开更多
Through the systematic analysis of the ground settlement generated by the process of shield tunneling,the relationships between ground deformation and construction parameters are studied in this paper.Based on the ass...Through the systematic analysis of the ground settlement generated by the process of shield tunneling,the relationships between ground deformation and construction parameters are studied in this paper.Based on the assumption of linear small deformation,a mathematical model of the relationship between ground deformation and construction parameters is set up.The principle and method of optimization for estimating ground deformation is studied.The actual measured data are compared with the results of theoretical analysis in a case.Considering different ground formations in different construction sites with different adverse effects on surface and underground structures,the ground surface deformations caused by shield tunneling is an aimed topic in this paper.The contributions and research implications are the revealed relationships between the ground deformation and the shield tunneling parameters during construction.展开更多
Formation deformation is inevitable in subway tunnel construction, and serious consequences will be caused if it is not controlled in time. Especially for shield tunnel under the condition of soft soil stratum, the st...Formation deformation is inevitable in subway tunnel construction, and serious consequences will be caused if it is not controlled in time. Especially for shield tunnel under the condition of soft soil stratum, the stratum deformation will be more complicated due to its high water content, large pore ratio, high compressibility, low strength, high sensitivity, easy thixotropy, rheology and other undesirable characteristics. Therefore, how to effectively guarantee the safety of tunnel construction in soft soil stratum has become the focus and difficulty of engineering control. Taking the large shield tunnel construction as an example, this paper analyzes the data of shield construction in soft soil stratum, and puts forward the shield tunneling construction technology and matters needing attention in similar stratum, so as to provide reference for shield construction in soft soil stratum in the future.展开更多
文摘With the rapid development of modern society and the public's demand for travel efficiency, cities around the country with the ability and conditions are building subways, but most of the subway lines in the city underground, so the construction environment is easy to be affected by geological conditions and other factors, leading to frequent safety accidents. This paper enumerates the relevant accident cases for discussion, analyzes and studies the risk sources of subway shield construction by combining the background, and puts forward relevant control measures for typical risk points, so as to provide reference for the same type of subway shield construction and promote the development of the industry.
文摘In order to study the shield construction under an existing highway,the initial displacement and the excess pore water pressure solution from Biot consolidation equation were used to derive the analytical solutions of the vertical deformation and pore water pressure of saturated soil caused by the frontal friction and side friction of the cutterhead.In addition,by introducing the layered method and combining it with other theoretical analytical equations,the expressions of total vertical deformation and total pore water pressure caused by tunnel excavation with different overlying materials were obtained.The simulation results on an engineering project showed that the angleαbetween the direction of the road and the propulsion axis of the shield had a significant influence on the surface settlement of the road.When the angleαwas increased,the settlement curve had higher variation;but the variation would not exceed the maximum settlement value above the shield axis.When the road was perpendicular to the shield axis,a critical point of the road bulging and settlement was formed above the incision.Due to the grinding resistance of the cutterhead,the pore water pressure under the roadbed was distributed asymmetrically on both sides of the shield axis.
文摘This study delves into the effects of shield tunneling in complex coastal strata, focusing on how this constructionmethod impacts surface settlement, the mechanical properties of adjacent rock, and the deformation of tunnelsegments. It investigates the impact of shield construction on surface settlement, mechanical characteristics ofnearby rock, and segment deformation in complex coastal strata susceptible to construction disturbances. Utilizingthe Fuzhou Binhai express line as a case study, we developed a comprehensive numerical model using theABAQUS finite element software. The model incorporates factors such as face force, grouting pressure, jack force,and cutterhead torque. Its accuracy is validated against field monitoring data from engineering projects. Simulationswere conducted to analyze ground settlement and mechanical changes in adjacent rock and segments acrossfive soil layers. The results indicate that disturbances are most significant near the excavation zone of the shieldmachine, with a prominent settlement trough forming and stabilizing around 2.0–3.0 D from the excavation. Theexcavation face compresses the soil, inducing lateral expansion. As grouting pressure decreases, the segmentexperiences upward buoyancy. In mixed strata, softer layers witness increased cutting, intensifying disturbancesbut reducing segment floatation. These findings offer valuable insights for predicting settlements, ensuring segmentand rock safety, and optimizing tunneling parameters.
文摘Through the systematic analysis of the ground settlement generated by the process of shield tunneling,the relationships between ground deformation and construction parameters are studied in this paper.Based on the assumption of linear small deformation,a mathematical model of the relationship between ground deformation and construction parameters is set up.The principle and method of optimization for estimating ground deformation is studied.The actual measured data are compared with the results of theoretical analysis in a case.Considering different ground formations in different construction sites with different adverse effects on surface and underground structures,the ground surface deformations caused by shield tunneling is an aimed topic in this paper.The contributions and research implications are the revealed relationships between the ground deformation and the shield tunneling parameters during construction.
文摘Formation deformation is inevitable in subway tunnel construction, and serious consequences will be caused if it is not controlled in time. Especially for shield tunnel under the condition of soft soil stratum, the stratum deformation will be more complicated due to its high water content, large pore ratio, high compressibility, low strength, high sensitivity, easy thixotropy, rheology and other undesirable characteristics. Therefore, how to effectively guarantee the safety of tunnel construction in soft soil stratum has become the focus and difficulty of engineering control. Taking the large shield tunnel construction as an example, this paper analyzes the data of shield construction in soft soil stratum, and puts forward the shield tunneling construction technology and matters needing attention in similar stratum, so as to provide reference for shield construction in soft soil stratum in the future.
