Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation...Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation of rectangular jacked pipes and the distribution of the earth pressure on jacked pipes,we present an analytical solution for predicting the vertical earth pressure on deep-buried rectangular pipe jacking tunnels,incorporating the tunnelling-induced ground loss distribution.Our proposed analytical model consists of the upper multi-layer parabolic soil arch and the lower friction arch.The key parameters(i.e.,width and height of friction arch B and height of parabolic soil arch H 1)are determined according to the existing research,and an analytical solution for K l is derived based on the distribution characteristics of the principal stress rotation angle.With consideration for the transition effect of the mechanical characteristics of the parabolic arch zone,an analytical solution for soil load transfer is derived.The prediction results of our analytical solution are compared with tests and simulation results to validate the effectiveness of the proposed analytical solution.Finally,the effects of different parameters on the soil pressure are discussed.展开更多
The first permanent magnet driven rectangular pipe jacking machine independently developed in China is used for the construction of pedestrian passage in Banxuegang Science and Technology City area of Shenzhen. The re...The first permanent magnet driven rectangular pipe jacking machine independently developed in China is used for the construction of pedestrian passage in Banxuegang Science and Technology City area of Shenzhen. The rectangular pipe jacking machine occupies a small area during the initial excavation. It is suitable for shallow soil covering and short-distance excavation. It is more economical and applicable than shield machine and has high construction efficiency. During the construction process, technical measures such as attitude measurement and adjustment of pipe jacking machine, surrounding rock grouting and friction reduction can effectively ensure the smooth construction of pipe jacking machine, and provide reference for large section pipe jacking machine in shallow soil construction.展开更多
Rectangular pipe jacking or box jacking has become more popular in municipal applications because of its better adaptability to shallow overburdens and its higher structural section utilization than the conventional c...Rectangular pipe jacking or box jacking has become more popular in municipal applications because of its better adaptability to shallow overburdens and its higher structural section utilization than the conventional circular pipe jacking.This case study presents a utility tunnel constructed by using rectangular box jacking in Suzhou,China.The utility tunnel,which has a cross section of 9.1 m in width and 5.5 m in height,was jacked 233.6 m,which is the longest known single jacking length of a rectangular box jacking project in China.The box jacking mainly passed through a silty sand layer with high groundwater levels with a minimum depth of cover of only 3.5 m underneath the Yuanhetang River.In this zone,the structures on the surface are sensitive to external disturbance,thus increasing the challenges of construction.A series of measures were taken during the jacking process,and the project was successfully completed.This paper provides an overview of this project and introduces key techniques in the construction of working shafts as well as in the installation and retrieval of the box jacking machine.In addition,the use of lubrication to reduce friction resistance,navigation and application of an anti-buoyancy slab under the Yuanhetang River,and analyses of soil deformation caused by box jacking are described.展开更多
1 Project overview The Shasan station of Phase II of Shenzhen’s urban rail transit Line 12 is situated in Bao’an District,Shenzhen.It comprises a two-level underground island platform station,measuring 212 m in leng...1 Project overview The Shasan station of Phase II of Shenzhen’s urban rail transit Line 12 is situated in Bao’an District,Shenzhen.It comprises a two-level underground island platform station,measuring 212 m in length,and 22.6 m in width,with an overburden thickness of about 7.0 m.Fig.1 illustrates the presence of a large underground reinforced concrete stormwater culvert,measuring 11.5 m by 3.6 m,traversing the station’s center.展开更多
基金Project(2022YJS073)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2024YFE0198500)supported by the National Key Research and Development Program of China:Intergovernmental International Science and Technology Innovation CooperationProject(U2469207)supported by the National Natural Science Foundation Railway Innovation and Development Joint Fund Project,China。
文摘Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation of rectangular jacked pipes and the distribution of the earth pressure on jacked pipes,we present an analytical solution for predicting the vertical earth pressure on deep-buried rectangular pipe jacking tunnels,incorporating the tunnelling-induced ground loss distribution.Our proposed analytical model consists of the upper multi-layer parabolic soil arch and the lower friction arch.The key parameters(i.e.,width and height of friction arch B and height of parabolic soil arch H 1)are determined according to the existing research,and an analytical solution for K l is derived based on the distribution characteristics of the principal stress rotation angle.With consideration for the transition effect of the mechanical characteristics of the parabolic arch zone,an analytical solution for soil load transfer is derived.The prediction results of our analytical solution are compared with tests and simulation results to validate the effectiveness of the proposed analytical solution.Finally,the effects of different parameters on the soil pressure are discussed.
文摘The first permanent magnet driven rectangular pipe jacking machine independently developed in China is used for the construction of pedestrian passage in Banxuegang Science and Technology City area of Shenzhen. The rectangular pipe jacking machine occupies a small area during the initial excavation. It is suitable for shallow soil covering and short-distance excavation. It is more economical and applicable than shield machine and has high construction efficiency. During the construction process, technical measures such as attitude measurement and adjustment of pipe jacking machine, surrounding rock grouting and friction reduction can effectively ensure the smooth construction of pipe jacking machine, and provide reference for large section pipe jacking machine in shallow soil construction.
文摘Rectangular pipe jacking or box jacking has become more popular in municipal applications because of its better adaptability to shallow overburdens and its higher structural section utilization than the conventional circular pipe jacking.This case study presents a utility tunnel constructed by using rectangular box jacking in Suzhou,China.The utility tunnel,which has a cross section of 9.1 m in width and 5.5 m in height,was jacked 233.6 m,which is the longest known single jacking length of a rectangular box jacking project in China.The box jacking mainly passed through a silty sand layer with high groundwater levels with a minimum depth of cover of only 3.5 m underneath the Yuanhetang River.In this zone,the structures on the surface are sensitive to external disturbance,thus increasing the challenges of construction.A series of measures were taken during the jacking process,and the project was successfully completed.This paper provides an overview of this project and introduces key techniques in the construction of working shafts as well as in the installation and retrieval of the box jacking machine.In addition,the use of lubrication to reduce friction resistance,navigation and application of an anti-buoyancy slab under the Yuanhetang River,and analyses of soil deformation caused by box jacking are described.
基金This engineering is a demonstration project for Key Research and Development Project of Guangdong Province under Grant No.2019B111105001part of research related to this engineering was financially supported by the project.
文摘1 Project overview The Shasan station of Phase II of Shenzhen’s urban rail transit Line 12 is situated in Bao’an District,Shenzhen.It comprises a two-level underground island platform station,measuring 212 m in length,and 22.6 m in width,with an overburden thickness of about 7.0 m.Fig.1 illustrates the presence of a large underground reinforced concrete stormwater culvert,measuring 11.5 m by 3.6 m,traversing the station’s center.
