Steel sleeve receiving key technologies for large diameter slurry shield in water-rich silty-fine sand stratum

2021 ◽  
Author(s):  
zheng li ◽  
jun wang cao ◽  
feilei zhang
Keyword(s):  
Large Diameter ◽  
Fine Sand ◽  
Key Technologies ◽  
Sand Stratum ◽  
Steel Sleeve ◽  
Slurry Shield

scholarly journals Risk Analysis and Control Measures for Slurry Shield Tunneling Diagonally under an Urban River Embankment

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yu Liang ◽  
Xiangyu Chen ◽  
Junsheng Yang ◽  
Linchong Huang
Keyword(s):  
Large Diameter ◽  
Fine Sand ◽  
Urban River ◽  
Control Measures ◽  
Additional Stress ◽  
Shield Tunneling ◽  
Cross River ◽  
Sand Stratum ◽  
Slurry Shield ◽  
River Embankment

The construction of urban cross-river tunnels usually requires passing under river embankments, which inevitably disturbs the embankment substratum and causes ground deformation. Previous engineering cases have shown that embankment settlement is greater than ordinary surface settlement and that uneven settlement results in cracks of in the embankment, reducing the embankment stability. Based on a cross-river tunnel project in China, the construction risks caused by the additional stress on the embankment substratum, asymmetrical embankment load, and shield tunneling in saturated fine sand are analyzed during a large-diameter slurry shield tunneling below an urban river embankment diagonally. Additionally, relevant risk control measures, such as slurry pressure, jacking thrust setting, and driving velocity in the saturated fine sand stratum, are evaluated. The results show that during shield tunneling under a diagonal urban river embankment, the additional stress and asymmetrical load effects should be considered, and the shield slurry pressure and jacking thrust should be adjusted according to the distance between the cutter head and the embankment. Furthermore, based on settlement monitoring data, the driving velocity of the shield should be reasonably adjusted in a timely manner to avoid disturbing the fine sand stratum below the embankment.

Research on key technologies for steel sleeve launching of large diameter slurry shield

2021 ◽  
Author(s):  
ming pang ◽  
meng yang ◽  
jingtao yu ◽  
feilei zhang
Keyword(s):  
Large Diameter ◽  
Key Technologies ◽  
Steel Sleeve ◽  
Slurry Shield

Study on Microfine Cement Grouting Material for Silty Fine Sand Stratum

2013 ◽  
Vol 838-841 ◽  
pp. 1457-1462
Author(s):  
Chun Lei Xia ◽  
Ying Ye ◽  
Guan Ming Wang ◽  
Li Cui
Keyword(s):  
Portland Cement ◽  
Particle Diameter ◽  
Fine Sand ◽  
Cement Grouting ◽  
Grouting Material ◽  
Soluble Glass ◽  
Microfine Cement ◽  
Sand Flow ◽  
Sand Stratum ◽  
Grouting Materials

Silty fine sand is the second smallest sand with a particle diameter ranging from 0.0625 to 0.120 mm.This kind of sand exists in a large amount in Beijing subway excavation project. Due to the poor self-stabilization of this stratum,seeping , sand flow and collapse take place frequently. Grouting materials such as Portland cement and soluble glass (also called sodium silicate) are employed in most of excavation projects to reinforce this sand stratum. However, the reinforcement is not effective, leading to a large amount of accidents in the process of construction. The reason may be attributed to the fact that Portland cement is unable to penetrate into the stratum and the strength of soluble glass (0.6MPa) is too weak to resist the stratum pressure. To solve this problem, a modified microfine cement grouting material able to penetrate into silty fine sand stratum is developed in this paper. A combination of suspension and diluent is used to increase the penetration extension of the grouts,and the experimental results reveal that the addition of the mixture of suspension and diluent in microfine cement grouting materials improves the penetration property substantially.

Experiment of Slurry Shield Tunnel Recycling Waste Sand in Sand-Pebble Layer

2014 ◽  
Vol 919-921 ◽  
pp. 1104-1109
Author(s):  
Chen Rui Pang ◽  
Xin Wen
Keyword(s):  
Fine Sand ◽  
The Other ◽  
Shield Tunnel ◽  
Tunnel Construction ◽  
Sand Layer ◽  
Large Space ◽  
City Environment ◽  
Slurry Shield ◽  
Sand Source ◽  
Waste Soil

Waste soil progressing in shield tunnel construction should occupy large space, on the other hand, do harm to city environment. If the waste sand in silt and fine sand layer can be used as sand source of synchronous grouting, it will bring benefits for the enterprise and society. In indoor experiment, we select waste sand in different layers, sieved as sand source, then use the waste sand to produce slurry and compare their strength with the construction slurry’s. The study found, sieved waste sand in silt and fine sand layer can be used as sand source for making synchronous grouting slurry.

scholarly journals Realization of Super-Large-Diameter Slurry Shield Passing through Settlement-Sensitive Area Based on Unreinforced Disturbance Control Technology

2022 ◽  
Vol 2022 ◽  
pp. 1-9
Author(s):  
Dongshuang Liu ◽  
Xinrong Liu ◽  
Zuliang Zhong ◽  
Yafeng Han ◽  
Fei Xiong ◽  
...  
Keyword(s):  
Water Pressure ◽  
Large Diameter ◽  
High Density ◽  
Control Technology ◽  
Construction Process ◽  
Sensitive Areas ◽  
Excavation Process ◽  
Complex Construction ◽  
Slurry Shield ◽  
Subway Tunnels

Due to the complex construction conditions of shield tunnels, ground disturbance is inevitable during the construction process, which leads to surface settlement and, in serious cases, damage to surrounding buildings (structures). Therefore, it is especially important to effectively control the constructive settlement of subway tunnels when crossing settlement-sensitive areas such as high-density shantytowns. Based on the project of Wuhan Metro Line 8 Phase I, the shield of Huangpu Road Station-Xujiapang Road Station interval crossing high-density shantytowns, we study the disturbance control technology of oversized diameter mud and water shield crossing unreinforced settlement-sensitive areas during the construction process. By optimizing the excavation parameters and evaluating the ground buildings, the excavation process can be monitored at the same time, and the water pressure, speed, and tool torque required during the excavation during the construction process can be finely adjusted; the control of tunneling process parameters can provide reference and basis for analyzing the construction control of large-diameter shield through old shantytowns.

scholarly journals Experimental Study on the Formation and Characteristics of Mud Filtration Cake in Large-Diameter Slurry Shield Tunneling

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Lei Kou ◽  
Jinjie Zhao ◽  
Fanglei Lian ◽  
Ronghu Miao
Keyword(s):  
Fractal Dimension ◽  
Large Diameter ◽  
Test Results ◽  
Shield Tunneling ◽  
Mud Cake ◽  
Filtration Loss ◽  
Pore Area ◽  
Mud Filtration ◽  
Slurry Shield ◽  
Penetration Tests

Multiple soil layers may be exposed simultaneously on the excavated surface of a large-diameter slurry shield. To study the formation and characteristics of mud filtration cake on the excavation surface during large-diameter slurry shield tunneling, penetration tests of mud slurries in different soils were carried out using a self-made device, and the microstructures of different mud filtration cakes were observed using scanning electron microscopy. The test results showed that there were three categories of filling forms for mud slurries permeating the soils: mud filtration cake, mud cake + permeation zone, and permeation zone; correspondingly, there were three types of filtration loss, which was mainly affected by the specific gravity of mud slurry. Finally, the porosity and the fractal dimension for the pore area of the mud filtration cake were calculated, and it is found that the fractal dimension of pore area is beneficial to classify the type of mud filtration cake.

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