scholarly journals Analysis of Ground Movement during Large-Scale Pipe Roof Installation and Artificial Ground Freezing of Gongbei Tunnel

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xiao-qi Zhou ◽  
Jian-li Pan ◽  
Yang Liu ◽  
Cai-cheng Yu
Keyword(s):  
Large Scale ◽  
Volume Ratio ◽  
Frozen Soil ◽  
Ground Movement ◽  
Frost Heave ◽  
Ground Settlement ◽  
Soil Thickness ◽  
Ground Freezing ◽  
Artificial Ground Freezing ◽  
Ground Heave

This paper analyzes the vertical ground movement during large-scale pipe roof installation and artificial ground freezing of Gongbei tunnel of the Hong Kong-Zhuhai-Macau bridge project. The transverse ground settlement during pipe roof installation is analyzed. The ground loss volume ratio and settlement trough width coefficient during pipe jacking are estimated based on the field measurement of ground settlement. The interaction of pipes during multiple jacking is investigated. The effect of frost heave control by pregrouting, limiting frozen soil thickness, and combination of the two methods is evaluated. The analysis shows that the ground settlement during pipe roof installation by jacking 37 pieces of 1620 mm steel pipes is relatively small with a maximum value of 2.2 cm. The reinforcement to ground provided by the fore-jacked pipes reduces the ground loss volume ratio and, consequently, the ground settlement during the follow-up pipe jacking. The artificial ground freezing generates a relatively large ground heave with a maximum value of 7.8 cm. Pregrouting plays a critical role in the frost heave control by reducing the heave by about 33%. Limiting the frozen soil thickness by heating pipes serves as an effective supplement to frost heave control by reducing the heave by about 9%. The combination of the two measures reduces the ground heave by about 42%. Findings from this paper provide valuable reference to the tunnel construction using pipe roof and artificial ground freezing as presupport.

Properties of Frozen Soils for Cross Passage Construction in Line 1 and 2 of Wuxi Metro

2013 ◽  
Vol 353-356 ◽  
pp. 1662-1665 ◽  
Author(s):  
Xiang Dong Hu ◽  
Yan Guang Han
Keyword(s):  
Mechanical Properties ◽  
Laboratory Tests ◽  
Freezing Point ◽  
Frozen Soil ◽  
Frost Heave ◽  
Soil Test ◽  
Frozen Soils ◽  
Freezing Method ◽  
Ground Freezing ◽  
Artificial Ground Freezing

Artificial ground freezing method (AGF) was applied in cross passage constructing of line 1 and 2 of Wuxi Metro. Mechanical properties of frozen soils such as uniaxial compressive strength, modulus of elasticity, Poissons Ratio, frost heave rate and freezing point are prerequisite for design and construction of AGF. In order to obtain the parameters mentioned, laboratory tests were conducted. One was the basic geotechnical test. Another was the frozen soil test.

Ice lens formation at a silt–sand interface

1995 ◽  
Vol 32 (3) ◽  
pp. 488-495 ◽  
Author(s):  
Sharon L. Smith ◽  
Peter J. Williams
Keyword(s):  
Soil Structure ◽  
Frozen Soil ◽  
Frost Heave ◽  
Controlled Environment ◽  
Freezing And Thawing ◽  
Ground Freezing ◽  
Residual Deformations ◽  
Cumulative Residual ◽  
Lens Formation ◽  
Soil Interface

A major experiment simulating ground freezing around a buried chilled pipeline in a controlled-environment facility provided an opportunity to examine the form and orientation of ice lenses associated with a vertical interface between silt and sand. The heave of the silt decreased towards the interface and ice lenses in the silt were found to dip at an increasing angle in the same direction. Consideration of the thermal regime suggests that the direction of heat flow influences the orientation of the lenses. The interface was irregular and ice lenses at the lower part of the interface were closely aligned to it, indicating that changes in soil texture also influence ice lens orientation. Deformation of ice lenses appears to have occurred in the silt near to the interface. The arrangement of the lenses can be explained by the different thermal properties and thermodynamic behaviour of the two materials and by the mechanical "anchorage" of the sand in which there is no ice lens formation. Cycles of freezing and thawing modify soil structure and produce cumulative residual deformations which are modified by a soil interface. Key words : frost heave, ice lenses, frozen soil, vertical silt–sand interface, chilled pipeline, differential heave.

scholarly journals In situ monitoring of frost heave pressure during cross passage construction using ground-freezing method

2016 ◽  
Vol 53 (3) ◽  
pp. 530-539 ◽  
Author(s):  
Lei Han ◽  
Guan-lin Ye ◽  
Yuan-hai Li ◽  
Xiao-he Xia ◽  
Jian-hua Wang
Keyword(s):  
Pressure Gauge ◽  
Earth Pressure ◽  
In Situ Monitoring ◽  
Frost Heave ◽  
Freezing Process ◽  
Groundwater Levels ◽  
Freezing Method ◽  
Ground Freezing ◽  
Artificial Ground Freezing

The artificial ground-freezing method has the dual effect of ground reinforcement and waterproof sealing, and the frozen curtain can be designed flexibly. It is widely used in the construction of cross passages for shield tunnels in soft ground with high groundwater levels. However, due to the lack of in situ monitoring data, it remains difficult to determine the frost heave pressure acting upon a tunnel. In this study, based on the use of an anti-freezing pad-type earth pressure gauge, in situ monitoring was carried out to measure the frost heave pressure acting upon tunnel segments during the construction of cross passages for the Shanghai Yangtze River Tunnel. The monitoring results show that the earth pressure acting upon the tunnel could decrease dramatically during freezing, and this kind of decrease can take place suddenly and unpredictably, which can be illustrated using the finite element method. The maximum measured frost heave pressure during freezing and cross passage excavation was approximately 0.2 MPa, which was much smaller than the predicted value. Combining the distribution of temperature in the ground and construction countermeasures, the observed phenomena are mainly related to three factors: water migration during the freezing process, the tunnel–ground interaction, and the countermeasure of pressure release holes. The tunnel showed a horizontal extension–deformation, which was consistent with the releasing frost heave pressure acting upon it.

Study on Site Measurement of Freezing Soft Aquifer in Cretaceous Strata

2013 ◽  
Vol 774-776 ◽  
pp. 771-774
Author(s):  
Tie Qi Zheng ◽  
Hua Jun Xue ◽  
Jun Chen ◽  
Ming Nan Ji ◽  
Zeng Lin Zhen
Keyword(s):  
Frozen Soil ◽  
Operating Conditions ◽  
Freezing Process ◽  
Refrigeration System ◽  
Ground Freezing ◽  
Complex Process ◽  
Geological Conditions ◽  
Efficient Construction ◽  
Artificial Ground Freezing ◽  
System Operating

Artificial ground freezing is a time-varying dynamic and complex process. Traits of the frozen soil wall are influenced by the refrigeration system operating conditions, geological conditions, boundary cooling, construction conditions and many other factors. Nature of the frozen soil and the structural state of the frozen soil wall is a function of temperature, yet the temperature field of the frozen soil wall is changing with time. Further, it has a bad influence on the buildings nearby when Frost-heaving and Thawing-settlement happened during freezing process. it will be necessary to comprehend their real-time settlement and deformation as well as to keep sure the frozen soil wall and the buildings nearby are on regular service. The Lindong mine wellbore is located in the Cretaceous Stratum. A information technology of freezing construction method is used to ensure the safe and efficient construction of the wellbore. It made a great contribution to the lingdong mine yielding and other similar projects.

Sign in / Sign up

Export Citation Format

Share Document