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ArticleName Normal contact forces in jacking of casings under conditions of their floating-up and sticking
DOI 10.17580/gzh.2021.07.07
ArticleAuthor Shornikov I. I.

College of Mining, NUST MIS IS, Moscow, Russia:

I. I. Shornikov, Associate Professor, Candidate of Engineering Sciences,


Trenchless technologies are commonly used in the collector tunnel construction in the world. The most advanced technology in this regard is microtunneling/casing jacking—when casing pipes are forced in ground using bentonite slurry to reduce friction and to make soil mass stable. Two phenomena are possible in this case: floating-up of the casing and its sticking under differential pressure. Tunneling in water-saturated ground necessitates prediction of jacking forces. Here, it is critical to determine resistance to the casing moving off from the rest. To this effect, tangential forces along the casing–soil contact are analyzed, as a rule. The main characteristics are usually the contact area in the roof of the underground opening and the normal force distribution along the casing. The estimation procedure uses three parameters: flexural stiffness of casing, soil hardness and construction clearance. This article offers a model representation of joint casing–soil deformation under conditions of floating-up and sticking of the casing in the roof of the opening under the action of differential pressure. The system of ordinary differential equations describing the casing behavior in the zones of contact and no-contact with soil is obtained and solved. The analytical solution is used to determine the contact zone size and to estimate the normal contact forces. The contact zone sizes versus reduced floating-up lengths of casing and soil hardness in the actual value range are plotted. It is found that the contact zone sizes grow when casing length is within the typical floating-up inflexion length and drop when casing length is 5–10 typical inflexion lengths with respect to soil hardness. In a general case, the contact zone size increases with decreasing flexural stiffness of casing and hardness of soil. The normal contact force distribution has a shape of a hip roof and features higher concentration at the end points of the contact zone in soil of higher hardness. The research results can be used to improve the model of casing breakaway in order to have more accurate estimates of jacking forces.

keywords Casing, jacking, casing floating-up, sticking, contact forces, typical inflexion length in floating-up, typical inflexion length versus soil hardness, casing breakaway, Winkler model

1. Thomson J. C. Pipejacking and Microtunnelling. Boston : Springer, 1993. 273 p.
2. Sterling R. L. Developments and research directions in pipe jacking and microtunneling. Underground Space. 2020. Vol. 5, Iss. 1. pp. 1–19.
3. Praetorius S., Schößer B. Bentonite Handbook: Lubrication for Pipe Jacking. Berlin : Ernst & Sohn, 2017. 228 p.
4. O’Dwyer K. G., McCabe B. A., Sheil B. B. Interpretation of pipe-jacking and lubrication records for drives in silty soil. Underground Space. 2020. Vol. 5, Iss. 3. pp. 199–209.
5. CI/ASCE 36-01. Standard Construction Guidelines for Microtunneling. ASCE Standard. Reston : American Society of Civil Engineers, 2001. 41 p.
6. DWA-A 125E. Pipe Jacking and Related Techniques. Hennef : DWA German Association for Water, Wastewater and Waste-Heuss-Allee, 2010. 69 s.
7. An introduction to pipe jacking and microtunnelling. London : Pipe Jacking Association, 2017. 23 p.
8. STO NOSTROY 2.27.124–2013. Micro-tunneling. Performance regulations, control and standards. Moscow : BST, 2015. 93 p.
9. Cherepanov G. P. The contact problem of the mathematical theory of elasticity with stick and slip areas. The theory of rolling and tribology. Journal of Applied Mathematics and Mechanics. 2015. Vol. 79, Iss. 1. pp. 81–101.
10. Shornikov I. I. Estimation of jacking forces on casings in microtunneling. Gornyi Zhurnal. 2020. No. 2. pp. 45–50. DOI: 10.17580/gzh.2020.02.05
11. Andrusenko E. N., Gulyaev V. I., Shlyun N. V. Critical states of drill strings in the channels of inclined boreholes. Mechanics of Solids. 2016. Vol. 51, No. 2. pp. 234–243.
12. Salikhov I. F. Calculation in well downforce and experimental substantiation of its influence on the friction between the casing and drill pipes in environment the various mud fluid. Neftegazovoe delo. 2016. No. 1. pp. 39–51.
13. Neskoromnykh V. V., Petenev P. G. Results of theoretical and skilled works on studying the mechanism of operation of boring configurations with a displaced cross section mass center. Izvestiya Tomskogo politekhnicheskogo universiteta. Inzhiniring georesursov. 2016. Vol. 327, No. 5. pp. 75–86.
14. Rabotnov Yu. N. Mechanics of deformable solid : tutorial. 2nd revised edition. Moscow : Nauka, 1988. 711 p.
15. Robert D. J., Thusyanthan N. I. Uplift Resistance of Buri ed Pipelines in Partially Saturated Sands. Computers and Geotechnics. 2018. Vol. 97. pp. 7–19.
16. Johnson K. L. Contact Mechanics. Cambridge : Cambridge University Press, 1985. 452 p.
17. Kulikova E. Yu., Shornikov I. I. Justification of driving forces in micro-tunneling. Gornyi Zhurnal. 2020. No. 5. pp. 15–19. DOI: 10.17580/gzh.2020.05.02
18. Katz S., Givli S. The Postbuckling Behavior of Planar Elastica Constrained by a Deformable Wall. Journal of Applied Mechanics. 2017. Vol. 84, Iss. 5. 051001. DOI: 10.1115/1.4036018
19. Mazein S. V. Researches of a raising of liner block rings at tunnel shield driving. Transportnoe stroitelstvo. 2009. No. 3. pp. 25–28.

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