Methodology for evaluating the bearing capacity of a deep excavation barrette in complex geotechnical conditions in Hanoi

Introduction. At present, the rate of growth in the development of urbanisation processes in large cities is increasing rapidly every year. At the stage of preliminary design of pile foundations, an important part is to determine the bearing capacity of the pile. Barrettes are effective foundation structures, also for high-rise buildings on soft soils. In such conditions, long barrettes are designed. At the same time the used normative methods used of calculating the bearing capacity and settlement do not take into account the features of the stress-strain state of the foundation and the interaction with barrettes in the foundations of high-rise buildings with a developed underground part.

Materials and methods. The task has been considered on the basis of the results of field testing with piles (static load method) with the calculation by the analytical method according to the strength characteristics of the soil foundation, described in the regulatory documents SP 24.13330.2011 “Pile Foundations”. A new calculation method is proposed, which is set out in Appendix D of the specified set o.rules, taking into account relevant factors, such as the relative position of piles in the ground, their length, pitch, etc.

Results. A graph of the dependence of settlement on load was obtained based on the results of full-scale tests of barrettes with a limiting settlement of 40 mm. Analytical results are compared with field testing of a pile in difficult engineering and geological conditions in Hanoi, Vietnam.

Conclusions. The conclusions obtained by the analytical method of calculating the bearing capacity of a single barrette in terms of strength characteristics, taking into account unloading on soft soils during the development of a deep pit, are quite close to the results of static field tests. These solutions can be applied to determine the bearing capacity of piles and barrettes on soft soils.

1. Hung Huu Dam. Settlement and bearing capacity of barrettes and barret foundations, taking into account elastic-viscous and elastic-plastic properties of soils : dissertations for the degree of candidate of technical sciences. Moscow, 2023; 152. (rus.).

2. Shulyatiev O.A., Dzagov A.M., Minakov D.K. Changes in stress-strained soil mass resulting from the installation of bored cast-in-situ piles and barrettes. Bulletin of Science and Research Center of Construction. 2022; 34(3):26-44. DOI: 10.37538/2224-9494-2022-3(34)-26-44 (rus.).

3. Ter-Martirosyan Z.G., Ter-Martirosyan A.Z., Hung Huu Dam. Interaction between a barrette and multilayered surrounding and underlying soils, taking into account their elastic and elastic-viscoplastic properties. Vestnik MGSU [Monthly Journal on Construction and Architecture]. 2022; 17(9):1135-1144. DOI: 10.22227/1997-0935.2022.9.1135-1144 (rus.)

4. Mangushev R., Nikitina N., Van Chong Le, Tereshchenko I. Numerical assessment of carrying capacity and analysis of pilot barett behavior in geological conditions of Vietnam. International Journal for Computational Civil and Structural Engineering. 2022; 18(1):119-128. DOI: 10.22337/2587-9618-2022-18-1-119-128

5. Makovetsky O.A., Zuev S.S. Field testing of long barrettes in conditions of dense urban development. Zhilishchnoe Stroitel’stvo (Housing Construction). 2018; 9:13-18. (rus.).

6. Sidorov V.V., Stepanishchev K.I. Study of interaction between barrettes and soil base considering their sizes and shapes. Bulletin of Perm National Research Poly­technic University. Construction and Architecture. 2017; 3:78-88. DOI: 10.15593/2224-9826/2017.3.09 (rus.).

7. Nguyen T.D., Lai V.Q., Phung D.L., Phan T.P. Shaft resistance of shaft-grouted bored piles and barrettes recently constructed in Ho Chi Minh City. Geotechnical Engineering Journal of the SEAGS & AGSSEA. 2019; 50(3):155-162.

8. Nguyen H.М., Fellenius B.H., Puppala A., Pedarla A., Tran Q.T. Bidirectional tests on two shaft-grouted barrette piles in Mekong Delta, Vietnam. Geotechnical Engineering Journal of the SEAGS & AGSSEA. 2016; 47(1):15-25.

9. Mangushev R., Nikitina N., Le Trung Hieu, Tereshchenko I. Analytical and numerical methods for determining the bearing capacity of barret piles on soft soils in deep pits. International journal for the calculation of civil and building structures (IJCCSE journal). 2021; 17(3):94-101. DOI: 10.22337/2587-9618-2021-17-3-94-101

10. Mangushev R.A., Nikitina N. Bearing capacity of deep pile foundation for high-rise facility on weak soils: comparing of analysis results and experimental data. International Journal of Civil and Structural Analy­sis (IJCCSE journal). 2019; 15(1):90-97. DOI: 10.22337/2587-9618-2019-15-1-90-97

11. Shulyatiev O.A. Basic principles of calculation and design of slab and pile foundations for high-rise buildings : dissertations for the degree of Doctor of Technical Sciences. Moscow, 2019; 352. (rus.).

12. Le M.C. Analysis effective of shaft grouting method for Barrette pile capacity base on the O-cell load test. 2018; 82-86.

13. Le T.H. To the question of the methodology for assessing the bearing capacity of barrettes in soft soils in the development of deep pits (on the example of Hanoi). Actual problems of modern science: the view of the young : Proceedings of the XI All-Russian (National) Scientific and Practical Conference. D.V. Valko, A.M. Romodina (Ed.). Chelyabinsk, South Ural Technological University, 2022; 965-974. URL: https://www.elibrary.ru/item.asp?id=48745364&pff=1 (rus.).

14. Prokopov A.Yu., Nguyen V.N., Chan D.Ch. Comparative analysis of piles of various designs in engineering and geological conditions of Hanoi (Vietnam). 2016; 6. URL: http://www.rusnauka.com/11_DN_2016/Stroitelstvo/3_210440.doc.htm (rus.).

15. Nguyen V.H., Nikiforova N.S. Taking into account the peculiarities of engineering and geological conditions in the development of the underground space of Vietnam. Geotechnical engineering surveys, design and construction of foundations, foundations and underground structures : proceedings of the All-Russian Scientific and Technical Conference on Geotechnics (St. Petersburg. SPBGASU, February 1-3, 2017). St. Petersburg, 2017; 277-281. (rus.).

16. Pham T.T.D. A study on bearing capacity of shaft — grouted bored piles and barrettes for high-rise in Ho Chi Minh city : Master’s thesis. Hanoi, 2021; 48.

17. Kharin Yu.I. Choosing the best options for pile foundations in the coastal areas of Vietnam and Tunisia. Science Prospects. 2020; 5(128):58-61. URL: https://www.elibrary.ru/item.asp?id=43858773 (rus.).

18. Strokova L.A., Phi H.T. Features of the engineering and geological conditions of Hanoi (Vietnam) : monograph. Tomsk, Publishing House of Tomsk Polytechnic University, 2013; 335. (rus.).

19. Thien D.Q. Địa chất công trình việt nam: Engineering geology of Vietnam : Lectures for students of the faculties of geology and geotechnics. Vietnam, Vietnam, 2014; 148.

20. Dao S.D. The assessment of building danmage degree due to deep excavations in Hanoi. Geotechnical. 2017; 1:36-43.

21. Tereshchenko I.Yu. Stress-strain state of the soil mass during the construction of buildings by the semi-closed method (Top-Down) : final qualification work for the competition of a master’s degree. Moscow, 2021; 89. (rus.).

22. Le Van Trong. Bearing capacity of deep bored piles. Vestnik Grazhdanskikh Inzhenerov/Bulletin of Civil Engineers. 2020; 3(80):116-126. DOI: 10.23968/1999-5571-2020-17-3-116-126 (rus.).