--

11 (1) 2021

Predicting the bearing capacity of pile installed into cohesive soil concerning the spatial variability of SPT data (A case study)


Author - Affiliation:
Duong Hong Tham - Ho Chi Minh City Open University, Vietnam
Truong Nhu Manh - Ho Chi Minh City Open University, Vietnam
Corresponding author: tham.dh@ou.edu.vn
DOI:10.46223/HCMCOUJS.tech.en.11.1.1405.2021

Abstract
Nowadays, in situ tests have played a viable role in geotechnical engineering and construction technology. Besides lab tests conducted on undisturbed soil samples, many different kinds of in-situ tests were used and proved to be more efficient in foundation design such as pressuremeter PMT, cone penetration test CPT, standard SPT, etc. Among them, a standard penetration test (SPT for short) is easy to carry out at the site. For decades, it has proved reliable to sandy soil, but many viewpoints and opinions argued that the test was not appropriately applicable to cohesive soil because of scattered and dispersed data of SPT blow counts through different layers. This paper firstly studies how reliable the SPT data can predict the physical and mechanical properties; secondly, the soil strength is determined in terms of corrected N-SPT values, and finally the bearing capacity of a pile penetrating cohesion soil. By analyzing data from 40 boreholes located in 18 projects in Ho Chi Minh City, South VietNam, coefficients of determination between SPT numbers and physical and mechanical properties of different soil kinds are not the same: R2 = 0.623 for sand, =0.363 for sandy clay and =0.189 for clay. The spatial variability of soil properties is taken into account by calculating the scale of fluctuation θ=4.65m beside the statistically-based data in horizontal directions. Finally, the results from two theoretical approaches of predicting pile bearing capacity were compared to those of finite element program Plaxis 3D and static load test at site. Correlation between the capacity computed by using corrected N-values instead of soil strength and results of static load test has proved to be well suitable in evaluating the bearing capacity of driven and jack-in piles, particularly installing in the cohesive soil using the SPT blows.

Keywords
Standard Penetration Test (SPT);cohesive soil; spatial variability; variance reduction factor; the scale of fluctuation; bearing capacity of pile

Full Text:
PDF

References

Aoki, N., & Velloso, D. A. (1975). An approximate method to estimate the bearing capacity of piles. Proceedings of the Fifth Pan-American conference on soil mechanics and foundation engineering (pp. 367-376). Buenos Aires, Argentina: Sociedad Argentina de Mecanica de suelos e Ingenieria de Fundaciones.


Bazaraa, A. R., & Kurkur, M. M. (1986). N-Values used to predict settlements of piles in Egypt. Proccedings of in situ tests in Geotechnical engineering (pp. 462-474). New York, NY: American Society of Civil Engineers.


Cherubini, C., & Vessia, G. (2010). Reliability based pile design in sandy soils by CPT measurements. Georisk: Assessment and Management of Risk for Engineered Systems and Geo-hazards, 4(1), 2-12. doi:10/1080/17499510902798156


Civilblog. (2013). Correction applied to SPT value. Retrieved January 20, 2021, from https://civilblog.org/2013/05/13/correction-applied-to-spt-value


Duong, T. T. (2017). Estimating allowable bearing capacity of bored pile using Plaxis incorporated with theory of FORM reliability (Unpublished master’s thesis). Ho Chi Minh City Open University, Ho Chi Minh, Vietnam.


Hatanaka, M., & Uchida, A. (1996). Empirical correlation between penetration resistance and internal friction angle of sandy soils. Soils and Foundations, Japanese Geotechnical Society, 36(4), 1-9.


Hoang, T. Q., & Tam, N. M. (2016). Predicting bearing capacity of pile from N-SPT and method of numerical model (Unpublished master’s thesis). University of Technology, Vietnam National University, Ho Chi Minh, Vietnam.


Honjo, Y. (2011). Challenges in geotechnical reliability based design. Retrieved December 15, 2020, from https://henry.baw.de/bitstream/20.500.11970/99549/1/1_02.pdf


Kudmetha, K. K., & Dey, A. (January, 2012). Uncertainty in predicting bearing capacity of piles in sand using SPT data. Paper presented at the International symposium on engineering under uncertainty: Safety assessment and management (ISEUSAM), Howrah, India.


Kulhawy, F. H., & Mayne, P. W. (1990). Manual on estimating soil properties for foundation design. Palo Alto, California: Electric Power Research Institute.


Kulhawy, F. H., Traumann, C. H., Beech, J. F., O’Rourke, T. D., McGuire, W., Wood W. A., & Capano, C. (1983). Transmission line structure foundations for uplift-compression loading. Palo Alto, California: Electric Power Research Institute.


Luo, Z., & Juang, C. H. (2012). Efficient reliability-based design of drilled shafts in sand considering spatial variability. Journal of GeoEngineering, 7(2), 59-68.


Mahmoud, M. A. A. N. (2013). Reliability of using standard penetration test (SPT) in predicting properties of silty clay with sand soil. International Journal of Civil and Structural Engineering, 3(3), 545-556. doi:10.6088/ijcser.201203013050


Meyerhoff, G. G. (1976). Bearing capacity and settlement of pile foundation, The Eleventh Terzaghi Lecture. Journal of The Geotechnical Engineering Division, 102(3), 197-228.


Ministry of Sciences and Technology, Vietnamese Government. (2014). TCVN 10304:2014. Móng cọc - Tiêu chuẩn thiết kế [National Standard TCVN 10304:2014. Pile foundation - Design standard]. Hanoi, Vietnam: Ministry of Sciences and Technology, Vietnamese Government.


Phoon, K. K., & Kulhawy, F. H. (1999). Characterization of geotechnical variability. Canadian Geotechnical Journal, 36(4), 612-624.


Shioi, Y., & Fukui, J. (1982). Application of N-values to design of foundation in Japan. In Proceedings of the second European symposium on penetrating testing, Penetration testing 1 (pp. 159-164). Amsterdam, Netherlands: CRC Press.


Skempton, A. W. (1986). No access standard penetration test procedures and the effects in sands of overburden pressure, relative density, particle size, ageing and overconsolidation. Géotechnique, 36(3), 425-447. doi:10.1680/geot.1986.36.3.425


Truong, M. N. (2017). Assessment of reliability of N-SPT numbers in predicting the bearing capacity of precast pile installed into cohesive soil in District 1, Ho Chi Minh City (Unpublished master’s thesis). Ho Chi Minh City Open University, Ho Chi Minh, Vietnam.


Vanmarcke, E. H. (1977). Probabilistic modeling of soil properties. Journal of Geotechnical Division, ASCE, 103(11), 1227-1246.


Vanmarcke, E. H. (1983). Random fields: Analysis and synthesis. Cambridge, MA: The MIT Press.


Zekkos, D. P., Bray, J. D., & Der Kiureghian, A. (2004). Reliability of shallow foundation design using the standard penetration test. In A.V. Fonseca & P. W. Mayne (Eds), Geotechnical and geophysical site characterization (pp. 1575-1582). Porto, Portugal: Proceedings ISC-2 on geotechnical and geo-physical site characterization.



View Counter: Abstract | 2 | times
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.