Target Reliability Based Design of Foundations on Jointed Rock Masses with Two Sets of Discontinuities
Publication: IFCEE 2021
ABSTRACT
Jointed rock mass is inherently heterogeneous because of the presence of discontinuities. The discontinuities may occur in the form of joints, faults, and fissures. The variability of engineering properties of jointed rock mass depends on geometrical shapes due to past geological processes. The spatial arrangement, surface roughness, number, length, orientation, and inter-connectivity of discontinuities may play a significant role in an accurate prediction of jointed rock mass strength. The jointed rock mass strength is pivotal for the safe and economical design of strip foundations in rock engineering. The reliability method used in this work provides a more rational approach over the conventional factor of safety approach by accounting for the variability of properties of the jointed rock mass. A reliability based optimization of foundations built on jointed rocks with two discontinuity sets is presented to compute the optimum value of the allowable bearing capacity of strip footings. The discontinuity strength model along with the modified Bell approach is adopted to determine the ultimate bearing capacity. Reliability analysis is conducted by treating uniaxial compressive strength of intact rock, discontinuity cohesion, discontinuity orientation, joint spacing, rock material frictional angle, and discontinuity frictional angle as random variables. The effects of orientation on the allowable bearing capacity are presented for the target probability of failure of 0.13%.
Get full access to this article
View all available purchase options and get full access to this chapter.
REFERENCES
Akram, M., and Bakar, M. Z. A. (2007). “Correlation between uniaxial compressive strength and point load index for salt-range rocks.”, Pak. J. Engg. & Appl. Sci. Vol. 1, 1-8.
Basha, B. M., and Babu, G. L. S. (2010). “Optimum design for external seismic stability of geosynthetic reinforced soil walls: A Reliability Based Approach.” J. Geotechnical & Geoenv. Engrg., Vol. 136 (6): 797-812.
Basha, B. M., Chandrakanth, K., and Moghal, A. A. B. (2016). Lower bound bearing capacity of strip footings on jointed rock masses: a reliability-based approach. In: Fourth Geo-China International Conference, July 25–27, 2016, Shandong, China, ASCE Geotechnical Special Publication: 267: 67-74.
Basha, B. M., Chandrakanth, K., and Moghal, A. A. B. (2015). Allowable bearing capacity of strip footings on jointed rock masses: a reliability based approach. In Proc. International Foundations Congress and Equipment Expo 2015, San Antonio, Texas. 2015, March 17–21, 1-10.
Bell, A. L. (1915). “Lateral pressure & resistance of clay, and supporting power of clay foundations.” Minutes of Proc. of Institution of Civil Engineers: Vol. 199, 233-336.
Kahraman, S. (2001). “Evaluation of simple methods for assessing the uniaxial compressive strength of rock”, Int. J. of Rock Mech. & Mining Sciences, Vol. 38:981–994.
Kulhawy, F. H., and Goodman, R. E. (1980). “Design of foundations on discontinuous rock.” In Proc. Int. Conf. Structural Foundations on Rock, Sydney, 209–220.
Singh, M., and Rao, K. S. (2004). “Bearing Capacity of Shallow Foundations in Anisotropic Non-Hoek–Brown Rock Masses.”, J. Geotechnical & Geoenv. Engrg., Vol. 131:1014-1023.
Mao, N., Al-Bittar, T., and Soubra, A. H. (2012). “Probabilistic analysis and design of strip foundations resting on rocks obeying Hoek–Brown failure criterion.”, Int. J. Rock Mechanics & Mining Sciences, Vol. 49: 45–58.
Naghibi, F., and Fenton, G. A. (2017). “Target geotechnical reliability foundations systems.” Canadian Geotechnical Journal, 54: 945-952.
Ramamurthy, T., and Arora, V. K. (1994). “Strength prediction for jointed rocks in confined and unconfined states.” Int. J. Rock Mechanics Mining Sciences Geomechanics Abstracts, Vol. 31 (1): 9–22.
Ruffolo, R. M., and Shakoor, A. (2009). “Variability of unconfined compressive strength in relation to number of test samples.”, Engrg. Geology, Vol.108:16–23.
Prakoso, W. A., and Kulhawy, F. H. (2004). “Bearing Capacity of Strip Footings on Jointed Rock Masses.”, J. Geotechnical & Geoenv. Engrg., Vol. 30:1347-1349.
U.S. Army Corps of Engineers. (1997). Engineering and design: Introduction to probability and reliability methods for use in geotechnical engineering, U.S. Dept. of the Army, Washington, DC.
Information & Authors
Information
Published In
IFCEE 2021
Pages: 388 - 396
Copyright
© 2021 American Society of Civil Engineers.
History
Published online: May 6, 2021
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.