Welcome to Francis Academic Press

Academic Journal of Architecture and Geotechnical Engineering, 2021, 3(1); doi: 10.25236/AJAGE.2021.030102.

Formation mechanism of hexagonal structure of basalt columnar joints based on Mechanics of Materials and infinitesimal method


Zirong Wang1, Siyun Zhou2

Corresponding Author:
Zirong Wang

1School of Reliability and System Engineering, Beihang University, Beijing, China

2School of Physics, Beihang University, Beijing, China


The perfect hexagon showed by columnar jointed basalt gets great public appeal. However, the accurate illustration was not given. A new explanation, which has rigid calculation, is proposed here for their origin. With the cooling of basalt, the distribution of stress changes while the normal stress equal to the tensile strength of basalt. Using an equation as τθf, where τθ is the force tangentially acting on the unit shear boundaries and τf represents the shear strength of basalt, to indicate the condition of the shear fracture. The result of numerical calculation shows that cleavages appear at angles of ±59.53° with the σ1, which effectively illustrate why the columnar jointed occur in conjugate pairs with ~120° angle between cleavages. The angle depends on the internal friction angle, the cohesive force, the tensile strength and Poisson’s ratio of basalt. Other factors on the sides and diameter of columnar jointed, such as the velocity of cooling and components of magma, will be deeply researched in our future work.


columnar jointed basalt, the internal friction angle, the cohesive force, the tensile strength, Poisson’s ratio, the percentage composition of quartz

Cite This Paper

Zirong Wang, Siyun Zhou. Formation mechanism of hexagonal structure of basalt columnar joints based on Mechanics of Materials and infinitesimal method. Academic Journal of Architecture and Geotechnical Engineering (2021) Vol. 3, Issue 1: 7-13. https://doi.org/10.25236/AJAGE.2021.030102.


[1] J. C. Phillips, M. C. S. Humphreys, K. A. Daniels, R. J. Brown, F. Witham. The formation of columnar joints produced by cooling in basalt at Staffa, Scotland. Bulletin of Volcanology, 2013, Vol.75 (6), pp.1-17.

[2] Quanhai Li, Huan Zhang. A preliminary study on the characteristics and genesis of columnar joint group in Hua'ao Island, Xiangshan County [J]. Resources, Environment and Engineering, 2013, 27(05): 640-642 655.

[3] Shiming Fang, Jiangfeng Li, Shiliang Wu, Guo Xu. Geogenetic significance of hexagonal columnar joint structure of large-scale acidic volcanic rocks in Hong Kong, China [J]. Marine Science, 2011, 35(05): 89-94.

[4] Hailong Zhang, Chenglu Hao, Hongju Hao. Characteristics of columnar joints and comprehensive evaluation of volcanic rocks in Xiangzhide, Duran, Qinghai Province [J]. China Metal Bulletin, 2018(08): 284-286.

[5] Jianli Sui. The genetic mechanism of basalt columnar joints——local Bernard convection model [C]. China mineral rock geochemistry society. Abstract of the 15th Annual Conference of the Chinese Society of Mineral Rock Geochemistry (1). China Mineral Rock Geochemistry Society: China Mineral Rock Geochemistry Society, 2015: 159.

[6] Chunsheng Zhang, Yongsheng Zhu, Weijiang Chu, Ning Liu. Mechanical Properties and Hoek-Brown Constitutive Model of Cryptographic basalt in Baihetan Hydropower Station [J]. Journal of Rock Mechanics and Engineering, 2019, 38(10): 1964-1978.

[7] Yadong Zheng, Tao Wang, Mingbo Ma, Gregory. A. Davis. Maximum effective moment criterion and the origin of low-angle normal faults [J]. Journal of Structural Geology, 2004, 26(2).

[8] Xiangguo Kong. Comparative Analysis of Effective Stress and Total Stress Strength and Its Indexes[J]. Western Prospecting Works, 2005(05): 33-34.

[9] Xingfen Ming, Xiaodong Ming. Experimental Study on Damage Effect of the Mechanical Properties of rock in High Temperature Environment [J]. Mining Research and Development, 2017, 37(05): 40-43.

[10] Quan Jiang, Xia-ting Feng, Yossef H. Hatzor, Xian-jie Hao, Shao-jun Li. Mechanical anisotropy of columnar jointed basalts: An example from the Baihetan hydropower station, China. Engineering Geology 175 (2014) 35-45.