Meso-mechanical anisotropy and fracture evolution of reef limestones from the Maldives Islands and the South China Sea  

作　　者：Lihui Li Chenglong Li Beixiu Huang Jianguang Li Shouding Li Xiao Li 

机构地区：[1]Key Laboratory of Shale Gas and Geoengineering,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing,100029,China [2]Innovation Academy for Earth Science,Chinese Academy of Sciences,Beijing,100029,China [3]College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing,100049,China [4]College of Geoscience and Surveying Engineering,China University of Mining and Technology,Beijing,100083,China [5]AVIC Institute of Geotechnical Engineering Co.,Ltd.,Beijing,100098,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2023年第12期3173-3187,共15页岩石力学与岩土工程学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.41977248 and 42207219);the Key Research Program of the Institute of Geology and Geophysics,Chinese Academy of Sciences(CAS)(Grant No.IGGCAS-201903).

摘　　要：Reef limestone is a biogenic sedimentary rock widely distributed in coral reef areas, acting as an important foundation for coast construction. Due to its special biogenic origin, reef limestone is different from conventional rocks both in terms of rock structure and mechanical properties. In this study, mesoscale uniaxial compression experiments with five different loading directions were conducted on two kinds of reef limestones from the Maldives Islands and the South China Sea, respectively. The real-time high-resolution videos and images of failure processes were recorded simultaneously to investigate the fracture evolution and fracture surface roughness of reef limestones. It demonstrated that the reef limestones belonged to extremely soft to soft rocks, and their uniaxial compressive strength (UCS) values fluctuated with high discreteness. The mesoscale mechanical properties of reef limestones were highly anisotropic and mainly controlled by pore structure. The occurrence of dissolution pores in reef limestone tended to intensify mechanical anisotropy. With the integration of the fracture initiation and propagation features of reef limestones, it is supposed that the intrinsic mechanism of anisotropy was probably attributed to the differences in coral growth direction and dissolution. Furthermore, the quantified fracture surface roughness was revealed to have a good consistency with density and UCS for the reef limestones from the South China Sea. The findings are helpful for providing theoretical and experimental references for engineering construction in coral reef areas.

关 键 词：Reef limestone Mechanical anisotropy Failure mode Pore structure Fracture surface roughness 

分 类 号：TU45[建筑科学—岩土工程]