Taking the carbonaceous phyllite as investigative subject, which is the weak layer widely distributed in Yunfu pyrite, Guangdong province, the deformation characteristics and strength properties of the carbonaceous phyllite rock mass are analyzed through laboratory uniaxial and triaxial compression tests. Based on the tests on natural and saturated carbonaceous phyllite, the elastic constitutive equations of the carbonaceous phyllite, considering the closing of micro cracks, are established; and the deformation characteristics and strength properties of water-weakening influence is analyzed. Through the tests, the deformation characteristics and strength properties of the carbonaceous phyllite are further understood, which can give some advices to the design of rock slope containing weak layers of the carbonaceous phyllite.
Master the rock mass characteristics is the basis of geotechnical design and stability evaluation. Many scholars do quite a lot of research work in rock mechanics properties and deformation characteristics, and achieved certain results[1–9].
Water on rock physics, chemical reactions lead to the variation of the nature of the rock mechanics. Therefore, the study of deformation and strength property under the action of water-rock interaction, and making qualitative and quantitative analysis and evaluation of rock mass have a very important role of the research on the basic mechanical properties and stability analysis of rock mass. Currently, the strength of rock mass often be used to be the standard of stability evaluation and design. However, in practical engineering, deformation of a lot of rock mass(especially soft rock) tend to be the determinants of the stability of the construction projects.
The carbonaceous phyllite, which is a standard soft rock and has a tendency to split into sheets, has a good fissility and will form under low grade metamorphic conditions. As soft rock, the engineering geological characteristics of the carbonaceous phyllite is complex, especially water-weakening properties have a great influence on construction projects. The research on the Engineering geological characteristics and water-weakening properties of the soft rock has had many achievements [10–12]. Deformation properties of the carbonaceous phyllite are also crucial for the project construction. During the slope excavation of Yunfu pyrite, the instability and destruction mostly due to the large rock mass deformation.