17:15 〜 18:45
[HRE12-P04] Influences of anisotropy of rock on the development of cracks induced by hydraulic fracturing revealed by Distinct Element Method
キーワード：hydraulic fracturing, in-situ stress, anisotropy, distinct element analysis
Hydraulic fracturing (HF) is a common in-situ stress measurement method. HF enables the determination of values and directions of the horizontal maximum and minimum principal stresses. In-situ stress is a crucial parameter for the design, analysis, and excavation of underground projects, particularly major endeavors such as long tunnels, geothermal energy investigation and development, military underground bunkers, and facilities for the underground disposal of radioactive waste. The measurement and evaluation of in-situ stress represent crucial tasks during the planning and design stage. However, when dealing with geological conditions involving sheet metamorphic rocks like schist, slate, and gneiss, or sedimentary rocks with sedimentary structures such as sandstone, shale, limestone, etc., foliation and cleavage may occur. The presence of bedding planes, cracks, and joints introduces anisotropy in the mechanical properties of rocks.
When conducting hydraulic fracturing on such rock masses, it is essential to consider the influence of existing weak surfaces on the development of cracks induced by hydraulic fracturing. Therefore, this study employs distinct element analysis software, UDEC (Universal Distinct Element Code), to create a 2 × 2 m two-dimensional numerical model consisting of a total of 1690 Voronoi polygon blocks with an average size of 0.02 m. A homogeneous model and an anisotropic rock mass model with varying weak plane inclination angles (θ) and spacing (S) were established, respectively. Simulations of hydraulic fracturing were then conducted to investigate the effects of rock anisotropy on the development of cracks induced by hydraulic fracturing under horizontal maximum and minimum pressures of 2.8 and 1.12 MPa, respectively.
When conducting hydraulic fracturing on such rock masses, it is essential to consider the influence of existing weak surfaces on the development of cracks induced by hydraulic fracturing. Therefore, this study employs distinct element analysis software, UDEC (Universal Distinct Element Code), to create a 2 × 2 m two-dimensional numerical model consisting of a total of 1690 Voronoi polygon blocks with an average size of 0.02 m. A homogeneous model and an anisotropic rock mass model with varying weak plane inclination angles (θ) and spacing (S) were established, respectively. Simulations of hydraulic fracturing were then conducted to investigate the effects of rock anisotropy on the development of cracks induced by hydraulic fracturing under horizontal maximum and minimum pressures of 2.8 and 1.12 MPa, respectively.