摘要
了解岩石力学性质对非常规油气藏的开发具有重要意义。然而，大量的层理使得岩石力学规律模糊不清。为了研究层理性质对岩石单轴力学性质的影响，基于连续-不连续方法建立了含层理煤模型，研究了层理角度、层理强度、层理数目和加载速率对岩石单轴力学性质的影响。详细分析和讨论了断裂形态、应力应变演化、峰值应力和断裂程度。通过与室内试验的对比，验证了本文数值模型的可靠性。结果表明，顺层角为0°时，岩石的应力峰值最大，为8.16mpa；顺层角为90°时，岩石的断裂程度最大，为3.74%。对于不同的层理强度，峰值应力首先随着层理强度的降低而线性减小。层理强度小于0.5mpa时，峰值应力变化不大。岩石破裂程度随顺层强度的增加呈非线性增长。对于不同层理数，层理活化与层理数无关。加载速度对岩石力学性质也有很大影响。随着加载速率的增加，层理活化难度逐渐增大，裂缝复杂性逐渐增大。本研究旨在进一步加深对层理性质对岩石单轴力学性质影响的认识。
Abstract
Understanding the mechanical properties of rock is of great significance for the development of unconventional reservoirs. However, a large number of bedding makes the mechanical laws of rock unclear. To investigate the effect of bedding properties on the uniaxial mechanical properties of rock, the coal model containing bedding is developed based on the continuous–discontinuous method, and the effect of bedding angle, bedding strength, bedding number, and loading rate on the uniaxial mechanical properties of rock is investigated. The failure morphology, stress–strain evolution, peak stress, and fracture degrees are analyzed and discussed in detail. The reliability of the numerical model in this paper has been verified by comparison with the indoor experiments. The results show that when the bedding angle is 0°, the peak stress of the rock is maximum, 8.16 MPa, and when the bedding angle is 90°, the fracture degree of the rock is maximum, 3.74%. For the different bedding strengths, the peak stress first decreases linearly with the decrease of the bedding strength. The peak stress barely varies when the bedding strength is less than 0.5 MPa. The fracture degree of the rock shows a nonlinear increase with the increase in bedding strength. For different bedding numbers, the activation of the bedding is not related to the bedding number. The loading speed also has a great influence on the mechanical properties of rock. With the increase in loading rate, the difficulty of bedding activation gradually increases, and the complexity of fractures gradually increases. This study aims to further improve the understanding of the effect of bedding properties on the uniaxial mechanical properties of rock.
NETL
NSTL
Wiley