裂隙几何特征对岩石强度影响模拟实验研究

Simulation experiment study on the effect of fracture geometry on rock strength

为探究裂隙几何特征(倾角、长度、位置)的综合作用对岩石峰值强度的影响,对含单裂隙岩石进行单轴压缩的数值模拟实验,分析裂隙倾角、长度、位置对岩石强度特性和破裂特征的影响,同时基于多元逐步回归分析,将三者对岩石峰值强度的影响性进行评价。结果表明:倾角对新生裂纹的起裂位置与起裂时间作用明显,长度与岩石的完整性与稳定程度具有相关性,位置影响裂纹扩展规模和岩石破坏形态;裂隙倾角、长度与位置对岩石峰值强度的影响程度在不同区间内有所差异,从整体来看,由于位置影响因子较小被作为无关变量剔除,在小于45°区间内,对岩石峰值强度的影响程度大小为长度>倾角>位置,长度与倾角的影响因子为0.82、0.36,在大于45°区间内,对岩石峰值强度的影响程度大小为倾角>长度>位置,长度与倾角的影响因子为0.344、0.866,同时,建立的逐步回归模型可以有效评价岩石强度,对岩石初始损伤判定具有一定参考价值。

In order to explore the influence of the comprehensive effects on fracture inclination,length and location distribution on the peak strength of rock,the numerical simulation experiment of uniaxial compression on rock containing single fracture is made.In this experiment,the influence of fracture inclination,length and position on rock strength and fracture characteristics were analysed.This article also use the multiple stepwise regression analysis to evaluate the influence of the three factors on the peak strength of rock.The results show that the fracture inclination has an obvious effect on the crack initiation position and time of the new crack,the length is correlated with the rock integrity and stability,and the location affects the crack growth scale and rock failure form.The influence of fracture inclination,length and position on rock peak strength varies in different intervals.Because of the position influence factor is small,it is eliminated as an irrelevant variable.On the whole,in less than 45°interval,the influence degree of the peak strength of rock size for length>inclination>position,length and inclination of impact factor of 0.82 and 0.36;in more than 45°interval,the influence degree of the peak strength of rock size of inclination>length>position,length and inclination of impact factor of 0.344 and 0.866.Meanwhile,the stepwise regression model can be used to evaluate the strength of rock and has some reference value for determining the initial damage of rock.