为了测定原生层理构造引起各向异性对无烟煤断裂韧度和断裂过程区(FPZ)孕育特性的影响，在MTS液压伺服试验系统上对不同层理倾角直切槽半圆弯曲(NSCB)无烟煤试样进行了I型三点弯曲加载试验。结合数字图像相关法(DICM)和声发射(AE)定位技术研究了裂纹尖端FPZ孕育过程。同时，基于Irwin-Bazant模型、Strip-yield均匀牵引模型和Strip-yield线性牵引模型，对无烟煤样完全发育FPZ长度进行预测，并与试验结果进行了对比分析。探讨了各向异性无烟煤FPZ几何形态以及不同层理角度无烟煤FPZ孕育过程中剪切和拉伸变形时序特征。结果表明：无烟煤的峰值载荷、峰值位移和断裂韧度均随层理倾角的增加而增大；与0°层理角度煤样相比，层理角度为22.5°、45.0°、67.5°和90.0°的煤样平均断裂韧度分别增大了6.76%、86.82%、85.47%和134.46%。Irwin-Bazant模型和Strip-yield均匀牵引模型预测的不同层理角度试样FPZ长度比试验值更短，而Strip-yield线性牵引模型预测值普遍高于试验值，Strip-yield均匀牵引模型对无烟煤FPZ长度预测与试验值最为接近。表明无烟煤试样裂纹尖端黏聚力分布形态更加趋于均匀。无烟煤试样FPZ长度(L)与断裂韧度(K_IC)和抗拉强度(σ_t)比值的平方成正比：L∝(K_IC/σ_t)²。裂纹尖端变形以拉伸为主，剪切为辅，拉伸变形起始时刻的范围分布于峰值载荷的27.71%～57.26%，剪切变形起始时刻的范围分布于峰值载荷的72.88%～92.40%，裂纹尖端的拉伸变形发生时刻优先于剪切变形。层理角度为0°和45°试样各环向测量线上的应变场分布呈类似洋葱切面纹理分布，而90°试样的最大主应变监测值在大部分测量角度呈波动无序分布。无烟煤试样FPZ尖端各方向发散测线上，应变增加梯度并不相同。研究成果有助于进一步理解掌握含层理弱面无烟煤裂纹起裂与扩展机制，为煤层压裂增透缝网改造调控方法提供理论指导。

In order to determine the influence of anisotropy induced by primary bedding structure on fracture toughness and fracture process zone (FPZ) incubation characteristics of anthracite, the notched semi-circular bending (NSCB) anthracite samples with different bedding angles were subjected to the mode I three-point bending loading test on the MTS hydraulic servo test system. The incubation process of FPZ at crack tip was monitored by the digital image correlation method (DICM) combined with the acoustic emission (AE) localization technique. Based on the Irwin-Bazant model, the Strip-yield uniform traction model and the Strip-yield linear traction model, the fully developed FPZ length of anthracite samples were predicted and compared with the experimental results. The geometric morphology of anisotropic anthracite FPZ and the shear and tensile deformation time series of anthracite FPZ during its incubation at different bedding angles were discussed. The results show that the peak load, peak displacement and fracture toughness of anthracite increase with the increase of bedding inclination. Compared with the coal samples with the bedding angle of 0°, the average fracture toughness of the coal samples with the bedding angle of 22.5°, 45.0°, 67.5° and 90.0° increases by 6.76%, 86.82%, 85.47% and 134.46%, respectively. The FPZ length predicted by the Irwin-Bazant model and the Strip-yield uniform traction model is shorter than the test value, while the prediction of the Strip-yield linear traction model is generally higher than the test value. The estimation of FPZ length of anthracite by the Strip-yield uniform traction model is most close to the experimental value, indicating that the distribution of the cohesive force at the crack tip of the anthracite sample tends to be more uniform. The FPZ length of anthracite sample is proportional to the square of the ratio of fracture toughness and tensile strength: L∝(K_IC/σ_t)². The prefabricated crack tip deformation of the sample is dominated by tensile deformation and assisted by shear. The tensile deformation ranges from 27.71% to 57.26% P_max, and the shear deformation ranges from 72.88% to 92.4% P_max. The time of tensile deformation of the crack tip is superior to that of shear deformation. The strain field distribution on the circumferential measuring lines of the samples with the bedding angle of 0° and 45° is similar to the texture distribution of onion cross section, while the maximum principal strain monitoring value of the samples with the bedding angle of 90° shows a fluctuation and disordered distribution at most measuring angles. The strain gradient of anthracite sample is different on the divergence line of FPZ tip in each direction. The research results are helpful to further understand the crack initiation and propagation mechanism of weak surface anthracite with bedding, and provide theoretical guidance for the control method of anti-reflection fracture network of coal seams.