孔隙水压力对砂岩剪切力学性质及断口表面形貌影响的研究

Study on the influence of pore water pressure on shear mechanical properties and fracture surface morphology of sandstone.

作者信息

Cheng Jiaxin, Liu Yixin, Xu Chuanhua, Xu Jiang, Sun Mingzhi

机构信息

College of Safety and Environmental Engineering, Shandong University of Science and Technology, Qingdao, 266590, China.

State Key Laboratory of Mining Disaster Prevention and Control Co-Founded By Shandong Province and Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao, 266590, China.

出版信息

Sci Rep. 2024 Mar 8;14(1):5761. doi: 10.1038/s41598-024-55834-8.

DOI:10.1038/s41598-024-55834-8

PMID:38459079

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10923814/

Abstract

To further investigate the weakening effect of pore water pressure on intact rock mechanics properties and characteristics of fracture surface after failure, direct shear tests of sandstone were conducted under different pore pressure. A 3D scanner was employed to digitize the morphology of the post-shear fracture surface. The variogram function was applied to quantify the anisotropic characteristics of post-shear fracture surface. The relationship between deformation during shear failure of intact rock and quantitative parameters of fracture surface after shear failure was initially established. It can be found that amplitudes of the sinusoidal surface determine the maximum value of variogram, and period affect lag distance that reach the maximum value of variogram. Test results revealed that the increase of pore pressure has obvious weakening effect on shear strength and deformation of rock. Moreover, the increase of pore pressure makes the shear fracture surface flatter. It can be obtained that both Sill and Range are positively related to shear strain, but negatively related to normal strain.

摘要

为进一步研究孔隙水压力对完整岩石力学性质及破坏后断裂面特征的弱化作用，在不同孔隙压力下进行了砂岩的直剪试验。采用三维扫描仪对剪切后断裂面的形态进行数字化。应用变异函数量化剪切后断裂面的各向异性特征。初步建立了完整岩石剪切破坏过程中的变形与剪切破坏后断裂面定量参数之间的关系。研究发现，正弦曲面的幅值决定变异函数的最大值，周期影响变异函数达到最大值时的滞后距离。试验结果表明，孔隙压力的增加对岩石的抗剪强度和变形有明显的弱化作用。此外，孔隙压力的增加使剪切断裂面更加平整。研究得出，基台值和变程均与剪应变呈正相关，但与法向应变呈负相关。