Experimental Investigation on Fracture Evolution in Sandstone Containing an Intersecting Hole under Compression Using DIC Technique

Abstract

Failure of underground structures, especially intersections, becomes more severe as the depth increases, which poses a new challenge for the safe construction and operation of deep rock engineering. To investigate the mechanical properties and fracture behavior of rock with an intersecting hole under compressive loads, a series of uniaxial compression tests was carried out on cuboid red sandstone specimens containing an intersecting hole with three types of shapes by digital image correlation (DIC) technique. The results showed that the existing hole inside specimens leads to almost a 50% reduction of mechanical parameters from that of intact ones, and this weakening effect is associated with the shapes of holes. Failure of specimens is a progressive process in which cracks, i.e., primary tensile cracks, secondary tensile cracks, and shear cracks, initiate from stress concentration zones, propagate along certain direction, and coalesce with each other into macrofractures. Both the real-time principal strain fields and horizontal displacement fields of specimens under compression could be visually displayed by DIC system, and they were in good consistency in characterizing the fracture behavior. Moreover, the propagation characteristics of primary tensile cracks were studied further by quantitatively analyzing the strain variation during the loading process, and the propagation mechanism of “open-close-reopen” of primary tensile cracks was explained in detail.

Progressive Failure and Acoustic Emission Characteristics of Red Sandstone with Different Geometry Parallel Cracks under Uniaxial Compression Loading

“…Zhang and Zhao [15] studied the fracture toughness and failure micromechanisms of marble under different loading rates. Yang et al [16] and Wu et al [17] investigated the crack propagation of sandstone with oval flaws and a single hole under the uniaxial loading. Xu et al [18] analyzed the compression-shear behaviors of brittle rocks under the static-dynamic loading by lab tests and numerical modeling.…”

Prediction of Fracture Damage of Sandstone Using Digital Image Correlation

“…As one typical type of sedimentary rock, often consisting of sand-scale mineral particles (e.g., quartz, feldspar), sandstone has long been used as a functional construction material in various project types of pavements, hydraulic systems, warehouses, and underground structures for structural purposes in diverse agricultural and industrial sectors [1][2][3][4]. The failure mechanism and pattern of sandstone imposes an important role on the safe construction and operation of pertinent structures.…”

“…Significant research efforts were committed to understanding and profiling mechanical behavior, material properties, and failure modes of sandstone through various methods, techniques, and tools, e.g., multi-scale analysis, digital image correlation technique, strain gage method, three-point bending test, and empirical simulation in [2,4,[8][9][10]. Traditional engineering measurement methods for motions and strains were often criticized for their limitations in real applications due to their underlying deficiencies resulting from contacting and localized operations [11].…”

“…In their study, the applicability of DIC to substitute for traditional strain measurement methods for Brazilian testing process was demonstrated. To support the applications of rock and sandstone materials in secure underground construction, Wu et al [4] performed uniaxial compression tests to understand the mechanical behavior of holed sandstone using the DIC method. Compared to the intact specimens, those artificially holed ones show almost half of the expected mechanical performance depending on hole shapes.…”

Application of Improved Single‐Hole Superposition Theory in Nonequal Cross‐Section Tunnel Intersection

“…erefore, numerical simulation data are used to evaluate the roof support plan, and the method of rock reinforcement is used to improve the roof support around the intersection according to his conclusion. Hao Wu et al [9] conducted a series of uniaxial compression tests on rocks with intersecting holes to simulate rocks with deep underground structures. Based on the test results, they figured out how the prefabricated cavity affects the mechanical properties of the specimen.…”