Thermal effects on fracture toughness of cracked straight-through Brazilian disk green sandstone and granite  

作　　者：Lei Zhou Weiting Gao Liyuan Yu Zheming Zhu Jianxing Chen Xingkai Wang 

机构地区：[1]Key Laboratory of Deep Earth Science and Engineering,Ministry of Education,Sichuan University,Chengdu,610065,China [2]State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou,221116,China [3]Failure Mechanics and Engineering Disaster Prevention and Mitigation,Key Laboratory of Sichuan Province,Sichuan University,Chengdu,610065,China [4]Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province,Shaoxing University,Shaoxing,312000,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2022年第5期1447-1460,共14页岩石力学与岩土工程学报（英文版）

基　　金：funding support from the Sichuan Science and Technology Program (Grant No. 2021YJ0511);the State Key Laboratory for Geo-Mechanics and Deep Underground Engineering,China University of Mining&Technology (Grant No.SKLGDUEK2111);the Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province (Grant No. ZJRMG-2020-01)。

摘　　要：Cracked straight-through Brazilian disc(CSTBD) samples prepared using two rock materials were used for thermal treatment from room temperature to 700℃. Uniaxial splitting experiments were performed using an automatic electro-hydraulic servo press to study the evolution laws of physical and fracture properties of different deep rock materials under high-temperature geological conditions. The fracture characteristics were measured using an industrial camera and digital image correlation technology to analyze the effect of high temperature on fracture properties and failure modes of the CSTBD samples after different thermal treatments. The micro-damage properties of green sandstone and granite materials were obtained using a scanning electron microscope(SEM). The following conclusions were drawn from the test results:(1) With the increasing temperature, the fracture characteristics of green sandstone and granite change from brittle fracture to plasticity fracture, the longitudinal wave velocity of granite decreases sharply at 600℃, and the damage factor reaches 0.8748 at 700℃.(2) The fracture toughness of green sandstone and granite decreases with increasing temperature;however, the decreasing range of granite is larger than that of green sandstone.(3) As the temperature increases, the fracture morphologies of green sandstone and granite materials become rougher, whereas thermal damage cracks of granite and intergranular fractures inside sandstone as well as pores of sandstone increase.(4) The crack tip opening displacement and peak strain corresponding to peak load increase with the temperature.

关 键 词：High temperature Cracked straight-through Brazilian disc(CSTBD)sample Fracture toughnessm Scanning electron microscope(SEM) 

分 类 号：TU45[建筑科学—岩土工程]