文献类型：期刊文献

英文题名：Investigation of the Mechanical and Permeability Evolution Effects of High-Temperature Granite Exposed to a Rapid Cooling Shock with Liquid Nitrogen

作者：Wang, Tianzuo[1,2];Wang, Linxiang[1];Xue, Fei[1,2];Xue, Mengya[1];Xie, Hangcheng[1];Tang, Ningbo[1]

机构：[1]Shaoxing Univ, Coll Civil Engn, Key Lab Rock Mech & Geohazards Zhejiang Prov, Shaoxing 312000, Zhejiang, Peoples R China;[2]Zhejiang Collaborat Innovat Ctr Prevent & Control, Shaoxing 312000, Zhejiang, Peoples R China

年份：2021

卷号：2021

外文期刊名：GEOFLUIDS

收录：SCI-EXPANDED(收录号：WOS:000753727100005)、、Scopus(收录号：2-s2.0-85118918702)、WOS

基金：The authors would like to acknowledge the financial support for this study supported by the Second Tibetan Plateau Scientific Expedition and Research Program (grant No. 2019QZKK0904), the National Natural Science Foundation of China (grant Nos. 42007254 and 41831290), and the Natural Science Foundation of Zhejiang Province (grant No. LQ20E080006).

语种：英文

外文摘要：Liquid nitrogen (LN2), which can greatly improve the efficiency of hot dry rock (HDR) mining, is commonly used as a cooling material in the enhanced geothermal system (EGS). Physical property, triaxial compression, and permeability tests were undertaken on treated granite samples, for a better scientific understanding of the effect of the LN2 cooling method on the mechanical and permeability properties of the rocks after heat treatment. The experimental results indicated that the physical properties of the treated granite change significantly, such as the density and wave velocity are substantially reduced. Meanwhile, with the increase of treatment temperature, the macroscopic cracks on its surface are gradually generated and the volume is expanded clearly. In addition, the surface wettability of granite gradually increases with increasing temperature. Compared with the air/water cooling methods, under LN2 cooling condition, the mechanical properties decrease markedly. When the temperature exceeds 600 degrees C, the granite strength decreases significantly to only 56.16% of the reference value. The deformation properties also change significantly, with a final strain of about 3% at failure for a sample at 800 degrees C, showing an obvious ductile deformation characteristic. Further, an appreciable correlation also exists between the initial permeability of granite and temperature. Once the temperature exceeds 200 degrees C, the increase in temperature contributes to the increase in initial permeability. In addition to the effect of temperature, the increase in load also leads to a change in the permeability coefficient. When the temperature reaches 600 degrees C, the permeability of granite first decreases and then increases with the increases in axial stress. The results of this paper are valuable in understanding the effect of thermal shock by LN2 on the fracturing efficiency and permeability characteristics of dry hot rocks.