夏开文^{1, 2}，蔡英鹏^{1, 2}，徐 颖^{1, 2}，王 帅^{1, 2}，潘永庆³
AuthorsHTML:夏开文^{1, 2}，蔡英鹏^{1, 2}，徐 颖^{1, 2}，王 帅^{1, 2}，潘永庆³
AuthorsListE:Xia Kaiwen ^{1, 2}，Cai Yingpeng ^{1, 2}，Xu Ying ^{1, 2}，Wang Shuai ^{1, 2}，Pan Yongqing³
AuthorsHTMLE:Xia Kaiwen ^{1, 2}，Cai Yingpeng ^{1, 2}，Xu Ying ^{1, 2}，Wang Shuai ^{1, 2}，Pan Yongqing³
Unit:1. 天津大学水利工程仿真与安全国家重点实验室，天津300072；
2. 天津大学建筑工程学院，天津 300350；
3. 中水东北勘测设计研究有限责任公司，长春 130021
Unit_EngLish:1. State Key Laboratory of Hydraulic Engineering Simulation and Safety，Tianjin University，Tianjin 300072，China；
2. School of Civil Engineering，Tianjin University，Tianjin 300350，China；
3. China Water Northeastern Investigation，Design and Research Corporation Limited，Changchun 130021，China
Abstract_Chinese:处于高温高地应力等复杂地质环境下的深部围岩，可能遭受爆破、地震等动态荷载影响，在岩石工程开挖区附近多导致张拉破坏，因此，研究热损伤岩石在不同地应力条件下的动态拉伸特性，在深部岩石工程中具有重要意义．选取均质细粒房山大理岩，利用自主研发的多功能分离式霍普金森压杆(SHPB)系统，进行4种温度(25℃、250℃、450℃、700℃)损伤梯度下，4种静水压环境(0MPa、5MPa、10MPa和20MPa)下，房山大理岩巴西圆盘试样动态加载试验．研究结果表明：①随着温度的增加，房山大理岩内部微裂纹增多，矿物成分由CaMg(CO₃)₂向CaCO₃和MgO转变，密度和波速均随着损伤温度的增加而逐渐降低；②静水压条件下试样拉伸应力曲线呈现为双峰特征，这主要是由于侧向围压的存在抑制了试样的劈裂，使试样拉伸破坏后继续承载造成的；③在固定围压环境下，各温度梯度下热损伤大理岩的动态拉伸强度均具有明显的率相关性；同时动态拉伸强度随着温度的升高而明显降低；④在固定温度下，围压的存在明显提高了房山大理岩动态拉伸强度，但拉伸强度的增幅随着围压的增加而减弱．此外，当试样的热处理温度超过450℃后，动态拉伸强度的围压效应小于25℃和250℃热处理情况．这可能与高温处理后的岩石在高围压状态下发生了脆性向延性转变有关．
Abstract_English:The environment of rocks in deep engineering applications is characterized by high temperatures and high in-situ stresses. During excavation，these rocks are affected by blasting，excavation unloading，earthquakes，and other dynamic loads. Therefore，understanding the dynamic tensile characteristics of thermally damaged rocks under in-situ stress conditions is crucial. In this study，Brazilian disk(BD)specimens made of homogeneous fine-grained Fangshan marble(FM) were heat-treated at various temperatures(25℃，250℃，450℃，and 700℃). Subsequently，a modified split Hopkinson pressure bar(SHPB)system with hydrostatic confinement was utilized to conduct dynamic tests on the BD specimens. Four groups of thermally damaged samples under hydrostatic confinements of 0MPa，5MPa，10MPa，and 20MPa were tested at different loading rates. The results showed the following. ①With an increase in the heat-treatment temperature，the internal microcracks in the marble increased and the mineral composition changed from CaMg(CO₃)₂ to CaCO₃ and MgO. The density and longitudinal wave velocity values of the specimens decreased owing to increases in the heat-treatment temperature. ②The tensile stress-time curves of tests with confining pressure had two peaks，whereas those of tests without confinement had only one peak. This difference is mainly caused by the existence of lateral confining pressure，which suppresses the occurrence of splitting in the specimens such that the specimens continue to bear load even after tensile fracture. ③Under a given confining pressure，the dynamic tensile strength of the thermally damaged FM specimens increased with the loading rate. Further，the dynamic tensile strength decreased with increases in the treatment temperature at a given hydrostatic confining pressure and loading rate. ④At a given treatment temperature，the dynamic tensile strength increased with the confining pressure. However，the increment of the tensile strength decreased with the hydrostatic confinement. In addition，when the heat-treatment temperature of the sample exceeded 450℃，the confining pressure effect of the dynamic tensile strength was clearly lower than those at 25℃ and 250℃. This may be due to the brittle-to-ductile transition of the rock under high confining pressure after high-temperature treatment. These results indicate the dynamic tensile failure characteristics of thermally damaged rocks under hydrostatic confinement and provide theoretical guidance for ensuring the safety of deep-rock engineering construction and disaster prevention.
Keyword_Chinese:深部岩石动力学；热损伤；动态拉伸强度；分离式霍普金森压杆；房山大理岩
Keywords_English:deep rock dynamics；thermal damage；dynamic tensile strength；split Hopkinson pressure bar (SHPB)；Fangshan marble

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