Wang Chun, Li Xin-Ru, Xie Mei-Zhi, Xiong Zu-Qiang, Wang Cheng, Wang Huai-Bin, Zhan Shuai-Fei, Hu Ya-Chao
School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo, 454000, Henan, China.
Guangxi Key Laboratory of Disaster Prevention and Engineering Safety, Guangxi University, Nanning, 530029, Guangxi, China.
Sci Rep. 2021 Mar 15;11(1):5927. doi: 10.1038/s41598-021-85314-2.
Based on the engineering environment where rocks surrounding wellbores in energy storage areas are influenced by high temperature, cool and hot water, thermal stress etc. in the exploitation of hydrothermally geothermal energy, the experimental study on mechanical properties of ring granite under the static and dynamic loads in the water-heat condition was performed. The experimental results showed that when the ring granite was influenced by the inner diameters, heating temperatures, curing temperatures and heat recovery cycle times, the impact load-strain curves were nonlinear. However, the concave stages, platform stages and cliff-like drop stages appeared in the load-strain curves under the static loads. The radical peak loads decreased exponentially with the growth of the damage factors and the dynamic peak loads were far greater than the static peak loads. By analyzing the damage cracks and broken fragments, it was found that under the static and dynamic radical loads, the cracks generated in the ring specimens were tensile cracks and the failure mode was tensile failure. However, the dynamic failure was more aggressive than the static failure. Then, the apparent deformation modulus was defined to describe the deformation characteristics of ring granite before the radical peak loads. And it is found that the variation law of dynamic apparent deformation modulus is more dispersed than the changes of static apparent deformation modulus. Finally, based on the deformation and failure characteristics of ring granite obtained from the tests, the static and dynamic failure criteria considering whether the cracks along the loading direction were generated in the inner ring wall were deduced and verified by the corresponding tests.
基于储能区井筒围岩在高温、冷水热水、热应力等影响下的工程环境，在水热型地热能开发中，开展了水热条件下环形花岗岩在静动荷载作用下力学性能的试验研究。试验结果表明，环形花岗岩受内径、加热温度、养护温度和热回收循环次数影响时，冲击荷载-应变曲线呈非线性。然而，在静荷载作用下，荷载-应变曲线出现凹阶段、平台阶段和悬崖状下降阶段。径向峰值荷载随损伤因子的增加呈指数下降，动态峰值荷载远大于静态峰值荷载。通过分析损伤裂纹和破碎碎片发现，在静动径向荷载作用下，环形试件产生的裂纹为拉伸裂纹，破坏模式为拉伸破坏。然而，动态破坏比静态破坏更剧烈。然后，定义了表观变形模量来描述环形花岗岩在径向峰值荷载之前的变形特性。发现动态表观变形模量的变化规律比静态表观变形模量的变化更离散。最后，根据试验得到的环形花岗岩的变形和破坏特性，推导了考虑内环壁是否产生沿加载方向裂纹的静动破坏准则，并通过相应试验进行了验证。
