The hydro-mechanical coupling often leads to both mechanical properties and stability deterioration during excavation of water-rich tunnel rock mass. Deformation and mechanical, fracture, and strain energy characteristics of limestone from Maixi tunnel in Guiyang (China) are investigated by hydro-mechanical coupling tests in this paper. Results show that the water pressure has a significant influence on the stress-strain curve, strength characteristics, and macro-fracture degree. The compaction stage is relatively prolonged and elastic phase is shortened. With increasing water pressure, average peak strength decreases exponentially and both average elastic modulus and deformation modulus decrease linearly. The larger the water pressure, the better the fragment uniformity, and fragment uniformity increases exponentially but decreases logarithmically with peak strength. Mercury-injection curve shows a rapid increase then develops gently; the pore volume per unit mass increases exponentially revealing that water pressure has a significant effect on the dissolution pores. Strain energy dissipation characteristics show that total strain energy, dissipation strain energy, and releasable strain energy decrease exponentially with increasing water pressure. Energy ratio U_d/U_t experiences a slow increase, then dramatic rise, and finally develops gently, but U_e/U_t goes through a negative development tend and its boundary points of water pressure are both 2 MPa and 4 MPa. U_d/U_t has a typical logistic function with water pressure reflecting the damage degree and sensitivity of dissipation strain energy to water pressure.

中文翻译：

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水压耦合作用下麦溪隧道石灰岩的力学特性

在开挖富水隧道岩体的过程中，水力耦合通常会导致机械性能和稳定性下降。本文通过水力耦合试验研究了贵阳麦溪隧道石灰岩的变形，力学，断裂和应变能特征。结果表明，水压对应力-应变曲线，强度特性和宏观断裂程度有显着影响。压实阶段相对延长并且弹性相缩短。随着水压的增加，平均峰值强度呈指数下降，平均弹性模量和变形模量均呈线性下降。水压越大，碎片均匀度越好，碎片的均匀性随峰值强度呈指数增加，但对数减小。汞喷射曲线显示出快速增加，然后逐渐发展；每单位质量的孔体积呈指数增长，表明水压对溶蚀孔有显着影响。应变能耗散特性表明，总应变能，耗散应变能和可释放应变能随着水压的增加呈指数下降。能量比 可释放的应变能随水压的增加呈指数下降。能量比 可释放的应变能随水压的增加呈指数下降。能量比U _d / U _t经历缓慢的上升，然后急剧上升，最终逐渐缓和发展，但U _e / U _t经历负向发展趋势，其水压的边界点分别为2 MPa和4 MPa。U _d / U _t具有典型的逻辑函数，水压反映了损伤程度和耗散应变能对水压的敏感性。