输电线路塔基卸荷损伤砂岩循环加卸载特性研究  

Study on cyclic loading and unloading characteristics of sandstone damaged by unloading in transmission line tower ground

作　　者：赵延辉 郑武略 张恒宾 王瑞显 陈浩[1] Zhao Yanhui;Zheng Wulue;Zhang Hengbin;Wang Ruixian;Chen Hao(Guangzhou Bureau EHV Power Transmission Company of CSG,Guangzhou 510405,China;College of Civil Engineering&Architecture,China Three Gorges University,Yichang 443000,China)

机构地区：[1]中国南方电网超高压输电公司广州局,广州510405 [2]三峡大学土木与建筑学院,湖北宜昌443000

出　　处：《工程勘察》2025年第5期14-20,共7页Geotechnical Investigation & Surveying

基　　金：湖北省自然科学基金(2022CFB345);三峡大学学位论文培优基金(2020BSPY006)。

摘　　要：输电线路杆塔地基土失稳已成为影响高压输电线路正常运行的关键因素之一。为揭示三峡库区输电线路塔基砂岩在卸荷条件下经循环加卸载损伤劣化的力学行为,开展砂岩常规三轴压缩试验、卸荷损伤砂岩循环加卸载试验,探究循环加卸载作用下砂岩耗散能的演化特征,并基于此提出损伤变量。研究结果表明:砂岩在不同应力路径下展现为脆性破坏,以剪切破坏为主。随循环次数增加,卸荷损伤加剧,导致弹性模量与变形模量显著降低。初期循环抑制裂隙发展,但随耗散能密度增大,承载能力下降。高卸荷量加速裂隙扩展,引起大变形,围压卸荷成为破坏主导因素。试验结果有助于深入理解循环荷载作用下岩石力学行为及破裂演化的规律,可为三峡库区输电线路塔基砂岩在应力扰动和卸载围压作用下的结构长期稳定性提供必要的理论依据。The instability of transmission line tower ground soil has become one of the key factors affecting the normal operation of high-voltage transmission lines.To reveal the mechanical behavior of sandstone in the tower ground of transmission lines in the Three Gorges Reservoir area under cyclic loading and unloading damage degradation under unloading conditions,conventional triaxial compression tests,cyclic loading and unloading tests of sandstone with unloading damage were conducted to explore the evolution characteristics of dissipated energy of sandstone under cyclic loading and unloading,and based on this,damage variables were proposed.The results of the study show that sandstone exhibits brittle damage under different stress paths,dominated by shear damage.The unloading damage increases with the increase of cycling,leading to a significant decrease in the modulus of elasticity and deformation modulus.Initial cycling suppresses the development of cracks,but the bearing capacity decreases with the increase of dissipated energy density.High unloading quantity accelerates the crack extension,causes large deformation,and the peripheral pressure unloading becomes the dominant damage factor.The test results contribute to an in-depth understanding of the effects of rock mechanical behavior and fracture evolution under cyclic loading,and can provide the necessary theoretical basis for the long-term stability of the transmission line tower base sandstone in Three Gorges Reservoir Area under stress disturbance and unloading of the surrounding pressure.

关 键 词：卸荷损伤 循环加卸载 耗散能密度 损伤变量 

分 类 号：TU45[建筑科学—岩土工程]