岩溶土(暗)洞对临近高压输电杆塔基础安全影响

土洞是覆盖型岩溶区一种隐伏的不良地质现象。输电线路在经过岩溶地质区域时,岩溶暗(土)洞的存在会对邻近的杆塔基础安全产生威胁,严重时使得输电杆塔产生倾斜甚至倾覆。以湖北省恩施-水布垭输电线路为工程背景,采用ABAQUS有限元软件,分析了土洞的尺寸、覆盖层厚度以及土洞与输电杆塔的相对位置对500 k V输电杆塔的影响。以正常使用极限状态下地基倾斜限制值为安全控制指标,得到了保证该输电杆塔基础安全的不同尺寸土洞的洞顶位置安全影响线,并且采用该影响线对某实际案例进行验证。该方法可为类似地质条件下输电工程选线、输电杆塔基础设计以及地基处理提供参考。本文模拟研究对邻近岩溶土洞输电杆塔安全评价及灾害处理有着重要的指导意义。

Effects of Karst Soil Cavity on Foundation Safety of Adjacent High Voltage Transmission Tower

Soil cavity is a kind of hidden bad geological phenomenon in the overlying karst area.When the transmission line passes through the karst geological region, the existence of karst soil cavity will threaten the foundation safety of the adjacent tower. In serious cases, the tower will tilt or even overturn.Taking the Enshi-Shuibuya transmission line in Hubei province as the project background, this paper uses the finite element software Abaqus to analyze the influence of the size of soil cavity, the thickness of overburden and the relative position of soil cavity on the 500KV transmission tower.Taking the limit value of foundation inclination under normal service limit as the safety control index, the influence line of roof position safety of soil holes of different sizes to ensure the safety of the transmission tower foundation was obtained, and the influence line was used to verify a practical case.This method can provide reference for transmission line selection, transmission tower foundation design and foundation treatment under similar geological conditions.The simulation study in this paper has important guiding significance for the safety evaluation and disaster treatment of power transmission tower near karst cave.