杆塔基础邻侧土洞发育诱发应力场及其对基础稳定性的影响

The stress induced by soil cave development adjacent to tower foundation and its effect on foundation stability

高压输电杆塔在施工过程中一般会对杆塔基础底部土层进行处理,却往往容易忽略杆塔基础底部邻侧潜在土洞发育造成的威胁。鉴于此,建立最不利因素下的简化理论计算模型,推导了岩溶土洞发育对邻侧输电杆塔基础底部产生的诱发应力,继而通过参数分析讨论了土洞位置以及土洞的发育特征对杆塔底部地基诱发应力场的影响规律。在此基础上,结合鄂西某工程实例,采用FLAC3D有限元软件分析了杆塔地基邻侧下卧土洞在不断发育扩大的过程中对500kV输电杆塔稳定性的影响。在计算分析时通过监测地基周围土的应力状态和变形情况,得到了距离杆塔底部侧向不同位置处对应的土洞发育半径的最大允许值。研究成果可为岩溶地质区域输电杆塔安全运营和灾害评估提供参考。

In the construction process of high voltage transmission tower,the soil layer at the bottom of the tower foundation is usually treated,but the threat caused by the development of potential soil caves on the adjacent side is often ignored.In view of this,a simplified theoretical calculation model under the most unfavorable factors is established in this paper,the induced stress caused by the development of soil cave on the tower foundation is deduced,and then the law of the influence of the location and development characteristics of soil cave on the induced stress field is discussed through parameter analysis.On this basis,combined with a project in western Hubei,FLAC3D finite element software is used to analyze the influence of the underground cave on the 500 kV transmission tower in the process of continuous development and expansion.The stress state and deformation of the soil around the foundation are monitored during the calculation and analysis,and the maximum allowable value of the development radius of the soil cavity at different locations is obtained.This study can provide references for safe operation of transmission tower and possible disaster assessment in karst geological region.