青藏联网工程冻土地基装配式基础载荷试验研究

Loading Test of the Assembly Foundation in Frozen Soil of the Qinghai-Tibet AC and DC Interconnection Project

为评价青藏交直流联网工程冻土地基杆塔基础稳定性,进行了粗粒冻土地基装配式真型基础在竖向上拔与水平荷载或下压与水平荷载共同作用下的载荷试验,试验基础施工采取与工程基础尺寸、施工工艺和时期一致的原则,根据试验结果,分析了基础极限及破坏状态,研究了荷载与位移关系曲线特征及承载特性,求得试验基础的承载能力及"土重法"上拔角等设计参数的取值。试验研究结果表明,试验荷载作用下粗粒冻土装配式基础因水平位移过大而失稳,荷载与位移关系曲线表现为非陡降型,活动层冻结状态时地基强度及基础承载性能优于融化状态,粗粒冻土地基上拔角大于13°,装配式基础承载力满足设计要求。

To analyze the safety and stability of tower foundation for the Qinghai-Tibet AC and DC Network Project,loading tests were carried out on an assembly prototype foundations in the frozen soil under vertical and horizontal loads in the Tibetan Plateau Wudaoliang area.The principle adopted for the prototype test was to keep consistence between the prototype test and the tower foundation construction in foundation dimensions,construction technique and construction time.According to the test results,the limit and destruction state of the foundation were analyzed,and the characteristics of load vs.displacement curves and the bearing properties were studied.The bearing capacity of the test foundations and uplift angle value were obtained.The test results show that the assembly foundations in coarse-grained frozen soil failed in stability due to large horizontal displacement under test loads,and the load vs.displacement curves are of non-steep-drop type,and the soil strength and foundation's bearing capacity with the active zone in frozen state are better than that with the active zone in melt state,and uplift angle of coarse-grained soil is greater than 13 degrees,and bearing capacity of assembly foundation meets the design requirements.