研制小型打桩机加固运行变电站基础试验

软弱地基上变电站基础的沉降会影响电力设施的正常运行和安全,现有的加固方法和机械设备往往不能适应高压带电场区作业的技术要求。针对沿海某市海淤地基220kV变电站设备基础沉降问题,在限制安全高度2.2m、不停电的要求下,研制小型打桩机,进行了加固试验研究。研究表明:所研制的小型打桩机能够在运行变电站的限高空间中作业,突破了运行变电站不便进行基础加固打桩的禁区;所打微型钢管桩托换能够有效阻止独立基础沉降;其桩顶施加预应力的"先顶后焊"技术,能够提高加固效果。

TEST OF FOUNDATION REINFORCEMENT OF OPERATIONAL SUBSTATION BY DEVELOPING SMALL-SCALE PILE DRIVER

The settlement of the foundation on the soft ground would affect the normal operation and safety of the substation. The existing reinforcing methods and machinery can't work in the high-voltage fields. For a 220 kV substation on the sea sediment foundation in a city along the coast,Jiangsu Province,China,the settlement should be controlled at a 2. 2 m high security restrictions with the requirement of the original operation of the substation. A small-scale pile-driver was developed,and reinforcement tests were carried out. The results show that the small-scale pile driver can work well for running substation,which is a breakthrough of the reinforcement of substation foundation at the restricted space. The micro-steel pipe pile can effectively prevent the settlement of independent foundation. The technology of prestressing on the pile top,"soldering after withstand",can improve reinforcement effect.