一、前言热网是各种供热体系中的一个重要组成部分。目前它也是供热体系中的一个最薄弱环节，其保温结构不能适应复杂的湿热条件（90％以上都埋于地下）。在当前的热网建设中仍然在使用保温性能很低的保温材料，这将极大地增加维修资金，并且使热网的安全性逐年恶化。保温层中 I. INTRODUCTION Heating networks are an important part of various heating systems. At present, it is also one of the weakest links in the heating system. Its thermal insulation structure cannot adapt to the complex conditions of hot and humid (over 90% are buried underground). In the current heating network construction, insulation materials with very low thermal insulation properties are still being used, which will greatly increase the maintenance funds and deteriorate the safety of the heating network year by year. Insulation layer