为解决二次衬砌脱空的问题，实现在浇筑过程中对衬砌脱空的主动监测，结合隧道二次衬砌衬背脱空的成因，研发基于分布式压密传感器的隧道衬砌脱空主动监测系统。该系统由分布式压密传感带、延长线、直显终端及工业电脑组成，具有原理简单、安装便捷等优点。通过在衬砌层间预埋分布式压密传感器，对浇筑过程进行主动监测，结合带模注浆技术，实现对衬砌脱空的精准注浆与快速处治，有效解决隧道衬砌脱空问题。在验证试验中，系统在浇筑过程中共发现2处拱顶空洞，证明该系统对脱空监测的有效性。同时，该系统在国内部分重点铁路线已经取得应用，现场应用情况表明，该系统对二次衬砌拱顶脱空的识别准确率可达到95.5%。

In order to solve the problem of secondary lining void and to realize the active monitoring of lining void during casting process, a active monitoring system for lining void prevention based on the distributed compaction sensor is independently developed considering the causes of tunnel lining void. The system consists of distributed compact sensing belt, extension line, direct display terminal and industrial computer with the advantages of simple principle and convenient installation. It is proposed that by embedding distributed compaction sensors among lining layers, active monitoring of lining compactness can be realized during casting. In this way, cavities can be found and grouted not only quickly but also accurately with mould grouting technology, which effectively solve the problem of tunnel lining void. In the validation test, the system identified two vault holes during the casting process, which proved the effectiveness of the system for void monitoring. At present, the system has been applied in some key railway lines in China. The accuracy rate of identification of secondary lining vault void reaches 95.5%.