Innovative loading system for applying internal pressure to a test model of pre-stressed concrete lining in pressure tunnels

摘要

Pre-stressed linings are often used in tunnels subjected to internal water pressure. Model tests are important for the better understanding of their performance. We present an innovative loading system to apply internal pressure on such linings. The loading system consists of flat jacks inside the pre-stressed lining. The flat jacks are cushions of steel membrane. Uniform pressure can be generated by inflating the steel cushions against the pre-stressed lining and an inner lining. The inner lining serves as a reaction buttress. The design principles and manufacture details of this system are discussed in this paper. And its performance is demonstrated by some test results.