Mechanical Property Research on the Water Pressure Test for a Prestressed Precast Concrete Segmental Lining

摘要

The traditional shield construction technology has many defects, such as intensive labor in the process of assembling segments, high cost of the bolts, cannot stand inner water pressure directly and so on, so the shield tunnel cannot be applied in the field of tunnels rapidly that can stand inner water pressure. In recent years, post-tensioned pre-stress technology of concrete has been introduced in the production of shield tunneling segments and the assembly of segments at home and abroad, which extend the shield tunnels application in hydraulic field. Based on the literatures and the existent researches, the paper takes the formation of a region in Beijing as the engineering background. Firstly, according to the load-structure method, the probability-based limit state design and the concept of prestressing degree, prestressed & precast concrete segments had been designed for a water conveyance tunnel. Secondly, in reference to the prestressing technology of domestic tunnel standing inner water pressure, a encircled anchorage technology was chose to use, meanwhile, in order to reduce the testing cost, these existing segment moulds were transformed to produce these segments to meet the testing requirements. Thirdly, it was the first time to carry out the water pressure test for a full-scale and horizontal model of prestressed & precast concrete segmental lining in China, the results were satisfactory and could meet the design requirements. In the end, the mechanical properties of prestressed & precast concrete segmental lining at 0.5 MPa inner water pressure were analyzed by the three-dimensional finite element method, the theoretical results approached the full-scale experimental results. Some promising research results were obtained.