Schematic study on temperature control and crack prevention during spillway tunnel concreting period

摘要

Spillway tunnel is regarded as hydraulic thin-slab concrete structure which is subject to easy cracking. Temperature stress during construction period is a major reason causing cracking, and selection of timely and reasonable temperature control schemes can result in good crack prevention effect. The researches have shown that a method combining internal water pipe cooling and surface heat preservation is an effective measure that is able to prevent such cracking, and the selection of heat preservation timing and cooling method of internal water pipe will be the major factor influencing temperature control effect. Aiming at this issue, based on certain spillway tunnel and by virtue of 3D finite elements and water pipe cooling calculation method, simulated calculations and analyses on concrete temperature field and stress field of different temperature control schemes are carried out, and the temperature control effects are brought to comparison. Selected results indicate that good temperature control effect can be obtained under timely and reasonable surface heat preservation and water-flow method. This type of method has reference values on similar projects.