Abstract:Multiple joints such as fault F13 developed in K1 350～400 of a diversion tunnel of hydropower station in the southwest, which was deep-buried with high crustal stress and complex geological conditions. Using three-dimensional discrete element software 3DEC, the numerical simulation on the diversion tunnel is conducted combining with field monitoring data to analyze the stability of surrounding rock. The results show that the stability of surrounding rock is mainly controlled by the structural plane. There are many fall-blocks at the lower right spandrel with larger displacement. After being supported, the surrounding rock stability of the diversion tunnel is strengthened.

Abstract:The diversion tunnel was used to deal with the serious Wenjiagou debris flow induced by Wenchuan earthquake. According to the dynamic management thinking, various means were taken to get the information. Based on the stresses and the strain characteristics, the construction methods and the support structure suitable to the geological conditions were determined. The paper introduced the design of diversion tunnel and the technical measures in dynamic construction.

Abstract:F86 compress-shear fault was crossed for Cuijiachong tunnel of the diversion works and water quality environment project in Changsha; with 110m overburden layer, the fault was more than 100 m in width and more than 1000 m in length. Because of the low rock mass strength and good permeability, the fault fracture zone crossing became important and difficult construction problem; several methods were adopted in several poor geological sections for tunnel construction. The paper introduced pilot pre-grouting grouting, advanced support and long pipe roof techniques in F86 compress-shear fault crossing, which could be the reference for the similar projects.

Abstract:There are many faults and sericite slate sandwich development in initial diversion tunnel of Lianghekou hydropower station, especially f25, f3, f8 series, f4, f28 and other faults are composed of multiple secondary dislocation bands with wide fracture zone, poor rock integrity and unstable surrounding rocks. In order to ensure the safe operation of the diversion tunnel, Ⅳ and Ⅴ-class surrounding rocks inside the diversion tunnel should have consolidation grouting; and according to the requirement, grouting test should also be made. The paper mainly introduced the process of consolidation grouting test construction.