MC systems impress in Indonesia

MC showcases its know-how in injection technology to the benefit of two repair projects in the world’s largest island state, namely the Mrawan railway tunnel and the Jatibarang rockfill dam.
The sealing and repair of the Mrawan railway tunnel in Jemba, in the east of the island of Java, had already been attempted several times without success, before MC submitted its proposal in response to a project tender issued by the state railway authority.
Difficult conditions encountered in the Mrawan tunnel

The tunnel was completed in 1902 during the Dutch colonial period, and exhibits a masonry stone arch with a thickness of 90 cm. In all the earlier attempts to repair the structure, water seepage through the soil above constantly gave rise to leakages through the tunnel roof. The-Tuong Do, Business Development Manager for South-East Asia at MC, realised that an efficient and permanent repair of the tunnel could only be achieved with complete gelling of the crown, that is to say the upper third of the tunnel arch. He therefore recommended that a curtain be injected behind the tunnel arch with the soft elastic sealing injection resin MC-Injekt GL-95 to provide a permanent water barrier. “Drilling through the natural stone bricks with their various thicknesses was difficult. The packers had to be extended through to the soil to ensure that the injected hydrostructural resin would create a leak-tight curtain around the tunnel arch,” reports civil engineer The-Tuong Do. There was no road access to the tunnel, which made the logistics of the job significantly more difficult. In addition, work could only be carried out between 2 a.m. and 6 a.m. Thanks to the outstanding properties of MC-Injekt GL-95, the injection work brought the desired success, despite difficult climatic conditions. And because of the controllable reaction time and reversible swellability, the applicators were able to adapt the injection system to the varying soil conditions. The bore holes were sealed with MC’s fiber-reinforced PCC concrete replacement Nafufill KM 250.

Two-stage injection for the Jatibarang reservoir dam

The repair of cracks in the inspection tunnel serving the Jatibarang rockfill dam in Central Java represented a further challenge, with high-pressure bodies of water additionally hampering the work. The structure serves both as a storm barrier and as a source of local water supply. MC and the Indonesian application firm PACA, which has been working with MC product systems for many years now, were called upon by the general contractor PT. Wijaya Karya, a company well acquainted with the expertise that MC can offer in the field of tunnel injection. Following a site inspection, the MC team recommended a two-stage injection system to solve the problems prevailing, and this was then implemented. The water ingress was temporarily stopped by the rapidly foaming injection resin MC-Injekt 2033, with the cracks then being injected and permanently sealed with the elastic resin MC-Injekt 2300.
With a high degree of professionalism, problem-solving expertise and outstanding product systems, MC was therefore able to produce impressive results in relation to both projects, thus attracting further attention to its capabilities from within the marketplace. Further enquiries from dam operators have already been received.