Nisshin Steel and its steel pipe making subsidiary Nisshin Kokan and Sumitomo Forestry announced on Tuesday they developed new method to improve ground sinking without move the housing. The method is to lift up housing with Nisshin Steel’s expansion type pipe of zinc-aluminium-magnesium coated steel, ZAM. They launch the new method especially for soft ground condition appealing lower damage on housing and 40% lower cost than traditional method.
The method is to lift up housing by pouring 200-250 times of atmospheric pressure water into expanding ZAM pipe in space between the ground and the foundation of the housing. With the lift up, ground sinking is easily adjusted and fixed by infill. They already submitted application for the patent. The method can adjust up to 15 centimeters of sinking for two-story wooden housing with 10-15 ZAM pipes. The method can reduce the cost by around 20% compared with chemical grouting method calculated based on 80 square meters site. The cost is 30-40% lower compared with jack and steel sheet pile using method. The method can be applied both before the housing construction and for after care. The construction cost is slightly more than 500,000 yen including 200,000-300,000 yen of material cost for new housing. ZAM expansion pipe is traditionally used for stabilization of ground for tunnel excavation. Nisshin Steel adjusted the surface into flat type for the jack working. The firm expects the high performance corrosion resistance pipe can be used for up to 60 years.