Abstract: A sand pile driving method for making a sand pile which does not cause trouble in terms of strength even at a soft point in the actual ground, and enables secure limitation of the increase in total construction time and total amount of sand. A compaction procedure is a procedure for compacting a granule pile 15 by pressing and rotating the casing pipe 13 downward. This is performed based on thrust force P by which the casing pipe presses a granule pile and a driving torque T for rotating the casing pipe against a granule pile.

Abstract: A railroad track has a roadbed made of concrete and a pair of track beams of precast concrete mounted to the roadbed. Main bodies of the track beams have at the tops thereof a plurality of protrusions serving as ties and a plurality of recesses for receiving adjusting ties. The protrusions and the recesses are alternately disposed in the longitudinal direction of the beams. The track beams extend continuously in parallel, and a pair of rails are laid on the track beams. A method of constructing the track includes the steps of supporting the track beams on the roadbed with screwjacks embedded in the main bodies of the track beams, and forcing concrete between the main bodies of the track beams and the roadbed to form concrete layers securing the track beams to the roadbed.

Abstract: A method and apparatus is provided to embed paper drain material in water-laden soil by means of a mandrel driven into the soil by power means. The paper drain material is intermittently treated with a substance detectable by a signal emitted electronic sensing means secured to the lower end of the mandrel. When the paper drain is believed to be in place, the mandrel is withdrawn. During mandrel withdrawal, as each sensing means passes by each detectable substance, the signal from the sensing means is modulated, thereby indicating that the paper drain is embedded in place and the mandrel has disengaged from the paper drain. If the paper drain adheres to the mandrel and is being withdrawn with the mandrel, no modulated signal will be generated, thereby indicating that the paper drain is not properly anchored in the soil.

Abstract: A method for uniformly improving a soft ground is proposed. It includes the steps of driving a pipe into the ground, putting sand thereinto and pulling up the pipe gradually while discharging and compacting the sand. In forming the sand piles, the diameter and/or strength of the sand piles are changed according to the soil nature of the ground to be improved to improve the ground uniformly.