CONSTRUCTION METHOD FOR MULTI-STAGE UNDERGROUND PARKING PIT AND CONCRETE RETAINING BLOCK USED FOR BUILDING THEREOF

摘要

PROBLEM TO BE SOLVED: To improve workability, save construction cost and shorten the construction time by installing an L-type concrete retaining wall block along walls surrounding a pit excavated underground with the bottom plate of the L-type concrete retaining wall block directed toward the inner side, cast-in-place concrete is poured on the bottom surface of the pit surrounded by the retaining wall blocks along the walls surrounding the pit excavated underground. SOLUTION: Underground is excavated and a hole 1 for building a pit is formed by excavating underground. Next, crushed stone 2 is laid at the bottom portion of the hole 1, on which a foundation concrete 3 is poured by cast-in-place method. At this time, a recessed groove 4a for a water drain pit is formed. Then, corner retaining wall blocks 10 are arranged at 4 corners, intermediate retaining wall blocks 20, 30 are arranged between the blocks 10, the space between blocks is coupled with coupling fittings 40, and mortar is filled between vertical plates of blocks 10, 20 and 30. In succession, cast-in-place concrete is placed to build the bottom 6 of the pit surrounded by the blocks 10 to 30 in alignment with the height of the bottom plate of each block. At this time, concrete is poured in each notched portion of blocks between the bottom plates 10 to 30.