Therefore, the steps of excavation of the excavation site to install the plurality of first heat stakes at a predetermined interval (s10); Doedoe provided on the back side of the first heat stakes, comprising: at a predetermined distance to the position between the first open pile installing a plurality of second heat stake (s20); The steps for installing the lower wale (40) connecting the first heat stake the transverse direction (s40); Once the other end to the lower sheet of the upper side band is step (s50) for installing horizontal yeongyeoljae 60 to any one of the second heat stake; Across the horizontal yeongyeoljae, steps for installing the upper portion to the lower wale wale upper (s60); The first step to open the excavation site excavation piles are installed along the excavation (s70); The steps for installing the toryupan 50 between the first heat stake (s80); A step for performing horizontal perforated at a predetermined depth (s90); The horizontal fabric pore size into the tube member 80 and the rod member 85, the insert and the second heat stake (20) by using a first fixing nut 130, tubular member 80 and the beams 70 and 71 step for fixing the stopper and the wedge (88) (s100); C step (s120) for fixing the other end of the rod member 85 and tube member 80 in the ground connecting wale (100); the method comprising the freestanding retaining is provided.