INSTALLATION METHODS OF MICRO-PILES BY THE RIGIDITY OF PILE AND THE DEPTH OF ROCK LAYER

The present invention is to provide a construction method of a micropile considering the location of a rock layer in the limited depth and the stiffness condition of a micropile, wherein the construction method of a micropile performs a model test and a numerical analysis on the earth and sand ground or the ground which has a rock layer in the limited depth for the applicability evaluation of the micropile, such that the bearing power of the ground is reinforced based on that the bearing power of the pile reinforced ground is changed depending on the locations of the front end part of the pile and the rock layer in a case where the pile which is installed in the ground performs rigid motion or that foundation bearing power increase is changed depending on the embedded length of the pile and the installation length of the pile with respect to the stiffness of the pile rather than the locations of the rock layer and the front end part of the pile in a case where the pile installed in the ground performs ductile motion. The construction method of a micropile considering the location of a rock layer in the limited depth and the stiffness condition of a micropile according to the present invention for achieving the purpose constructs the micropile to be vertical in a case where the pile which is installed in the ground performs rigid motion because the length-diameter ratio of the pile regarding the stiffness condition of the pile is low, and constructs the micropile to be inclined in a case where the pile which is installed in the ground performs ductile motion because the length-diameter ratio of the pile is high. Further, the construction method of a micropile considering the location of a rock layer in the limited depth and the stiffness condition of a micropile according to the present invention for achieving the purpose, in a case where the pile stiffness condition is ductile, installs the micropile with an embedded pile length of 0.5 times of the expected ground fracture zone depth or more in a case where the micropile is constructed to be inclined and with an embedded pile length of one time of the ground fracture zone depth in a case where the micropile is constructed to be vertical because of the intimate relation with a foundation ground fracture surface.