Abstract: A ground improvement apparatus includes: an irrotational sun gear fixed to an irrotational inner pipe inside a rotatable outer pipe; a planetary gear rotatably supported on a rotatable agitation shaft and configured to rotate while meshing with the sun gear; and an inverse rotation mechanism meshing with the planetary gear and rotating the agitation shaft in an opposite direction of the planetary gear. The agitation shaft is suspended on a connection member attached to the outer pipe so as to rotate in synchronization with a rotation center of the inverse rotation mechanism. A ground where the outer pipe is penetrated and a solidifying material discharged from the agitation shaft are agitated and mixed with each other by agitation blades radially attached to the agitation shaft with a trajectory of distal ends of the agitation blades drawing a substantially polygonal shape by rotation of the agitation shaft.

Abstract: A ground improvement apparatus includes: an irrotational sun gear fixed to an irrotational inner pipe inside a rotatable outer pipe; a planetary gear rotatably supported on a rotatable agitation shaft and configured to rotate while meshing with the sun gear; and an inverse rotation mechanism meshing with the planetary gear and rotating the agitation shaft in an opposite direction of the planetary gear. The agitation shaft is suspended on a connection member attached to the outer pipe so as to rotate in synchronization with a rotation center of the inverse rotation mechanism. A ground where the outer pipe is penetrated and a solidifying material discharged from the agitation shaft are agitated and mixed with each other by agitation blades radially attached to the agitation shaft with a trajectory of distal ends of the agitation blades drawing a substantially polygonal shape by rotation of the agitation shaft.

Abstract: A ground improvement apparatus includes: an inner shaft arranged inside an outer pipe and including a mechanism for rotating a crank at a rotation speed four times as fast as that of the outer pipe; agitation blades supported by the outer pipe so as to reciprocate in a radial direction of the outer pipe and including discharge outlets; and a slider crank mechanism for converting a rotation movement of the crank to a reciprocating movement of the agitation blades. A ground at a location where the outer pipe is penetrated and a solidifying material discharged from the discharge outlets are agitated and mixed with each other to form an improved body having a substantially rectangular cross section by rotating the agitation blades while advancing and retreating the agitation blades relative to each other via the slider crank mechanism by rotation of the crank.

Abstract: A method of compacting soil performing the steps of establishing a grid pattern of individual partitions at a jobsite, performing a first tamping session to tamper each partition using a 10?×10? vibro tamper plate for about 90 seconds followed by at least 4 days of settling. Performing a second tamping session to tamper each partition using the 10?×10? vibro tamper plate timed for about 120 seconds followed by at least 4 days of settling. Performing a third tamping session to tamper each partition using a 7?×7? vibro tamper plate for about 90 seconds followed by about 6 days of settling.

Abstract: A method of soil improvement work drills the ground with a drilling head arranged at a lower end of a rotary shaft and sends the rotary shaft into the ground. The method mixes pressurized water with compressed air on the ground, to prepare a fluid mixture, feeds the fluid mixture through a feed path arranged along the rotary shaft into an ejector arranged on the drilling head, and ejects the fluid mixture from the ejector toward the ground to drill. An envelope defined by a front end of the drilling head has a conical shape.

Abstract: A method of soil improvement work drills the ground with a drilling head arranged at a lower end of a rotary shaft and sends the rotary shaft into the ground. The method mixes pressurized water with compressed air on the ground, to prepare a fluid mixture, feeds the fluid mixture through a feed path arranged along the rotary shaft into an ejector arranged on the drilling head, and ejects the fluid mixture from the ejector toward the ground to drill. An envelope defined by a front end of the drilling head has a conical shape.