DEVICE FOR AUTOMATICALLY CONDUCTING STANDARD PENETRATION TEST

摘要

PURPOSE: An automatic conducting device for a standard penetration test is provided to regularly keep the drop height of a hammer with an automatic drawing and dropping device and a locking device, to prevent energy loss and secondary impact caused by mutual interference by freely dropping only the hammer while the locking device is released, to reduce an installation space by drawing the hammer with the locking device inside the hammer, and to automatically conduct all testing processes by a controller measuring the hitting number of the hammer and the penetration amount of a sampler and deciding if the test stops or continues. CONSTITUTION: An automatic standard penetration test conducting device contains; an automatic drawing and dropping device penetrating a sampler into the ground using a hammer(5); a hitting number calculating sensor(26) calculating how many times the hammer hits an anvil(700); a penetration amount measuring sensor(9) measuring the penetration amount of the sampler; and a controller deciding if the test stops of continues by comparing data from the hitting number calculating device and the penetration amount measuring device, with a reference value and outputting a testing result. In detail, the conducting device consists of; a first hydraulic cylinder vertically fixed to a boring machine; a cylindrical pipe(4) rotatively fixed to a connector formed in the piston rod of the first hydraulic cylinder while holding a sampler penetrating rod(600) and the anvil; the hammer hitting the anvil inside the cylindrical pipe with opened upper portion and many uneven portions(10); a second hydraulic cylinder(2) installed on the cylindrical pipe on the same vertical central shaft as the hammer; a lift(11) fixed to a piston rod(3) of the second hydraulic cylinder and reciprocated in the cylindrical pipe; a locking device(6) drawing and dropping the hammer while lifted with the lift; and a dual pipe(23,24) of which one end is fixed to the lift and the other end is fixed to the locking device to enable the locking device to fix and release the hammer depending of the movement of the lift. Herein, the automatic drawing and dropping device comprises the hydraulic cylinders and the locking device.