CONTROL SYSTEM FOR COMPACTION OF ROADBED

摘要

PURPOSE:To speed up construction work and raise the accuracy of the construction work by a method in which the penetration amount of metal bars under a fixed condition at an adequate number of places is measured, electric resistance values are measured by using the metal bars as electrodes, and these values are compared with allowable values. CONSTITUTION:A copper bar with an about 30 deg. pointed tip, having a diameter of about 1cm and a length of about 20cm, is driven by a 2.5kg rammer for example into a specimen or field roadbed to measure the amount of penetration. Two copper bars as electrodes are then driven to a depth of about 7cm at an interval of about 10cm to measure electric resistance value between both the electrodes. Water content ratio is obtained from the electric resistance value and dry density is obtained from the penetration amount. These values are compared with a testing curve of the same soil quality as field which is obtained in laboratory in advance. If actually measured values of the field are within a given range, they are judged to be eligible. Quick and highly accurate measurements can thus be made and the construction work can be smoothly performed.