Feasibility Study on Improvements to Dynamic Cone Penetrometer

摘要

One of the tools that its use in pavement engineering is becoming more common isthe Dynamic Cone Penetrometer (DCP). In that test, a cone is penetrated into the ground under repeated impact loading. The rate of penetration as a function of depth is an indirect measurement of the strength of a layer. This test can reasonably quantify the layer thickness and qualify the type of material used. However, it is desirable to determine more quantitative information about the base and subgrade. Two approaches were followed for this purpose. First, a DCP type device was constructed which contained a three dimensional accelerometer package in its tip. With this device, the modulus and Poisson's ratio of the base and subgrade can be determined with a minimal coring requirement. Second, an ordinary DCP was instrumented with a load cell and an accelerometer to determine the amount of energy imparted to the ground, and to determine the resistance to and amount of penetration of the device into the base and subgrade. This goal is achieved by theoretically simulating the penetration of a rod into an elastic medium. The two devices were used at seven pavement sections to determine their versatility and field-worthiness. Both devices ae proven to be feasible. However further work is needed to make them rugged, and more advanced analysis procedure is needed to more reliably extract data from them.