The Research Of Field Test Detection Method For Subgrade Modulus

Subgrade is a carrier of the structure of a road. Its bearing capacity can influence the use of the whole road. So, whether the bearing capacity of the subgrade can be evaluate correctly is very important. The indexes of evaluation are different in the different structure design methods of road. CBR is a main index which is used by Classical method, experiential method and so on. And the dominant theory developing in modern times is based on elastic multilayer theory. So that modulus is the main index of road bearing capacity evaluation.We always use bearing plate method and Benkleman bean static deflection method which are much more classical and familiar to measure the modulus of subgrade .Recently, road project of our country is developing fast. Subsequently, methods and means of subgrade bearing capacity evaluation also need developing. And the traditional method has got behind with the road project of our nation not only in simulation of stress state but also in efficiency of measure . So we need a method which is much more convenient and rapid. The discovery of the method of using portable falling weight deflectometer and Rayleigh wave satisfy our need.In order to study correlation of bearing plate method, Benkleman bean static deflection method, portable falling weight deflectometer method, Rayleigh wave method and field CBR in subgrade bearing capacity field measure, we perform comparison experiment of modulus and CBR field measure on 3 tentative roads which are different in filling materials. By considering bearing plate method modulus which is widely used as norm and comparing the modulus and CBR got by methods mentioned above with each other, the conversion formula which get by comparing the result got by the several methods mentioned above with the result got by bearing plate method is got.The research finding of this thesis provide the test and theory foundation for application and generalization of portable falling weight deflectometer method and Rayleigh wave method used in subgrade bearing capacity measure.