Abstract:As an important and fast construction method for drilling holes, rotary drilling rig is superior to other drilling machines. The drilling parameters based on the online monitoring system which we can get from the drilling process provide not only significant information for construction operation, but also original data for identification of the bearing strata. Due to the complex original site environment, the drilling parameters such as drilling rate, rotation rate, rotary force and torque of the power head would be changed with time and space during the drilling process. According to the parameters database and theoretical analysis, the curves of drilling parameters varying with drilling depth are establishecl, from which we can find that the single-factor curves cannot identity the bearing strata accurately. In addition, a multi-factor collaborative control method for identification is proposed, and a load-strength model of the rock masses is built to determine the bearing strata, which is based on comprehensive index and all the drilling parameters are included. And then the model is applied to analyze the strength and bearing capacity of the formation considering the rotary drilling. By comparing the analysis results with the results from strength testing values in the geological survey, we can find that the strata property identified by the proposed method is in accordance with the real characteristics. Therefore, the above identification method based on drilling parameters is rational and reliable to determine the strata properties and identify the bearing strata, and it could be used for formation identification considering drilling process under different geological environment.