Research On Rock-breaking Drilling Tools Based On The Principle Of Microwave-assisted Mechanical Rock-Breaking

For a long time in the mining,tunnelling and water conservancy industries,blasting has been the main method of rock excavation and drilling due to its high efficiency,especially for hard rocks where other methods are incomparable.However,as the times have changed,technology has advanced and demand has grown,the disadvantages of blasting have become apparent,such as large disturbances to the surrounding rock and long operational cycles.Of these,safety and environmental issues,particularly due to blasting dust,and the difficulty of adapting to automated and intelligent trends due to discontinuous operations,are two of the most important concerns.This has led to the implementation of non-explosive continuous mining in soft and medium soft rock formations such as coal mines,and the use of mechanised continuous mining is highly efficient and has led to an increase in coal production.However,hard rock mining,represented by metal mines,has been slow to promote the use of non-explosive mining equipment for economic reasons,with the vast majority still using blasting as the primary option.Therefore,many scholars have conducted in-depth research in the field of non-blasted rock,and a series of important results have been achieved.New rock-breaking techniques include the use of both mechanical and thermal energy.In addition to the conventional drilling rigs,roadheaders and TBMs,there are also other methods of breaking rock using mechanical energy,such as hydraulic breaking and ultrasonic breaking.The more common rock-breaking techniques using thermal energy include laser rock-breaking,plasma rock-breaking and microwave rockbreaking.However,these new rock-breaking techniques have more or less their own shortcomings and are slow to be applied in industrial production.Therefore,this paper is based on the principle of microwave heating,combined with the idea of mechanical rock-breaking methods to start research.The specific research in this paper is as follows.1.An experimental study of the deterioration of granite due to microwave heating was carried out to compare the heating of granite using different microwave powers and heating times.The performance of the granite in terms of temperature,porosity and mechanical properties under various conditions is summarised to find the optimum solution for the microwave heating power and heating time.2.To establish a finite element simulation model for microwave heating of granite,and to study the relationship between the internal temperature field of granite and microwave by means of numerical simulation and calculation,and to compare and analyse with the experimental results.3.Combining experimental findings and numerical simulations,the rock breaking work of the disk hob with microwave assistance is investigated.The forces on the disc-shaped hob are analysed and the rock-breaking effect is evaluated under both conditions with and without microwave heating.40 figures,13 tables and 77 references throughout the text...