The Basic Research On Single Large Diameter DTH Hammer

In recent years, infrastructure projects continue to expand, the need for large pile foundations gradually increasing, Then the requirement for the construction of rock-socketed pile equipment is more and more high. It is required that the equipment can not only break the high hardness and complicated rock strata, but also put forward many kinds of requirements such as high efficiency and low pollution. Under these conditions, the single large diameter DTH hammer is more and more popular in the construction unit as the high efficiency rock-socketed pile construction equipment. In this paper, the structure and parameters of the single large DTH diameter at home and abroad are compared and analyzed, and the corresponding research is carried out. In this thesis, we consider monomer large diameter DTH with working particularity and complexity, so the work process is broken down into impact, rotation and slag discharge. The structure refers to large diameter DTH hammer of the domestic and foreign well-known manufacturers, taking crushing granite for example, and DTH hammer model is established. Through the study of the crushing mechanism and the ABAQUS analysis, the impact force and drilling speed of the broken granite are determined.1. Based on the physical and mechanical properties of the rock, the basic physical parameters of the granite are determined. Combined with structural parameters of the single large diameter DTH hammer, establish the three-dimensional models of the central concave hammer, of convex hammer and of granite through Solidworks. And simulate that the hammer crushes granite through using ABAQUS. Set hammer impact speed as 7m/s, 8.5m/s, 10m/s, rotary speed is 30r/min, 35r/min and 40r/min, combined into 9 kinds of conditions, and carry out solving. Obtain hammer rock renderings under various conditions, determine the hammer impact force and time change curve and stress contour, so as to achieve a φ775mm large diameter DTH hammer is most suitable for the speed and impact velocity were 35r/ min and 7m / s, high crushing efficiency.2. This thesis mainly introduces the rotating pressure mechanism and the working principle of the single large diameter DTH hammer. The parameters of DTH hammer from six manufacturers, including Bulroc In England, Kwang sung and Dong woo in Korea, Zhenzhong in Shanghai, Changsha Tianhe in Changsha and Ingersoll Rand, were analyzed and compared. Then parametric curve were drawn According to the requirements of the project and the results of parameter curves, the main parameters, internal structure and principle of the gas distribution of the single large diameter hole hammer were determined.3. By comparing characteristics of a variety of circulating mediators and cycle styles, expounds the new circulation deslagging mode and principle and The role of the blowout preventer. Combining mechanics theory formula, demonstrate the drilling machine plunger like slag formation mechanism and mode of operation. By using the MATLAB software, simulate and compute. The center discharge pipe diameter, rock pillars attenuation speed, the air flow on the delivery in unit time, of the effect on the height of the curve. The analysis results show that when the unit time air intake is only 15m3/min, the plunger can be transported to the 50 m height in 10 seconds. The device reduces the diameter of the slag discharging channel, set up anti spray device, dramatically reducing air consumption, to achieve the effect of energy saving and environmental protection, cost savings.