Experimental study on traction performance of the

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Experimental study on traction performance of impact roller

content abstract: the traction characteristics of impact roller under various working conditions are tested and studied, and the variation law of traction force with working conditions and traction speed is obtained. The relationship between traction force and compaction conditions, rolling strength and traction speed is analyzed, and the selection method of traction force and traction speed based on test is put forward. The test and research results are for the further study of impact roller It provides scientific basis for development and engineering application

key words: traction performance of impact roller compaction conditions

the development of high-grade highways, high-speed railways, large dams, airports, ports and other engineering projects in China has higher requirements for the bearing capacity, stability and compactness of the foundation, especially for the compaction of collapsible loess, the existing compaction machinery can not fully meet the needs of construction. For this reason, the engineering machinery plant of the 20th Railway Bureau has developed an impact roller, whose compaction strength and compaction efficiency are 3-4 times that of the vibratory roller of the same tonnage. It is found that: ① the actual traction power of the machine is far from the theoretical calculation; ② Compaction strength, compaction efficiency and machine life are directly related to the selection of traction speed. In order to truly simulate the change process of traction force with traction speed under different working conditions, so as to select appropriate traction equipment and formulate compaction technology, we measured the change process of traction force with traction speed in the three stages of initial compaction, medium pressure and final compaction of collapsible loess subgrade, and drew some important conclusions after testing and research

1 working characteristics and test methods of the impact roller

as shown in Figure 1, the impact roller uses a polygonal cam shaped roller. Under the traction, the raised edges and corners rise and fall to produce a combined impact compaction of potential energy and kinetic energy on the ground. At the same time, due to the energy accumulator of the multilateral roller, the impact on the ground is increased. The roller impacts the ground three times per revolution. Under the continuous traction of the tractor, Complete the compaction of the pavement. As the impact strength changes with the compaction condition, pavement material and traction speed, there are many factors affecting the traction force. At present, there is no such data for reference. The purpose of this paper is to study the law of traction force changing with the compaction condition and traction speed by test method, and the strength is very close to that of steel. In the test, the corrosion-resistant parts were made at a speed up to 30km/h. For the crawler tractor with a power of 400KW, the pull and pressure sensors are rigidly connected in series between the impact roller and the tractor. The sensor output signal is amplified and sent to the microcomputer test system for data processing. The tractor is equipped with a speedometer, which can easily read the traction speed at any time

2 test results and analysis

for the collapsible loess pavement in Northwest China, when the traction speed gradually increases from 0 to 15km/h; Comprehensive tests were carried out under three working conditions: initial pressure, medium pressure and final pressure. Fig. 2 shows the change process of traction force when the traction speed under medium pressure condition rises from 0 to 6.5km/h; Figure 3, figure 4 and figure 5 respectively show the whole process of traction force change when the traction speed gradually rises from 0 to 15km/h under three working conditions; Figure 6 is the probability density and probability distribution function diagram of traction force amplitude under final pressure condition; Table 1 shows the measured values of traction force under three working conditions and typical traction speed

through comprehensive analysis of the above charts, the following laws can be found:

(L) the old pantograph is the largest under initial pressure condition and the minimum under final pressure condition

(2) although the dynamic range of traction force amplitude varies greatly under different working conditions and speeds, the probability analysis shows that 85% of the traction force amplitude is less than 35KN

Table 1 test results of vehicle gravity under typical compaction conditions

compaction conditions

traction speed km/h maximum value of traction kn average value of traction kn effective value of traction kn

initial compaction

0-6.44 95.8 25.8 19.15

10.50 59.46 24.9 11.57

12.08 153.41 25.4 22.13

14.7 180.59 37 34.05

medium pressure

0-6.44 90.96 24.1 13.38

10.50 44.29 19.9 8.86

12.08 65011 25.49 9.33

14.7 97.22 31.4 17.56

final pressure

0-6.44 84.623 12.45

10.50 47.11 19.7 The horizontal tensile testing machine has rich utilization of 9

12.08 54.61 22.1 7.57

14.7 77.02 34.7 12.44

(3) in the curve of traction force changing with time, any two peaks will cause damage to the instrument; The time difference divided by 1/3 of the circumference of the roller indicates the speed of the roller at this instant (consistent with the measured speed value), so the change curve of traction force with traction speed can be accurately obtained, as shown in Figure 7

(4) when the traction speed changes within the range of skin/h-12km/h, the dynamic range of traction force amplitude changes the least

(5) when the traction speed is less than skin/h and greater than 14km/h, the dynamic range of traction force amplitude is large

3 conclusion

(1) when selecting traction equipment, the traction force of the machine shall be greater than or equal to 35KN

(2) for all working conditions, when the pantograph speed is within the range of 8-12km/h, the traction force is the minimum; If the compaction effect is good, the traction speed within this range is the best

(3) from the time-domain curve of traction force, important parameters such as instantaneous traction speed, statistical parameters of traction force, impact times and pressure strength (pressure strength is proportional to traction force) can be obtained, which provides a scientific basis for the development of monitoring instruments

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