Hole-arrangement Experiment And Numerial Simulation Research On Static Crushing Of Concrete

Since the appearance of the static crushing agent in 1960 s,static crushing technology had been widely used in practical engineering.In view of its disadvantages of intensive hole and monotonous arrangement mode in practical engineering,this paper explores an efficient,reasonable and applicable way through the combination of test and simulation.In order to study the reasonable hole layout of static crushing technology,the maximum expansion pressure that the commercial static crushing agent,with a water-agent of 0.28,can reach was 62.32 Mpa by using a new expansion pressure test device.The test not only solved the problem of spraying out from the hole in the test process of the old expansion pressure test device,but also ensured the accuracy of the test data,and it provided effective parameters for subsequent simulation.On this basis,by analyzing five groups of single-hole concrete crushing models with the same aperture but different sizes,I obtained the development situation of the broken cracks and its breaking law of single-hole concrete.There are three main forms of single-hole concrete crushing cracks,namely "cruciform","herringbone" and "T-shape" cracks.Under the condition of the same aperture,the longer the distance of the minimum resistance line,the worse the crushing effect,and vice versa,the better the crushing effect.Based on the experimental research,I carried out the numerical simulation of single hole concrete crushing.Through comparing and analyzing with the numerical simulation results of single hole concrete crushing and the test results of single hole concrete crushing,I obtained the reasonable numerical simulation parameters and cracking model;and it is found that 275 mm is the ultimate minimum resistance line length of a commercial static crushing agent in a single hole concrete specimen,with a hole diameter of 32 mm.Then,the numerical simulation of two-hole and four-hole concrete crushing were carried out,which was obtained that the limit hole distance between both holes of the two-hole concrete specimen that can be broken by the commercial static crushing agent is 550 mm;by comparing and analyzing with the crushing results of both four-hole concrete hole layout methods(parallel and crossed hole layout),it was obtained that the optimal method is parallel hole layout.Finally,I carried out the numerical simulation of 16-hole concrete crushing,and analyzed the generation and development process of cracks on the crushing surface of mass concrete.The results show that the first through crack appeared along the direction of the minimum resistance line of the specimen,then the hole connecting line cracked,and two through cracks were generated in the four corner holes along the direction of the minimum resistance line.At least one through crack was generated at the connecting line between the holes,and the final crushing effect was good.This research result provided not only an effective method for the field of test and simulation of static crushing technology,but also a reference for the practical engineering application of static crushing agent.