چكيده به لاتين
Soil improvement is one of the main options in dealing with soil that does not have enough resistance to bear the burden of constructing a new structure. One of the methods for soil improvement is Jet Grouting. In the jet grouting method (injection of high pressure), the water or slurry is injected into the soil at very high pressure and high velocity of the nozzles, causing the destruction of the soil structure and the formation of soil-cement composition. An appropriate method for clarifying the precision injection technique in perimeter environments and obtaining details of this process is the use of physical models.
In the present study, the jet grouting device was designed and constructed on laboratory scale, and then various types of elements with pressure, velocity and type of extract and velocity of rotation were implemented. This way, the effect of each of the parameters mentioned on the diameter is investigated. Also, the cores in vertical and horizontal directions are taken from elements. On the cores, unconfined compressive strength, point-loading and ultrasonic loading tests have been performed.
Based on the results obtained, there can be an estimate of the optimum injection time at each level based on the performance parameters. With decrease velocity of extract, the diameter increases, but the slope of the diameters & velocity of extract decreases with decreasing speed. Also, To reach the maximum diameter must the velocity of the rotation has also increased with increasing speed. The type of rising is effective at the location of maximum diameter formation. Decreasing the pressure reduces the diameter, but in the fixed run-off specifications, the location of maximum diameter changes with the pressure drop.
The compressive strength of the micro-jet grouting columns was high (up to 74 mega-pc), and these values were confirmed by the point load test. Of course, according to the results of compressive strength, coring reduces resistance by 60%. Also, the cores taken in the horizontal direction represent the least resistance in the cores taken along the vertical (about 33% of the lateral resistance).
