Study On Compressive Strength Of Microjet Grouting Columns By Physical Model

Jet grouting method is considered as one of the most widely used improvement methods among the others and is applicable in most geotechnical problems such as increasing load capacity, reducing settlement, creating seals, stabilizing slopes, etc. One of the challenges faced by designers is finding the strength and geometry of the elements made using this method. The most effective components in the resistance of jet grouting columns are the type and parameters of injection, soil characteristics (such as aggregation), the amount of cement inside the sample, water to cement ratio of slurry, the type of cement and the method of sampling (coring or wet sampling). In this paper, after the construction of jet grouting columns in the laboratory and taking core of them, the impact of coring on uniaxial compressive strength is studied. Also, the point load test was used to study more about the strength parameters of the microjet grouting columns. Based on the results, the compressive strength of microjet grouting columns is high (up to 59 MPa), and these values are confirmed by the point load test. It was also observed that with increasing speed of soil-cement columns formation, compressive strength decreases. Based on the compressive strength results, coring reduces resistance by 60%. Also, the cores taken in the horizontal direction showed about 33% less uniaxial compressive strength than the vertical cores.