An Investigation of Geomechanical and Microstructural Properties of Full-Scale Jet Grout Column Constructed in Organic Soil

Abstract

Jet grouting methods have recently become one of the soil enhancement technologies utilized to provide strength improvement and solve most problems of weak soils. In this study, a full-scale 1 m diameter and 5 m length jet grout (soilcrete) column was constructed in the field with a water-to-cement ratio of 1 and 400 bar pressure injections. A mechanical, physical, and microstructural investigation was performed on jet grout samples taken from six different depths (0.0, 0.5, 1.0, 1.5, 2.0, and 2.5 m) and at the same depth at five different locations, including the center. For normal conditions, samples were prepared for six periods to study dry and saturated conditions. The following tests are performed on each sample: compressive strength index (I-s) in all conditions, water absorption, density, porosity, and interface friction. Additionally, SEM was performed on selected samples to investigate the microstructures of jet grout columns (JGCs). The test results showed that the I-s varies with depth, and within the same depth, the variation is approximately 20%. Other properties also vary with depth and location; for example, the average percentage of water absorption and porosity are considered minimum values at the same location, which are 53 and 30%, respectively. However, the interface friction angle of organic soil-cement grout gains 48 degrees and 10 kPa cohesion. The theoretical part of this study is to predict the diameter of JGC in organic soil.