Instant Solidification of Soft Ground Horizontally Using Jet-Grouting

Jet-grouting is usually used in underground construction in the Shanghai soft deposits. In some cases, jet-grouting is conducted horizontally. However, immediately after the mixing, the soil-cement admixture is in a fluid state, which will flow out from the hole. In order to solve this problem, Twin-Jet Technology was invented to solidify soft soil instantly. Two types of binders with cement and accelerator such as sodium silicate are jetted under high pressure of about 10 to 40 MPa and mixed with in-situ soil to create the instant solidification. A field test was conducted in the soft clayey deposit in Shanghai. Field and laboratory results showed that the admixture can be gelled within 10 to 20 seconds. The diameter of the jet-grouted column reached 1.2 m and the strength after 14 days reached 1.2 MPa.