Abstract:

Saline silt has many special characteristics, such as high salt content, extremely low content of clay and uneven gradation. Due to these special properties, it is hard to compact, so that the strength is very low. In order to understand mechanical characteristics of saline silt, in-situ pressuremeter tests (PMT) and triaxial tests of undisturbed samples were conducted after physico- chemical analysis of this saline silt. The tests results show that the content of soluble salt is 2.9%, and the main ingredients are Cl－ and Na＋. The silt belongs to alkaline soil with chlorine saline. The PMT test results indicate that pre-plastic pressure is 350 kPa and limit pressure is 500 kPa. In that area, pressuremeter and shear modulus can be adopted by 1 750 kPa and 700 kPa respectively. Laboratory test results represent that this soil have strong dilatancy effect. When the axis strain reaches to 12%, the sample will be close to steady state. The peak and residual strength can be achieved to 600~800 kPa and 450~550 kPa respectively when the confining pressure is 150 kPa.

Key words: silt with high saline, pressuremeter test, mechanical properties, strength test