Dianchi Peat Soil Engineering Geological Characteristics Of The Pilot Study

With the highly development of Kunming city and countryside, the soft clay ground treatment is more widespread and complicate day by day. Distribution of the peat soil in Kunming Pond basin area is so extensive. As one of the soft soil that has the worse geotechnical engineering properties, peat soil brings a lot of questions to the economic construction of Kunming city. According to studying of peat soil, there are few research theories about it. So the studying of the project properties of peat soil of Kunming Pond and dealing with the peat soil foundation become one of the important contents of geotechnical engineering.This paper mainly carries on experimental study to the geological properties of peat land near Kunming pond.First, a test site was choosed by the bank of Chuanfang River in the Kunming Pond area. And the in-situ test have been carried here, that include static cone penetration, vane shear test and flat dilatometer test. Among them, flat dilatometer test belongs to a newer method of in-situ test which has not popularized in the field of geotechnical engineering in Yunnan Province. The in-situ test results show that the peat soil in Kunming Pond is the high sensitive soil. Its sensitivity is larger than the sensitivity of other kinds of soil. That proves structure and dynamic factor exercise a great influence on the strength of peat soil. The result of DTM test explained that peat soil has great water content. And Its pore water pressure is higher than other soil, so the effective stress is lower.Secondly, the laboratory experiment to the sample of peat soil was taken. It concludes experiments of physical parameter, direct shear test and triaxial test. According to the results of laboratory test, this paper analyzes the effect of water content on the parameter of shear strength of peat soil. Then, put forward to a formulation about the coherent strength and the fiction angle respectively and the relevant relations between every physics mechanics parameter. By the way of inductive method to deal with the results of triaxial test, and, through the nonlinear elastic analysis based on the normalization, it was proposed that the stress-strain relation of peat soil conforms to hyperbolic model by Duncan&Chang. And then the change relational expression of the modulus was obtained through analyzing. All of these will contribute to calculating the stability of slope and deep excavation as well as the displacement of foundation.