Test of Consolidation-Collapse Properties of the Black Soil of Northeast China Based on Burland Model

Abstract

Organic matter is widely distributed in soils, which has remarkably influenced geotechnical engineering. The difference of the soil's structure, chemical constitution, and organic content leads to the distinction of mechanical property. The current research concentrates on the mechanical property of peaty soil and peat, and research on organic soil is rare. Several slope engineering issues show that the rainwater contact with the organic soil layer causes soil landslide, and the mechanism of landslide is that organic matter softens when it soaks the water under the vertical press. Studying the mechanical influence of organic soil with change in moisture content is meaningful because the moisture content of organic soil is much less than that of peat. This study mainly has the following content. The one-dimensional compression test with a variation of organic matter (F) and water (W) is selected to reveal the compression characteristics of organic soil. According to the analysis of the research consequence, the collapsibility with different organic contents and the same void ratio was further analyzed, and the research revealed the influence factor by analyzing the process of the collapse. Burland intrinsic compression theory, which reveals the soil's structure by analyzing the difference of undisturbed soil and remolded soil, was suitable for the initial moisture content of 1.5 to 2 times the liquid limit but not for organic soil with a moisture content lower than the liquid limit. Therefore, a modified model was provided to widen the range of liquid limit and present the phenomenon of collapse, and good prediction outcome can be obtained based on the linear-regression analysis model and the modified model. A black soil collapsibility model was established based on the experimental results, and it has good prediction outcome.