Peat classification by sensitivity to mechanical technogenic impacts

Abstract

Relevance. The problems associated with the weakening of the bearing capacity of peat soils because of technogenic impacts are very relevant in the development of oil and gas industry facilities in the wetlands of Western Siberia. Separately taken classifications according to undrained strength and sensitivity do not reveal the peculiarities of the behavior of weak soils at the base of structures. Therefore, the authors have proposed a different scheme of their classification. It allows assessing the change in physical and mechanical properties when their natural structure is violated during engineering and geological surveys. Aim. Peat classification in the territories of Tomsk, Novosibirsk and Omsk regions according to indicators of undrained strength and sensitivity to mechanical technogenic impacts. Object. Peat soils of Western Siberia. Methods. In accordance with current standards, the research methods included the laboratory methods for determining ash content, humidity, degree of decomposition, field tests to determine the undrained strength and sensitivity coefficient of soils, the information obtained was analyzed in Excel and Statistica software packages. Results. The authors have carried out the review of russian and foreign classifications in terms of soil sensitivity, as well as methods for determining the characteristics used to calculate it and proposed a classification scheme for changes in strength indicators under mechanical influences on peat soils. The article presents the results of experimental data from field and laboratory studies of the physico-mechanical properties of the most common types of peat, their variability after technogenic impacts is estimated according to the proposed scheme using examples of well-known classifications used in the construction of roads, pipelines and for predicting vehicle cross-country ability in swampy areas. The scope of application of the proposed scheme – engineering geological survey for the design, construction, repair and reconstruction of structures – is recommended.

Keywords

• peat
• soil sensitivity
• undrained shear strength
• vane test
• peat strength classification