The Effect of the Selection of Three-Dimensional Random Numerical Soil Models on Strip Foundation Settlements

This paper delivers a probabilistic attempt to prove that the selection of a random three-dimensional finite element (FE) model of a subsoil affects the computed settlements. Parametric analysis of a random soil block is conducted, assuming a variable subsoil Young’s modulus in particular finite elements. The modulus is represented by a random field or different-sized sets of random variables; in both cases, the same truncated Gaussian model is assumed. Mean values and standard deviations of random soil settlement are estimated by a Monte Carlo simulation procedure. With regard to the adopted FE model, the estimated settlement mean values do not vary significantly, but standard deviations do strongly. Similarities also appear in the diagrams of random field correlation length versus settlement standard deviation and the diagrams displaying a total number of model random variables versus settlement standard deviation. Thus, relevant single random variable models represent the random field approach well with regard to settlement parameter estimation. This remark is verified upon a settlement analysis of a three-dimensional FE model of a hypothetical strip foundation. Following the preliminary model observations, various probabilistic geotechnical analyses may be supported, e.g., continuous footing design, slope stability analysis, and foundation reliability assessment.

REINFORCEMENT OF SUBGRADE DOUBLE-CONE PILES

Statement of the problem. The problem of designing the reinforcement method of weak seasonally freezing soils in subgrade base by using double-cone hollow piles and geotechnical materials for roads in the northern regions of the Russian Federation is investigated. Results. As a result of the study, the construction of the subgrade in the form of pile strip foundation of double-cone piles reinforced by geotechnical materials on weak heaving soils taking into account traffic loads and weight of subgrade is considered. A method has been developed of calculating the road base in the form of pile strip foundation of double-cone piles reinforced by geotechnical materials on weak heaving soils taking into account traffic loads and weight of subgrade is considered. The developed method of calculation is based on the formation of soil compaction zones in the near-pile space as a result of pile driving into the ground, which leads to an increase in the structural strength of the weak soil, and also takes the arch effect that occurs in the soil between adjacent pile heads. Conclusions. The obtained research results allow us to conclude that the developed subgrade design and its calculation method are of great interest both to scientists and design engineers, and can be used in construction practice.

REINFORCEMENT OF SUBGRADE DOUBLE-CONE PILES

Постановка задачи. Рассматривается разработка способа усиления конструкции земляного полотна двухконусными сваями и геотехническими материалами для дорог северных регионов Российской Федерации. Результаты. Создана конструкция земляного полотна на усиленном двухконусными сваями грунтовом основании с армированием геотехническими материалами. Разработан метод расчета конструкции земляного полотна на усиленном двухконусными сваями грунтовом основании с армированием геотехническими материалами, а также на слабых сезоннопромерзающих грунтах с учетом нагрузок при движении транспорта и веса земляного полотна. Данный метод расчета основан на образовании зон уплотнения грунта в околосвайном пространстве в результате внедрения свай в грунт, что приводит к увеличению структурной прочности слабого грунта, а также учитывает арочный эффект, возникающий в грунтах между соседними головами свай. Выводы. Разработанная конструкция земляного полотна и ее метод расчета представляют большой интерес как для научных работников, так и для инженеров-проектировщиков, и могут быть использованы в строительной практике. Statement of the problem. The problem of designing the reinforcement method of weak seasonally freezing soils in subgrade base by using double-cone hollow piles and geotechnical materials for roads in the northern regions of the Russian Federation is investigated. Results. As a result of the study, the construction of the subgrade in the form of pile strip foundation of double-cone piles reinforced by geotechnical materials on weak heaving soils taking into account traffic loads and weight of subgrade is considered. A method has been developed of calculating the road base in the form of pile strip foundation of double-cone piles reinforced by geotechnical materials on weak heaving soils taking into account traffic loads and weight of subgrade is considered. The developed method of calculation is based on the formation of soil compaction zones in the near-pile space as a result of pile driving into the ground, which leads to an increase in the structural strength of the weak soil, and also takes the arch effect that occurs in the soil between adjacent pile heads. Conclusions. The obtained research results allow us to conclude that the developed subgrade design and its calculation method are of great interest both to scientists and design engineers, and can be used in construction practice.