217 results about "Subgrade soils" patented technology

The invention discloses an ultrasonic technology-based method for detecting and evaluating damage of subgrade soil materials in seasonal frozen regions. The method comprises the following steps: an initial state sample and a test sample are prepared according to an evaluation scheme on the basis of a formed sample meeting requirements of subgrade soil; the initial state sample is not subjected tofreeze-thaw cycles and has humidity being the evaluation standard moisture content; the test sample is a soil sample which is subjected to freezing and thawing cycling and has humidity at the requiredmoisture content for testing; the initial state sample and the test sample are both subjected to geometric parameter measurement and ultrasonic wave velocity test, the volume deformation rate of thetest sample and the longitudinal wave velocity of the test sample and the initial state sample are obtained, the longitudinal wave velocity, the moisture content and the volume deformation rate of thetest sample are measured according to the longitudinal wave velocity and moisture content of the initial state sample, and the damage variable of the test sample is calculated. Therefore, with the method, the damage degree of soil can be evaluated accurately, comprehensively and non-destructively and the damage mechanism can be reflected without destructive tests.

The invention belongs to the field of computer tests and particularly relates to a CBR numerical test method for soil-stone filled subgrade soil. Simulation is performed through discrete element software PFC2D. The method comprises the steps that first, particles are grouped, the grouping range of each group of particles is determined, and an initial void ratio is preset; second, a domain and a boundary wall are defined, and traversing conditions are set; third, a soil-stone filled particle two-dimensional discrete element constitutive model and relevant parameters are selected; fourth, particle balls are generated, external conditions are applied, and a two-dimensional discrete element test piece of a soil-stone filled body is obtained through calculation and analysis; and last, loading conditions are applied, a California bearing ratio (CBR) test is simulated in PFC2D, test data is recorded, and a CBR value is calculated. The method is an efficient and accurate computer numerical simulation method, and the process of loading the CBR test value to the soil-stone mixture molding test piece is simulated to deeply study mechanical properties of the soil-stone filled subgrade soil.