A Model for Automatic Control of Vibratory Plate Compactor
of the most Application of automatic control into compaction eglenineering works. This isoduel to problem compared with other machines used in civil g the difficulties in getting proper feedback, consisting of a transfer to the compactor and information on the state of the soil being just under compaction. The The paper presents an approach to this difficult and practically ti p ort nt p h have been discussion contains evaluation of several different responses possibility of a1 in information on g used so far in compaction analysis. compactor without Additionally, involving mathematical model of soil is mechanical behaviour of c pacto considered.
Simulation of Soil-Compaction with Vibratory Rollers
Most frequently, vibratory rollers are used for compaction tasks during earth works and road construction. An increase in roller performance can be achieved by automatically adapting the machine's parameters which determine the compaction result and by automatically controlling the state of compaction continuously. The actual problem is, that because of the extensive variety in properties of the materials to be compacted and the conditions in job site, it is very difficult to state the criteria for the feedback control of the roller parameters. By means of modelling and simulating, the vibration behaviour and compaction effect as well as the interdependence between the state of roller-operation and the state of soil-compaction is investigated. The goal is to aquire knowledge about the interactions between vibratory rollers and soil during compaction in order to improve roller construction and automatic compaction measuring-systems.
Effect of a Porous Sand Bed on Incipient Sediment Motion
Incipient motion tests were conducted for flow into and out of a porous bed. Seepage out of a bed does not affect incipient motion measurably because the seepage force is lost once a sediment particle rocks. Seepage into a bed may either enhance or hinder incipient motion, depending upon the relative effect of the boundary shear stress and the seepage force, both of which depend on the seepage flow. For a given hydraulic gradient the size of the sand grains is critical regarding incipient motion. For turbid water flow over a bed, fine particles of the mixture may become deposited in the bed, resulting in a concrete-like, more resistant bed. Typical values of the hydraulic gradient are given for flow out of a canal and in an ocean bed under oscillatory waves.