| The main object of the investigation presented in this thesis was, to study the general tendency in which the reduction of lateral stress with time takes place in a frozen sand layer subjected to radial pressure.;The reduction in lateral stress, Rt, in frozen sand was found to be a function of five variables; the initial porosity of the sand (n), the degree of ice saturation (Si), sample temperature (TF ), initial pressure (sigmai) and the time (t) elapsed after the application of initial pressure.;Experimental results were plotted in the form of "pressure time " curves which showed the same tendency of rapid decrease in pressure for the first few hours and then a very slow rate of reduction in pressure with time. Reduction in stress, Rt, expressed as a percentage of Initial Pressure, was also plotted against time for each test to study the influence of the above mentioned variables.;Summarizing the experimentally obtained results a general equation, to predict the value of lateral pressure retained by the sand ice layer at any time after the application of a known initial pressure, was derived empirically in terms of the variables, i.e. n, Si, T, sigmai and t.;Two different types of sand were used to prepare 62 specimens. The specimens were composed of either sand and a variety of initial porosity and degree of ice saturation. They were tested at various constant temperatures under selected initial pressure. The magnitude of pressure retained by the frozen sand sample at any time was measured by means of a pressure gauge attached to the pressure unit. The strain in the frozen soil was measured by using bonded resistance strain gauges embedded in the sand-ice system. |
