Tensile Strength of Snow using Centrifugal Technique

Tensile strength of snow was determined using indigenously developed automated centrifugalmachine. Processed snow (sintered at 20 °C for 4 days) samples of dia: 65 mm andheight:130 mm were tested using this machine.The experiments were conducted on sieved snowat four temperature levels of 0 °C, 3 °C,6 °C and 9 °C at density ranging from 200-460 kg/m3.Results of these experiments have been compared with the earlier  suggested models. Probabilitydistribution of snow strength on the basis of current experimental data has also been presented

Estimation of Rheological Properties of Snow Subjected to Creep

Creep is one of the most important phenomenons to determine the settlement of snow. Snow,in natural conditions, exists at temperature quite close to its melting point and deforms very fast.The settlement of snow is the result of creep phenomenon under the action of overburdenpressure as well as due to metamorphic processes going on within the snowpack. In thiscommunication, creep behaviour of snow is simulated with four-parameter viscoelastic fluidmodel. This viscoelastic character is basically controlled or monitored by various rheologicalconstants. Estimation of all the rheological constants in the four-parameter viscoelastic fluidmodel appropriate for the creep properties of snow is done. Total 91 uniaxial unconfined constantstress experiments on sieved snow were conducted at controlled temperature conditions. Theeffect of density and varying temperature on these constants is found to be remarkable

Quantitative Step-loading Block Test: A Substitute for Loaded-column Test

A new snowpack stability test, quantitative step-loading block test (QSLBT) has beendeveloped and used operationally by the Snow and Avalanche Study Establishment during thewinter 2004-05 at Patsio Research Station in Great Himalayan range. This test is simple, takesless time in measurement, and effectively communicates the results. In this test, an isolated snowcolumn of area 13 cm x 18 cm (0.234 m2 or may be up to 0.30 m2) is cut out of the wall of a snowpit. A wooden block of known weight (0.21 kg) and of the dimension 13 cm x 18 cm is placedover the snow block and loaded in steps with iron weights of known quantity. On loading if theblock fails, the height of failure from ground and the load by which the failure of block has takenplace, are noted. While most of the stability tests in snow provide just an estimate of snowpackinstability, this test provides the quantity of load required to fail the snowpack. More than 40tests were carried out in Great Himalayan range during the winter 2004-05 and were comparedwith the shear strength of the failure plane. The results are in good agreement with shear frametest