Soils laboratory
Soil and sediment samples are often collected in the field for a variety of projects. The Water Research Laboratory’s soils lab is used for the processing and analysis of these samples. Samples can be dried in the oven, sieved through an automated shaker and weighed to great accuracy on a variety of scales. The room temperature of the laboratory can be set to between 18-25°C and controlled to within ±2°C.
Equipment
- Mettler scale type K7T (maximum load: 800 g, readability: 0.1 g).
- Endecotts “Endrock” mechanical shaker for sieve analysis (mesh sizes from 45 μm to 16 mm).
- Bench top centrifuge for pore water extraction. The Beckman GS-6 centrifuge includes four swinging buckets that can be rotated at up to 3,000 RPM. Each bucket can be fitted with 1 x 750 mL container, or 4 x 50 mL centrifuge tubes, or a custom made pore water extraction filter for sediments or cores (up to 50 mm length by 75 mm diameter). A new geotechnical centrifuge with permeameter chambers is being installed and commissioned at WRL in early 2011.
- Rotational agitator for slow mixing of fluids and sediments. The rotational agitator, designed and built at WRL, is 1 m diameter, holding close to a hundred sample tubes for slow mixing over several hours or overnight.
- Automatic drying oven for moisture and bulk density on porous materials. The oven is available for drying soil and sediment samples at standard temperatures of 45-105°C and up to several hundred degrees celsius. The oven is essential for moisture and bulk density measurements on soils, sediments and rock cores and as a preparation step for some physical tests.
- Settling tube for analysis of particle size distribution of soils. Settling tubes are an alternative method of measurement of particle size distributions which is based on the fall velocity of particles within water. The tube is filled with clean water, and a sample of approximately 10 grams of soil is released instantaneously into the top of the tube by a trapdoor mechanism. A precision time and data logger is activated and measures the accumulation of mass of the soil particles on a suspended plate at the base of the tube. The rate of the accumulation of mass reveals a distribution of particles within the soil sample, which is a function of particle size, shape and density. The settling tube method provides a particle size distribution analysis with a higher resolution than comparable sieving techniques, and one which is also based on particle density and fundamental behaviours in nature.
- Hydraulic experiment tank for investigating transport phenomena in any type of porous material under different flow rates and directions.