Filtration of broadly graded cohesionless soils

210A a borehole. Single well electrical tracer tests are effective, but require monitoring of the injection of significant volumes of fluid into the formation.

904104 Analysis of aquifer tests conducted in fractured rock: a review of the physical background and the design of a computer program for generating type curves. Computer note Novakowski, K S Ground Water 1/28, NI, Jan-Feb 1990, P99-107 Analysis of hydrological characteristics of fractured rocks between wells can be undertaken by traditional pumping tests or by pulse interference tests. A F O R T R A N program has been developed to generate type curves for these tests which takes into account wellbore storage, wellbore skin effects, and the heterogeneity of the rock mass. It will generate single type curves on a PC in only a few minutes.

904105 Turbulent seepage flow through rockfill structures Martins. R Int Water Power Dam Constr V42, N3. March 1990, P41-45 Rockfill is widely used in hydraulic engineering. Mean seepage velocity is one of the parameters required to predict hydraulic conditions in rockfill structures such as cofferdams, weirs, and filters. Mean seepage flow velocity was determined in the laboratory under turbulent conditions (Reynold's number above 300) for a variety of uniform angular (crushed), uniform rounded (gravel), and non-uniform angular particles. A parameter which allows estimation of seepage velocity at lower Reynold's number is given.

904106 Filtration of broadly graded cohesionless soils Lafleur, J; Mlynarek, J; Rollin, A L J Geotech Engng Div ASCE VlI5, NI2, Dec 1989. P17471768 Filter criteria of soils are relevant to piping erosion. The filtration process of a broady graded soil is essentially different to that of uniform soil, and the same filter criteria do not apply to both. Laboratory tests on graded soils have examined selffiltration at the base-filter interface. Potential migration of base materials, the self filtration layer, and particles carried away have been quantified. The last two properties are related to gradation curve profiles and soil broadness coefficient. Representative grain size of the base material promoting the self filtration process was also examined.

904107 Influence of pore distribution on the hydraulic conductivity of some Swedish tills Lind, B B J Hydroi VII2, NI/2, Dec 1989. P41-53 Relations between pore size distribution and hydraulic conductivity were studied on 42 undisturbed samples. Conductivity was randomly related to total porosity. There was a significant correlation between hydraulic conductivity and pore volume in the 35-90 micron interval, but no similar relation for coarser pores. It is suggested that this is because a continuous network of microfissui'es, 50-100 microns wide, is found in the till, but larger pores tend to be isolated.

904108 Hydrologic responses of compacted forest soils Gardner, B D" Chong. S K J Hydrol VII2. N3 4. Jan 1990. P327-334 Compaction due to machinery is a recent phenomenon for field soils. Samples of a fine silty soil were taken and compacted at pressures 45-315kPa after wetting to 10, 15, and 20% water content by weight. Sorptivity, effective hydraulic conductivity and Boltzmann's constant were measured and related to bulk density and degree of saturation. Unexpectedly low sorptivity and hydraulic conductivity were seen at low water content. Cores with low water content and bulk density had relatively low sorptivity, indicating water unfillable porosity, attributed to entrapped air. Consequences to runoff on field-compacted soils are examined. 904109 Fractal methods improve Mitsue miscible predictions Mathews, J L; Emanuel, A S: Edwards, K A J Pet Technol V41. Nil, Nor 1989, Pl136-I142 Reservoir modelling, whereby a representative geological cross section between injection and producing wells is created using log and core details and fractal geostatistics, is described. Response to a miscible hydrocarbon water-alternating-gas (WAG) flood is modelled using a hybrid finite difference/streamflow approach. The technique is efficient in terms of both output and computer time. Predictions are close to field observations, and a considerable improvement over coarse-grid simulation models. 904110 Numerical model of contaminant transport through conduitporous matrix system Bobba, A G Math Geol V21, N8, Oct 1989, P861-890 A mathematical model is derived for contaminant transport within a cylindrically symmetrical conduit-porous matrix system. Convection and diffusion are considered in the conduit, diffusion only in the matrix. The two subsystems are coupled using continuity conditions imposed at their interface. Transport solutions are solved by the alternating-direct-implicitmethod (ADIM). Solute concentration profiles are illustrated and discussed. 904111 Multiphase flow and transport in porous media Parker, J C Rev Geophys V27, N3. Aug 1989, P311-328 Principles of modelling flow in systems containing up to 3 fluid pahses (air, water, organic) are outlined. Knowledge is required of functional relations between fluid pressures, saturation, and permeabilities, which may be formulated on the basis of conceptual models of fluid-porous medium reactions. Hypothetical numerical problems are presented to illustrate applications. 904112 Multiscale study of the permeability of a thick clayey till Keller, C K: van der Kamp, G: Cherry, J A Water Resour Res V23, N i l , Nor 1989, P2299-2317 Low permeability clay layers can control groundwater flow in many situations. Bulk values of K on scales from hundreds to thousands of metres are required for management purposes. Measurement at this scale is usually costly and time consuming. Two new methods of evaluating bulk permeability are

~-' 1990 Pergamon Press pie. Reproduction not permitted